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Sample records for human homo sapiens

  1. Spatial Construction Skills of Chimpanzees ("Pan Troglodytes") and Young Human Children ("Homo Sapiens Sapiens")

    ERIC Educational Resources Information Center

    Poti, Patrizia; Hayashi, Misato; Matsuzawa, Tetsuro

    2009-01-01

    Spatial construction tasks are basic tests of visual-spatial processing. Two studies have assessed spatial construction skills in chimpanzees (Pan troglodytes) and young children (Homo sapiens sapiens) with a block modelling task. Study 1a subjects were three young chimpanzees and five adult chimpanzees. Study 1b subjects were 30 human children…

  2. The Emergence of Homo sapiens.

    ERIC Educational Resources Information Center

    Rensberger, Boyce

    1980-01-01

    Describes chronologically the evolution of the human race on earth so as to refute Darwin's theory of descent from animals. Skull fragments from sites around the world suggest at least two possible routes toward the emergence of Homo sapiens sapiens. (Author/SK)

  3. Homo Sapiens, All Too Homo Sapiens: Wise Man, All Too Human

    ERIC Educational Resources Information Center

    Ketcham, Amaris

    2015-01-01

    The emphasis on STEM education should not be interpreted as an omen of the death of humanities; art, literature, history, and philosophy can inform and enlighten STEM studies if the walls of academic silos are broken down and taught in combination. Where the physical universe collides with the fanciful and flawed human experience of life, there is…

  4. LB1 and LB6 Homo floresiensis are not modern human (Homo sapiens) cretins.

    PubMed

    Brown, Peter

    2012-02-01

    Excavations in the late Pleistocene deposits at Liang Bua cave, Flores, have uncovered the skeletal remains of several small-bodied and small-brained hominins in association with stone artefacts and the bones of Stegodon. Due to their combination of plesiomorphic, unique and derived traits, they were ascribed to a new species, Homo floresiensis, which, along with Stegodon, appears to have become extinct ∼17 ka (thousand years ago). However, recently it has been argued that several characteristics of H. floresiensis were consistent with dwarfism and evidence of delayed development in modern human (Homo sapiens) myxoedematous endemic (ME) cretins. This research compares the skeletal and dental morphology in H. floresiensis with the clinical and osteological indicators of cretinism, and the traits that have been argued to be associated with ME cretinism in LB1 and LB6. Contrary to published claims, morphological and statistical comparisons did not identify the distinctive skeletal and dental indicators of cretinism in LB1 or LB6 H. floresiensis. Brain mass, skeletal proportions, epiphyseal union, orofacial morphology, dental development, size of the pituitary fossa and development of the paranasal sinuses, vault bone thickness and dimensions of the hands and feet all distinguish H. floresiensis from modern humans with ME cretinism. The research team responsible for the diagnosis of ME cretinism had not examined the original H. floresiensis skeletal materials, and perhaps, as a result, their research confused taphonomic damage with evidence of disease, and thus contained critical errors of fact and interpretation. Behavioural scenarios attempting to explain the presence of cretinous H. sapiens in the Liang Bua Pleistocene deposits, but not unaffected H. sapiens, are both unnecessary and not supported by the available archaeological and geochronological evidence from Flores.

  5. Global and local processing in adult humans (Homo sapiens), 5-year-old children (Homo sapiens), and adult cotton-top tamarins (Saguinus oedipus).

    PubMed

    Neiworth, Julie J; Gleichman, Amy J; Olinick, Anne S; Lamp, Kristen E

    2006-11-01

    This study compared adults (Homo sapiens), young children (Homo sapiens), and adult tamarins (Saguinus oedipus) while they discriminated global and local properties of stimuli. Subjects were trained to discriminate a circle made of circle elements from a square made of square elements and were tested with circles made of squares and squares made of circles. Adult humans showed a global bias in testing that was unaffected by the density of the elements in the stimuli. Children showed a global bias with dense displays but discriminated by both local and global properties with sparse displays. Adult tamarins' biases matched those of the children. The striking similarity between the perceptual processing of adult monkeys and humans diagnosed with autism and the difference between this and normatively developing human perception is discussed.

  6. Earliest evidence of modern human life history in North African early Homo sapiens.

    PubMed

    Smith, Tanya M; Tafforeau, Paul; Reid, Donald J; Grün, Rainer; Eggins, Stephen; Boutakiout, Mohamed; Hublin, Jean-Jacques

    2007-04-10

    Recent developmental studies demonstrate that early fossil hominins possessed shorter growth periods than living humans, implying disparate life histories. Analyses of incremental features in teeth provide an accurate means of assessing the age at death of developing dentitions, facilitating direct comparisons with fossil and modern humans. It is currently unknown when and where the prolonged modern human developmental condition originated. Here, an application of x-ray synchrotron microtomography reveals that an early Homo sapiens juvenile from Morocco dated at 160,000 years before present displays an equivalent degree of tooth development to modern European children at the same age. Crown formation times in the juvenile's macrodont dentition are higher than modern human mean values, whereas root development is accelerated relative to modern humans but is less than living apes and some fossil hominins. The juvenile from Jebel Irhoud is currently the oldest-known member of Homo with a developmental pattern (degree of eruption, developmental stage, and crown formation time) that is more similar to modern H. sapiens than to earlier members of Homo. This study also underscores the continuing importance of North Africa for understanding the origins of human anatomical and behavioral modernity. Corresponding biological and cultural changes may have appeared relatively late in the course of human evolution.

  7. Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution.

    PubMed

    Zihlman, Adrienne L; Bolter, Debra R

    2015-06-16

    The human body has been shaped by natural selection during the past 4-5 million years. Fossils preserve bones and teeth but lack muscle, skin, fat, and organs. To understand the evolution of the human form, information about both soft and hard tissues of our ancestors is needed. Our closest living relatives of the genus Pan provide the best comparative model to those ancestors. Here, we present data on the body composition of 13 bonobos (Pan paniscus) measured during anatomical dissections and compare the data with Homo sapiens. These comparative data suggest that both females and males (i) increased body fat, (ii) decreased relative muscle mass, (iii) redistributed muscle mass to lower limbs, and (iv) decreased relative mass of skin during human evolution. Comparison of soft tissues between Pan and Homo provides new insights into the function and evolution of body composition.

  8. Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution

    PubMed Central

    Zihlman, Adrienne L.; Bolter, Debra R.

    2015-01-01

    The human body has been shaped by natural selection during the past 4–5 million years. Fossils preserve bones and teeth but lack muscle, skin, fat, and organs. To understand the evolution of the human form, information about both soft and hard tissues of our ancestors is needed. Our closest living relatives of the genus Pan provide the best comparative model to those ancestors. Here, we present data on the body composition of 13 bonobos (Pan paniscus) measured during anatomical dissections and compare the data with Homo sapiens. These comparative data suggest that both females and males (i) increased body fat, (ii) decreased relative muscle mass, (iii) redistributed muscle mass to lower limbs, and (iv) decreased relative mass of skin during human evolution. Comparison of soft tissues between Pan and Homo provides new insights into the function and evolution of body composition. PMID:26034269

  9. The origin and evolution of Homo sapiens.

    PubMed

    Stringer, Chris

    2016-07-05

    If we restrict the use of Homo sapiens in the fossil record to specimens which share a significant number of derived features in the skeleton with extant H. sapiens, the origin of our species would be placed in the African late middle Pleistocene, based on fossils such as Omo Kibish 1, Herto 1 and 2, and the Levantine material from Skhul and Qafzeh. However, genetic data suggest that we and our sister species Homo neanderthalensis shared a last common ancestor in the middle Pleistocene approximately 400-700 ka, which is at least 200 000 years earlier than the species origin indicated from the fossils already mentioned. Thus, it is likely that the African fossil record will document early members of the sapiens lineage showing only some of the derived features of late members of the lineage. On that basis, I argue that human fossils such as those from Jebel Irhoud, Florisbad, Eliye Springs and Omo Kibish 2 do represent early members of the species, but variation across the African later middle Pleistocene/early Middle Stone Age fossils shows that there was not a simple linear progression towards later sapiens morphology, and there was chronological overlap between different 'archaic' and 'modern' morphs. Even in the late Pleistocene within and outside Africa, we find H. sapiens specimens which are clearly outside the range of Holocene members of the species, showing the complexity of recent human evolution. The impact on species recognition of late Pleistocene gene flow between the lineages of modern humans, Neanderthals and Denisovans is also discussed, and finally, I reconsider the nature of the middle Pleistocene ancestor of these lineages, based on recent morphological and genetic data.This article is part of the themed issue 'Major transitions in human evolution'.

  10. What constitutes Homo sapiens? Morphology versus received wisdom.

    PubMed

    Schwartz, Jeffrey

    2016-06-20

    Although Linnaeus coined Homo sapiens in 1735, it was Blumenbach forty years later who provided the first morphological definition of the species. Since humans were not then allowed to be ante-Diluvian, his effort applied to the genus, as well. After the Feldhofer Grotto Neanderthal disproved this creationist notion, and human-fossil hunting became legitimate, new specimens were allocated either to sapiens or new species within Homo, or even to new species within new genera. Yet as these taxonomic acts reflected the morphological differences between specimens, they failed to address the question: What constitutes H. sapiens? When in 1950 Mayr collapsed all human fossils into Homo, he not only denied humans a diverse evolutionary past, he also shifted the key to identifying its species from morphology to geological age - a practice most paleoanthropologists still follow. Thus, for example, H. erectus is the species that preceded H. sapiens, and H. sapiens is the species into which H. erectus morphed. In order to deal with a growing morass of morphologically dissimilar specimens, the non-taxonomic terms "archaic" (AS) and "anatomically modern" (AMS) were introduced to distinguish between the earlier and later versions of H. sapiens, thereby making the species impossible to define. In attempting to disentangle fact from scenario, I begin from the beginning, trying to delineate features that may be distinctive of extant humans (ES), and then turning to the fossils that have been included in the species. With the exception of Upper Paleolithic humans - e.g. from Cro-Magnon, Dolni Vestonice, Mladeč - I argue that many specimens regarded as AMS, and all those deemed AS, are not H. sapiens. The features these AMS do share with ES suggest the existence of a sapiens clade. Further, restudy of near-recent fossils, especially from southwestern China (∼11-14.5 ka), reinforces what discoveries such as H. floresiensis indicate: "If it's recent, it's not necessarily H. sapiens".

  11. Homo Sapiens as Geological Agents

    NASA Astrophysics Data System (ADS)

    Holloway, T.; Bedsworth, L. W.; Caldeira, K.; Rosenzweig, C.; Kelley, G.; Rosenzweig, C.; Caldeira, K.; Bedsworth, L. W.; Holloway, T.; Purdy, J. S.; Vince, G.; Syvitski, J. A.; Bondre, N. R.; Kelly, J.; Vince, G.; Seto, K. C.; Steffen, W.; Oreskes, N.

    2015-12-01

    In the 18th and 19th centuries, earth scientists came to understand the magnitude and power of geological and geophysical processes. In comparison, the activities of humans seemed paltry if not insignificant. With the development of radiometric dating in the 20th century, scientists realized that human history was but a miniscule part of Earth history. Metaphors to this effect abounded, and filled textbooks: If Earth history were a 24-hour day, human history would not occupy even the final second. If Earth history were a yardstick, the human portion would not even be visible to the naked eye. Generations of scientists were taught that one of the principal contributions of geology, qua science, was the demonstration of our insignificance. The Anthropocene concept disrupts this. To affirms its existence is to insist that human activities compete in scale and significance with other Earth processes, and may threaten to overwhelm them. It also inverts our relation to normative claims. For more than a century earth scientists and evolutionary biologists insisted that their theories were descriptive and not normative—that there was no moral conclusion to be drawn from either planetary or human evolution. Now, we confront the suggestion that there is a moral component to our new paradigm: we can scarcely claim that humans are disrupting the climate, destroying biodiversity, and acidifying the oceans without implying that there is something troubling about these developments. Thus, the Anthropocene concept suggests both a radical redefinition of the scope of Earth science, and a radical reconsideration of the place of normative judgments in scientific work.

  12. Crystal structure of Homo sapiens kynureninase.

    PubMed

    Lima, Santiago; Khristoforov, Roman; Momany, Cory; Phillips, Robert S

    2007-03-13

    Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.

  13. Copying results and copying actions in the process of social learning: chimpanzees (Pan troglodytes) and human children (Homo sapiens).

    PubMed

    Call, Josep; Carpenter, Malinda; Tomasello, Michael

    2005-07-01

    There is currently much debate about the nature of social learning in chimpanzees. The main question is whether they can copy others' actions, as opposed to reproducing the environmental effects of these actions using their own preexisting behavioral strategies. In the current study, chimpanzees (Pan troglodytes) and human children (Homo sapiens) were shown different demonstrations of how to open a tube-in both cases by a conspecific. In different experimental conditions, demonstrations consisted of (1) action only (the actions necessary to open the tube without actually opening it); (2) end state only (the open tube, without showing any actions); (3) both of these components (in a full demonstration); or (4) neither of these components (in a baseline condition). In the first three conditions subjects saw one of two different ways that the tube could open (break in middle; caps off ends). Subjects' behavior in each condition was assessed for how often they opened the tube, how often they opened it in the same location as the demonstrator, and how often they copied the demonstrator's actions or style of opening the tube. Whereas chimpanzees reproduced mainly the environmental results of the demonstrations (emulation), human children often reproduced the demonstrator's actions (imitation). Because the procedure used was similar in many ways to the procedure that Meltzoff (Dev Psych 31:1, 1995) used to study the understanding of others' unfulfilled intentions, the implications of these findings with regard to chimpanzees' understanding of others' intentions are also discussed.

  14. The comparative psychology of same-different judgments by humans (Homo sapiens) and monkeys (Macaca mulatta).

    PubMed

    Smith, J David; Redford, Joshua S; Haas, Sarah M; Coutinho, Mariana V C; Couchman, Justin J

    2008-07-01

    The authors compared the performance of humans and monkeys in a Same-Different task. They evaluated the hypothesis that for humans the Same-Different concept is qualitative, categorical, and rule-based, so that humans distinguish 0-disparity pairs (i.e., same) from pairs with any discernible disparity (i.e., different); whereas for monkeys the Same-Different concept is quantitative, continuous, and similarity-based, so that monkeys distinguish small-disparity pairs (i.e., similar) from pairs with a large disparity (i.e., dissimilar). The results supported the hypothesis. Monkeys, more than humans, showed a gradual transition from same to different categories and an inclusive criterion for responding Same. The results have implications for comparing Same-Different performances across species--different species may not always construe or perform even identical tasks in the same way. In particular, humans may especially apply qualitative, rule-based frameworks to cognitive tasks like Same-Different.

  15. Black-capped chickadee (Poecile atricapillus) and human (Homo sapiens) chord discrimination.

    PubMed

    Hoeschele, Marisa; Cook, Robert G; Guillette, Lauren M; Brooks, Daniel I; Sturdy, Christopher B

    2012-02-01

    Human music perception is related both to musical experience and the physical properties of sound. Examining the processing of music by nonhuman animals has been generally neglected. We tested both black-capped chickadees and humans in a chord discrimination task that replicates and extends prior research with pigeons. We found that chickadees and humans, in common with pigeons, showed similar patterns of discrimination across manipulations of the 3rd and 5th notes of the triadic chords. For all species (chickadee and humans here, pigeons previously), chords with half-step alterations in the 5th note were easier to discriminate than half-step manipulations of the 3rd note, which is likely due to the sensory consonance of these chords. There were differences among species in terms of the fine discrimination of the chords within this larger pattern of results. Further, the ability to relearn the chords when transposed to a new root differed across species. Our results provide new comparative data suggesting some similarities in chord perception that span a wide range of species, from pigeons (nonvocal learners) to songbirds and humans (vocal learners).

  16. Implicit and Explicit Category Learning by Macaques (Macaca mulatta) and Humans (Homo sapiens)

    PubMed Central

    Smith, J. David; Beran, Michael J.; Crossley, Matthew J.; Boomer, Joseph. T.; Ashby, F. Gregory

    2010-01-01

    An influential theoretical perspective differentiates in humans an explicit, rule-based system of category learning from an implicit system that slowly associates different regions of perceptual space with different response outputs. This perspective was extended for the first time to the category learning of nonhuman primates. Humans and macaques learned categories composed of sine-wave gratings that varied across trials in bar width and bar orientation. The categories had either a single-dimensional, rule-based solution or a two-dimensional, information-integration solution. Humans strongly dimensionalized the stimuli and learned the rule-based task far more quickly. Six macaques showed the same performance advantage in the rule-based task. In humans, rule-based category learning is linked to explicit cognition, consciousness, and to declarative reports about the contents of cognition. The present results demonstrate an empirical continuity between human and nonhuman primate cognition, suggesting that nonhuman primates may have some structural components of humans’ capacity for explicit cognition. PMID:20141317

  17. Generalization of Category Knowledge and Dimensional Categorization in Humans (Homo sapiens) and Nonhuman Primates (Macaca mulatta)

    PubMed Central

    Smith, J. David; Zakrzewski, Alexandria C.; Johnston, Jennifer J. R.; Roeder, Jessica L.; Boomer, Joseph; Ashby, F. Gregory; Church, Barbara A.

    2015-01-01

    A theoretical framework within neuroscience distinguishes humans’ implicit and explicit systems for category learning. We used a perceptual-categorization paradigm to ask whether nonhumans share elements of these systems. Participants learned categories that foster implicit or explicit categorization in humans, because they had a multidimensional, information-integration (II) solution or a unidimensional, rule-based (RB) solution. Then humans and macaques generalized their category knowledge to new, untested regions of the stimulus space. II generalization was impaired, suggesting that II category learning is conditioned and constrained by stimulus generalization to its original, trained stimulus contexts. RB generalization was nearly seamless, suggesting that RB category knowledge in humans and monkeys has properties that grant it some independence from the original, trained stimulus contexts. These findings raise the question of 1) how closely macaques’ dimensional categorization verges on humans’ explicit/declarative categorization, and 2) how far macaques’ dimensional categorization has advanced beyond that in other vertebrate species. PMID:26167774

  18. Side biases in humans ( Homo sapiens): three ecological studies on hemispheric asymmetries

    NASA Astrophysics Data System (ADS)

    Marzoli, Daniele; Tommasi, Luca

    2009-09-01

    Hemispheric asymmetries and side biases have been studied in humans mostly in laboratory settings, and evidence obtained in naturalistic settings is scarce. We here report the results of three studies on human ear preference observed during social interactions in noisy environments, i.e., discotheques. In the first study, a spontaneous right-ear preference was observed during linguistic exchange between interacting individuals. This lateral bias was confirmed in a quasi-experimental study in which a confederate experimenter evoked an ear-orienting response in bystanders, under the pretext of approaching them with a whispered request. In the last study, subjects showed a greater proneness to meet an experimenter’s request when it was directly addressed to the right rather than the left ear. Our findings are in agreement both with laboratory studies on hemispheric lateralization for language and approach/avoidance behavior in humans and with animal research. The present work is one of the few studies demonstrating the natural expression of hemispheric asymmetries, showing their effect in everyday human behavior.

  19. Timbre influences chord discrimination in black-capped chickadees (Poecile atricapillus) but not humans (Homo sapiens).

    PubMed

    Hoeschele, Marisa; Cook, Robert G; Guillette, Lauren M; Hahn, Allison H; Sturdy, Christopher B

    2014-11-01

    Timbre is an important attribute of sound both in music and nature. Previously, using an operant conditioning paradigm, we found that black-capped chickadees and humans show similar response patterns in discriminating triadic chords of the same timbre and transferred this discrimination to a novel key center (novel absolute pitch). The current study examined how varying the timbre of the chords influenced discrimination. Using a similar operant conditioning procedure, we trained humans (Experiment 1) and chickadees (Experiments 2 and 3) to discriminate a major chord from 6 other chord types that had semitone deviations from the major chord. The pattern of errors of the 2 species replicated our previous findings. We then tested participants with novel timbres. We found that humans readily transferred their discrimination to novel timbres, suggesting they were attending to triadic pitch relations. The chickadees failed to transfer to novel timbres, suggesting they were using a different strategy to perform the original chord discrimination. We conducted an acoustic analysis examining frequency ranges that are biologically relevant to chickadees. We found that the relative intensity within each chord of the frequencies used in black-capped chickadee song significantly correlated with chickadees' percent response during probe testing. In Experiment 3, we trained a new set of chickadees by including either expanded pitch or timbre training before testing. Although chickadees showed some transfer to novel chords following this expanded training, we found that neither type of expanded training helped the chickadees when probe tested with novel stimuli.

  20. Neanderthal paintings? Production of prototypical human (Homo sapiens) faces shows systematic distortions.

    PubMed

    Carbon, Claus-Christian; Wirth, Benedikt Emanuel

    2014-01-01

    People's sketches of human faces seem to be systematically distorted: the eye position is always higher than in reality. This bias was experimentally analyzed by a series of experiments varying drawing conditions. Participants either drew prototypical faces from memory (studies 1 and 2: free reconstruction; study 3: cued reconstruction) or directly copied average faces (study 4). Participants consistently showed this positioning bias, which is even in accord with facial depictions published in influential research articles by famous face researchers (study 5). We discuss plausible explanations for this reliable and stable bias, which is coincidentally similar to the morphology of Neanderthals.

  1. The use of interval ratios in consonance perception by rats (Rattus norvegicus) and humans (Homo sapiens).

    PubMed

    Crespo-Bojorque, Paola; Toro, Juan M

    2015-02-01

    Traditionally, physical features in musical chords have been proposed to be at the root of consonance perception. Alternatively, recent studies suggest that different types of experience modulate some perceptual foundations for musical sounds. The present study tested whether the mechanisms involved in the perception of consonance are present in an animal with no extensive experience with harmonic stimuli and a relatively limited vocal repertoire. In Experiment 1, rats were trained to discriminate consonant from dissonant chords and tested to explore whether they could generalize such discrimination to novel chords. In Experiment 2, we tested if rats could discriminate between chords differing only in their interval ratios and generalize them to different octaves. To contrast the observed pattern of results, human adults were tested with the same stimuli in Experiment 3. Rats successfully discriminated across chords in both experiments, but they did not generalize to novel items in either Experiment 1 or Experiment 2. On the contrary, humans not only discriminated among both consonance-dissonance categories, and among sets of interval ratios, they also generalized their responses to novel items. These results suggest that experience with harmonic sounds may be required for the construction of categories among stimuli varying in frequency ratios. However, the discriminative capacity observed in rats suggests that at least some components of auditory processing needed to distinguish chords based on their interval ratios are shared across species.

  2. Discrimination of holograms and real objects by pigeons (Columba livia) and humans (Homo sapiens).

    PubMed

    Stephan, Claudia; Steurer, Michael M; Aust, Ulrike

    2014-08-01

    The type of stimulus material employed in visual tasks is crucial to all comparative cognition research that involves object recognition. There is considerable controversy about the use of 2-dimensional stimuli and the impact that the lack of the 3rd dimension (i.e., depth) may have on animals' performance in tests for their visual and cognitive abilities. We report evidence of discrimination learning using a completely novel type of stimuli, namely, holograms. Like real objects, holograms provide full 3-dimensional shape information but they also offer many possibilities for systematically modifying the appearance of a stimulus. Hence, they provide a promising means for investigating visual perception and cognition of different species in a comparative way. We trained pigeons and humans to discriminate either between 2 real objects or between holograms of the same 2 objects, and we subsequently tested both species for the transfer of discrimination to the other presentation mode. The lack of any decrements in accuracy suggests that real objects and holograms were perceived as equivalent in both species and shows the general appropriateness of holograms as stimuli in visual tasks. A follow-up experiment involving the presentation of novel views of the training objects and holograms revealed some interspecies differences in rotational invariance, thereby confirming and extending the results of previous studies. Taken together, these results suggest that holograms may not only provide a promising tool for investigating yet unexplored issues, but their use may also lead to novel insights into some crucial aspects of comparative visual perception and categorization.

  3. Planning in human children (Homo sapiens) assessed by maze problems on the touch screen.

    PubMed

    Miyata, Hiromitsu; Itakura, Shoji; Fujita, Kazuo

    2009-02-01

    The authors examined how human children perform on maze tasks on the touch screen and whether the children plan the solution of the mazes. In Experiment 1, the authors exposed children around 3 years of age to a maze having an L-shaped line as a barrier that can be solved by moving an illustration of a dog (the target) to that of a bone (the goal) with their fingers. The participants successfully solved the maze by taking efficient routes more frequently than chance, although the authors found no evidence that a preview of the maze before starting to solve the task facilitated their performance. In Experiment 2, using a plus-shaped maze, the authors found that 3- and 4-year-old children plan and adjust their moves while solving the maze, with 4-year-olds showing more advanced and higher-level planning than 3-year-olds. Similarity of these results to what the authors previously found in pigeons tested in the same tasks may suggest an analogy for planning capacity in the behavioral level across taxa and developmental stages.

  4. The evolution and development of cranial form in Homo sapiens

    PubMed Central

    Lieberman, Daniel E.; McBratney, Brandeis M.; Krovitz, Gail

    2002-01-01

    Despite much data, there is no unanimity over how to define Homo sapiens in the fossil record. Here, we examine cranial variation among Pleistocene and recent human fossils by using a model of cranial growth to identify unique derived features (autapomorphies) that reliably distinguish fossils attributed to “anatomically modern” H. sapiens (AMHS) from those attributed to various taxa of “archaic” Homo spp. (AH) and to test hypotheses about the changes in cranial development that underlie the origin of modern human cranial form. In terms of pattern, AMHS crania are uniquely characterized by two general structural autapomorphies: facial retraction and neurocranial globularity. Morphometric analysis of the ontogeny of these autapomorphies indicates that the developmental changes that led to modern human cranial form derive from a combination of shifts in cranial base angle, cranial fossae length and width, and facial length. These morphological changes, some of which may have occurred because of relative size increases in the temporal and possibly the frontal lobes, occur early in ontogeny, and their effects on facial retraction and neurocranial globularity discriminate AMHS from AH crania. The existence of these autapomorphies supports the hypothesis that AMHS is a distinct species from taxa of “archaic” Homo (e.g., Homo neanderthalensis). PMID:11805284

  5. Face and eye scanning in gorillas (Gorilla gorilla), orangutans (Pongo abelii), and humans (Homo sapiens): unique eye-viewing patterns in humans among hominids.

    PubMed

    Kano, Fumihiro; Call, Josep; Tomonaga, Masaki

    2012-11-01

    Because the faces and eyes of primates convey a rich array of social information, the way in which primates view faces and eyes reflects species-specific strategies for facial communication. How are humans and closely related species such as great apes similar and different in their viewing patterns for faces and eyes? Following previous studies comparing chimpanzees (Pan troglodytes) with humans (Homo sapiens), this study used the eye-tracking method to directly compare the patterns of face and eye scanning by humans, gorillas (Gorilla gorilla), and orangutans (Pongo abelii). Human and ape participants freely viewed pictures of whole bodies and full faces of conspecifics and allospecifics under the same experimental conditions. All species were strikingly similar in that they viewed predominantly faces and eyes. No particular difference was identified between gorillas and orangutans, and they also did not differ from the chimpanzees tested in previous studies. However, humans were somewhat different from apes, especially with respect to prolonged eye viewing. We also examined how species-specific facial morphologies, such as the male flange of orangutans and the black-white contrast of human eyes, affected viewing patterns. Whereas the male flange of orangutans affected viewing patterns, the color contrast of human eyes did not. Humans showed prolonged eye viewing independently of the eye color of presented faces, indicating that this pattern is internally driven rather than stimulus dependent. Overall, the results show general similarities among the species and also identify unique eye-viewing patterns in humans.

  6. Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks

    DTIC Science & Technology

    2012-09-21

    transduction components between organelle such as the nucleus and mitochondria as the cell strives to maintain homeostasis. Many of these communication... Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks Paulo Shakarian1*, J. Kenneth Wickiser2 1 Paulo Shakarian...pathogens on host protein networks for humans and Arabidopsis - noting striking similarities . Specifically, we preform k-shell decomposition analysis on

  7. Molecular docking of the scorpion toxin Tc1 to the structural model of the voltage-gated potassium channel Kv1.1 from human Homo sapiens.

    PubMed

    Liu, Hsuan-Liang; Lin, Jin-Chung

    2004-04-01

    In this study, structural model of the pore loop region of the voltage-gated potassium channel Kv1.1 from human Homo sapiens was constructed based on the crystallographic structure of KcsA by structural homology. The pore loop region of Kv1.1 exhibits similar folds as that of KcsA. The structural feature of the selectivity filter of Kv1.1 is nearly identical to that of KcsA, whereas most of the structural variations occur in the turret as well as in the inner and outer helices. Molecular docking experiments of the scorpion toxin Tc1 from Tityus cambridgei to the outer vestibule of KcsA as well as Kv1.1 were subsequently performed with various initial Tc1 orientations. Tc1 was found to form the most stable complexes with these two K+ channels when the side chain of Lys14 occupies the pore of the selectivity filter through electrostatic interaction. Tc1 binds preferentially towards Kv1.1 than KcsA due to stronger hydrophobic and electrostatic interactions formed between the toxin and the selectivity filter and outer vestibule of Kv1.1. Furthermore, surface complementarity of the outer vestibules of the channels to the Tc1 spatial conformations also plays an important role in stabilizing both the Tc1/KcsA and Tc1/Kv1.1 complexes.

  8. Ecospaces occupied by Homo erectus and Homo sapiens in insular Southeast Asia in the Pleistocene

    NASA Astrophysics Data System (ADS)

    Hertler, Christine; Haupt, Susanne; Volmer, Rebekka; Bruch, Angela

    2014-05-01

    Hominins migrated to the islands of the Sunda Shelf multiple times. At least two immigration events are evident, an early immigration of Homo erectus in the late Early Pleistocene and a second immigration of Homo sapiens during the Late Pleistocene. Regional environments changed considerably in the Pleistocene. Expansion patterns among hominins are at least co-determined by their ecologies and environmental change. We examine these expansion patterns on the basis of habitat reconstructions. Mammalian communities provide a geographically extensive record and permit to assess hominin ecospaces. Although chronological resolution is low, they represent the most complete record of habitat changes associated with hominin expansion patterns. In order to reconstruct and compare hominin ecospaces on a quantitative scale, we set up a reference sample consisting of mammalian communities of 117 national parks in South Asia and Sub-Saharan Africa. The diversity of such communities is assessed by ecological profiling of specialized herbivore taxa. Moreover, datasets on climate and vegetation correlate with the diversity structure of such specialized herbivore communities. Reconstructing the diversity structure of communities at key sites in Pleistocene Southeast Asia permits to infer features of the climatic and vegetation framework associated with different hominin taxa. Our results show that Homo erectus and Homo sapiens did not occupy similar ecospaces. The ecospace of Homo erectus is characterized by comparatively low diversity among frugivorous and folivorous taxa, while obligate grazers are part of the assemblages. Specialized herbivore communities with such a diversity structure occur at present in East Africa, while they are absent in Southeast Asia. In the reference sample, this type of ecospace corresponds to seasonal wetlands. Although Homo sapiens still inhabits this type of environment in Southeast Asia, his ecospace is wider. Homo sapiens is associated with

  9. Karyotype evolution of giraffes (Giraffa camelopardalis) revealed by cross-species chromosome painting with Chinese muntjac (Muntiacus reevesi) and human (Homo sapiens) paints.

    PubMed

    Huang, L; Nesterenko, A; Nie, W; Wang, J; Su, W; Graphodatsky, A S; Yang, F

    2008-01-01

    Considering the giraffe (Giraffa camelopardalis, GCA, 2n = 30) as a primitive species, its comparative genomic data are critical for our understanding of the karyotype evolution of pecorans. Here, we have established genome-wide chromosomal homologies between giraffe, Chinese muntjac (Muntiacus reevesi, MRE, 2n = 46) and human (Homo sapiens, HSA, 2n = 46) with whole sets of chromosome-specific paints from Chinese muntjac and human, in addition to providing a high-resolution G-banding karyotype of giraffe. Chinese muntjac and human chromosome paints detected 32 and 45 autosomal homologs in the genome of giraffe, respectively. Our results suggest that it would require at least thirteen fissions, six fusions and three intrachromosomal rearrangements to 'transform' the 2n = 44 eutherian ancestral karyotype to the 2n = 58 pecoran ancestral karyotype. During giraffe evolution, some ancestral eutherian syntenies (i.e. association of HSA3/21, 4/8, 7/16, 14/15, 16/19 and two forms of 12/22) have been retained, while several derived syntenies (i.e. associations of human homologous segments 2/1, 2/9, 5/19, 4/12/22, 8/9, and 10/20) have been produced. The reduction of chromosome number in giraffe from the 2n = 58 pecoran ancestral karyotype could be primarily attributed to extensive Robertsonian translocations of ancestral chromosomal segments. More complex chromosomal rearrangements (including tandem fusion, centromere repositioning and pericentric inversion) have happened during the evolution of GCA2 and GCA8.

  10. Crystal structure of Homo sapiens protein LOC79017

    SciTech Connect

    Bae, Euiyoung; Bingman, Craig A.; Aceti, David J.; Phillips, Jr., George N.

    2010-02-08

    LOC79017 (MW 21.0 kDa, residues 1-188) was annotated as a hypothetical protein encoded by Homo sapiens chromosome 7 open reading frame 24. It was selected as a target by the Center for Eukaryotic Structural Genomics (CESG) because it did not share more than 30% sequence identity with any protein for which the three-dimensional structure is known. The biological function of the protein has not been established yet. Parts of LOC79017 were identified as members of uncharacterized Pfam families (residues 1-95 as PB006073 and residues 104-180 as PB031696). BLAST searches revealed homologues of LOC79017 in many eukaryotes, but none of them have been functionally characterized. Here, we report the crystal structure of H. sapiens protein LOC79017 (UniGene code Hs.530024, UniProt code O75223, CESG target number go.35223).

  11. Differences in compact bone tissue microscopic structure between adult humans (Homo sapiens) and Assam macaques (Macaca assamensis).

    PubMed

    Nganvongpanit, Korakot; Phatsara, Manussabhorn; Settakorn, Jongkolnee; Mahakkanukrauh, Pasuk

    2015-09-01

    This study investigated the osteon structure of adult humans and Assam macaques, which served as a nonhuman primate model, to find an adequate key for species identification. Samples of compact bone from humans (n=5) and Assam macaques (n=5) - including humerus (n=20), radius (n=20), ulna (n=20), femur (n=20), tibia (n=20) and fibula (n=20) - were processed using conventional histological techniques. 100 secondary osteons from each sample were evaluated under light microscopy. Parameter measurements included: diameter, perimeter and area of Haversian canal and osteon; distance between centers of Haversian canals; and ratio between diameter of Haversian canal and osteon. Four parameters, including diameters and areas of Haversian canal and osteon, demonstrated significantly higher (P<0.05) values in humans than in Assam macaques. Therefore, compact bone microstructure could thus be used as a potential tool to differentiate human and nonhuman primates.

  12. Frequency-range discriminations: special and general abilities in zebra finches (Taeniopygia guttata) and humans (Homo sapiens).

    PubMed

    Weisman, R; Njegovan, M; Sturdy, C; Phillmore, L; Coyle, J; Mewhort, D

    1998-09-01

    The acoustic frequency ranges in birdsongs and human speech can provide important pitch cues for recognition. Zebra finches and humans were trained to sort contiguous frequencies into 3 or 8 ranges, based on associations between the ranges and reward. The 3-range task was conducted separately in 3 spectral regions. Zebra finches discriminated 3 ranges in the medium and high spectral regions faster than in the low region and discriminated 8 ranges with precision. Humans discriminated 3 ranges in all 3 spectral regions to the same modest standard and acquired only a crude discrimination of the lowest and highest of 8 ranges. The results indicate that songbirds have a special sensitivity to the pitches in conspecific songs and, relative to humans, have a remarkable general ability to sort pitches into ranges.

  13. Use of social information in the problem solving of orangutans (Pongo pygmaeus) and human children (Homo sapiens).

    PubMed

    Call, J; Tomasello, M

    1995-09-01

    Fourteen juvenile and adult orangutans and 24 3- and 4-year-old children participated in 4 studies on imitative learning in a problem-solving situation. In all studies a simple to operate apparatus was used, but its internal mechanism was hidden from subjects to prevent individual learning. In the 1st study, orangutans observed a human demonstrator perform 1 of 4 actions on the apparatus and obtain a reward; they subsequently showed no signs of imitative learning. Similar results were obtained in a 2nd study in which orangutan demonstrators were used. Similar results were also obtained in a 3rd study in which a human encouraged imitation from an orangutan that had previously been taught to mimic arbitrary human actions. In a 4th study, human 3- and 4-year-old children learned the task by means of imitation.

  14. Cashing out: The decisional flexibility of uncertainty responses in rhesus macaques (Macaca mulatta) and humans (Homo sapiens).

    PubMed

    Zakrzewski, Alexandria C; Perdue, Bonnie M; Beran, Michael J; Church, Barbara A; Smith, J David

    2014-10-01

    Researchers are exploring whether animals share with humans something like a metacognitive capacity. Though some results point to human-animal continuities in this domain, they face the dominant criticism that animals' performances might be associative. A persistent problem is that animal-metacognition paradigms present static environments of risk and reward that may foster inflexible and conditioned responding. Those environments do not challenge animals to show the flexibility in their decision strategies that could indicate an antecedent capacity to metacognition. Accordingly, we tested macaques and humans on an uncertainty-monitoring paradigm in which risk changed dynamically. Participants classified stimuli of different difficulties while also choosing when to use a cashout response to collect the accumulated rewards that would be forfeit on a discrimination error. Macaques (Macaca mulatta) and humans flexibly adjusted their decision criteria to achieve appropriate protection against the cost of error that could differ depending on trial difficulty and the number of rewards at risk. In particular, monkeys widened their cashout-response region as their accumulated rewards increased, providing more protection against a more costly error. These findings demonstrate a new continuity between humans' and animals' uncertainty systems. They reveal a calibration by macaques of present risk to trial difficulty tolerated. They show that animals' uncertainty-monitoring and risk-management systems have substantial trial-by-trial flexibility.

  15. Homo sapiens, Homo neanderthalensis and the Denisova specimen: New insights on their evolutionary histories using whole-genome comparisons

    PubMed Central

    Paixão-Côrtes, Vanessa Rodrigues; Viscardi, Lucas Henrique; Salzano, Francisco Mauro; Hünemeier, Tábita; Bortolini, Maria Cátira

    2012-01-01

    After a brief review of the most recent findings in the study of human evolution, an extensive comparison of the complete genomes of our nearest relative, the chimpanzee (Pan troglodytes), of extant Homo sapiens, archaic Homo neanderthalensis and the Denisova specimen were made. The focus was on non-synonymous mutations, which consequently had an impact on protein levels and these changes were classified according to degree of effect. A total of 10,447 non-synonymous substitutions were found in which the derived allele is fixed or nearly fixed in humans as compared to chimpanzee. Their most frequent location was on chromosome 21. Their presence was then searched in the two archaic genomes. Mutations in 381 genes would imply radical amino acid changes, with a fraction of these related to olfaction and other important physiological processes. Eight new alleles were identified in the Neanderthal and/or Denisova genetic pools. Four others, possibly affecting cognition, occured both in the sapiens and two other archaic genomes. The selective sweep that gave rise to Homo sapiens could, therefore, have initiated before the modern/archaic human divergence. PMID:23413113

  16. A slowing effect on visual search by advance information in pigeons (Columba livia): a comparison with humans (Homo sapiens).

    PubMed

    Sekiguchi, Katsuo; Ushitani, Tomokazu; Jitsumori, Masako

    2011-01-01

    A comparative study was conducted to investigate whether the search for a target letter was facilitated when the target and prime (preceding stimulus) letters were identical. Pigeons (Section 2) and human participants (Section 3) were first trained to search for "A" among "Y"s and "E" among "D"s in a condition in which a square shape appeared as the prime (Neutral condition). In subsequent testing, a prime was identical either to the corresponding target (Target-priming condition) or to the distractor (Distractor-priming condition). Humans and pigeons responded differently to the two priming conditions. On early trials, the Target prime facilitated search in humans, reducing reaction times (RTs) to targets. In pigeons, however, RTs were longer with Target primes, suggesting that pre-exposure to target letters may directly inhibit the search for targets in subsequent search displays. Furthermore, pre-exposure to the distractor letters may inhibit the processing of the distractor. On later trials, RTs of humans were faster in both priming conditions than in the Neutral condition, suggesting that expectation of a target facilitated search ("Y" predicted "A" and "D" predicted "E"). In contrast, the pigeons showed no evidence of expectation-based facilitation, with constant slowing effects of the Target prime extending across sessions. Possible mechanisms underlying such a slowing priming effect in pigeons were discussed.

  17. Can Chimpanzee Infants ("Pan Troglodytes") Form Categorical Representations in the Same Manner as Human Infants ("Homo Sapiens")?

    ERIC Educational Resources Information Center

    Murai, Chizuko; Kosugi, Daisuke; Tomonaga, Masaki; Tanaka, Masayuki; Matsuzawa, Tetsuro; Itakura, Shoji

    2005-01-01

    We directly compared chimpanzee infants and human infants for categorical representations of three global-like categories (mammals, furniture and vehicles), using the familiarization-novelty preference technique. Neither species received any training during the experiments. We used the time that participants spent looking at the stimulus object…

  18. Spatial working memory in immersive virtual reality foraging: path organization, traveling distance and search efficiency in humans (Homo sapiens).

    PubMed

    De Lillo, Carlo; Kirby, Melissa; James, Frances C

    2014-05-01

    Search and serial recall tasks were used in the present study to characterize the factors affecting the ability of humans to keep track of a set of spatial locations while traveling in an immersive virtual reality foraging environment. The first experiment required the exhaustive exploration of a set of locations following a procedure previously used with other primate and non-primate species to assess their sensitivity to the geometric arrangement of foraging sites. The second experiment assessed the dependency of search performance on search organization by requiring the participants to recall specific trajectories throughout the foraging space. In the third experiment, the distance between the foraging sites was manipulated in order to contrast the effects of organization and traveling distance on recall accuracy. The results show that humans benefit from the use of organized search patterns when attempting to monitor their travel though either a clustered "patchy" space or a matrix of locations. Their ability to recall a series of locations is dependent on whether the order in which they are explored conformed or did not conform to specific organization principles. Moreover, the relationship between search efficiency and search organization is not confounded by effects of traveling distance. These results indicate that in humans, organizational factors may play a large role in their ability to forage efficiently. The extent to which such dependency may pertain to other primates and could be accounted for by visual organization processes is discussed on the basis of previous studies focused on perceptual grouping, search, and serial recall in non-human species.

  19. Human (Homo sapiens) responses to the pig (Sus scrofa) sex pheromone 5 alpha-androst-16-en-3-one.

    PubMed

    Filsinger, E E; Braun, J J; Monte, W C; Linder, D E

    1984-06-01

    Previous studies have suggested that the pig sex pheromone 5 alpha-androst-16-en-3-one may function as a human sex pheromone. Two hundred male and female college students were assigned to one of four odor conditions (androstenone, methyl anthranilate, skatole, and a no-odor control) and were asked to rate photographs of a male stimulus and to rate their own mood in the presence of each odorant. There was a significant overall sex by treatment condition interaction. Men in the androstenone condition rated the stimulus male as more passive, and women in the androstenone condition rated themselves as less sexy; these effects were specific to the androstenone condition.

  20. Feature versus spatial strategies by orangutans (Pongo abelii) and human children (Homo sapiens) in a cross-dimensional task.

    PubMed

    Marsh, Heidi L; Adams, Laura; Floyd, Catherine; MacDonald, Suzanne E

    2013-05-01

    Despite the fact that photographic stimuli are used across experimental contexts with both human and nonhuman subjects, the nature of individuals' perceptions of these stimuli is still not well understood. In the present experiments, we tested whether three orangutans and 36 human children could use photographic information presented on a computer screen to solve a perceptually corresponding problem in the physical domain. Furthermore, we tested the cues that aided in this process by pitting featural information against spatial position in a series of probe trials. We found that many of the children and one orangutan were successfully able to use the information cross-dimensionally; however, the other two orangutans and almost a quarter of the children failed to acquire the task. Species differences emerged with respect to ease of task acquisition. More striking, however, were the differences in cues that participants used to solve the task: Whereas the orangutan used a spatial strategy, the majority of children used a feature one. Possible reasons for these differences are discussed from both evolutionary and developmental perspectives. The novel results found here underscore the need for further testing in this area to design appropriate experimental paradigms in future comparative research settings.

  1. Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: population affinities and pathological abnormalities.

    PubMed

    Jacob, T; Indriati, E; Soejono, R P; Hsü, K; Frayer, D W; Eckhardt, R B; Kuperavage, A J; Thorne, A; Henneberg, M

    2006-09-05

    Liang Bua 1 (LB1) exhibits marked craniofacial and postcranial asymmetries and other indicators of abnormal growth and development. Anomalies aside, 140 cranial features place LB1 within modern human ranges of variation, resembling Australomelanesian populations. Mandibular and dental features of LB1 and LB6/1 either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave. We propose that LB1 is drawn from an earlier pygmy H. sapiens population but individually shows signs of a developmental abnormality, including microcephaly. Additional mandibular and postcranial remains from the site share small body size but not microcephaly.

  2. Molecular biology of Homo sapiens: Abstracts of papers presented at the 51st Cold Spring Harbor symposium on quantitative biology

    SciTech Connect

    Watson, J.D.; Siniscalco, M.

    1986-01-01

    This volume contains abstracts of papers presented at the 51st Cold Springs Harbor Symposium on Quantitative Biology. The topic for this meeting was the ''Molecular Biology of Homo sapiens.'' Sessions were entitled Human Gene Map, Human Cancer Genes, Genetic Diagnosis, Human Evolution, Drugs Made Off Human Genes, Receptors, and Gene Therapy. (DT)

  3. Bone strength and athletic ability in hominids: Ardipithecus ramidus to Homo sapiens

    NASA Astrophysics Data System (ADS)

    Lee, S. A.

    2013-03-01

    The ability of the femur to resist bending stresses is determined by its midlength cross-sectional geometry, its length and the elastic properties of the mineral part of the bone. The animal's athletic ability, determined by a ``bone strength index,'' is limited by this femoral bending strength in relation to the loads on the femur. This analysis is applied to the fossil record for Homo sapiens, Homo neanderthalensis, Homo erectus, Homo habilis, Australopithecus afarensis and Ardipithecus ramidus. Evidence that the femoral bone strength index of modern Homo sapiens has weakened over the last 50,000 years is found.

  4. Identification of the ancestral haplotype for apolipoprotein B suggests an African origin of Homo sapiens sapiens and traces their subsequent migration to Europe and the Pacific

    SciTech Connect

    Rapacz, J.; Hasler-Rapacz, J.O. ); Chen, L.; Wu, Mingjiuan; Schumaker, V.N. ); Butler-Brunner, E.; Butler, R. )

    1991-02-15

    The probable ancestral haplotype for human apolipoprotein B (apoB) has been identified through immunological analysis of chimpanzee and gorilla serum and sequence analysis of their DNA. Moreover, the frequency of this ancestral apoB haplotype among different human populations provides strong support for the African origin of Homo sapiens sapiens and their subsequent migration from Africa to Europe and to the Pacific. The approach used here for the identification of the ancestral human apoB haplotype is likely to be applicable to many other genes.

  5. Tissue-Specific Methylation of Long Interspersed Nucleotide Element-1 of Homo Sapiens (L1Hs) During Human Embryogenesis and Roles in Neural Tube Defects.

    PubMed

    Wang, L; Chang, S; Guan, J; Shangguan, S; Lu, X; Wang, Z; Wu, L; Zou, J; Zhao, H; Bao, Y; Qiu, Z; Niu, B; Zhang, T

    2015-01-01

    Epigenetic regulation of long interspersed nucleotide element-1 (LINE-1) retrotransposition events plays crucial roles during early development. Previously we showed that LINE-1 hypomethylation in neuronal tissues is associated with pathogenesis of neural tube defect (NTD). Herein, we further evaluated LINE-1 Homo sapiens (L1Hs) methylation in tissues derived from three germ layers of stillborn NTD fetuses, to define patterns of tissue specific methylation and site-specific hypomethylation at CpG sites within an L1Hs promoter region. Stable, tissue-specific L1Hs methylation patterns throughout three germ layer lineages of the fetus, placenta, and maternal peripheral blood were observed. Samples from maternal peripheral blood exhibited the highest level of L1Hs methylation (64.95%) and that from placenta showed the lowest (26.82%). Between samples from NTDs and controls, decrease in L1Hs methylation was only significant in NTD-affected brain tissue at 7.35%, especially in females (8.98%). L1Hs hypomethylation in NTDs was also associated with a significant increase in expression level of an L1Hs-encoded transcript in females (r = -0.846, p = 0.004). This could be due to genomic DNA instability and alternation in chromatins accessibility resulted from abnormal L1Hs hypomethylation, as showed in this study with HCT-15 cells treated with methylation inhibitor 5-Aza.

  6. Sky Luminaries in the Space Orienting Activity of Homo Sapiens in the Middle Palaeolithic

    NASA Astrophysics Data System (ADS)

    Kaurov, E. N.

    Data describing the beginnings of the space orienting activity of Homo sapiens is analysed and systematized: observation of the Pole and the recognition of Ursa Major were used as the basis of the determination of the points of the compass. Data and results from astronomy, history of astronomy, archaeology and palaeoanthropology were used for the reconstruction of the evolution of the space orienting activity of Homo sapiens.

  7. Bone strength and athletic ability in hominids: Ardipithecus ramidus to Homo sapiens

    NASA Astrophysics Data System (ADS)

    Lee, Scott

    2012-10-01

    A methodology for the evaluation of the athletic ability of animals based on the strength of their femur and their body mass is developed. The ability of the femur to resist bending stresses is determined by its midlength cross-sectional geometry, its length and the elastic properties of the mineral part of the bone. The animal's athletic ability, determined by a ``bone strength index,'' is limited by this femoral bending strength in relation to the loads on the femur. This analysis is applied to the fossil record for Homo sapiens, Homo neanderthalensis, Homo erectus, Homo habilis, Australopithecus afarensis and Ardipithecus ramidus. Evidence that the femoral bone strength index of modern Homo sapiens has weakened over the last 50,000 years is found.

  8. Evaluating the transitional mosaic: frameworks of change from Neanderthals to Homo sapiens in eastern Europe

    NASA Astrophysics Data System (ADS)

    Davies, William; White, Dustin; Lewis, Mark; Stringer, Chris

    2015-06-01

    Defining varying spatial and temporal analytical scales is essential before evaluating the responses of late Neanderthals and early Homo sapiens to Abrupt Environmental Transitions (AETs) and environmental disasters for the period 130-25 ka. Recent advances in addressing the population histories and interactions (using both genetic and archaeological evidence) of Neanderthals and H. sapiens have encouraged consideration of more subtle dynamics of archaeological change. Descriptions of change based on methodologies pioneered some 160 years ago are no longer adequate to explain the patterning we now see in the record. New chronological results, using multiple dating methods, allow us to begin to unpick the spatial and temporal scales of change. Isochronic markers (such as specific volcanic eruptions) can be used to create temporal frameworks (lattices), and results from other dating techniques compared against them. A combination of chronological lattices and direct dating of diagnostic artefacts and human fossils permits us, for the first time, to have greater confidence in connecting human (recent hominin) species and their behavioural responses to environmental conditions, and in quantifying scales of change over time and space (time-transgression). The timing of innovations, particularly those in bone, antler and ivory, can be directly quantified and tested, and used to re-evaluate longstanding models of cultural change. This paper also uses these new chronologies to explore the ecologies of late Neanderthals and early H. sapiens: their population densities, mobilities, resources exploited and possible interactions. Environmental productivity estimates are used to generate new questions of potential population densities and mobilities, and thus the sensitivity of these groups to environmental perturbations. Scales and intensities of effect on environments from natural disasters and AETs (notably Heinrich Events and the Campanian Ignimbrite eruption) are defined

  9. Development of the palatal size in Pan troglodytes, Hominids and Homo sapiens.

    PubMed

    Arnold, W H; Zoellner, A; Sebastian, T

    2004-12-01

    As the hard palate plays an important role in speech production it was the aim of this study whether similarities or dissimilarities in palatal size may allow conclusions about the ability to produce speech in the extant investigated species. The palatal size of Pan troglodytes, Homo sapiens, Australopithecus afarensis, Australopithecus africanus, Australopithecus robustus, Australopithecus boisei, Homo erectus, Homo neanderthalensis and Cro-Magnon has been investigated using euclidian distance matrix analysis (EDMA) and thin-plate-spline analysis. The results show that the palatal size of all australopithecine specimens and H. erectus is very similar to that of P toglodytes, whereas the palatal size of H. neanderthalensis more closely resembles that of H. sapiens. Postnatal development of palatal size in P troglodytes is different from that of H. sapiens. In P troglodytes not only the size of the palate changes but also the form. In H. sapiens there is little change in form, but a continuos uniform growth from infantile to adult specimens. From the results we conclude that in all australopithecine samples which have been investigated, the palatal size is similar to that of P troglodytes. Therefore, it is unlikely that austraopithecine individuals were capable of producing vowels and consonants. The palatal size of H. neandethalensis and Cro-Magnon is similar to that of H. sapiens which may indicate the possibility that they were capable of speech production.

  10. A comparative analysis of the categorization of multidimensional stimuli: I. Unidimensional classification does not necessarily imply analytic processing; evidence from pigeons (Columba livia), squirrels (Sciurus carolinensis), and humans (Homo sapiens).

    PubMed

    Wills, A J; Lea, Stephen E G; Leaver, Lisa A; Osthaus, Britta; Ryan, Catriona M E; Suret, Mark B; Bryant, Catherine M L; Chapman, Sue J A; Millar, Louise

    2009-11-01

    Pigeons (Columba livia), gray squirrels (Sciurus carolinensis), and undergraduates (Homo sapiens) learned discrimination tasks involving multiple mutually redundant dimensions. First, pigeons and undergraduates learned conditional discriminations between stimuli composed of three spatially separated dimensions, after first learning to discriminate the individual elements of the stimuli. When subsequently tested with stimuli in which one of the dimensions took an anomalous value, the majority of both species categorized test stimuli by their overall similarity to training stimuli. However some individuals of both species categorized them according to a single dimension. In a second set of experiments, squirrels, pigeons, and undergraduates learned go/no-go discriminations using multiple simultaneous presentations of stimuli composed of three spatially integrated, highly salient dimensions. The tendency to categorize test stimuli including anomalous dimension values unidimensionally was higher than in the first set of experiments and did not differ significantly between species. The authors conclude that unidimensional categorization of multidimensional stimuli is not diagnostic for analytic cognitive processing, and that any differences between human's and pigeons' behavior in such tasks are not due to special features of avian visual cognition.

  11. Gracility of the modern Homo sapiens skeleton is the result of decreased biomechanical loading

    PubMed Central

    Ryan, Timothy M.; Shaw, Colin N.

    2015-01-01

    The postcranial skeleton of modern Homo sapiens is relatively gracile compared with other hominoids and earlier hominins. This gracility predisposes contemporary humans to osteoporosis and increased fracture risk. Explanations for this gracility include reduced levels of physical activity, the dissipation of load through enlarged joint surfaces, and selection for systemic physiological characteristics that differentiate modern humans from other primates. This study considered the skeletal remains of four behaviorally diverse recent human populations and a large sample of extant primates to assess variation in trabecular bone structure in the human hip joint. Proximal femur trabecular bone structure was quantified from microCT data for 229 individuals from 31 extant primate taxa and 59 individuals from four distinct archaeological human populations representing sedentary agriculturalists and mobile foragers. Analyses of mass-corrected trabecular bone variables reveal that the forager populations had significantly higher bone volume fraction, thicker trabeculae, and consequently lower relative bone surface area compared with the two agriculturalist groups. There were no significant differences between the agriculturalist and forager populations for trabecular spacing, number, or degree of anisotropy. These results reveal a correspondence between human behavior and bone structure in the proximal femur, indicating that more highly mobile human populations have trabecular bone structure similar to what would be expected for wild nonhuman primates of the same body mass. These results strongly emphasize the importance of physical activity and exercise for bone health and the attenuation of age-related bone loss. PMID:25535352

  12. Emergence of a Homo sapiens-specific gene family and chromosome 16p11.2 CNV susceptibility

    PubMed Central

    Nuttle, Xander; Giannuzzi, Giuliana; Duyzend, Michael H.; Schraiber, Joshua G.; Narvaiza, Iñigo; Sudmant, Peter H.; Penn, Osnat; Chiatante, Giorgia; Malig, Maika; Huddleston, John; Benner, Chris; Camponeschi, Francesca; Ciofi-Baffoni, Simone; Stessman, Holly A.F.; Marchetto, Maria C. N.; Denman, Laura; Harshman, Lana; Baker, Carl; Raja, Archana; Penewit, Kelsi; Janke, Nicolette; Tang, W. Joyce; Ventura, Mario; Banci, Lucia; Antonacci, Francesca; Akey, Joshua M.; Amemiya, Chris T.; Gage, Fred H.; Reymond, Alexandre; Eichler, Evan E.

    2016-01-01

    Genetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates1, including more recently the genomes of archaic hominins2,3. Not all regions of the genome, however, are equally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2 accounts for ~1% of autism cases4,5 and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. We reconstructed the evolutionary history of the locus and identified BOLA2 (bolA family member 2) as a gene duplicated exclusively in Homo sapiens. We estimate that a 95 kbp segment containing BOLA2 duplicated across the critical region ~282 thousand years ago (kya), one of the latest among a series of genomic changes that dramatically restructured the locus during hominid evolution. All humans examined carry one or more copies of the duplication, which nearly fixed early in the human lineage—a pattern unlikely to have arisen so rapidly in the absence of selection (p < 0.0097). We show that the duplication of BOLA2 led to a novel, human-specific in-frame fusion transcript and that BOLA2 copy number correlates with both RNA expression (r = 0.36) and protein level (r = 0.65), with the greatest expression difference between human and chimpanzee in experimentally derived stem cells. Analyses of 152 patients carrying a chromosome 16p11.2 rearrangement showed that >96% of breakpoints occur within the Homo sapiens-specific duplication. In summary, the duplicative transposition of BOLA2 at the root of the Homo sapiens lineage ~282 kya simultaneously increased copy number of a gene associated with iron homeostasis and predisposed our species to recurrent rearrangements associated with disease. PMID:27487209

  13. Do primates see the solitaire illusion differently? A comparative assessment of humans (Homo sapiens), chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Cebus apella).

    PubMed

    Agrillo, Christian; Parrish, Audrey E; Beran, Michael J

    2014-11-01

    An important question in comparative psychology is whether human and nonhuman animals share similar principles of perceptual organization. Despite much empirical research, no firm conclusion has been drawn. The Solitaire illusion is a numerosity illusion in humans that occurs when one misperceives the relative number of 2 types of items presented in intermingled sets. To date, no study has investigated whether nonhuman animals perceive the Solitaire illusion as humans do. Here, we compared the perception of the Solitaire illusion in human and nonhuman primates in 3 experiments. We first observed (Experiment 1) the spontaneous behavior of chimpanzees when presented with 2 arrays composed of a different number of preferred and nonpreferred food items. In probe trials, preferred items were presented in the Solitaire pattern in 2 different spatial arrangements (either clustered centrally or distributed on the perimeter). Chimpanzees did not show any misperception of quantity in the Solitaire pattern. Next, humans, chimpanzees, rhesus monkeys, and capuchin monkeys underwent the same testing of relative quantity judgments in a computerized task that also presented the Solitaire illusion (Experiments 2 and 3). Unlike humans, chimpanzees did not appear to perceive the illusion, in agreement with Experiment 1. The performance of rhesus monkeys and capuchin monkeys was also different from that of humans, but was slightly more indicative of a potential Solitaire illusion. On the whole, our results suggest a potential discontinuity in the visual mechanisms underlying the Solitaire illusion between human and nonhuman primates.

  14. Co-evolution of Mycobacterium tuberculosis and Homo sapiens

    PubMed Central

    Brites, Daniela; Gagneux, Sebastien

    2015-01-01

    The causative agent of human tuberculosis (TB), Mycobacterium tuberculosis, is an obligate pathogen that evolved to exclusively persist in human populations. For M. tuberculosis to transmit from person to person, it has to cause pulmonary disease. Therefore, M. tuberculosis virulence has likely been a significant determinant of the association between M. tuberculosis and humans. Indeed, the evolutionary success of some M. tuberculosis genotypes seems at least partially attributable to their increased virulence. The latter possibly evolved as a consequence of human demographic expansions. If co-evolution occurred, humans would have counteracted to minimize the deleterious effects of M. tuberculosis virulence. The fact that human resistance to infection has a strong genetic basis is a likely consequence of such a counter-response. The genetic architecture underlying human resistance to M. tuberculosis remains largely elusive. However, interactions between human genetic polymorphisms and M. tuberculosis genotypes have been reported. Such interactions are consistent with local adaptation and allow for a better understanding of protective immunity in TB. Future ‘genome-to-genome’ studies, in which locally associated human and M. tuberculosis genotypes are interrogated in conjunction, will help identify new protective antigens for the development of better TB vaccines. PMID:25703549

  15. Life as a Cosmic Phenomenon: 2. the Panspermic Trajectory of Homo Sapiens

    NASA Astrophysics Data System (ADS)

    Tokoro, Gensuke; Wickramasinghe, N. Chandra

    We discuss the origin and evolution of Homo sapiens in a cosmic context, and in relation to the Hoyle-Wickramasinghe theory of panspermia for which there is now overwhelming evidence. It is argued that the first bacteria (archea) incident on the Earth via the agency of comets 3.8-4 billion years ago continued at later times to be augmented by viral genes (DNA, RNA) from space that eventually led to the evolutionary patterns we see in present-day biology. We argue that the current evolutionary status of Homo sapiens as well as its future trajectory is circumscribed by evolutionary processes that were pre-determined on a cosmic scale -- over vast distances and enormous spans of cosmic time. Based on this teleological hypothesis we postulate that two distinct classes of cosmic viruses (cosmic viral genes) are involved in accounting for the facts relating to the evolution of life.

  16. Direct and indirect reputation formation in nonhuman great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) and human children (Homo sapiens).

    PubMed

    Herrmann, Esther; Keupp, Stefanie; Hare, Brian; Vaish, Amrisha; Tomasello, Michael

    2013-02-01

    Humans make decisions about when and with whom to cooperate based on their reputations. People either learn about others by direct interaction or by observing third-party interactions or gossip. An important question is whether other animal species, especially our closest living relatives, the nonhuman great apes, also form reputations of others. In Study 1, chimpanzees, bonobos, orangutans, and 2.5-year-old human children experienced a nice experimenter who tried to give food/toys to the subject and a mean experimenter who interrupted the food/toy giving. In studies 2 and 3, nonhuman great apes and human children could only passively observe a similar interaction, in which a nice experimenter and a mean experimenter interacted with a third party. Orangutans and 2.5-year-old human children preferred to approach the nice experimenter rather than the mean one after having directly experienced their respective behaviors. Orangutans, chimpanzees, and 2.5-year-old human children also took into account experimenter actions toward third parties in forming reputations. These studies show that the human ability to form direct and indirect reputation judgment is already present in young children and shared with at least some of the other great apes.

  17. Stereology of the thyroid gland in Indo-Pacific bottlenose dolphin (Tursiops aduncus) in comparison with human (Homo sapiens): quantitative and functional implications.

    PubMed

    Kot, Brian Chin Wing; Lau, Thomas Yue Huen; Cheng, Sammy Chi Him

    2013-01-01

    The mammalian thyroid gland maintains basal metabolism in tissues for optimal function. Determining thyroid volume is important in assessing growth and involution. Volume estimation is also important in stereological studies. Direct measurements of colloid volume and nuclear-to-cytoplasmic ratio of the follicular cells may provide important information about thyroid gland function such as hormone storage and secretion, which helps understand the changes at morphological and functional levels. The present study determined the colloid volume using simple stereological principle and the nuclear-to-cytoplasmic ratio of 4 Indo-Pacific bottlenose dolphins and 2 human thyroid glands. In both dolphin and human thyroid glands, the size of the follicles tended to be quite variable. The distribution of large and small follicles within the thyroid gland was also found to be random in both the dolphin and human thyroid gland; however, the size of follicles appeared to decrease as a function of increasing age in the dolphin thyroid gland. The mean colloid volume of the dolphin thyroid gland and human thyroid gland was 1.22×10(5) µm(3) and 7.02×10(5) µm(3) respectively. The dolphin and human subjects had a significant difference in the mean colloid volume. The mean N/C ratio of the dolphin thyroid follicular epithelia and human follicular epithelia was 0.50 and 0.64 respectively. The dolphin and human subjects had a significant difference in the mean N/C ratio. This information contributes to understanding dolphin thyroid physiology and its structural adaptations to meet the physical demands of the aquatic environment, and aids with ultrasonography and corrective therapy in live subjects.

  18. Transfer between local and global processing levels by pigeons (Columba livia) and humans (Homo sapiens) in exemplar- and rule-based categorization tasks.

    PubMed

    Aust, Ulrike; Braunöder, Elisabeth

    2015-02-01

    The present experiment investigated pigeons' and humans' processing styles-local or global-in an exemplar-based visual categorization task in which category membership of every stimulus had to be learned individually, and in a rule-based task in which category membership was defined by a perceptual rule. Group Intact was trained with the original pictures (providing both intact local and global information), Group Scrambled was trained with scrambled versions of the same pictures (impairing global information), and Group Blurred was trained with blurred versions (impairing local information). Subsequently, all subjects were tested for transfer to the 2 untrained presentation modes. Humans outperformed pigeons regarding learning speed and accuracy as well as transfer performance and showed good learning irrespective of group assignment, whereas the pigeons of Group Blurred needed longer to learn the training tasks than the pigeons of Groups Intact and Scrambled. Also, whereas humans generalized equally well to any novel presentation mode, pigeons' transfer from and to blurred stimuli was impaired. Both species showed faster learning and, for the most part, better transfer in the rule-based than in the exemplar-based task, but there was no evidence of the used processing mode depending on the type of task (exemplar- or rule-based). Whereas pigeons relied on local information throughout, humans did not show a preference for either processing level. Additional tests with grayscale versions of the training stimuli, with versions that were both blurred and scrambled, and with novel instances of the rule-based task confirmed and further extended these findings.

  19. Cryptosporidium hominis n. sp. (Apicomplexa: Cryptosporidiidae) from Homo sapiens.

    PubMed

    Morgan-Ryan, Una M; Fall, Abbie; Ward, Lucy A; Hijjawi, Nawal; Sulaiman, Irshad; Fayer, Ronald; Thompson, R C Andrew; Olson, M; Lal, Altaf; Xiao, Lihua

    2002-01-01

    The structure and infectivity of the oocysts of a new species of Cryptosporidium from the feces of humans are described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum. Oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). Oocysts were not infectious for ARC Swiss mice, nude mice. Wistar rat pups, puppies, kittens or calves, but were infectious to neonatal gnotobiotic pigs. Pathogenicity studies in the gnotobiotic pig model revealed significant differences in parasite-associated lesion distribution (P = 0.005 to P = 0.02) and intensity of infection (P = 0.04) between C. parvum and this newly described species from humans. In vitro cultivation studies have also revealed growth differences between the two species. Multi-locus analysis of numerous unlinked loci, including a preliminary sequence scan of the entire genome demonstrated this species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further support for its species status. Based on biological and molecular data, this Cryptosporidium infecting the intestine of humans is proposed to be a new species Cryptosporidium hominis n. sp.

  20. The Arrival of Homo sapiens into the Southern Cone at 14,000 Years Ago

    PubMed Central

    Politis, Gustavo G.; Gutiérrez, María A.; Blasi, Adriana

    2016-01-01

    The Arroyo Seco 2 site contains a rich archaeological record, exceptional for South America, to explain the expansion of Homo sapiens into the Americas and their interaction with extinct Pleistocene mammals. The following paper provides a detailed overview of material remains found in the earliest cultural episodes at this multi-component site, dated between ca. 12,170 14C yrs B.P. (ca. 14,064 cal yrs B.P.) and 11,180 14C yrs B.P. (ca. 13,068 cal yrs B.P.). Evidence of early occupations includes the presence of lithic tools, a concentration of Pleistocene species remains, human-induced fractured animal bones, and a selection of skeletal parts of extinct fauna. The occurrence of hunter-gatherers in the Southern Cone at ca. 14,000 cal yrs B.P. is added to the growing list of American sites that indicate a human occupation earlier than the Clovis dispersal episode, but posterior to the onset of the deglaciation of the Last Glacial Maximum (LGM) in the North America. PMID:27683248

  1. Looking Ahead? Computerized Maze Task Performance by Chimpanzees (Pan troglodytes), Rhesus Monkeys (Macaca mulatta), Capuchin Monkeys (Cebus apella), and Human Children (Homo sapiens)

    PubMed Central

    Beran, Michael J.; Parrish, Audrey E.; Futch, Sara E.; Evans, Theodore A.; Perdue, Bonnie M.

    2015-01-01

    Human and nonhuman primates are not mentally constrained to the present. They can remember the past and – at least to an extent – anticipate the future. Anticipation of the future ranges from long-term prospection such as planning for retirement to more short-term future oriented cognition such as planning a route through a maze. Here we tested a great ape species (chimpanzees), an Old World monkey species (rhesus macaques) a New World monkey species (capuchin monkeys) and human children on a computerized maze task. All subjects had to move a cursor through a maze to reach a goal at the bottom of the screen. For best performance on the task, subjects had to “plan ahead” to the end of the maze to move the cursor in the correct direction, avoid traps, and reverse directions if necessary. Mazes varied in difficulty. Chimpanzees were better than both monkey species, and monkeys showed a particular deficit when moving away from the goal or changing directions was required. Children showed a similar pattern to monkeys regarding the effects of reversals and moves away from the goal, but their overall performance in terms of correct maze completion was similar to the chimpanzees. The results highlight similarities as well as differences in planning across species and the role that inhibitory control may play in future oriented cognition in primates. PMID:25798793

  2. Transfer of spatial search between environments in human adults and young children (Homo sapiens): implications for representation of local geometry by spatial systems.

    PubMed

    Lew, Adina R; Usherwood, Barrie; Fragkioudaki, Frantzeska; Koukoumi, Varvara; Smith, Shamus P; Austen, Joe M; McGregor, Anthony

    2014-04-01

    Whether animals represent environmental geometry in a global and/or local way has been the subject of recent debate. We applied a transfer of search paradigm between rectangular- and kite-shaped arenas to examine the performance of human adults (using virtual environments) and children of 2.5-3.5 years (using real arenas). Adults showed robust transfer to a congruent corner in a kite-shaped arena, following training in a rectangular-shaped arena in two paradigms modeled on those used with rats and young children respectively. In contrast, the children showed no evidence of transfer of search, despite above chance performance in the rectangular arena, and above chance performance in a study where search occurred in the kite arena only. The pattern of findings suggests global aspects of environmental geometry may be used to re-establish heading, and that the matching of elements of local geometry in new global contexts may be an advanced developmental achievement.

  3. [The emergence of obstetrical mechanism: From Lucy to Homo sapiens].

    PubMed

    Frémondière, P; Thollon, L; Marchal, F

    2017-03-01

    The evolutionary history of modern birth mechanism is now a renewed interest in obstetrical papers. The purpose of this work is to review the literature in paleo-obstetrical field. Our analysis focuses on paleo-obstetrical hypothesis, from 1960 to the present day, based on the reconstruction of fossil pelvis. Indeed, these pelvic reconstructions usually provide an opportunity to make an obstetrical assumption in our ancestors. In this analysis, we show that modern birth mechanism takes place during the emergence of our genus 2 million years ago. References are made to human specificities related to obstetrical mechanism: exclusive bipedalism, increase of brain size at birth, metabolic cost of the pregnancy and deep trophoblastic implantation.

  4. Comparing the performances of apes (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus) and human children (Homo sapiens) in the floating peanut task.

    PubMed

    Hanus, Daniel; Mendes, Natacha; Tennie, Claudio; Call, Josep

    2011-01-01

    Recently, Mendes et al. [1] described the use of a liquid tool (water) in captive orangutans. Here, we tested chimpanzees and gorillas for the first time with the same "floating peanut task." None of the subjects solved the task. In order to better understand the cognitive demands of the task, we further tested other populations of chimpanzees and orangutans with the variation of the peanut initially floating or not. Twenty percent of the chimpanzees but none of the orangutans were successful. Additional controls revealed that successful subjects added water only if it was necessary to obtain the nut. Another experiment was conducted to investigate the reason for the differences in performance between the unsuccessful (Experiment 1) and the successful (Experiment 2) chimpanzee populations. We found suggestive evidence for the view that functional fixedness might have impaired the chimpanzees' strategies in the first experiment. Finally, we tested how human children of different age classes perform in an analogous experimental setting. Within the oldest group (8 years), 58 percent of the children solved the problem, whereas in the youngest group (4 years), only 8 percent were able to find the solution.

  5. Preliminary Study to Test the Feasibility of Sex Identification of Human (Homo sapiens) Bones Based on Differences in Elemental Profiles Determined by Handheld X-ray Fluorescence.

    PubMed

    Nganvongpanit, Korakot; Buddhachat, Kittisak; Brown, Janine L; Klinhom, Sarisa; Pitakarnnop, Tanita; Mahakkanukrauh, Pasuk

    2016-09-01

    Sex assignment of human remains is a crucial step in forensic anthropological studies. The aim of this study was to examine elemental differences between male and female bones using X-ray fluorescence (XRF) and determine if elemental profiling could be used for sex discrimination. Cranium, humerus, and os coxae of 60 skeletons (30 male, 30 female) from the Chiang Mai University Skeletal Collection were scanned by XRF and differences in elemental profiles between male and female bones determined using discriminant analysis. In the cranium, three elements (S, Ca, Pb) were significantly higher in males and five elements (Si, Mn, Fe, Zn, Ag) plus light elements (atomic number lower than 12) were higher in females. In humerus and os coxae, nine elements were significantly higher in male and one element was higher in female samples. The accuracy rate for sex estimation was 60, 63, and 61 % for cranium, humerus, and os coxae, respectively, and 67 % when data for all three bones were combined. We conclude that there are sex differences in bone elemental profiles; however, the accuracy of XRF analyses for discriminating between male and female samples was low compared to standard morphometric and molecular methods. XRF could be used on small samples that cannot be sexed by traditional morphological methods, but more work is needed to increase the power of this technique for gender assignment.

  6. Variability in first Homo: Analysis of the ratio between the skulls KNM-ER 1470 and KNM-ER 1813 based on sexual dimorphism of Homo sapiens.

    PubMed

    Guimarães, S W Ferreira; Lorenzo, C

    2015-10-01

    The study of the skulls KNM-ER 1470 and KNM-ER 1813, considered the first members of the genus Homo, has raised some debates. While some of researchers maintain that there is only one species, another group argues that there are two species. On one hand these two fossils are still taxonomically undetermined, on the other hand they bring up another problem related to the existence of a genus with multiple species since its beginning, according to the last discoveries. In this paper, we have compared the size ratio between these fossils with ratios established in populations of Homo sapiens, in order to know if they fit into the human standard, considering intra-sexual and inter-sexual variation. Results help to establish whether these fossils correspond to different species or their differences could be related to sexual dimorphism within a single species.

  7. Humans (Homo sapiens) judge the emotional content of piglet (Sus scrofa domestica) calls based on simple acoustic parameters, not personality, empathy, nor attitude toward animals.

    PubMed

    Maruščáková, Iva L; Linhart, Pavel; Ratcliffe, Victoria F; Tallet, Céline; Reby, David; Špinka, Marek

    2015-05-01

    The vocal expression of emotion is likely driven by shared physiological principles among species. However, which acoustic features promote decoding of emotional state and how the decoding is affected by their listener's psychology remain poorly understood. Here we tested how acoustic features of piglet vocalizations interact with psychological profiles of human listeners to affect judgments of emotional content of heterospecific vocalizations. We played back 48 piglet call sequences recorded in four different contexts (castration, isolation, reunion, nursing) to 60 listeners. Listeners judged the emotional intensity and valence of the recordings and were further asked to attribute a context of emission from four proposed contexts. Furthermore, listeners completed a series of questionnaires assessing their personality (NEO-FFI personality inventory), empathy [Interpersonal Reactivity Index (IRI)] and attitudes to animals (Animal Attitudes Scale). None of the listeners' psychological traits affected the judgments. On the contrary, acoustic properties of recordings had a substantial effect on ratings. Recordings were rated as more intense with increasing pitch (mean fundamental frequency) and increasing proportion of vocalized sound within each stimulus recording and more negative with increasing pitch and increasing duration of the calls within the recording. More complex acoustic properties (jitter, harmonic-to-noise ratio, and presence of subharmonics) did not seem to affect the judgments. The probability of correct context recognition correlated positively with the assessed emotion intensity for castration and reunion calls, and negatively for nursing calls. In conclusion, listeners judged emotions from pig calls using simple acoustic properties and the perceived emotional intensity might guide the identification of the context.

  8. Pair-bonding, romantic love, and evolution: the curious case of Homo sapiens.

    PubMed

    Fletcher, Garth J O; Simpson, Jeffry A; Campbell, Lorne; Overall, Nickola C

    2015-01-01

    This article evaluates a thesis containing three interconnected propositions. First, romantic love is a "commitment device" for motivating pair-bonding in humans. Second, pair-bonding facilitated the idiosyncratic life history of hominins, helping to provide the massive investment required to rear children. Third, managing long-term pair bonds (along with family relationships) facilitated the evolution of social intelligence and cooperative skills. We evaluate this thesis by integrating evidence from a broad range of scientific disciplines. First, consistent with the claim that romantic love is an evolved commitment device, our review suggests that it is universal; suppresses mate-search mechanisms; has specific behavioral, hormonal, and neuropsychological signatures; and is linked to better health and survival. Second, we consider challenges to this thesis posed by the existence of arranged marriage, polygyny, divorce, and infidelity. Third, we show how the intimate relationship mind seems to be built to regulate and monitor relationships. Fourth, we review comparative evidence concerning links among mating systems, reproductive biology, and brain size. Finally, we discuss evidence regarding the evolutionary timing of shifts to pair-bonding in hominins. We conclude there is interdisciplinary support for the claim that romantic love and pair-bonding, along with alloparenting, played critical roles in the evolution of Homo sapiens.

  9. LocDB: experimental annotations of localization for Homo sapiens and Arabidopsis thaliana.

    PubMed

    Rastogi, Shruti; Rost, Burkhard

    2011-01-01

    LocDB is a manually curated database with experimental annotations for the subcellular localizations of proteins in Homo sapiens (HS, human) and Arabidopsis thaliana (AT, thale cress). Currently, it contains entries for 19,604 UniProt proteins (HS: 13,342; AT: 6262). Each database entry contains the experimentally derived localization in Gene Ontology (GO) terminology, the experimental annotation of localization, localization predictions by state-of-the-art methods and, where available, the type of experimental information. LocDB is searchable by keyword, protein name and subcellular compartment, as well as by identifiers from UniProt, Ensembl and TAIR resources. In comparison to other public databases, LocDB as a resource adds about 10,000 experimental localization annotations for HS proteins and ∼900 for AS proteins. Over 40% of the proteins in LocDB have multiple localization annotations providing a better platform for development of new multiple localization prediction methods with higher coverage and accuracy. Links to all referenced databases are provided. LocDB will be updated regularly by our group (available at: http://www.rostlab.org/services/locDB).

  10. The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: a Y chromosome perspective.

    PubMed

    Semino, O; Passarino, G; Oefner, P J; Lin, A A; Arbuzova, S; Beckman, L E; De Benedictis, G; Francalacci, P; Kouvatsi, A; Limborska, S; Marcikiae, M; Mika, A; Mika, B; Primorac, D; Santachiara-Benerecetti, A S; Cavalli-Sforza, L L; Underhill, P A

    2000-11-10

    A genetic perspective of human history in Europe was derived from 22 binary markers of the nonrecombining Y chromosome (NRY). Ten lineages account for >95% of the 1007 European Y chromosomes studied. Geographic distribution and age estimates of alleles are compatible with two Paleolithic and one Neolithic migratory episode that have contributed to the modern European gene pool. A significant correlation between the NRY haplotype data and principal components based on 95 protein markers was observed, indicating the effectiveness of NRY binary polymorphisms in the characterization of human population composition and history.

  11. Forearm articular proportions and the antebrachial index in Homo sapiens, Australopithecus afarensis and the great apes.

    PubMed

    Williams, Frank L'Engle; Cunningham, Deborah L; Amaral, Lia Q

    2015-12-01

    When hominin bipedality evolved, the forearms were free to adopt nonlocomotor tasks which may have resulted in changes to the articular surfaces of the ulna and the relative lengths of the forearm bones. Similarly, sex differences in forearm proportions may be more likely to emerge in bipeds than in the great apes given the locomotor constraints in Gorilla, Pan and Pongo. To test these assumptions, ulnar articular proportions and the antebrachial index (radius length/ulna length) in Homo sapiens (n=51), Gorilla gorilla (n=88), Pan troglodytes (n=49), Pongo pygmaeus (n=36) and Australopithecus afarensis A.L. 288-1 and A.L. 438-1 are compared. Intercept-adjusted ratios are used to control for size and minimize the effects of allometry. Canonical scores axes show that the proximally broad and elongated trochlear notch with respect to size in H. sapiens and A. afarensis is largely distinct from G. gorilla, P. troglodytes and P. pygmaeus. A cluster analysis of scaled ulnar articular dimensions groups H. sapiens males with A.L. 438-1 ulna length estimates, while one A.L. 288-1 ulna length estimate groups with Pan and another clusters most closely with H. sapiens, G. gorilla and A.L. 438-1. The relatively low antebrachial index characterizing H. sapiens and non-outlier estimates of A.L. 288-1 and A.L. 438-1 differs from those of the great apes. Unique sex differences in H. sapiens suggest a link between bipedality and forearm functional morphology.

  12. Genetic characterization of general transcription factors TFIIF and TFIIB of Homo sapiens sapiens.

    PubMed

    Purrello, M; Di Pietro, C; Rapisarda, A; Mirabile, E; Motta, S; Sichel, G; Grzeschik, K H

    1995-01-01

    Analysis of loci GTF2F1 and GTF2B, encoding Rap 74 (a subunit of TFIIF) and TFIIB, respectively, showed that they are present in a single copy in the human genome and are localized at 19p13.3 and 1p22, respectively. By using as probe a cDNA for Rap 30 (the other subunit of TFIIF), we localized the GTF2F2 locus to 13q14; the same probe also detected a cross-hybridizing sequence at 4q31 whose functional importance remains to be elucidated. These data and those previously published by our group demonstrate that genes coding for class II general transcription factors with reported sequence similarity to bacterial sigma proteins are scattered in different regions of the human genome, with no evidence of clustering. This dispersion and the identification of homologs of both TBP and TFIIB in Archaea suggest an early evolutionary origin of the general transcription apparatus of contemporary eukaryotes.

  13. Genetic evidence of an early exit of Homo sapiens sapiens from Africa through eastern Africa.

    PubMed

    Quintana-Murci, L; Semino, O; Bandelt, H J; Passarino, G; McElreavey, K; Santachiara-Benerecetti, A S

    1999-12-01

    The out-of-Africa scenario has hitherto provided little evidence for the precise route by which modern humans left Africa. Two major routes of dispersal have been hypothesized: one through North Africa into the Levant, documented by fossil remains, and one through Ethiopia along South Asia, for which little, if any, evidence exists. Mitochondrial DNA (mtDNA) can be used to trace maternal ancestry. The geographic distribution and variation of mtDNAs can be highly informative in defining potential range expansions and migration routes in the distant past. The mitochondrial haplogroup M, first regarded as an ancient marker of East-Asian origin, has been found at high frequency in India and Ethiopia, raising the question of its origin. (A haplogroup is a group of haplotypes that share some sequence variations.) Its variation and geographical distribution suggest that Asian haplogroup M separated from eastern-African haplogroup M more than 50,000 years ago. Two other variants (489C and 10873C) also support a single origin of haplogroup M in Africa. These findings, together with the virtual absence of haplogroup M in the Levant and its high frequency in the South-Arabian peninsula, render M the first genetic indicator for the hypothesized exit route from Africa through eastern Africa/western India. This was possibly the only successful early dispersal event of modern humans out of Africa.

  14. Dental size reduction in Indonesian Homo erectus: Implications for the PU-198 premolar and the appearance of Homo sapiens on Java.

    PubMed

    Polanski, Joshua M; Marsh, Hannah E; Maddux, Scott D

    2016-01-01

    The recent recovery of a hominin maxillary third premolar, PU-198, within the faunal collections from Punung Cave (East Java) has led to assertions that Homo sapiens appeared on Java between 143,000 and 115,000 years ago. The taxonomic assignment of PU-198 to H. sapiens was based predominantly on the small size of the specimen, following an analysis which found little to no overlap in premolar size between Homo erectus and terminal Pleistocene/Holocene H. sapiens. Here, we re-evaluate the use of size in the taxonomic assignment of PU-198 in light of 1) new buccolingual and mesiodistal measurements taken on the fossil, 2) comparisons to a larger sample of H. erectus and H. sapiens maxillary third premolars, and 3) evidence of a diachronic trend in post-canine dental size reduction among Javan H. erectus. Our results demonstrate PU-198 to be slightly larger than previously suggested, reveal substantial overlap in premolar size between H. erectus and H. sapiens, and indicate a statistically significant reduction in premolar size between early and late Javan H. erectus. Our findings cast doubt on the assignment of PU-198 to H. sapiens, and accordingly, question the appearance of H. sapiens on Java between 143,000 and 115,000 years ago.

  15. Emergence of a Homo sapiens-specific gene family and chromosome 16p11.2 CNV susceptibility.

    PubMed

    Nuttle, Xander; Giannuzzi, Giuliana; Duyzend, Michael H; Schraiber, Joshua G; Narvaiza, Iñigo; Sudmant, Peter H; Penn, Osnat; Chiatante, Giorgia; Malig, Maika; Huddleston, John; Benner, Chris; Camponeschi, Francesca; Ciofi-Baffoni, Simone; Stessman, Holly A F; Marchetto, Maria C N; Denman, Laura; Harshman, Lana; Baker, Carl; Raja, Archana; Penewit, Kelsi; Janke, Nicolette; Tang, W Joyce; Ventura, Mario; Banci, Lucia; Antonacci, Francesca; Akey, Joshua M; Amemiya, Chris T; Gage, Fred H; Reymond, Alexandre; Eichler, Evan E

    2016-08-11

    Genetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates, including more recently the genomes of archaic hominins. Not all regions of the genome, however, are equally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2 accounts for approximately 1% of cases of autism and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. Here we reconstruct the evolutionary history of the locus and identify bolA family member 2 (BOLA2) as a gene duplicated exclusively in Homo sapiens. We estimate that a 95-kilobase-pair segment containing BOLA2 duplicated across the critical region approximately 282 thousand years ago (ka), one of the latest among a series of genomic changes that dramatically restructured the locus during hominid evolution. All humans examined carried one or more copies of the duplication, which nearly fixed early in the human lineage--a pattern unlikely to have arisen so rapidly in the absence of selection (P < 0.0097). We show that the duplication of BOLA2 led to a novel, human-specific in-frame fusion transcript and that BOLA2 copy number correlates with both RNA expression (r = 0.36) and protein level (r = 0.65), with the greatest expression difference between human and chimpanzee in experimentally derived stem cells. Analyses of 152 patients carrying a chromosome 16p11. rearrangement show that more than 96% of breakpoints occur within the H. sapiens-specific duplication. In summary, the duplicative transposition of BOLA2 at the root of the H. sapiens lineage about 282 ka simultaneously increased copy number of a gene associated with iron homeostasis and predisposed our species to recurrent rearrangements associated with disease.

  16. Before the Emergence of Homo sapiens: Overview on the Early-to-Middle Pleistocene Fossil Record (with a Proposal about Homo heidelbergensis at the subspecific level).

    PubMed

    Manzi, Giorgio

    2011-01-01

    The origin of H. sapiens has deep roots, which include two crucial nodes: (1) the emergence and diffusion of the last common ancestor of later Homo (in the Early Pleistocene) and (2) the tempo and mode of the appearance of distinct evolutionary lineages (in the Middle Pleistocene). The window between 1,000 and 500 thousand years before present appears of crucial importance, including the generation of a new and more encephalised kind of humanity, referred to by many authors as H. heidelbergensis. This species greatly diversified during the Middle Pleistocene up to the formation of new variants (i.e., incipient species) that, eventually, led to the allopatric speciation of H. neanderthalensis and H. sapiens. The special case furnished by the calvarium found near Ceprano (Italy), dated to 430-385 ka, offers the opportunity to investigate this matter from an original perspective. It is proposed to separate the hypodigm of a single, widespread, and polymorphic human taxon of the Middle Pleistocene into distinct subspecies (i.e., incipient species). The ancestral one should be H. heidelbergensis, including specimens such as Ceprano and the mandible from Mauer.

  17. Similarity analysis between chromosomes of Homo sapiens and monkeys with correlation coefficient, rank correlation coefficient and cosine similarity measures.

    PubMed

    Someswara Rao, Chinta; Viswanadha Raju, S

    2016-03-01

    In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship between the H. sapiens and monkey. This similarity will be helpful at theft identification, maternity identification, disease identification, etc.

  18. From Homo Sapiens to Homo Cosmicus - Astronautics, Darwinism abd Historical Determinism

    NASA Astrophysics Data System (ADS)

    Tolkowsky, G.

    Since its inception in late-nineteenth century, astronautics has been viewed as a historical outcome of human evolution as well as a future driver thereof. The history of astronautics-related, evolutionary thought reveals a tension between the Darwinian notion of natural selection and that of homocosmic predestination - be it of dialectical materialistic or theological nature. One can detect the influence of this ideological diversity on the American and Soviet space programs.

  19. Mitochondrial tRNA sequences as unusual replication origins: pathogenic implications for Homo sapiens.

    PubMed

    Seligmann, Hervé; Krishnan, Neeraja M; Rao, Basuthkar J

    2006-12-07

    The heavy strand of vertebrate mitochondrial genomes accumulates deaminations proportionally to the time it spends single-stranded during replication. A previous study showed that the strength of genome-wide deamination gradients originating from tRNA gene's locations increases with their capacities to form secondary structures resembling mitochondrial origins of light strand replication (OL), suggesting an alternative function for tRNA sequences. We hypothesize that this function is frequently pathogenic for those tRNA genes that normally do not form OL-like structures, because this could cause excess mutations in genome regions unadapted to tolerate them. In human mitochondrial genomes, pathogenic tRNA variants usually form less OL-like structures than non-pathogenic ones in cases where the normal non-pathogenic tRNA variant can function as OL, as evolutionary analyses reveal. For tRNAs lacking the putative OL-like functioning capacity, pathogenic variants form more OL-like secondary structures, particularly structures that might invoke bi-directional replication (true for 14 among 21 tRNA species, p<0.05, sign test; significantly at p<0.05 (1 tailed test) for 7 tRNA species), but not more unidirectional replication invoking structures. Accounting for the functional cloverleaf-like structure-forming capacities of tRNAs yields similar results. Rare, non-pathogenic tRNA mutants tend to form more OL-like structures than the common, non-pathogenic ones, suggesting weak directional selection also among non-pathogenic variants. The duration spent single stranded by a region of the heavy strand (D(ssH)) during replication, estimated by integrating over all regions that can function as OL in Homo sapiens mitochondrial genomes, increases with distance of that region from the Dloop. This suggests convergence of single-strandedness during replication and transcription, and explains conserved locations of tRNA species in mitochondrial genomes and bacterial operons. These

  20. Two conformational states in the crystal structure of the Homo sapiens cytoplasmic ribosomal decoding A site.

    PubMed

    Kondo, Jiro; Urzhumtsev, Alexandre; Westhof, Eric

    2006-01-01

    The decoding A site of the small ribosomal subunit is an RNA molecular switch, which monitors codon-anticodon interactions to guarantee translation fidelity. We have solved the crystal structure of an RNA fragment containing two Homo sapiens cytoplasmic A sites. Each of the two A sites presents a different conformational state. In one state, adenines A1492 and A1493 are fully bulged-out with C1409 forming a wobble-like pair to A1491. In the second state, adenines A1492 and A1493 form non-Watson-Crick pairs with C1409 and G1408, respectively while A1491 bulges out. The first state of the eukaryotic A site is, thus, basically the same as in the bacterial A site with bulging A1492 and A1493. It is the state used for recognition of the codon/anticodon complex. On the contrary, the second state of the H.sapiens cytoplasmic A site is drastically different from any of those observed for the bacterial A site without bulging A1492 and A1493.

  1. Laser-induced breakdown spectroscopy microanalysis of trace elements in Homo sapiens teeth.

    PubMed

    Alvira, F C; Ramirez Rozzi, F; Bilmes, G M

    2010-03-01

    Two of the main items from which to retrieve data in anthropology are teeth and bones. Identification of trace elements in their composition allows valuable information to be obtained about alimentary habits and community life conditions of groups and individuals. Conventional methods used to determine the presence of trace elements require sample preparation, with partial or total destruction of the pieces, which in most cases are unique. In this work we show the possibilities of laser-induced breakdown spectroscopy (LIBS) as a nearly nondestructive tool in anthropology and paleontology for the measurement of the presence and distribution of trace elements in teeth. We applied LIBS to the determination of strontium and magnesium in dentin and enamel of Neolithic, middle age, and modern Homo sapiens teeth. Mg/Ca and Sr/Ca distribution maps of dentin and enamel in modern teeth were created using the data obtained. Ablation threshold fluences of dentin and enamel were also measured using the photoacoustic signal induced by laser ablation. Significant variations were found in the Mg/Ca and Sr/Ca ratios in the tooth dental tissue and between the teeth of the groups and individuals studied. These results can be useful for evolutionary anthropology studies as they can provide information regarding early nutrition, seasonality, and residential mobility.

  2. Object permanence in orangutans (Pongo pygmaeus), chimpanzees (Pan troglodytes), and children (Homo sapiens).

    PubMed

    Call, J

    2001-06-01

    Juvenile and adult orangutans (n = 5; Pongo pygmaeus), chimpanzees (n = 7; Pan troglodytes), and 19- and 26-month-old children (n = 24; Homo sapiens) received visible and invisible displacements. Three containers were presented forming a straight line, and a small box was used to displace a reward under them. Subjects received 3 types of displacement: single (the box visited 1 container), double adjacent (the box visited 2 contiguous containers), and double nonadjacent (the box visited 2 noncontiguous containers). All species performed at comparable levels, solving all problems except the invisible nonadjacent displacements. Visible displacements were easier than invisible, and single were easier than double displacements. In a 2nd experiment, subjects saw the baiting of either 2 adjacent or 2 nonadjacent containers with no displacements. All species selected the empty container more often when the baited containers were nonadjacent than when they were adjacent. It is hypothesized that a response bias and inhibition problem were responsible for the poor performance in nonadjacent displacements.

  3. The mitogenome of a 35,000-year-old Homo sapiens from Europe supports a Palaeolithic back-migration to Africa

    PubMed Central

    Hervella, M.; Svensson, E. M.; Alberdi, A.; Günther, T.; Izagirre, N.; Munters, A. R.; Alonso, S.; Ioana, M.; Ridiche, F.; Soficaru, A.; Jakobsson, M.; Netea, M. G.; de-la-Rua, C.

    2016-01-01

    After the dispersal of modern humans (Homo sapiens) Out of Africa, hominins with a similar morphology to that of present-day humans initiated the gradual demographic expansion into Eurasia. The mitogenome (33-fold coverage) of the Peştera Muierii 1 individual (PM1) from Romania (35 ky cal BP) we present in this article corresponds fully to Homo sapiens, whilst exhibiting a mosaic of morphological features related to both modern humans and Neandertals. We have identified the PM1 mitogenome as a basal haplogroup U6*, not previously found in any ancient or present-day humans. The derived U6 haplotypes are predominantly found in present-day North-Western African populations. Concomitantly, those found in Europe have been attributed to recent gene-flow from North Africa. The presence of the basal haplogroup U6* in South East Europe (Romania) at 35 ky BP confirms a Eurasian origin of the U6 mitochondrial lineage. Consequently, we propose that the PM1 lineage is an offshoot to South East Europe that can be traced to the Early Upper Paleolithic back migration from Western Asia to North Africa, during which the U6 lineage diversified, until the emergence of the present-day U6 African lineages. PMID:27195518

  4. The mitogenome of a 35,000-year-old Homo sapiens from Europe supports a Palaeolithic back-migration to Africa.

    PubMed

    Hervella, M; Svensson, E M; Alberdi, A; Günther, T; Izagirre, N; Munters, A R; Alonso, S; Ioana, M; Ridiche, F; Soficaru, A; Jakobsson, M; Netea, M G; de-la-Rua, C

    2016-05-19

    After the dispersal of modern humans (Homo sapiens) Out of Africa, hominins with a similar morphology to that of present-day humans initiated the gradual demographic expansion into Eurasia. The mitogenome (33-fold coverage) of the Peştera Muierii 1 individual (PM1) from Romania (35 ky cal BP) we present in this article corresponds fully to Homo sapiens, whilst exhibiting a mosaic of morphological features related to both modern humans and Neandertals. We have identified the PM1 mitogenome as a basal haplogroup U6*, not previously found in any ancient or present-day humans. The derived U6 haplotypes are predominantly found in present-day North-Western African populations. Concomitantly, those found in Europe have been attributed to recent gene-flow from North Africa. The presence of the basal haplogroup U6* in South East Europe (Romania) at 35 ky BP confirms a Eurasian origin of the U6 mitochondrial lineage. Consequently, we propose that the PM1 lineage is an offshoot to South East Europe that can be traced to the Early Upper Paleolithic back migration from Western Asia to North Africa, during which the U6 lineage diversified, until the emergence of the present-day U6 African lineages.

  5. Foramen magnum position variation in Pan troglodytes, Plio-Pleistocene hominids, and recent Homo sapiens: implications for recognizing the earliest hominids.

    PubMed

    Ahern, James C M

    2005-07-01

    The anteroposterior position of the foramen magnum distinguishes living Homo sapiens from apes, and has been used as evidence for the hominid status of numerable fossils in the history of human paleontology. During the past decade, foramen magnum position has been cited as evidence of the hominid status of Ardipithecus and Sahelanthropus. Specifically, the basion of Ardpithecus is reported to be inline with the bicarotid chord, while the basion of Sahelanthropus is reported to both touch the biporion chord and intersect the bicarotid chord. In order to assess the effectiveness of anteroposterior foramen magnum position in distinguishing hominids from nonhominid apes, this study examined whether or not the positions of biporion and bicarotid relative to basion sufficiently distinguished Pan troglodytes from recent Homo sapiens and Plio-Pleistocene hominids. The distances from basion to the biporion chord (BSBIP) and from basion to the bicarotid chord (BSBIC) were measured on samples of chimpanzee (n = 69) and recent human (n = 42) crania and a sample of Plio-Pleistocene hominid fossils (n = 8). The data were used to test the hypothesis that BSBIP and BSBIC measurements do not sufficiently distinguish P. troglodytes from hominids. While basion to biporion (BSBIP) does not effectively distinguish P. troglodytes from Plio-Pleistocene hominids and humans when used univariately, basion to bicarotid (BSBIC), when used univariately or bivariately with BSBIP, can be used to test whether or not an unknown specimen is a hominid. These results are used to evaluate the hominid status of Ardipithecus and Sahelanthropus.

  6. [Annexins--proteins involved in organization and function of biological membranes--from Arabidopsis thaliana to Homo sapiens].

    PubMed

    Bandorowicz-Pikuła, Joanna

    2007-01-01

    The mini-review series presented in this issue of Postepy Biochemii is focussed on some aspects of biology of calcium- and membrane-binding proteins, annexins, ubiquitous in all eucaryotic organisms (excluding yeasts), from Arabidopsis thaliana to Homo sapiens. Annexins are encoded by twelve genes in verterbrates and by eight in higher plants. Their physiological significance is underlined by two facts: the numer of the annexin genes seems to grow during evolution and in some cell types they comprise up to 2% of total protein. In the present review the hypothesis is discussed suggesting that multiplication of annexin genes in evolution represents mechanism of organism adaptation to changes in environment. In addition, the experimental data are presented suggestive of annexins playing a crucial role in functioning of plasma membrane, such as signal transduction, ion and vesicular transport and membrane repair. The review is then followed by articlesdealing in details with participation of annexins in plant response to abiotic stress (Arabidopsis thaliana), in tissue mineralization (Gallus gallus), in exocytosis of catecholamines by PC12 cells (mammals) and in Niemann-Pick type C disease related to abnormal transport and intracellular storage of cholesterol (Homo sapiens).

  7. Testing for localized stimulus enhancement and object movement reenactment in pig-tailed macaques (Macaca nemestrina) and young children (Homo sapiens).

    PubMed

    Rigamonti, Marco M; Custance, Deborah M; Previde, Emanuela Prato; Spiezio, Caterina

    2005-08-01

    Four puzzle boxes were used to investigate localized stimulus enhancement and object movement reenactment (OMR) in 13 pig-tailed macaques (Macaca nemestrina) and 30 human infants (Homo sapiens). Participants received contrasting demonstrations on each box. A circular lid was gripped by its rim or handle and swiveled to the left or right. A flap door was pushed or flipped. A sliding lid was pushed to the left or right. A pin bolt was demonstrated being pushed down, or the participants were left to solve the puzzle for themselves. Despite the fact that the monkeys watched the demonstrations about 60% of the time, only a weak OMR effect was found on the sliding lid. In contrast, the children watched significantly more, and there was clear evidence of socially mediated learning on all of the boxes.

  8. Field-mapping and petrographic analysis of volcanoes surrounding the Lake Natron Homo sapiens footprint site, northern Tanzania

    NASA Astrophysics Data System (ADS)

    Hewitt, S. M.; Zimmer, B.; Liutkus, C.; Carmichael, S. K.; McGinnis, K.

    2010-12-01

    The Lake Natron Homo sapiens footprint site is located in northern Tanzania along the East African Rift escarpment. The site is positioned south of Lake Natron within an ephemeral channel of the Engare Sero River. The hominid footprints are preserved in a tuff, which originated from one of the volcanic centers surrounding the site. Two large volcanoes in the surrounding region, including the active carbonatite producing Oldoinyo L’engai and the now extinct Kerimasi are possible sources. This area also contains over 30 smaller tuff cones and tuff rings that have been poorly mapped and not analyzed in detail. The site is significant as it is the oldest modern human trackway in East Africa and one of the largest collections of hominid footprints in the world. Determining the source of the footprinted volcanic ash requires detailed field mapping, and both petrographic and geochemical analyses. Extensive field-mapping of the region revealed multiple regional beds that stratigraphically overlay the footprinted layer. Age dating as well as geochemical analysis is being conducted to relate these beds to the footprinted layer. Field-mapping showed that the footprinted tuff is over 35 cm thick, suggesting a large, sustained eruption. The bulk of the tuff cones examined in the field visibly varied in composition to the footprinted tuff and, based on proximity to the footprint site, are too small to produce the requisite volume of ash. Field analysis of samples collected from Oldoinyo L’engai reveal the most similar mineral assemblages to the footprinted layer, and the large volcano provides a source substantial enough to create a thick ash bed 10 km north of the summit. Preliminary research reveals that the footprinted tuff is a phonolite, characterized by silica depletion and the presence of sanidine, augite, and annite with interstitial calcite. XRD analysis of samples collected from Oldoinyo L’engai reveal a nepheline-rich phonolite with zeolites (ie. phillipsite

  9. Survival of the Friendliest: Homo sapiens Evolved via Selection for Prosociality.

    PubMed

    Hare, Brian

    2017-01-03

    The challenge of studying human cognitive evolution is identifying unique features of our intelligence while explaining the processes by which they arose. Comparisons with nonhuman apes point to our early-emerging cooperative-communicative abilities as crucial to the evolution of all forms of human cultural cognition, including language. The human self-domestication hypothesis proposes that these early-emerging social skills evolved when natural selection favored increased in-group prosociality over aggression in late human evolution. As a by-product of this selection, humans are predicted to show traits of the domestication syndrome observed in other domestic animals. In reviewing comparative, developmental, neurobiological, and paleoanthropological research, compelling evidence emerges for the predicted relationship between unique human mentalizing abilities, tolerance, and the domestication syndrome in humans. This synthesis includes a review of the first a priori test of the self-domestication hypothesis as well as predictions for future tests.

  10. Middle Stone Age (MSA) site distributions in eastern Africa and their relationship to Quaternary environmental change, refugia and the evolution of Homo sapiens

    NASA Astrophysics Data System (ADS)

    Basell, Laura S.

    2008-12-01

    This paper considers the evolution of Homo sapiens in eastern Africa in relation to refugia and bottlenecks around ˜200 ka BP, at a macro scale. Middle Stone Age (MSA) lithics, site distributions and locations are analysed in relation to palaeovegetation maps of the last glacial/interglacial cycle, which are used as a proxy for earlier climate cycles. A "push and pull" model is then postulated for the spread of Homo sapiens out of refugia in eastern Africa, involving both volcanism (push) and habitat availability (pull). A date within OIS 5 is suggested for this expansion to other parts of the continent, and potentially further afield, contrary to a frequently proposed expansion within OIS 3.

  11. Comparative in vivo forefoot kinematics of Homo sapiens and Pan paniscus.

    PubMed

    Griffin, Nicole L; D'Août, Kristiaan; Richmond, Brian; Gordon, Adam; Aerts, Peter

    2010-12-01

    The human metatarsophalangeal joints play a key role in weight transmission and propulsion during bipedal gait, but at present, the identification of when a habitual, human-like metatarsi-fulcrimating mechanism first appeared in the fossil record is debated. Part of this debate can be attributed to the absence of certain detailed quantitative data distinguishing human and great ape forefoot form and function. The aim of this study is to quantitatively test previous observations that human metatarsophalangeal joints exhibit greater amounts of dorsal excursion (i.e., dorsiflexion) than those of Pan at the terminal stance phase of terrestrial locomotion. Video recordings were made in order to measure sagittal excursions of the medial metatarsophalangeal joints in habitually shod/unshod adult humans and adult bonobos (Pan paniscus). Results indicate that the human first and second metatarsophalangeal joints usually dorsiflex more than those of bonobos. When timing of maximum excursion of the first metatarsophalangeal joint is coupled with existing plantar pressure data, the unique role of the human forefoot as a key site of leverage and weight transmission is highlighted. These results support hypotheses that significant joint functional differences between great apes and humans during gait underlie taxonomic distinctions in trabecular bone architecture of the forefoot.

  12. Structural modeling and docking studies of ribose 5-phosphate isomerase from Leishmania major and Homo sapiens: a comparative analysis for Leishmaniasis treatment.

    PubMed

    Capriles, Priscila V S Z; Baptista, Luiz Phillippe R; Guedes, Isabella A; Guimarães, Ana Carolina R; Custódio, Fabio L; Alves-Ferreira, Marcelo; Dardenne, Laurent E

    2015-02-01

    Leishmaniases are caused by protozoa of the genus Leishmania and are considered the second-highest cause of death worldwide by parasitic infection. The drugs available for treatment in humans are becoming ineffective mainly due to parasite resistance; therefore, it is extremely important to develop a new chemotherapy against these parasites. A crucial aspect of drug design development is the identification and characterization of novel molecular targets. In this work, through an in silico comparative analysis between the genomes of Leishmania major and Homo sapiens, the enzyme ribose 5-phosphate isomerase (R5PI) was indicated as a promising molecular target. R5PI is an important enzyme that acts in the pentose phosphate pathway and catalyzes the interconversion of d-ribose-5-phosphate (R5P) and d-ribulose-5-phosphate (5RP). R5PI activity is found in two analogous groups of enzymes called RpiA (found in H. sapiens) and RpiB (found in L. major). Here, we present the first report of the three-dimensional (3D) structures and active sites of RpiB from L. major (LmRpiB) and RpiA from H. sapiens (HsRpiA). Three-dimensional models were constructed by applying a hybrid methodology that combines comparative and ab initio modeling techniques, and the active site was characterized based on docking studies of the substrates R5P (furanose and ring-opened forms) and 5RP. Our comparative analyses show that these proteins are structural analogs and that distinct residues participate in the interconversion of R5P and 5RP. We propose two distinct reaction mechanisms for the reversible isomerization of R5P to 5RP, which is catalyzed by LmRpiB and HsRpiA. We expect that the present results will be important in guiding future molecular modeling studies to develop new drugs that are specially designed to inhibit the parasitic form of the enzyme without significant effects on the human analog.

  13. Co-dispersal of the blood fluke Schistosoma japonicum and Homo sapiens in the Neolithic Age

    PubMed Central

    Yin, Mingbo; Zheng, Hong-Xiang; Su, Jing; Feng, Zheng; McManus, Donald P.; Zhou, Xiao-Nong; Jin, Li; Hu, Wei

    2015-01-01

    The global spread of human infectious diseases is of considerable public health and biomedical interest. Little is known about the relationship between the distribution of ancient parasites and that of their human hosts. Schistosoma japonicum is one of the three major species of schistosome blood flukes causing the disease of schistosomiasis in humans. The parasite is prevalent in East and Southeast Asia, including the People’s Republic of China, the Philippines and Indonesia. We studied the co-expansion of S. japonicum and its human definitive host. Phylogenetic reconstruction based on complete mitochondrial genome sequences showed that S. japonicum radiated from the middle and lower reaches of the Yangtze River to the mountainous areas of China, Japan and Southeast Asia. In addition, the parasite experienced two population expansions during the Neolithic agriculture era, coinciding with human migration and population growth. The data indicate that the advent of rice planting likely played a key role in the spread of schistosomiasis in Asia. Moreover, the presence of different subspecies of Oncomelania hupensis intermediate host snails in different localities in Asia allowed S. japonicum to survive in new rice-planting areas, and concurrently drove the intraspecies divergence of the parasite. PMID:26686813

  14. Horizontal gene transfer events reshape the global landscape of arm race between viruses and homo sapiens

    PubMed Central

    Chen, Dong-Sheng; Wu, Yi-Quan; Zhang, Wei; Jiang, San-Jie; Chen, Shan-Ze

    2016-01-01

    Horizontal gene transfer (HGT) drives the evolution of recipient organism particularly if it provides a novel function which enhances the fitness or its adaption to the environment. Virus-host co-evolution is attractive for studying co-evolutionary processes, since viruses strictly replicate inside of the host cells and thus their evolution is inexorably tangled with host biology. HGT, as a mechanism of co-evolution between human and viruses, has been widely documented, however, the roles HGT play during the interaction between human and viruses are still in their infancy. In this study, we performed a comprehensive analysis on the genes horizontally transferred between viruses and their corresponding human hosts. Our study suggests that the HGT genes in human are predominantly enriched in immune related GO terms while viral HGT genes are tend to be encoded by viruses which promote the invasion of immune system of hosts. Based on our results, it gives us a hint about the evolution trajectory of HGT events. Overall, our study suggests that the HGT between human and viruses are highly relevant to immune interaction and probably reshaped the arm race between hosts and viruses. PMID:27270140

  15. Effect of mutation on aggregation propensity in homology model structures of syntaxin-3 from Homo sapiens.

    PubMed

    Maheshwari, Amutha Selvaraj; Rajesh, Durairaj; Padmanabhan, Parasuraman; Archunan, Govindaraju

    2014-10-01

    Perception of molecular mechanism would provide potent additional knowledge on mammalian membrane proteins involved in causing diseases. In human, syntaxin-3 (STX3) is a significant apical targeting protein in the epithelial membrane and in exocytosis process; it also acts as a vesicle transporter by cellular receptor in neutrophils, which is crucial for protein trafficking event. Structurally, syntaxin-3 has hydrophobic domain at carboxyl terminus that directs itself to intra-cellular compartments. In addition, the experimental structure of STX3 is not available and no mutational study has been carried out with natural variants of proteins. Moreover, there is no evidence so far for the natural variant Val286 of STX3 causing any diseases. Hence, in the present study, analyses of residue-based properties of the homology model STX3 were carried out along with mutations at carboxyl terminus of STX3 by implementing protein engineering and in silico approaches. The model structure of STX3 was constructed adopting Modeller v9.11 and the aggregation propensity was analyzed with BioLuminate tool. The results showed that there was reduction in aggregation propensity with point mutation at Val286, instead of Ile, resulting into increasing the structural stability of STX3. In conclusion, the Ccap exposed residue would be a suitable position for further mutational studies, particularly with Val286 of STX3 in human. This approach could gainfully be applied to STX3 for efficient drug designing which would be a valuable target in the cancer treatment.

  16. She more than he: gender bias supports the empathic nature of yawn contagion in Homo sapiens

    PubMed Central

    Norscia, Ivan; Demuru, Elisa; Palagi, Elisabetta

    2016-01-01

    Psychological, clinical and neurobiological findings endorse that empathic abilities are more developed in women than in men. Because there is growing evidence that yawn contagion is an empathy-based phenomenon, we expect that the female bias in the empathic abilities reflects on a gender skew in the responsiveness to others’ yawns. We verified this assumption by applying a linear model on a dataset gathered during a 5 year period of naturalistic observations on humans. Gender, age and social bond were included in the analysis as fixed factors. The social bond and the receiver’s gender remained in the best model. The rates of contagion were significantly lower between acquaintances than between friends and family members, and significantly higher in women than in men. These results not only confirm that yawn contagion is sensitive to social closeness, but also that the phenomenon is affected by the same gender bias affecting empathy. The sex skew, also found in other non-human species, fits with the female social roles which are likely to require higher empathic abilities (e.g. parental care, group cohesion maintenance, social mediation). The fact that female influence in social dynamics also relies on face-to-face emotional exchange raises concerns on the negative repercussions of having women’s facial expressions forcibly concealed. PMID:26998318

  17. Developmental Changes in Morphology of the Middle and Posterior External Cranial Base in Modern Homo sapiens

    PubMed Central

    Dalal, Deepal H.; Smith, Heather F.

    2015-01-01

    The basicranium has been described as phylogenetically informative, developmentally stable, and minimally affected by external factors and consequently plays an important role in cranial size and shape in subadult humans. Here basicranial variation of subadults from several modern human populations was investigated and the impact of genetic relatedness on basicranial morphological similarities was investigated. Three-dimensional landmark data were digitized from subadult basicrania from seven populations. Published molecular data on short tandem repeats were statistically compared to morphological data from three ontogenetic stages. Basicranial and temporal bone morphology both reflect genetic distances in childhood and adolescence (5–18 years), but not in infancy (<5 years). The occipital bone reflects genetic distances only in adolescence (13–18 years). The sphenoid bone does not reflect genetic distances at any ontogenetic stage but was the most diagnostic region evaluated, resulting in high rates of correct classification among populations. These results suggest that the ontogenetic processes driving basicranial development are complex and cannot be succinctly summarized across populations or basicranial regions. However, the fact that certain regions reflect genetic distances suggests that the morphology of these regions may be useful in reconstructing population history in specimens for which direct DNA evidence is unavailable, such as archaeological sites. PMID:26413515

  18. Similar pathogen targets in Arabidopsis thaliana and homo sapiens protein networks.

    PubMed

    Shakarian, Paulo; Wickiser, J Kenneth

    2012-01-01

    We study the behavior of pathogens on host protein networks for humans and Arabidopsis - noting striking similarities. Specifically, we preform [Formula: see text]-shell decomposition analysis on these networks - which groups the proteins into various "shells" based on network structure. We observe that shells with a higher average degree are more highly targeted (with a power-law relationship) and that highly targeted nodes lie in shells closer to the inner-core of the network. Additionally, we also note that the inner core of the network is significantly under-targeted. We show that these core proteins may have a role in intra-cellular communication and hypothesize that they are less attacked to ensure survival of the host. This may explain why certain high-degree proteins are not significantly attacked.

  19. Solution structure of a membrane-anchored ubiquitin-fold (MUB) protein from Homo sapiens.

    PubMed

    de la Cruz, Norberto B; Peterson, Francis C; Lytle, Betsy L; Volkman, Brian F

    2007-07-01

    The protein Bc059385, whose solution structure is reported here, is the human representative of a recently identified family of membrane-anchored ubiquitin-fold (MUB) proteins. Analysis of their similarity to ubiquitin indicates that homologous amino acid residues in MUBs form a hydrophobic surface very similar to the recognition patch surrounding Ile-44 in ubiquitin. This suggests that MUBs may interact with proteins containing an alpha-helical motif similar to those of some ubiquitin binding domains. A disordered loop common to MUBs may also provide a second protein interaction site. From the available data, it is probable that this protein is prenylated and associated with the membrane. With <20% identity to ubiquitin, the MUB family further expands the sequence space that maps to the beta-grasp fold, and adds membrane localization to its list of functional roles.

  20. Relationship of cranial robusticity to cranial form, geography and climate in Homo sapiens.

    PubMed

    Baab, Karen L; Freidline, Sarah E; Wang, Steven L; Hanson, Timothy

    2010-01-01

    Variation in cranial robusticity among modern human populations is widely acknowledged but not well-understood. While the use of "robust" cranial traits in hominin systematics and phylogeny suggests that these characters are strongly heritable, this hypothesis has not been tested. Alternatively, cranial robusticity may be a response to differences in diet/mastication or it may be an adaptation to cold, harsh environments. This study quantifies the distribution of cranial robusticity in 14 geographically widespread human populations, and correlates this variation with climatic variables, neutral genetic distances, cranial size, and cranial shape. With the exception of the occipital torus region, all traits were positively correlated with each other, suggesting that they should not be treated as individual characters. While males are more robust than females within each of the populations, among the independent variables (cranial shape, size, climate, and neutral genetic distances), only shape is significantly correlated with inter-population differences in robusticity. Two-block partial least-squares analysis was used to explore the relationship between cranial shape (captured by three-dimensional landmark data) and robusticity across individuals. Weak support was found for the hypothesis that robusticity was related to mastication as the shape associated with greater robusticity was similar to that described for groups that ate harder-to-process diets. Specifically, crania with more prognathic faces, expanded glabellar and occipital regions, and (slightly) longer skulls were more robust than those with rounder vaults and more orthognathic faces. However, groups with more mechanically demanding diets (hunter-gatherers) were not always more robust than groups practicing some form of agriculture.

  1. From Sea Anemone to Homo Sapiens: The Evolution of the p53 Family of Genes

    SciTech Connect

    Levine, Arnold

    2009-09-14

    The human genome contains three transcription factors termed p53, p63 and p73 which are related orthologues. The function of the p53 protein is to respond to a wide variety of stresses which can disrupt the fidelity of DNA replication and cell division in somatic cells of the body. These stress signals, such as DNA damage, increase the mutation rate during DNA duplication and so an active p53 protein responds by eliminating clones of cells with mutations employing apoptosis, senescence or cell cycle arrest. In this way the p53 protein acts as a tumor suppressor preventing the mutations that can lead to cancers. The p63 and p73 proteins act in a similar fashion to protect the germ line cells in females (eggs). In addition the p63 protein plays a central role in the formation of epithelial cell layers and p73 plays a critical role in the formation of several structures in the central nervous system. Based upon their amino acid sequences and structural considerations the oldest organisms that contain an ancestor of the p53/p63/p73 gene are the sea anemone or hydra. The present day representatives of these animals contain a p63/p73 like ancestor gene and the protein functions in germ cells of this animal to enforce the fidelity of DNA replication after exposure to ultraviolet light. Thus the structure and functions of this gene family have been preserved for over one billion years of evolution. Other invertebrates such as the worm, the fly and the clam contain a very similar ancestor gene with a similar set of functions. The withdrawal of a food source from a worm results in the p63/p73 mediated apoptosis of the eggs so that new organisms will not be hatched into a poor environment. A similar response is thought to occur in humans. Thus this ancestor gene ensures the fidelity of the next generation of organisms. The first time a clearly distinct new p53 gene arises is in the cartilaginous fish and in the bony fish a separation of the p

  2. From Sea Anemone to Homo sapiens: The Evolution of the p53 Family of Genes

    SciTech Connect

    Levine, Arnold

    2009-09-14

    The human genome contains three transcription factors termed p53, p63 and p73 which are related orthologues. The function of the p53 protein is to respond to a wide variety of stresses which can disrupt the fidelity of DNA replication and cell division in somatic cells of the body. These stress signals, such as DNA damage, increase the mutation rate during DNA duplication and so an active p53 protein responds by eliminating clones of cells with mutations employing apoptosis, senescence or cell cycle arrest. In this way the p53 protein acts as a tumor suppressor preventing the mutations that can lead to cancers. The p63 and p73 proteins act in a similar fashion to protect the germ line cells in females (eggs). In addition the p63 protein plays a central role in the formation of epithelial cell layers and p73 plays a critical role in the formation of several structures in the central nervous system. Based upon their amino acid sequences and structural considerations the oldest organisms that contain an ancestor of the p53/p63/p73 gene are the sea anemone or hydra. The present day representatives of these animals contain a p63/p73 like ancestor gene and the protein functions in germ cells of this animal to enforce the fidelity of DNA replication after exposure to ultraviolet light. Thus the structure and functions of this gene family have been preserved for over one billion years of evolution. Other invertebrates such as the worm, the fly and the clam contain a very similar ancestor gene with a similar set of functions. The withdrawal of a food source from a worm results in the p63/p73 mediated apoptosis of the eggs so that new organisms will not be hatched into a poor environment. A similar response is thought to occur in humans. Thus this ancestor gene ensures the fidelity of the next generation of organisms. The first time a clearly distinct new p53 gene arises is in the cartilaginous fish and in the bony fish a separation of the p

  3. XMAn: a Homo sapiens mutated-peptide database for the MS analysis of cancerous cell states.

    PubMed

    Yang, Xu; Lazar, Iulia M

    2014-12-05

    To enable the identification of mutated peptide sequences in complex biological samples, in this work, two novel cancer- and disease-related protein databases with mutation information collected from several public resources such as COSMIC, IARC P53, OMIM, and UniProtKB were developed. In-house developed Perl scripts were used to search and process the data and to translate each gene-level mutation into a mutated peptide sequence. The cancer and disease mutation databases comprise a total of 872,125 and 27,148 peptide entries from 25 642 and 2913 proteins, respectively. A description line for each entry provides the parent protein ID and name, the cDNA- and protein-level mutation site and type, the originating database, and the disease or cancer tissue type and corresponding hits. The two databases are FASTA-formatted to enable data retrieval by commonly used tandem MS search engines. While the largest number of mutations were encountered for the amino acids A/D/E/G/L/P/R/S, the global mutation profiles replicate closely the outcome of the 1000 Genomes Project aimed at cataloguing natural mutations in the human population. The affected proteins were primarily involved in transcription regulation, splicing, protein synthesis/folding/binding, redox/energy production, adhesion/motility, and to some extent in DNA damage repair and signaling. The applicability of the database to identifying the presence of mutated peptides was investigated with MCF-7 breast cancer cell extracts.

  4. Hypermutability of genes in Homo sapiens due to the hosting of long mono-SSR.

    PubMed

    Loire, Etienne; Praz, Françoise; Higuet, Dominique; Netter, Pierre; Achaz, Guillaume

    2009-01-01

    Simple sequence repeats (SSRs) are very common short repeats in eukaryotic genomes. "Long" SSRs are considered "hypermutable" sequences because they exhibit a high rate of expansion and contraction. Because they are potentially deleterious, long SSRs tend to be uncommon in coding sequences. However, several genes contain long SSRs in their exonic sequences. Here, we identify 1,291 human genes that host a mononucleotide SSR long enough to be prone to expansion or contraction, being called hypermutable hereafter. On the basis of Gene Ontology annotations, we show that only a restricted number of functions are overrepresented among those hypermutable genes including cell cycle and maintenance of DNA integrity. Using a probabilistic model, we show that genes involved in these functions are expected to host long SSRs because they tend to be long and/or are biased in nucleotide composition. Finally, we show that for almost all functions we observe fewer hypermutable sequences than expected under a neutral model. There are however interesting exceptions, for example, genes involved in protein and RNA transport, as well as meiosis and mismatch repair functions that have as many hypermutable genes as expected under neutrality. Conversely, there are functions (e.g., collagen-related genes) where hypermutable genes are more often avoided than in other functions. Our results show that, even though several functions harbor unusually long SSR in their exons, long SSRs are deleterious sequences in almost all functions and are removed by purifying selection. The strength of this purifying selection however greatly varies from function to function. We discuss possible explanations for this intriguing result.

  5. Crystal Structure of the Homo sapiens Kynureninase-3-Hydroxyhippuric Acid Inhibitor Complex: Insights into the Molecular Basis Of Kynureninase Substrate Specificity

    SciTech Connect

    Lima,Santiago; Kumar,Sunil; Gawandi,Vijay; Momany,Cory; Phillips,Robert S.

    2009-02-23

    Homo sapiens kynureninase is a pyridoxal-5'-phosphate dependent enzyme that catalyzes the hydrolytic cleavage of 3-hydroxykynurenine to yield 3-hydroxyanthranilate and L-alanine as part of the tryptophan catabolic pathway leading to the de novo biosynthesis of NAD{sup +}. This pathway results in quinolinate, an excitotoxin that is an NMDA receptor agonist. High levels of quinolinate have been correlated with the etiology of neurodegenerative disorders such as AIDS-related dementia and Alzheimer's disease. We have synthesized a novel kynureninase inhibitor, 3-hydroxyhippurate, cocrystallized it with human kynureninase, and solved the atomic structure. On the basis of an analysis of the complex, we designed a series of His-102, Ser-332, and Asn-333 mutants. The H102W/N333T and H102W/S332G/N333T mutants showed complete reversal of substrate specificity between 3-hydroxykynurenine and L-kynurenine, thus defining the primary residues contributing to substrate specificity in kynureninases.

  6. Metacarpal head biomechanics: a comparative backscattered electron image analysis of trabecular bone mineral density in Pan troglodytes, Pongo pygmaeus, and Homo sapiens.

    PubMed

    Zeininger, Angel; Richmond, Brian G; Hartman, Gideon

    2011-06-01

    Great apes and humans use their hands in fundamentally different ways, but little is known about joint biomechanics and internal bone variation. This study examines the distribution of mineral density in the third metacarpal heads in three hominoid species that differ in their habitual joint postures and loading histories. We test the hypothesis that micro-architectural properties relating to bone mineral density reflect habitual joint use. The third metacarpal heads of Pan troglodytes, Pongo pygmaeus, and Homo sapiens were sectioned in a sagittal plane and imaged using backscattered electron microscopy (BSE-SEM). For each individual, 72 areas of subarticular cortical (subchondral) and trabecular bone were sampled from within 12 consecutive regions of the BSE-SEM images. In each area, gray levels (representing relative mineralization density) were quantified. Results show that chimpanzee, orangutan, and human metacarpal III heads have different gray level distributions. Weighted mean gray levels (WMGLs) in the chimpanzee showed a distinct pattern in which the 'knuckle-walking' regions (dorsal) and 'climbing' regions (palmar) are less mineralized, interpreted to reflect elevated remodeling rates, than the distal regions. Pongo pygmaeus exhibited the lowest WMGLs in the distal region, suggesting elevated remodeling rates in this region, which is loaded during hook grip hand postures associated with suspension and climbing. Differences among regions within metacarpal heads of the chimpanzee and orangutan specimens are significant (Kruskal-Wallis, p < 0.001). In humans, whose hands are used for manipulation as opposed to locomotion, mineralization density is much more uniform throughout the metacarpal head. WMGLs were significantly (p < 0.05) lower in subchondral compared to trabecular regions in all samples except humans. This micro-architectural approach offers a means of investigating joint loading patterns in primates and shows significant differences in

  7. Expression, purification, crystallization and preliminary X-ray characterization of the GRP carbohydrate-recognition domain from Homo sapiens

    SciTech Connect

    Zhou, Dongwen; Sun, Jianping; Zhao, Wei; Zhang, Xiao; Shi, Yunyu; Teng, Maikun Niu, Liwen; Dong, Yuhui; Liu, Peng

    2006-05-01

    The CRD domain of GRP from H. sapiens has been expressed, purified and crystallized and X-ray diffraction data have been collected to a resolution of 2.0 Å. Galectins are a family of animal lectins which share similar carbohydrate-recognition domains (CRDs) and an affinity for β-galactosides. A novel human galectin-related protein named GRP (galectin-related protein; previously known as HSPC159) comprises only one conserved CRD with 38 additional N-terminal residues. The C-terminal fragment of human GRP (GRP-C; residues 38–172) containing the CRD has been expressed and purified. The protein was crystallized using the hanging-drop vapour-diffusion method from a solution containing 2% PEG 400 and 2M ammonium sulfate in 100 mM Tris–HCl buffer pH 7.5. Diffraction data were collected to a resolution limit of 2.0 Å at beamline 3W1A of Beijing Synchrotron Radiation Facility at 100 K. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 123.07, b = 96.67, c = 61.56 Å, β = 118.72°. The estimated Matthews coefficient was 2.6 Å{sup 3} Da{sup −1}, corresponding to 51.8% solvent content.

  8. Protein-protein interaction site prediction in Homo sapiens and E. coli using an interaction-affinity based membership function in fuzzy SVM.

    PubMed

    Sriwastava, Brijesh Kumar; Basu, Subhadip; Maulik, Ujjwal

    2015-10-01

    Protein-protein interaction (PPI) site prediction aids to ascertain the interface residues that participate in interaction processes. Fuzzy support vector machine (F-SVM) is proposed as an effective method to solve this problem, and we have shown that the performance of the classical SVM can be enhanced with the help of an interaction-affinity based fuzzy membership function. The performances of both SVM and F-SVM on the PPI databases of the Homo sapiens and E. coli organisms are evaluated and estimated the statistical significance of the developed method over classical SVM and other fuzzy membership-based SVM methods available in the literature. Our membership function uses the residue-level interaction affinity scores for each pair of positive and negative sequence fragments. The average AUC scores in the 10-fold cross-validation experiments are measured as 79.94% and 80.48% for the Homo sapiens and E. coli organisms respectively. On the independent test datasets, AUC scores are obtained as 76.59% and 80.17% respectively for the two organisms. In almost all cases, the developed F-SVM method improves the performances obtained by the corresponding classical SVM and the other classifiers, available in the literature.

  9. Human evolution. Evolution of early Homo: an integrated biological perspective.

    PubMed

    Antón, Susan C; Potts, Richard; Aiello, Leslie C

    2014-07-04

    Integration of evidence over the past decade has revised understandings about the major adaptations underlying the origin and early evolution of the genus Homo. Many features associated with Homo sapiens, including our large linear bodies, elongated hind limbs, large energy-expensive brains, reduced sexual dimorphism, increased carnivory, and unique life history traits, were once thought to have evolved near the origin of the genus in response to heightened aridity and open habitats in Africa. However, recent analyses of fossil, archaeological, and environmental data indicate that such traits did not arise as a single package. Instead, some arose substantially earlier and some later than previously thought. From ~2.5 to 1.5 million years ago, three lineages of early Homo evolved in a context of habitat instability and fragmentation on seasonal, intergenerational, and evolutionary time scales. These contexts gave a selective advantage to traits, such as dietary flexibility and larger body size, that facilitated survival in shifting environments.

  10. Tracking the displacement of objects: a series of tasks with great apes (Pan troglodytes, Pan paniscus, Gorilla gorilla, and Pongo pygmaeus) and young children (Homo sapiens).

    PubMed

    Barth, Jochen; Call, Josep

    2006-07-01

    The authors administered a series of object displacement tasks to 24 great apes and 24 30-month-old children (Homo sapiens). Objects were placed under 1 or 2 of 3 cups by visible or invisible displacements. The series included 6 tasks: delayed response, inhibition test, A not B, rotations, transpositions, and object permanence. Apes and children solved most tasks performing at comparable levels except in the transposition task, in which apes performed better than children. Ape species performed at comparable levels in all tasks except in single transpositions, in which chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) performed better than gorillas (Gorilla gorilla) and orangutans (Pongo pygmeaus). All species found nonadjacent trials and rotations especially difficult. The number of elements that changed locations, the type of displacement, and having to inhibit predominant reaching responses were factors that negatively affected the subjects' performance.

  11. The Middle Stone Age archaeology of the Lower Omo Valley Kibish Formation: excavations, lithic assemblages, and inferred patterns of early Homo sapiens behavior.

    PubMed

    Shea, John J

    2008-09-01

    This paper describes the excavation, stratigraphy, and lithic assemblages of Middle Stone Age sites from the Omo Kibish Formation (Lower Omo Valley, southwestern Ethiopia). Three sites were excavated, two in Kibish Member I (KHS and AHS) and one at the base of Member III (BNS). The assemblages are dominated by relatively high-quality raw materials procured as pebbles from local gravels. The principal modes of core preparation are radial/centripetal Levallois and discoidal. Retouched tools are rare. Foliate bifaces are present, as are larger tools, such as handaxes, picks, and lanceolates, but these are more common among surface finds than among excavated assemblages. Middle Stone Age assemblages shed light on the adaptations of the earliest-known Homo sapiens populations in Africa.

  12. Analytical morphies on mid-sagittal craniograms glabella-opisthocranion of Homo erectus and Homo sapiens neanderthalensis: Fourier parameters and synthesis of mean craniograms.

    PubMed

    Vacca, E; Pesce Delfino, V

    1991-03-01

    Among mathematic procedures used in morphological description, Fourier analysis was indicated as extremely effective in obtaining numerical representations of shape. In order to fully exploit its potentiality in morphology the worked data have to be referred exclusively to the shape of the investigated object and the application of suitable procedures of dimensional normalization are necessary, moreover the significance of the parameters obtained from the analysis must be referable univocally to the morphological datum. In these conditions the numerical characterization of shapes and the relations detectable from different parameters obtained from the description assume the significance of real "analytical morphies". These statements were verified by performing morphological description and comparison, by means of the Fourier harmonic analysis on two groups of mid-sagittal glabella-opisthocranIon craniograms to point out their possible distinctive analytical characteristics: the first group relates to classical neanderthalian group, the second one is made up of asiatic samples of Homo erectus. Some typical patterns of the obtained parameters were discussed and explained in terms of analytical morphies characterizing the given specimens, the traditional morphological classifications were verified and, above all, a numerical description of these samples was obtained.

  13. Correlation of the KHS Tuff of the Kibish Formation to volcanic ash layers at other sites, and the age of early Homo sapiens (Omo I and Omo II).

    PubMed

    Brown, Francis H; McDougall, Ian; Fleagle, John G

    2012-10-01

    Hominin specimens Omo I and Omo II from Member I of the Kibish Formation, Ethiopia are attributed to early Homo sapiens, and an age near 196 ka has been suggested for them. The KHS Tuff, within Member II of the Kibish Formation has not been directly dated at the site, but it is believed to have been deposited at or near the time of formation of sapropel S6 in the Mediterranean Sea. Electron microprobe analyses suggest that the KHS Tuff correlates with the WAVT (Waidedo Vitric Tuff) at Herto, Gona, and Konso (sample TA-55), and with Unit D at Kulkuletti in the Ethiopian Rift Valley. Konso sample TA-55 is older than 154 ka, and Unit D at Kulkuletti is dated at 183 ka. These correlations and ages provide strong support for the age originally suggested for the hominin remains Omo I and Omo II, and for correlation of times of deposition in the Kibish region with formation of sapropels in the Mediterranean Sea. The Aliyo Tuff in Member III of the Kibish Formation is dated at 104 ka, and correlates with Gademotta Unit 15 in the Ethiopian Rift Valley.

  14. Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens

    PubMed Central

    Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

    2014-01-01

    Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ΔGbinding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations. PMID:25214833

  15. A 3-D geometric morphometric study of intraspecific variation in the ontogeny of the temporal bone in modern Homo sapiens.

    PubMed

    Smith, Heather F; Ritzman, Terrence; Otárola-Castillo, Erik; Terhune, Claire E

    2013-11-01

    This study addresses how the human temporal bone develops the population-specific pattern of morphology observed among adults and at what point in ontogeny those patterns arise. Three-dimensional temporal bone shape was captured using 15 landmarks on ontogenetic series of specimens from seven modern human populations. Discriminant function analysis revealed that population-specific temporal bone morphology is evident early in ontogeny, with significant shape differences among many human populations apparent prior to the eruption of the first molar. As early as five years of age, temporal bone shape reflects population history and can be used to reliably sort populations, although those in closer geographic proximity and molecular affinity are more likely to be misclassified. The deviation of cold-adapted populations from this general pattern of congruence between temporal bone morphology and genetic distances, identified in previous work, was confirmed here in adult and subadult specimens, and was revealed to occur earlier in ontogeny than previously recognized. Significant differences exist between the ontogenetic trajectories of some pairs of populations, but not among others, and the angles of these trajectories do not reflect genetic relationships or final adult temporal bone size. Significant intrapopulation differences are evident early in ontogeny, with differences becoming amplified by divergent trajectories in some groups. These findings elucidate how the congruence between adult human temporal bone morphology and population history develops, and reveal that this pattern corresponds closely to that described previously for facial ontogeny.

  16. Homo sapiens dullard protein phosphatase shows a preference for the insulin-dependent phosphorylation site of lipin1.

    PubMed

    Wu, Rui; Garland, Megan; Dunaway-Mariano, Debra; Allen, Karen N

    2011-04-19

    Human lipin1 catalyzes the highly regulated conversion of phosphatidic acids to diacylglycerides. Lipin's cellular location, protein partners, and biological function are directed by phosphorylation-dephosphorylation events catalyzed by the phosphoserine phosphatase dullard. To define the determinants of dullard substrate recognition and catalysis, and hence, lipin regulation, steady-state kinetic analysis was performed on phosphoserine-bearing nonapeptides based on the phosphorylation sites of lipin. The results demonstrate that dullard shows specificity for the peptide corresponding to the insulin-dependent phosphorylation site (Ser106) of lipin with a k(cat)/K(m) of 2.9 × 10(4) M(-1) s(-1). These results are consistent with a coil-loop structure for the insulin-dependent phosphorylation site on human lipin1 and make unlikely the requirement for an adaptor protein to confer activity such as that proposed for the yeast homologue.

  17. Comprehensive characterization of evolutionary conserved breakpoints in four New World Monkey karyotypes compared to Chlorocebus aethiops and Homo sapiens.

    PubMed

    Fan, Xiaobo; Supiwong, Weerayuth; Weise, Anja; Mrasek, Kristin; Kosyakova, Nadezda; Tanomtong, Alongkoad; Pinthong, Krit; Trifonov, Vladimir A; Cioffi, Marcelo de Bello; Grothmann, Pierre; Liehr, Thomas; Oliveira, Edivaldo H C de

    2015-11-01

    Comparative cytogenetic analysis in New World Monkeys (NWMs) using human multicolor banding (MCB) probe sets were not previously done. Here we report on an MCB based FISH-banding study complemented with selected locus-specific and heterochromatin specific probes in four NWMs and one Old World Monkey (OWM) species, i.e. in Alouatta caraya (ACA), Callithrix jacchus (CJA), Cebus apella (CAP), Saimiri sciureus (SSC), and Chlorocebus aethiops (CAE), respectively. 107 individual evolutionary conserved breakpoints (ECBs) among those species were identified and compared with those of other species in previous reports. Especially for chromosomal regions being syntenic to human chromosomes 6, 8, 9, 10, 11, 12 and 16 previously cryptic rearrangements could be observed. 50.4% (54/107) NWM-ECBs were colocalized with those of OWMs, 62.6% (62/99) NWM-ECBs were related with those of Hylobates lar (HLA) and 66.3% (71/107) NWM-ECBs corresponded with those known from other mammalians. Furthermore, human fragile sites were aligned with the ECBs found in the five studied species and interestingly 66.3% ECBs colocalized with those fragile sites (FS). Overall, this study presents detailed chromosomal maps of one OWM and four NWM species. This data will be helpful to further investigation on chromosome evolution in NWM and hominoids in general and is prerequisite for correct interpretation of future sequencing based genomic studies in those species.

  18. Structure of the C-terminal heme-binding domain of THAP domain containing protein 4 from Homo sapiens

    SciTech Connect

    Bianchetti, Christopher M.; Bingman, Craig A.; Phillips, Jr., George N.

    2012-03-15

    The thanatos (the Greek god of death)-associated protein (THAP) domain is a sequence-specific DNA-binding domain that contains a C2-CH (Cys-Xaa{sub 2-4}-Cys-Xaa{sub 35-50}-Cys-Xaa{sub 2}-His) zinc finger that is similar to the DNA domain of the P element transposase from Drosophila. THAP-containing proteins have been observed in the proteome of humans, pigs, cows, chickens, zebrafish, Drosophila, C. elegans, and Xenopus. To date, there are no known THAP domain proteins in plants, yeast, or bacteria. There are 12 identified human THAP domain-containing proteins (THAP0-11). In all human THAP protein, the THAP domain is located at the N-terminus and is {approx}90 residues in length. Although all of the human THAP-containing proteins have a homologous N-terminus, there is extensive variation in both the predicted structure and length of the remaining protein. Even though the exact function of these THAP proteins is not well defined, there is evidence that they play a role in cell proliferation, apoptosis, cell cycle modulation, chromatin modification, and transcriptional regulation. THAP-containing proteins have also been implicated in a number of human disease states including heart disease, neurological defects, and several types of cancers. Human THAP4 is a 577-residue protein of unknown function that is proposed to bind DNA in a sequence-specific manner similar to THAP1 and has been found to be upregulated in response to heat shock. THAP4 is expressed in a relatively uniform manner in a broad range of tissues and appears to be upregulated in lymphoma cells and highly expressed in heart cells. The C-terminal domain of THAP4 (residues 415-577), designated here as cTHAP4, is evolutionarily conserved and is observed in all known THAP4 orthologs. Several single-domain proteins lacking a THAP domain are found in plants and bacteria and show significant levels of homology to cTHAP4. It appears that cTHAP4 belongs to a large class of proteins that have yet to be fully

  19. A novel primate specific gene, CEI, is located in the homeobox gene IRXA2 promoter in Homo sapiens.

    PubMed

    Wu, Qingfa; Tommerup, Niels; Ming Wang, San; Hansen, Lars

    2006-04-26

    The Iroquois (IRX) homeobox gene family consists of six highly conserved transcription factors that are of importance for normal embryonic development. They are organized in two gene clusters in human, one on 5p15.33 and the other one on 16q12.2, respectively, and both the organization and the structure of the genes are highly conserved. An open reading frame coding for an unknown protein is identified in the promoter of IRXA2 on chromosome 5p. This new gene is composed of four exons and it is orientated in a head-to-head manner to IRXA2. Only a short 851 bp segment separates the two translation start codons and the two genes may share a bi-directional promoter. This bi-directional promoter is embedded in a large CpG-island, that also continues into both genes. RT-PCR analysis of the new gene reveals two alternative mRNA transcripts and a third mRNA transcript can be predicted from EST clones. The expression profile of the gene analysed in 9 different human tissues reveals that it is expressed in a coordinated fashion with IRXA2, which has led to the name CEI (Coordinated Expression to IRXA2). The CEI protein lacks homology to any known protein or protein domain in public databases, and a putative amino terminal signal peptide suggests the protein is secreted or ER compartment located. The gene is only found in the human and the chimpanzee genome, but not in the mouse or the rat genome, which suggests that CEI is unique for higher primates. As the identified bi-directional promoter not being a relic of an ancient compact genome, CEI may play an important role in the evolution of higher primates in coordination with the IRX genes.

  20. Expression, purification, crystallization and preliminary X-ray characterization of the GRP carbohydrate-recognition domain from Homo sapiens

    PubMed Central

    Zhou, Dongwen; Sun, Jianping; Zhao, Wei; Zhang, Xiao; Shi, Yunyu; Teng, Maikun; Niu, Liwen; Dong, Yuhui; Liu, Peng

    2006-01-01

    Galectins are a family of animal lectins which share similar carbohydrate-recognition domains (CRDs) and an affinity for β-galactosides. A novel human galectin-related protein named GRP (galectin-related protein; previously known as HSPC159) comprises only one conserved CRD with 38 additional N-terminal residues. The C-terminal fragment of human GRP (GRP-C; residues 38–172) containing the CRD has been expressed and purified. The protein was crystallized using the hanging-drop vapour-diffusion method from a solution containing 2% PEG 400 and 2M ammonium sulfate in 100 mM Tris–HCl buffer pH 7.5. Diffraction data were collected to a resolution limit of 2.0 Å at beamline 3W1A of Beijing Synchrotron Radiation Facility at 100 K. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 123.07, b = 96.67, c = 61.56 Å, β = 118.72°. The estimated Matthews coefficient was 2.6 Å3 Da−1, corresponding to 51.8% solvent content. PMID:16682780

  1. Gestalt principle use in college students, children with autism, toddlers (Homo sapiens), and cotton top tamarins (Saguinus oedipus).

    PubMed

    Neiworth, Julie J; Whillock, Katherine M; Kim, Seo Hyun; Greenberg, Julia R; Jones, Katherine B; Patel, Anushka R; Steefel-Moore, David L; Shaw, Allyson J; Rupert, Deborah D; Gauer, Jacqueline L; Kudura, Aisha G

    2014-05-01

    The use of Gestalt principles of proximity, similarity, and closure to recognize objects by configural superiority was examined in college students, low- and high-functioning children with autism, toddlers, and adult cotton top tamarin monkeys. At issue was whether the monkeys showed differences from humans in perceptual processing and whether they showed any similarities with clinical or developmental groups. The method required a pointing response to discriminate an odd item in a 4-item visual display. All subjects were trained to a high accuracy to point to the odd item before being tested with graphic stimuli that differentiated feature changes based on configural superiority. The results were that college students and high-functioning children with autism responded faster and more accurately to trials in which the odd item was easily noticed by the use of Gestalt principles and configural superiority. Toddlers also responded more accurately to the Gestalt trials, but without being faster at making the response. Low-functioning children with autism and tamarins showed no advantage to Gestalt trials but exhibited different processing styles. The implications of these findings to track the evolution of human perception and to develop a primate model for the perceptual deficits of autism are discussed.

  2. Identification of a better Homo sapiens Class II HDAC inhibitor through binding energy calculations and descriptor analysis.

    PubMed

    Tambunan, Usman Sumo Friend; Wulandari, Evi Kristin

    2010-10-15

    Human papillomaviruses (HPVs) are the most common on sexually transmitted viruses in the world. HPVs are responsible for a large spectrum of deseases, both benign and malignant. The certain types of HPV are involved in the development of cervical cancer. In attemps to find additional drugs in the treatment of cervical cancer, inhibitors of the histone deacetylases (HDAC) have received much attention due to their low cytotoxic profiles and the E6/E7 oncogene function of human papilomavirus can be completely by passed by HDAC inhibition. The histone deacetylase inhibitors can induce growth arrest, differentiation and apoptosis of cancer cells. HDAC class I and class II are considered the main targets for cancer. Therefore, the six HDACs class II was modeled and about two inhibitors (SAHA and TSA) were docked using AutoDock4.2, to each of the inhibitor in order to identify the pharmacological properties. Based on the results of docking, SAHA and TSA were able to bind with zinc ion in HDACs models as a drug target. SAHA was satisfied almost all the properties i.e., binding affinity, the Drug-Likeness value and Drug Score with 70% oral bioavailability and the carbonyl group of these compound fits well into the active site of the target where the zinc is present. Hence, SAHA could be developed as potential inhibitors of class II HDACs and valuable cervical cancer drug candidate.

  3. OSBP-related protein 8 (ORP8) interacts with Homo sapiens sperm associated antigen 5 (SPAG5) and mediates oxysterol interference of HepG2 cell cycle

    SciTech Connect

    Zhong, Wenbin; Zhou, You; Li, Jiwei; Mysore, Raghavendra; Luo, Wei; Li, Shiqian; Chang, Mau-Sun; Olkkonen, Vesa M.; Yan, Daoguang

    2014-04-01

    We earlier identified OSBP-related protein 8 (ORP8) as an endoplasmic reticulum/nuclear envelope oxysterol-binding protein implicated in cellular lipid homeostasis, migration, and organization of the microtubule cytoskeleton. Here, a yeast two-hybrid screen identified Homo sapiens sperm associated antigen 5 (SPAG5)/Astrin as interaction partner of ORP8. The putative interaction was further confirmed by pull-down and co-immunoprecipitation assays. ORP8 did not colocalize with kinetochore-associated SPAG5 in mitotic HepG2 or HuH7 cells, but overexpressed ORP8 was capable of recruiting SPAG5 onto endoplasmic reticulum membranes in interphase cells. In our experiments, 25-hydroxycholesterol (25OHC) retarded the HepG2 cell cycle, causing accumulation in G2/M phase; ORP8 overexpression resulted in the same phenotype. Importantly, ORP8 knock-down dramatically inhibited the oxysterol effect on HepG2 cell cycle, suggesting a mediating role of ORP8. Furthermore, knock-down of SPAG5 significantly reduced the effects of both ORP8 overexpression and 25OHC on the cell cycle, placing SPAG5 downstream of the two cell-cycle interfering factors. Taken together, the present results suggest that ORP8 may via SPAG5 mediate oxysterol interference of the HepG2 cell cycle. - Highlights: • The oxysterol-binding protein ORP8 was found to interact with the mitotic regulator SPAG5/Astrin. • Treatment of HepG2 cells with 25-hydroxycholesterol caused cell cycle retardation in G2/M. • ORP8 overexpression caused a similar G2/M accumulation, and ORP8 knock-down reversed the 25-hydroxycholesterol effect. • Reduction of cellular of SPAG5/Astrin reversed the cell cycle effects of both 25-hydroxycholesterol and ORP8 overexpression. • Our results suggest that ORP8 mediates via SPAG5/Astrin the oxysterol interference of HepG2 cell cycle.

  4. Nuclear receptors, nuclear-receptor factors, and nuclear-receptor-like orphans form a large paralog cluster in Homo sapiens.

    PubMed

    Garcia-Vallvé, S; Palau, J

    1998-06-01

    We studied a human protein paralog cluster formed by 38 nonredundant sequences taken from the Swiss-Prot database and its supplement, TrEMBL. These sequences include nuclear receptors, nuclear-receptor factors and nuclear-receptor-like orphans. Working separately with both the central cysteine-rich DNA-binding domain and the carboxy-terminal ligand-binding domain, we performed multialignment analyses that included drawings of paralog trees. Our results show that the cluster is highly multibranched, with considerable differences in the amino acid sequence in the ligand-binding domain (LBD), and 17 proximal subbranches which are identifiable and fully coincident when independent trees from both domains are compared. We identified the six recently proposed subfamilies as groups of neighboring clusters in the LBD paralog tree. We found similarities of 80%-100% for the N-terminal transactivation domain among mammalian ortholog receptors, as well as some paralog resemblances within diverse subbranches. Our studies suggest that during the evolutionary process, the three domains were assembled in a modular fashion with a nonshuffled modular fusion of the LBD. We used the EMBL server PredictProtein to make secondary-structure predictions for all 38 LBD subsequences. Amino acid residues in the multialigned homologous domains--taking the beginning of helix H3 of the human retinoic acid receptor-gamma as the initial point of reference--were substituted with H or E, which identify residues predicted to be helical or extended, respectively. The result was a secondary structure multialignment with the surprising feature that the prediction follows a canonical pattern of alignable alpha-helices with some short extended elements in between, despite the fact that a number of subsequences resemble each other by less than 25% in terms of the similarity index. We also identified the presence of a binary patterning in all of the predicted helices that were conserved throughout the 38

  5. Should autism be considered a canary bird telling that Homo sapiens may be on its way to extinction?

    PubMed Central

    Christophersen, Olav Albert

    2012-01-01

    There has been a dramatic enhancement of the reported incidence of autism in different parts of the world over the last 30 years. This can apparently not be explained only as a result of improved diagnosis and reporting, but may also reflect a real change. The causes of this change are unknown, but if we shall follow T.C. Chamberlin's principle of multiple working hypotheses, we need to take into consideration the possibility that it partly may reflect an enhancement of the average frequency of responsible alleles in large populations. If this hypothesis is correct, it means that the average germline mutation rate must now be much higher in the populations concerned, compared with the natural mutation rate in hominid ancestors before the agricultural and industrial revolutions. This is compatible with the high prevalence of impaired human semen quality in several countries and also with what is known about high levels of total exposure to several different unnatural chemical mutagens, plus some natural ones at unnaturally high levels. Moreover, dietary deficiency conditions that may lead to enhancement of mutation rates are also very widespread, affecting billions of people. However, the natural mutation rate in hominids has been found to be so high that there is apparently no tolerance for further enhancement of the germline mutation rate before the Eigen error threshold will be exceeded and our species will go extinct because of mutational meltdown. This threat, if real, should be considered far more serious than any disease causing the death only of individual patients. It should therefore be considered the first and highest priority of the best biomedical scientists in the world, of research-funding agencies and of all medical doctors to try to stop the express train carrying all humankind as passengers on board before it arrives at the end station of our civilization. PMID:23990819

  6. Should autism be considered a canary bird telling that Homo sapiens may be on its way to extinction?

    PubMed

    Christophersen, Olav Albert

    2012-01-01

    There has been a dramatic enhancement of the reported incidence of autism in different parts of the world over the last 30 years. This can apparently not be explained only as a result of improved diagnosis and reporting, but may also reflect a real change. The causes of this change are unknown, but if we shall follow T.C. Chamberlin's principle of multiple working hypotheses, we need to take into consideration the possibility that it partly may reflect an enhancement of the average frequency of responsible alleles in large populations. If this hypothesis is correct, it means that the average germline mutation rate must now be much higher in the populations concerned, compared with the natural mutation rate in hominid ancestors before the agricultural and industrial revolutions. This is compatible with the high prevalence of impaired human semen quality in several countries and also with what is known about high levels of total exposure to several different unnatural chemical mutagens, plus some natural ones at unnaturally high levels. Moreover, dietary deficiency conditions that may lead to enhancement of mutation rates are also very widespread, affecting billions of people. However, the natural mutation rate in hominids has been found to be so high that there is apparently no tolerance for further enhancement of the germline mutation rate before the Eigen error threshold will be exceeded and our species will go extinct because of mutational meltdown. This threat, if real, should be considered far more serious than any disease causing the death only of individual patients. It should therefore be considered the first and highest priority of the best biomedical scientists in the world, of research-funding agencies and of all medical doctors to try to stop the express train carrying all humankind as passengers on board before it arrives at the end station of our civilization.

  7. Toward reduction in animal sacrifice for drugs: molecular modeling of Macaca fascicularis P450 2C20 for virtual screening of Homo sapiens P450 2C8 substrates.

    PubMed

    Rua, Francesco; Di Nardo, Giovanna; Sadeghi, Sheila J; Gilardi, Gianfranco

    2012-01-01

    Macaca fascicularis P450 2C20 shares 92% identity with human cytochrome P450 2C8, which is involved in the metabolism of more than 8% of all prescribed drugs. To date, only paclitaxel and amodiaquine, two substrate markers of the human P450 2C8, have been experimentally confirmed as M. fascicularis P450 2C20 drugs. To bridge the lack of information on the ligands recognized by M. fascicularis P450 2C20, in this study, a three-dimensional homology model of this enzyme was generated on the basis of the available crystal structure of the human homologue P450 2C8 using YASARA. The results indicated that 90.0%, 9.0%, 0.5%, and 0.5% of the residues of the P450 2C20 model were located in the most favorable, allowed, generously allowed, and disallowed regions, respectively. The root-mean-square deviation of the C-alpha superposition of the M. fascicularis P450 2C20 model with the Homo sapiens P450 2C8 was 0.074 Å, indicating a very high similarity of the two structures. Subsequently, the 2C20 model was used for in silico screening of 58 known P450 2C8 substrates and 62 inhibitors. These were also docked in the active site of the crystal structure of the human P450 2C8. The affinity of each compound for the active site of both cytochromes proved to be very similar, meaning that the few key residues that are mutated in the active site of the M. fascicularis P450 do not prevent the P450 2C20 from recognizing the same substrates as the human P450 2C8.

  8. From hominins to humans: how sapiens became behaviourally modern

    PubMed Central

    Sterelny, Kim

    2011-01-01

    This paper contributes to a debate in the palaeoarchaeological community about the major time-lag between the origin of anatomically modern humans and the appearance of typically human cultural behaviour. Why did humans take so long—at least 100 000 years—to become ‘behaviourally modern’? The transition is often explained as a change in the intrinsic cognitive competence of modern humans: often in terms of a new capacity for symbolic thought, or the final perfection of language. These cognitive breakthrough models are not satisfactory, for they fail to explain the uneven palaeoanthropological record of human competence. Many supposed signature capacities appear (and then disappear) before the supposed cognitive breakthrough; many of the signature capacities disappear again after the breakthrough. So, instead of seeing behavioural modernity as a simple reflection of a new kind of mind, this paper presents a niche construction conceptual model of behavioural modernity. Humans became behaviourally modern when they could reliably transmit accumulated informational capital to the next generation, and transmit it with sufficient precision for innovations to be preserved and accumulated. In turn, the reliable accumulation of culture depends on the construction of learning environments, not just intrinsic cognitive machinery. I argue that the model is (i) evolutionarily plausible: the elements of the model can be assembled incrementally, without implausible selective scenarios; (ii) the model coheres with the broad palaeoarchaeological record; (iii) the model is anthropologically and ethnographically plausible; and (iv) the model is testable, though only in coarse, preliminary ways. PMID:21320896

  9. A Model of an Integrated Immune System Pathway in Homo sapiens and Its Interaction with Superantigen Producing Expression Regulatory Pathway in Staphylococcus aureus: Comparing Behavior of Pathogen Perturbed and Unperturbed Pathway

    PubMed Central

    Tomar, Namrata; De, Rajat K.

    2013-01-01

    Response of an immune system to a pathogen attack depends on the balance between the host immune defense and the virulence of the pathogen. Investigation of molecular interactions between the proteins of a host and a pathogen helps in identifying the pathogenic proteins. It is necessary to understand the dynamics of a normally behaved host system to evaluate the capacity of its immune system upon pathogen attack. In this study, we have compared the behavior of an unperturbed and pathogen perturbed host system. Moreover, we have developed a formalism under Flux Balance Analysis (FBA) for the optimization of conflicting objective functions. We have constructed an integrated pathway system, which includes Staphylococcal Superantigen (SAg) expression regulatory pathway and TCR signaling pathway of Homo sapiens. We have implemented the method on this pathway system and observed the behavior of host signaling molecules upon pathogen attack. The entire study has been divided into six different cases, based on the perturbed/unperturbed conditions. In other words, we have investigated unperturbed and pathogen perturbed human TCR signaling pathway, with different combinations of optimization of concentrations of regulatory and signaling molecules. One of these cases has aimed at finding out whether minimization of the toxin production in a pathogen leads to the change in the concentration levels of the proteins coded by TCR signaling pathway genes in the infected host. Based on the computed results, we have hypothesized that the balance between TCR signaling inhibitory and stimulatory molecules can keep TCR signaling system into resting/stimulating state, depending upon the perturbation. The proposed integrated host-pathogen interaction pathway model has accurately reflected the experimental evidences, which we have used for validation purpose. The significance of this kind of investigation lies in revealing the susceptible interaction points that can take back the

  10. Geometric variation of the frontal squama in the genus homo: frontal bulging and the origin of modern human morphology.

    PubMed

    Bruner, Emiliano; Athreya, Sheela; de la Cuétara, José Manuel; Marks, Tarah

    2013-02-01

    The majority of studies of frontal bone morphology in paleoanthropology have analyzed the frontal squama and the browridge as a single unit, mixing information from different functional elements. Taking into account that the bulging of the frontal bone is often described as a species-specific trait of Homo sapiens, in this article we analyze variation in the midsagittal profile of the genus Homo, focusing on the frontal squama alone, using landmark-based superimpositions and principal components analysis. Our results demonstrate that anatomically modern humans are definitely separated from extinct human taxa on the basis of frontal bulging. However, there is minor overlap among these groups, indicating that it is necessary to exercise caution when using this trait alone to make taxonomic inferences on individual specimens. Early modern humans do not show differences with recent modern humans, and "transitional" individuals such as Jebel Irhoud 1, Maba, and Florisbad, show modern-like frontal squama morphology. The bulging of the frontal squama in modern humans may represent a structural consequence of more general cranial changes, or it could be a response to changes in the morphology of the underlying prefrontal brain elements. A subtle difference between Neandertals and the Afro-European Middle Pleistocene Homo sample is associated with flattening at bregma in the former group, a result that merits further investigation.

  11. Homo sapiens in the Americas. Overview of the earliest human expansion in the New World.

    PubMed

    Marangoni, Aurelio; Caramelli, David; Manzi, Giorgio

    2014-01-01

    Although it is widely recognised that America was the last continent to be populated by our species, researchers' views on various aspects of this process (e.g. the period in which it occurred, the area from which the colonizing populations came, the number of dispersal waves and the routes taken by these migrations) differ significantly. In this paper, we review both classical data and more recent findings from various research fields - including geology, paleoecology, archaeology, skeletal biology, and genetics - that may shed light on the dynamics of the colonization of the American continent, according to a critical reappraisal of the various hypotheses and models that have been advanced over time to explain this process.

  12. Sarcocystis heydorni, n. sp. (Apicomplexa: Protozoa) with cattle (Bos taurus) and human (Homo sapiens) cycle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle (Bos taurus) are intermediate hosts for four species of Sarcocystis, S. cruzi, S. hirsuta, S. hominis, and S. rommeli. Of these four species, mature sarcocysts of S. cruzi are thin-walled (< 1µm) whereas S. hirsuta, S. hominis, and S. rommeli have thick walls (4 µm or more). Here we describe ...

  13. Liquid conservation in orangutans (Pongo pygmaeus) and humans (Homo sapiens): individual differences and perceptual strategies.

    PubMed

    Call, J; Rochat, P

    1996-09-01

    Four orangutans (1 juvenile, 2 subadults, and 1 adult) and ten 6-8-year-old children were tested in 4 liquid conservation tasks of increasing levels of difficulty. Task difficulty depended on the type of transformation (continuous vs. discontinuous quantities) and the relative contrast between the shapes of the containers. Results indicate that orangutans did not display conservation in the strict sense; instead they showed "partial" conservation (intermediate reactions according to J. Piaget & B. Inhelder, 1941). In contrast, some of the children provided evidence of conservation in all 4 tasks, showing "true" or logically necessary conservation in the original sense proposed by J. Piaget and B. Inhelder (1941). Although orangutans did not show conservation in the strict sense, as J. Piaget (1955) and others have generally agreed it should be defined, orangutans behaved as individual and creative problem solvers, adopting different perceptual strategies depending on the task.

  14. Crystallization and preliminary X-ray crystallographic investigations on a βγ-crystallin domain of absent in melanoma 1 (AIM1), a protein from Homo sapiens

    SciTech Connect

    Aravind, Penmatsa; Rajini, Bheemreddy; Sharma, Yogendra; Sankaranarayanan, Rajan

    2006-03-01

    The crystallization and preliminary X-ray diffraction analysis of AIM1g1, a βγ-crystallin domain of absent in melanoma (AIM1) protein from H. sapiens, is reported. AIM1g1 is a single βγ-crystallin domain from the protein absent in melanoma 1 (AIM1), which appears to play a role in the suppression of melanomas. This domain is known to bind calcium and its structure would help in identifying calcium-coordinating sites in vertebrate crystallins, which have hitherto been believed to have lost this ability during evolution. Crystallization of this domain was performed by the hanging-drop vapour-diffusion method. Crystals diffracted to a maximum resolution of 1.86 Å and were found to belong to space group P6{sub 1} or P6{sub 5}, with unit-cell parameters a = b = 54.98, c = 59.73 Å. Solvent-content analysis indicated the presence of one monomer per asymmetric unit.

  15. New dates for the Fontéchevade (Charente, France) Homo remains.

    PubMed

    Chase, Philip G; Debénath, André; Dibble, Harold L; McPherron, Shannon P; Schwarcz, Henry P; Stafford, Thomas W; Tournepiche, Jean-François

    2007-02-01

    Homo I from the site of Fontéchevade, France, has long been an anomaly in the European fossil record. The specimen is a fragment of human frontal bone that lacks a supraorbital torus and appears to belong to an anatomically modern Homo sapiens. However, the level from which it was recovered in 1947 was dated on the basis of associated faunal and lithic material to the last interglacial or earlier. As a result, Homo I has been interpreted, among other things, as a representative of a pre-sapiens lineage in Europe. This paper reports on recent ESR and radiocarbon dates that indicate that the specimen almost certainly dates to oxygen isotope stage 3, which brings it in line with other evidence for the entry of modern Homo sapiens into Europe.

  16. In Silico Molecular Modeling and Docking Studies on Novel Mutants (E229V, H225P and D230C) of the Nucleotide-Binding Domain of Homo sapiens Hsp70.

    PubMed

    Elengoe, Asita; Hamdan, Salehhuddin

    2016-08-12

    In this study, we explored the possibility of determining the synergistic interactions between nucleotide-binding domain (NBD) of Homo sapiens heat-shock 70 kDa protein (Hsp70) and E1A 32 kDa of adenovirus serotype 5 motif (PNLVP) in the efficiency of killing of tumor cells in cancer treatment. At present, the protein interaction between NBD and PNLVP motif is still unknown, but believed to enhance the rate of virus replication in tumor cells. Three mutant models (E229V, H225P and D230C) were built and simulated, and their interactions with PNLVP motif were studied. The PNLVP motif showed the binding energy and intermolecular energy values with the novel E229V mutant at -7.32 and -11.2 kcal/mol. The E229V mutant had the highest number of hydrogen bonds (7). Based on the root mean square deviation, root mean square fluctuation, hydrogen bonds, salt bridge, secondary structure, surface-accessible solvent area, potential energy and distance matrices analyses, it was proved that the E229V had the strongest and most stable interaction with the PNLVP motif among all the four protein-ligand complex structures. The knowledge of this protein-ligand complex model would help in designing Hsp70 structure-based drug for cancer therapy.

  17. The Advantage of Throwing the First Stone: How Understanding the Evolutionary Demands of Homo sapiens Is Helping Us Understand Carpal Motion

    PubMed Central

    Rohde, Rachel S.; Crisco, Joseph J.; Wolfe, Scott W.

    2012-01-01

    Unlike any other diarthrodial joint in the human body, the “wrist joint” is composed of numerous articulations between eight carpal bones, the distal radius, the distal ulna, and five metacarpal bones. The carpal bones articulate with each other as well as with the distal radius, distal ulna, and the metacarpal bases. Multiple theories explaining intercarpal motion have been proposed; however, controversy exists concerning the degree and direction of motion of the individual carpal bones within the two carpal rows during different planes of motion. Recent investigations have suggested that traditional explanations of carpal bone motion may not entirely account for carpal motion in all planes. Better understanding of the complexities of carpal motion through the use of advanced imaging techniques and simultaneous appreciation of human anatomic and functional evolution have led to the hypothesis that the “dart thrower’s motion” of the wrist is uniquely human. Carpal kinematic research and current developments in both orthopaedic surgery and anthropology underscore the importance of the dart thrower’s motion in human functional activities and the clinical implications of these concepts for orthopaedic surgery and rehabilitation. PMID:20044492

  18. Non-random distribution of homo-repeats: links with biological functions and human diseases

    PubMed Central

    Lobanov, Michail Yu.; Klus, Petr; Sokolovsky, Igor V.; Tartaglia, Gian Gaetano; Galzitskaya, Oxana V.

    2016-01-01

    The biological function of multiple repetitions of single amino acids, or homo-repeats, is largely unknown, but their occurrence in proteins has been associated with more than 20 hereditary diseases. Analysing 122 bacterial and eukaryotic genomes, we observed that the number of proteins containing homo-repeats is significantly larger than expected from theoretical estimates. Analysis of statistical significance indicates that the minimal size of homo-repeats varies with amino acid type and proteome. In an attempt to characterize proteins harbouring long homo-repeats, we found that those containing polar or small amino acids S, P, H, E, D, K, Q and N are enriched in structural disorder as well as protein- and RNA-interactions. We observed that E, S, Q, G, L, P, D, A and H homo-repeats are strongly linked with occurrence in human diseases. Moreover, S, E, P, A, Q, D and T homo-repeats are significantly enriched in neuronal proteins associated with autism and other disorders. We release a webserver for further exploration of homo-repeats occurrence in human pathology at http://bioinfo.protres.ru/hradis/. PMID:27256590

  19. OSL dating of the Aterian levels at Dar es-Soltan I (Rabat, Morocco) and implications for the dispersal of modern Homo sapiens

    NASA Astrophysics Data System (ADS)

    Barton, R. N. E.; Bouzouggar, A.; Collcutt, S. N.; Schwenninger, J.-L.; Clark-Balzan, L.

    2009-09-01

    The Aterian is a distinctive Middle Palaeolithic industry which is very widely spread across North Africa. Its dating and significance have been debated for nearly a century. Renewed interest in the Aterian has arisen because of a recent proposal that its development and spread may be linked to the dispersal of anatomically modern humans. The industry contains technological innovations such as thin bifacially flaked lithic points and pedunculates as well as evidence for personal ornaments and use of red ochre. Such markers as shell beads are believed to be indicative of symbolic behaviour. Dar es-Soltan I on the Atlantic coast of Morocco contains a thick sequence of Aterian deposits that were thought to represent the later stages of development of this industry. New Optically Stimulated Luminescence dates and geomorphological study indicate a much older sequence and so far the earliest yet recorded ages for the Aterian. They suggest an appearance in the Maghreb region during MIS (Marine Isotope Stage) 5.

  20. The place of Homo floresiensis in human evolution.

    PubMed

    Baab, Karen

    2016-06-20

    Two main evolutionary scenarios have been proposed to explain the presence of the small-bodied and small-brained Homo floresiensis species on the remote Indonesian island of Flores in the Late Pleistocene. According to these two scenarios, H. floresiensis was a dwarfed descendent of H. erectus or a late-surviving remnant of a older lineage, perhaps descended from H. habilis. Each scenario has interesting and important implications for hominin biogeography, body size evolution, brain evolution and morphological convergences. Careful evaluation reveals that only a small number of characters support each of these scenarios uniquely. H. floresiensis exhibits a cranial shape and many cranial characters that appear to be shared derived traits with H. erectus, but postcranial traits are more primitive and resemble those of early Homo or even australopiths. Mandibular and dental traits show a mix of derived and primitive features. Unfortunately, many traits cannot be used to assess these two hypotheses because their distribution in H. erectus, early Homo (e.g., H. habilis), or both is unknown. H. erectus ancestry implies evolutionary convergence on a postcranial configuration similar to australopiths and early Homo, which could be explained by a return to more climbing behaviors. Body size reduction as well as brain size reduction on a scale only rarely documented in mammals would also accompany the origin of H. floresiensis from a H. erectus ancestor. H. habilis ancestry implies parallel evolution of numerous cranial characters, as well as a few dentognathic traits. A pre-H. erectus ancestry also suggests an early migration to Southeast Asia that is as yet undocumented in mainland Asia, but minimal body and brain size reduction.

  1. All great ape species (Gorilla gorilla, Pan paniscus, Pan troglodytes, Pongo abelii) and two-and-a-half-year-old children (Homo sapiens) discriminate appearance from reality.

    PubMed

    Karg, Katja; Schmelz, Martin; Call, Josep; Tomasello, Michael

    2014-11-01

    Nonhuman great apes and human children were tested for an understanding that appearance does not always correspond to reality. Subjects were 29 great apes (bonobos [Pan paniscus], chimpanzees [Pan troglodytes], gorillas [Gorilla gorilla], and orangutans [Pongo abelii]) and 24 2½-year-old children. In our task, we occluded portions of 1 large and 1 small food stick such that the size relations seemed reversed. Subjects could then choose which one they wanted. There was 1 control condition and 2 experimental conditions (administered within subjects). In the control condition subjects saw only the apparent stick sizes, whereas in the 2 experimental conditions they saw the true stick sizes as well (the difference between them being what the subjects saw first: the apparent or the real stick sizes). All great ape species and children successfully identified the bigger stick, despite its smaller appearance, in the experimental conditions, but not in the control. We discuss these results in relation to the understanding of object permanence and conservation, and exclude reversed reward contingency learning as an explanation.

  2. The molecular chaperone, Atp12p, from Homo sapiens. In vitro studies with purified wild type and mutant (E240K) proteins.

    PubMed

    Hinton, Ayana; Gatti, Domenico L; Ackerman, Sharon H

    2004-03-05

    Work in Saccharomyces cerevisiae has shown that Atp12p binds to unassembled alpha subunits of F(1) and in so doing prevents the alpha subunit from associating with itself in non-productive complexes during assembly of the F(1) moiety of the mitochondrial ATP synthase. We have developed a method to prepare recombinant Atp12p after expression of its human cDNA in bacterial cells. The molecular chaperone activity of HuAtp12p was studied using citrate synthase as a model substrate. Wild type HuAtp12p suppresses the aggregation of thermally inactivated citrate synthase. In contrast, the mutant protein HuAtp12p(E240K), which harbors a lysine at the position of the highly conserved Glu-240, fails to prevent citrate synthase aggregation at 43 degrees C. No significant differences were observed between the wild type and the mutant proteins as judged by sedimentation analysis, cysteine titration, tryptophan emission spectra, or limited proteolysis, which suggests that the E240K mutation alters the activity of HuAtp12p with minimal effects on the physical integrity of the protein. An additional important finding of this work is that the equilibrium chemical denaturation curve of HuAtp12p shows two components, the first of which is associated with protein aggregation. This result is consistent with a model for Atp12p structure in which there is a hydrophobic chaperone domain that is buried within the protein interior.

  3. Structural insight with mutational impact on tyrosinase and PKC-β interaction from Homo sapiens: Molecular modeling and docking studies for melanogenesis, albinism and increased risk for melanoma.

    PubMed

    Banerjee, Arundhati; Ray, Sujay

    2016-10-30

    Human tyrosinase, is an important protein for biosynthetic pathway of melanin. It was studied to be phosphorylated and activated by protein kinase-C, β-subunit (PKC-β) through earlier experimentations with in vivo evidences. Documentation documents that mutation in two essentially vital serine residues in C-terminal end of tyrosinase leads to albinism. Due to the deficiency of protective shield like enzyme; melanin, albinos are at an increased peril for melanoma and other skin cancers. So, computational and residue-level insight including a mutational exploration with evolutionary importance into this mechanism lies obligatory for future pathological and therapeutic developments. Therefore, functional tertiary models of the relevant proteins were analyzed after satisfying their stereo-chemical features. Evolutionarily paramount residues for the activation of tyrosinase were perceived via multiple sequence alignment phenomena. Mutant-type tyrosinase protein (S98A and S102A) was thereby modeled, maintaining the wild-type proteins' functionality. Furthermore, this present comparative study discloses the variation in the stable residual participation (for mutant-type and wild-type tyrosinase-PKCβ complex). Mainly, an increased number of polar negatively charged residues from the wild-type tyrosinase participated with PKC-β, predominantly. Fascinatingly supported by evaluation of statistical significances, mutation even led to a destabilizing impact in tyrosinase accompanied by conformational switches with a helix-to-coil transition in the mutated protein. Even the allosteric sites in the protein got poorly hampered upon mutation leading to weaker tendency for binding partners to interact.

  4. Genome-wide identification and functional annotation of miRNAs in anti-inflammatory plant and their cross-kingdom regulation in Homo sapiens.

    PubMed

    Sharma, Ankita; Sahu, Sarika; Kumari, Pooja; Gopi, Soundhara Rajan; Malhotra, Rajesh; Biswas, Sagarika

    2016-06-29

    MicroRNAs (miRNAs) are newly discovered non-coding small (~17-24 nucleotide) RNAs that regulate gene expression of its target mRNA at the post-transcriptional levels. In this study, total 12,593 ESTs of Curcuma longa were taken from database of expressed sequence tags (dbEST) and clustered into 2821 contigs using EGassembler web server. Precursor miRNAs (pre-miRNAs) were predicted from these contigs that folded into stem-loop structure using MFold server. Thirty-four mature C. longa miRNAs (clo-miRNAs) were identified from pre-miRNAs having targets involved in various important functions of plant such as self-defence, growth and development, alkaloid metabolic pathway and ethylene signalling process. Sequence analysis of identified clo-miRNAs indicated that 56% miRNAs belong to ORF and 44% belong to non-ORF region. clo-mir-5 and clo-mir-6 were established as the conserved miRNAs, whereas clo-mir-20 was predicted to be the most stable miRNA. Phylogenetic analysis carried out by molecular evolutionary genetics analysis (MEGA) software indicated close evolutionary relationship of clo-mir-5075 with osa-MIR5075. Further, identified clo-miRNAs were checked for their cross-kingdom regulatory potential. clo-mir-14 was found to regulate various gene transcripts in humans that has been further investigated for its biostability in foetal bovine serum (FBS). The results indicated higher degree of stability of clo-mir-14 (48 h) in FBS. Thus, contribution of this miRNA to the cellular immune response during the inflamed condition of rheumatoid arthritis and adequate stability may make it a good choice for the therapeutic agent in near future.

  5. Beyond the Pleistocene: Using Phylogeny and Constraint to Inform the Evolutionary Psychology of Human Mating

    ERIC Educational Resources Information Center

    Eastwick, Paul W.

    2009-01-01

    Evolutionary psychologists explore the adaptive function of traits and behaviors that characterize modern Homo sapiens. However, evolutionary psychologists have yet to incorporate the phylogenetic relationship between modern Homo sapiens and humans' hominid and pongid relatives (both living and extinct) into their theorizing. By considering the…

  6. Evolution of the Genus Homo

    NASA Astrophysics Data System (ADS)

    Tattersall, Ian; Schwartz, Jeffrey H.

    2009-05-01

    Definition of the genus Homo is almost as fraught as the definition of Homo sapiens. We look at the evidence for “early Homo,” finding little morphological basis for extending our genus to any of the 2.5-1.6-myr-old fossil forms assigned to “early Homo” or Homo habilis/rudolfensis. We also point to heterogeneity among “early African Homo erectus,” and the lack of apomorphies linking these fossils to the Asian Homo erectus group, a cohesive regional clade that shows some internal variation, including brain size increase over time. The first truly cosmopolitan Homo species is Homo heidelbergensis, known from Africa, Europe, and China following 600 kyr ago. One species sympatric with it included the >500-kyr-old Sima de los Huesos fossils from Spain, clearly distinct from Homo heidelbergensis and the oldest hominids assignable to the clade additionally containing Homo neanderthalensis. This clade also shows evidence of brain size expansion with time; but although Homo neanderthalensis had a large brain, it left no unequivocal evidence of the symbolic consciousness that makes our species unique. Homo sapiens clearly originated in Africa, where it existed as a physical entity before it began (also in that continent) to show the first stirrings of symbolism. Most likely, the biological underpinnings of symbolic consciousness were exaptively acquired in the radical developmental reorganization that gave rise to the highly characteristic osteological structure of Homo sapiens, but lay fallow for tens of thousands of years before being “discovered” by a cultural stimulus, plausibly the invention of language.

  7. Homo floresiensis Contextualized: A Geometric Morphometric Comparative Analysis of Fossil and Pathological Human Samples

    PubMed Central

    Baab, Karen L.; McNulty, Kieran P.; Harvati, Katerina

    2013-01-01

    The origin of hominins found on the remote Indonesian island of Flores remains highly contentious. These specimens may represent a new hominin species, Homo floresiensis, descended from a local population of Homo erectus or from an earlier (pre-H. erectus) migration of a small-bodied and small-brained hominin out of Africa. Alternatively, some workers suggest that some or all of the specimens recovered from Liang Bua are pathological members of a small-bodied modern human population. Pathological conditions proposed to explain their documented anatomical features include microcephaly, myxoedematous endemic hypothyroidism (“cretinism”) and Laron syndrome (primary growth hormone insensitivity). This study evaluates evolutionary and pathological hypotheses through comparative analysis of cranial morphology. Geometric morphometric analyses of landmark data show that the sole Flores cranium (LB1) is clearly distinct from healthy modern humans and from those exhibiting hypothyroidism and Laron syndrome. Modern human microcephalic specimens converge, to some extent, on crania of extinct species of Homo. However in the features that distinguish these two groups, LB1 consistently groups with fossil hominins and is most similar to H. erectus. Our study provides further support for recognizing the Flores hominins as a distinct species, H. floresiensis, whose affinities lie with archaic Homo. PMID:23874886

  8. Aristotle's "homo mimeticus" as an Educational Paradigm for Human Coexistence

    ERIC Educational Resources Information Center

    Scaramuzzo, Gilberto

    2016-01-01

    In the "Poetics" of Aristotle there is a definition of the human being that perhaps has not yet been well considered in educational theory and practice. This definition calls into question a dynamism that according to Plato was unavoidable for an appropriate understanding of the educational process that turns a human being into a…

  9. Comparison of inverse-dynamics musculo-skeletal models of AL 288-1 Australopithecus afarensis and KNM-WT 15000 Homo ergaster to modern humans, with implications for the evolution of bipedalism.

    PubMed

    Wang, Weijie; Crompton, Robin H; Carey, Tanya S; Günther, Michael M; Li, Yu; Savage, Russell; Sellers, Williams I

    2004-12-01

    Size and proportions of the postcranial skeleton differ markedly between Australopithecus afarensis and Homo ergaster, and between the latter and modern Homo sapiens. This study uses computer simulations of gait in models derived from the best-known skeletons of these species (AL 288-1, Australopithecus afarensis, 3.18 million year ago) and KNM-WT 15000 (Homo ergaster, 1.5-1.8 million year ago) compared to models of adult human males and females, to estimate the required muscle power during bipedal walking, and to compare this with those in modern humans. Skeletal measurements were carried out on a cast of KNM-WT 15000, but for AL 288-1 were taken from the literature. Muscle attachments were applied to the models based on their position relative to the bone in modern humans. Joint motions and moments from experiments on human walking were input into the models to calculate muscle stress and power. The models were tested in erect walking and 'bent-hip bent-knee' gait. Calculated muscle forces were verified against EMG activity phases from experimental data, with reference to reasonable activation/force delays. Calculated muscle powers are reasonably comparable to experimentally derived metabolic values from the literature, given likely values for muscle efficiency. The results show that: 1) if evaluated by the power expenditure per unit of mass (W/kg) in walking, AL 288-1 and KNM-WT 15000 would need similar power to modern humans; however, 2) with distance-specific parameters as the criteria, AL 288-1 would require to expend relatively more muscle power (W/kg.m(-1)) in comparison to modern humans. The results imply that in the evolution of bipedalism, body proportions, for example those of KNM-WT 15000, may have evolved to obtain an effective application of muscle power to bipedal walking over a long distance, or at high speed.

  10. Post-cranial skeletons of hypothyroid cretins show a similar anatomical mosaic as Homo floresiensis.

    PubMed

    Oxnard, Charles; Obendorf, Peter J; Kefford, Ben J

    2010-09-27

    Human remains, some as recent as 15 thousand years, from Liang Bua (LB) on the Indonesian island of Flores have been attributed to a new species, Homo floresiensis. The definition includes a mosaic of features, some like modern humans (hence derived: genus Homo), some like modern apes and australopithecines (hence primitive: not species sapiens), and some unique (hence new species: floresiensis). Conversely, because only modern humans (H. sapiens) are known in this region in the last 40 thousand years, these individuals have also been suggested to be genetic human dwarfs. Such dwarfs resemble small humans and do not show the mosaic combination of the most complete individuals, LB1 and LB6, so this idea has been largely dismissed. We have previously shown that some features of the cranium of hypothyroid cretins are like those of LB1. Here we examine cretin postcrania to see if they show anatomical mosaics like H. floresiensis. We find that hypothyroid cretins share at least 10 postcranial features with Homo floresiensis and unaffected humans not found in apes (or australopithecines when materials permit). They share with H. floresiensis, modern apes and australopithecines at least 11 postcranial features not found in unaffected humans. They share with H. floresiensis, at least 8 features not found in apes, australopithecines or unaffected humans. Sixteen features can be rendered metrically and multivariate analyses demonstrate that H. floresiensis co-locates with cretins, both being markedly separate from humans and chimpanzees (P<0.001: from analysis of similarity (ANOSIM) over all variables, ANOSIM, global R>0.999). We therefore conclude that LB1 and LB6, at least, are, most likely, endemic cretins from a population of unaffected Homo sapiens. This is consistent with recent hypothyroid endemic cretinism throughout Indonesia, including the nearby island of Bali.

  11. Postcranial robusticity in Homo. III: Ontogeny.

    PubMed

    Ruff, C B; Walker, A; Trinkaus, E

    1994-01-01

    The influence of developmental factors on long-bone cross-sectional geometry and articular size in modern humans is investigated using two approaches: (1) an analysis of the effects of increased mechanical loading on long-bone structure when applied during different developmental periods, using data collected for a study of upper limb bone bilateral asymmetry in professional tennis players; and (2) an analysis of the relative timing of age changes in femoral dimensions among juveniles from the Pecos Pueblo Amerindian archaeological sample. Results of these analyses are used to interpret the femoral morphology of three pre-Recent Homo juveniles--the H. erectus KNM-WT 15000 and the archaic H. sapiens La Ferrassie 6 and Teshik-Tash 1--as well as observed differences in postcranial morphology between adult Recent and earlier Homo (Ruff et al., 1993). Our findings indicate the following: (1) There are age-related changes in long-bone diaphyseal envelope sensitivity to increased mechanical loading, with the periosteal envelope more responsive prior to mid-adolescence, and the endosteal envelope more responsive thereafter. The periosteal expansion and endosteal contraction of the diaphysis documented earlier for adult pre-Recent Homo relative to Recent humans (Ruff et al., 1993) is thus consistent with a developmental response to increased mechanical loading applied throughout life. The relatively large medullary cavity in the 11-12-year-old KNM-WT 15000 femur is also consistent with this model. However, the two archaic H. sapiens juveniles show relatively small medullary cavities, possibly indicating a modified developmental pattern in this group. (2) Articulations follow a growth pattern similar to that of long-bone length (and stature), while cross-sectional diaphyseal dimensions (cortical area, second moments of area) show a contrasting growth pattern, with slower initial growth from childhood through mid-adolescence, followed by a "catch-up" period that continues

  12. No homo.

    PubMed

    Brown, Joshua R

    2011-01-01

    The phrase no homo arose in hip-hop lyrics of the 1990s as a discourse interjection to negate supposed sexual and gender transgressions. Today the phrase has gained currency beyond hip-hop culture and pervades racial and gender continua. As a result, its increasing prevalence in mainstream speech has caused critics to deplore no homo as outright homophobia. This article describes the origins and scope of no homo. Instead of easily identifying the phrase as homophobic, the article invites readers to examine the phrase as a way of understanding the complexities in gender identification processes along with the linguistic dexterity necessary for survival in certain sociocultural groups. By exploring the macrosociological issues which created and perpetuate the need for no homo, we arrive at a deeper understanding of sexuality, marginalized sexuality, and the (often unspoken) uneasiness with sexual and gendered nonconformity.

  13. Homo economicus belief inhibits trust.

    PubMed

    Xin, Ziqiang; Liu, Guofang

    2013-01-01

    As a foundational concept in economics, the homo economicus assumption regards humans as rational and self-interested actors. In contrast, trust requires individuals to believe partners' benevolence and unselfishness. Thus, the homo economicus belief may inhibit trust. The present three experiments demonstrated that the direct exposure to homo economicus belief can weaken trust. And economic situations like profit calculation can also activate individuals' homo economicus belief and inhibit their trust. It seems that people's increasing homo economicus belief may serve as one cause of the worldwide decline of trust.

  14. Evolution of M1 crown size and cusp proportions in the genus Homo

    PubMed Central

    Quam, Rolf; Bailey, Shara; Wood, Bernard

    2009-01-01

    Previous research into tooth crown dimensions and cusp proportions has proved to be a useful way to identify taxonomic differences in Pliocene and Pleistocene fossil hominins. The present study has identified changes in both M1 crown size and cusp proportions within the genus Homo, with M1 overall crown size reduction apparently occurring in two main stages. The first stage (a reduction of ca. 17%) is associated with the emergence of Homo ergaster and Homo erectus sensu stricto. The second stage (a reduction of ca. 10%) occurs in Homo sapiens, but the reduced modern human M1 tooth crown size was only attained in Upper Paleolithic times. The absolute sizes of the individual cusps are highly positively correlated with overall crown size and dental reduction produces a reduction in the absolute size of each of the cusps. Most of the individual cusps scale isometrically with crown size, but the paracone shows a negative allometric relationship, indicating that the reduction in paracone size is less than in the other M1 cusps. Thus, the phylogenetically oldest cusp in the upper molars also seems to be the most stable cusp (at least in the M1). The most striking change in M1 cusp proportions is a change in the relative size of the areas of the paracone and metacone. The combination of a small relative paracone and a large relative metacone generally characterizes specimens attributed to early Homo, and the presence of this character state in Australopithecus andParanthropus suggests it may represent the primitive condition for the later part of the hominin clade. In contrast, nearly all later Homo taxa, with the exception of Homo antecessor, show the opposite condition (i.e. a relatively large paracone and a relatively small metacone). This change in the relationship between the relative sizes of the paracone and metacone is related to an isometric reduction of the absolute size of the metacone. This metacone reduction occurs in the context of relative stability in the

  15. Human evolution.

    PubMed

    Wood, B

    1996-12-01

    The common ancestor of modern humans and the great apes is estimated to have lived between 5 and 8 Myrs ago, but the earliest evidence in the human, or hominid, fossil record is Ardipithecus ramidus, from a 4.5 Myr Ethiopian site. This genus was succeeded by Australopithecus, within which four species are presently recognised. All combine a relatively primitive postcranial skeleton, a dentition with expanded chewing teeth and a small brain. The most primitive species in our own genus, Homo habilis and Homo rudolfensis, are little advanced over the australopithecines and with hindsight their inclusion in Homo may not be appropriate. The first species to share a substantial number of features with later Homo is Homo ergaster, or 'early African Homo erectus', which appears in the fossil record around 2.0 Myr. Outside Africa, fossil hominids appear as Homo erectus-like hominids, in mainland Asia and in Indonesia close to 2 Myr ago; the earliest good evidence of 'archaic Homo' in Europe is dated at between 600-700 Kyr before the present. Anatomically modern human, or Homo sapiens, fossils are seen first in the fossil record in Africa around 150 Kyr ago. Taken together with molecular evidence on the extent of DNA variation, this suggests that the transition from 'archaic' to 'modern' Homo may have taken place in Africa.

  16. Nuclear receptors Homo sapiens Rev-erbβ and Drosophila melanogaster E75 are thiolate-ligated heme proteins, which undergo redox-mediated ligand switching and bind CO and NO

    PubMed Central

    Marvin, Katherine A.; Reinking, Jeffrey L.; Lee, Andrea J.; Pardee, Keith M.; Krause, Henry M.; Burstyn, Judith N.

    2009-01-01

    Nuclear receptors E75, which regulates development in D. melanogaster, and Rev-erbβ, which regulates circadian rhythm in humans, bind heme within their ligand binding domains (LBD). The heme-bound ligand binding domains of E75 and Rev-erbβ were studied using electronic absorption, MCD, resonance Raman and EPR spectroscopies. Both proteins undergo redox-dependent ligand switching and CO- and NO-induced ligand displacement. In the Fe(III) oxidation state, the nuclear receptor hemes are low-spin and 6-coordinate with cysteine(thiolate) as one of the two axial heme ligands. The sixth ligand is a neutral donor, presumably histidine. When the heme is reduced to the Fe(II) oxidation state, the cysteine(thiolate) is replaced by a different neutral donor ligand, whose identity is not known. CO binds to the Fe(II) heme in both E75(LBD) and Rev-erbβ(LBD) opposite a sixth neutral ligand, plausibly the same histidine that served as the sixth ligand in the Fe(III) state. NO binds to the heme of both proteins; however, the NO-heme is 5-coordinate in E75 and 6-coordinate in Rev-erbβ. These nuclear receptors exhibit coordination characteristics that are similar to other known redox and gas sensors, suggesting that E75 and Rev-erbβ may function in heme-, redox- or gas-regulated control of cellular function. PMID:19405475

  17. Nuclear receptors homo sapiens Rev-erbbeta and Drosophila melanogaster E75 are thiolate-ligated heme proteins which undergo redox-mediated ligand switching and bind CO and NO.

    PubMed

    Marvin, Katherine A; Reinking, Jeffrey L; Lee, Andrea J; Pardee, Keith; Krause, Henry M; Burstyn, Judith N

    2009-07-28

    Nuclear receptors E75, which regulates development in Drosophila melanogaster, and Rev-erbbeta, which regulates circadian rhythm in humans, bind heme within their ligand binding domains (LBD). The heme-bound ligand binding domains of E75 and Rev-erbbeta were studied using electronic absorption, MCD, resonance Raman, and EPR spectroscopies. Both proteins undergo redox-dependent ligand switching and CO- and NO-induced ligand displacement. In the Fe(III) oxidation state, the nuclear receptor hemes are low spin and 6-coordinate with cysteine(thiolate) as one of the two axial heme ligands. The sixth ligand is a neutral donor, presumably histidine. When the heme is reduced to the Fe(II) oxidation state, the cysteine(thiolate) is replaced by a different neutral donor ligand, whose identity is not known. CO binds to the Fe(II) heme in both E75(LBD) and Rev-erbbeta(LBD) opposite a sixth neutral ligand, plausibly the same histidine that served as the sixth ligand in the Fe(III) state. NO binds to the heme of both proteins; however, the NO-heme is 5-coordinate in E75 and 6-coordinate in Rev-erbbeta. These nuclear receptors exhibit coordination characteristics that are similar to other known redox and gas sensors, suggesting that E75 and Rev-erbbeta may function in heme-, redox-, or gas-regulated control of cellular function.

  18. A "g" beyond "Homo Sapiens"? Some Hints and Suggestions

    ERIC Educational Resources Information Center

    Lee, James J.

    2007-01-01

    This article proposes that a complete account of cognitive evolution may have to accommodate a domain-general source of variance in mental abilities accounting for differences among primate taxa. Deaner, van Schaik, and Johnson [Deaner, R.O., van Schaik, C.P. and Johnson, V.E. (2006). Do some taxa have better domain-general cognition than others?…

  19. The minerals and the light: Mineralogy and astronomy in the history of the homo sapiens sapiens

    NASA Astrophysics Data System (ADS)

    Giovanna Giovine, Laura

    2016-04-01

    Since the end of the '90s, when the concept of competence was introduced in the education world, the debate on teaching assessment of competences is going on in the Italian school system. Nonetheless, first cycle and second cycle State Exams and national tests (INVALSI), yet have a focus on knowledge and skills. In the education field competence is defined as the capability to face requests and complex tasks effectively, using knowledge and skills acquired by study, research, observation and experience. The proposal formulated here is directed to turn disciplinary knowledge and skills to personal competences through educational and unitary teaching, in order to overcome the discontinuities between Primary school - Secondary school - Universities - the world of work. The ultimate goal is to preserve throughout the didactic course of teaching the wholeness and unitarily of personal competence of the student, who uses acquired disciplinary knowledge and skills in a personal fashion, neither mnemonic nor mechanical. The course of study may begin in the first class of lower secondary school and go on up to the fifth class of upper secondary school, with didactic laboratorial strategies and teaching strategies for competences, involving multiple disciplines. The recipients are the classes where a greater difficulty for students to integrate into the life of the School is registered, or the learned input-skills are of low or inadequate level, possibly with the presence of students with Special Educational Needs. In involved classes the collaboration and sharing of all teachers of the Class Council has been requested, in order to build an educational unitary course, centered on the concept of competence. Contents of the course: • The materials of the solid earth: minerals (physical and chemical properties, classification) • Percentages, graphics, angles, geometric solids, symmetry • Measurement units, speed and acceleration, mass and weight, pressure, energy, heat, temperature, density • States of matter: solid state and liquid state • The periodic table of elements, atoms and molecules • Mixtures Introduction to the course: • History informs sciences: newspapers and books dating back to the First World War are read in the classroom, mineral resources used in everyday life and the their mining locations, in cooperation with Geohistory and Italian teachers. • Discussion groups and "questioning" by the test "Is it useful to study the Mineralogy?" and input test with open-ended questions. • Experiments in the laboratory shared with Physics teacher: we observe a mineral (recognition, classification, chemical composition) • Theoretical lesson: natural sciences, physics and chemistry, with the support of the textbook and using material found by students in the Internet • Visit to the local museum with the teacher of Geometric Design or Art History or Technology or Geohistory • Brainstorming and project with support of LIM to view video-on lab and specific software • Experiments in the laboratory shared with the teacher of Mathematics: growing crystals (shape and symmetry, recognition and classification, chemical composition and structure of atoms) • Final report on experiments, possibly with research hypotheses.

  20. Genetic analysis of lice supports direct contact between modern and archaic humans.

    PubMed

    Reed, David L; Smith, Vincent S; Hammond, Shaless L; Rogers, Alan R; Clayton, Dale H

    2004-11-01

    Parasites can be used as unique markers to investigate host evolutionary history, independent of host data. Here we show that modern human head lice, Pediculus humanus, are composed of two ancient lineages, whose origin predates modern Homo sapiens by an order of magnitude (ca. 1.18 million years). One of the two louse lineages has a worldwide distribution and appears to have undergone a population bottleneck ca. 100,000 years ago along with its modern H. sapiens host. Phylogenetic and population genetic data suggest that the other lineage, found only in the New World, has remained isolated from the worldwide lineage for the last 1.18 million years. The ancient divergence between these two lice is contemporaneous with splits among early species of Homo, and cospeciation analyses suggest that the two louse lineages codiverged with a now extinct species of Homo and the lineage leading to modern H. sapiens. If these lice indeed codiverged with their hosts ca. 1.18 million years ago, then a recent host switch from an archaic species of Homo to modern H. sapiens is required to explain the occurrence of both lineages on modern H. sapiens. Such a host switch would require direct physical contact between modern and archaic forms of Homo.

  1. Skulls and Human Evolution: The Use of Casts of Anthropoid Skulls in Teaching Concepts of Human Evolution.

    ERIC Educational Resources Information Center

    Gipps, John

    1991-01-01

    Proposes the use of a series of 11 casts of fossil skulls as a method of teaching about the theory of human evolution. Students explore the questions of which skulls are "human" and which came first in Homo Sapien development, large brain or upright stance. (MDH)

  2. Filling the gap. Human cranial remains from Gombore II (Melka Kunture, Ethiopia; ca. 850 ka) and the origin of Homo heidelbergensis.

    PubMed

    Profico, Antonio; Di Vincenzo, Fabio; Gagliardi, Lorenza; Piperno, Marcello; Manzi, Giorgio

    2016-06-20

    African archaic humans dated to around 1,0 Ma share morphological affinities with Homo ergaster and appear distinct in cranio-dental morphology from those of the Middle Pleistocene that are referred to Homo heidelbergensis. This observation suggests a taxonomic and phylogenetic discontinuity in Africa that ranges across the Matuyama/Brunhes reversal (780 ka). Yet, the fossil record between roughly 900 and 600 ka is notoriously poor. In this context, the Early Stone Age site of Gombore II, in the Melka Kunture formation (Upper Awash, Ethiopia), provides a privileged case-study. In the Acheulean layer of Gombore II, somewhat more recent than 875 ±10 ka, two large cranial fragments were discovered in 1973 and 1975 respectively: a partial left parietal (Melka Kunture 1) and a right portion of the frontal bone (Melka Kunture 2), which probably belonged to the same cranium. We present here the first detailed description and computer-assisted reconstruction of the morphology of the cranial vault pertaining to these fossil fragments. Our analysis suggest that the human fossil specimen from Gombore II fills a phenetic gap between Homo ergaster and Homo heidelbergensis. This appears in agreement with the chronology of such a partial cranial vault, which therefore represents at present one of the best available candidates (if any) for the origin of Homo heidelbergensis in Africa.

  3. The dual origin of modern humanity.

    PubMed

    Tattersall, Ian

    2004-01-01

    Living Homo sapiens can define itself using both behavioral and anatomical uniquenesses. But is this possible when looking backward? Using a strict morphological definition, Homo sapiens can probably be traced back in the fossil record to about 150 kyr ago, which fits well with molecular estimates for the ancestor of all living human populations. However, activities reliably indicating established symbolic cognition can be recognized in the archaeological record only back to under 100 kyr ago. Since it is probable that the potential for symbolic cognition was born in the genetic/structural alterations that also gave rise to the distinctive morphological entity Homo sapiens, it appears that the expression of the human symbolic cognitive potential had to await, for many millennia, the >discovery< of that potential through a cultural rather than a biological stimulus. Most plausibly, this stimulus was the invention of language. Modern human symbolic cognition is not an extrapolation of pre-existing evolutionary trends, suggesting that Homo sapiens is not biologically >fine-tuned< for any specific behavior patterns.

  4. Dental evidence for ontogenetic differences between modern humans and Neanderthals.

    PubMed

    Smith, Tanya M; Tafforeau, Paul; Reid, Donald J; Pouech, Joane; Lazzari, Vincent; Zermeno, John P; Guatelli-Steinberg, Debbie; Olejniczak, Anthony J; Hoffman, Almut; Radovcic, Jakov; Makaremi, Masrour; Toussaint, Michel; Stringer, Chris; Hublin, Jean-Jacques

    2010-12-07

    Humans have an unusual life history, with an early weaning age, long childhood, late first reproduction, short interbirth intervals, and long lifespan. In contrast, great apes wean later, reproduce earlier, and have longer intervals between births. Despite 80 y of speculation, the origins of these developmental patterns in Homo sapiens remain unknown. Because they record daily growth during formation, teeth provide important insights, revealing that australopithecines and early Homo had more rapid ontogenies than recent humans. Dental development in later Homo species has been intensely debated, most notably the issue of whether Neanderthals and H. sapiens differ. Here we apply synchrotron virtual histology to a geographically and temporally diverse sample of Middle Paleolithic juveniles, including Neanderthals, to assess tooth formation and calculate age at death from dental microstructure. We find that most Neanderthal tooth crowns grew more rapidly than modern human teeth, resulting in significantly faster dental maturation. In contrast, Middle Paleolithic H. sapiens juveniles show greater similarity to recent humans. These findings are consistent with recent cranial and molecular evidence for subtle developmental differences between Neanderthals and H. sapiens. When compared with earlier hominin taxa, both Neanderthals and H. sapiens have extended the duration of dental development. This period of dental immaturity is particularly prolonged in modern humans.

  5. [The technological character of the human being].

    PubMed

    Del Barco Collazos, José Luis

    2009-01-01

    Technique is not accidental, but essential, to human being. It is the homo sapiens sapiens way of life. There is neither pretechnological human life nor a historic period without it. Human being is making tools and instruments since the very moment he is on earth. And so will he go on. Plough, airship and future apparatus are stages of the technical progress. The enormous human aptitude for making is due to the connexion between brain and hands. Technique ought be neither venerated nor feared but ruled.

  6. The Human Story: From Hominids to Homo Intelligens. A Curriculum Map for 5th Grade.

    ERIC Educational Resources Information Center

    Fluellen, Jerry E., Jr.

    A curriculum map for a year-long, fifth-grade, multidisciplinary project takes a performance view of understanding from Harvard University Project Zero's Research Center. Throughout the project and in each assessment of understanding, learners show what they know about human evolution. This guide to deep disciplinary understanding of the big idea…

  7. Absolute and relative endocranial size in Neandertals and later Pleistocene Homo.

    PubMed

    Gallagher, Andrew

    2014-10-01

    Eurasian Neandertals encompass the entire observed range of recent and fossil Homo sapiens in absolute, but not relative endocranial volume, and Neandertals attest an average EQ significantly lower than their Upper Pleistocene successors. While the cognitive, social, and evolutionary implications of this phenomenon have been emphasised, the statistical basis of a mean inference of EQ in the Neandertal hypodigm has not been appropriately demonstrated. A demonstrable male bias in the available postcranial, not cranial, series has skewed perceptions of Neandertal brain-to-body size scaling towards a rejection of the null hypothesis. A simple resolution to this problem is a concise assessment of paired associated covariates against a suitable recent human comparator series. Permutations of Fisher's z and Student's t statistics are valid metrics in tests of significance in single datum hypotheses. Bootstrapped single observation tests determined significance in body size, absolute and relative endocranial volume in Pleistocene archaic, early modern, and late Pleistocene H. sapiens. With respect to absolute ECV, all current Middle-Upper Pleistocene crania fall within the substantial recent Homo range. Nevertheless, simple indices derived from raw and modified data in normal and logarithmic space reveal that Western European Neandertal males approach the lower extremes of our observed size range in relative ECV, yet none exceed statistical significance. Results confirm that relative ECV/brain size in Neandertals was not significantly depressed relative to recent and fossil H. sapiens and this is consistent with a substantial body of data from living humans dismissing any simple correspondence of relative brain size with intelligence and, by extension, evolutionary success.

  8. On the trail of the genus Homo between archaic and derived morphologies.

    PubMed

    Manzi, Giorgio

    2012-01-01

    The topic of this review is the evolution of the genus Homo, focusing on evolutionary transitions that occurred during the Early and Middle Pleistocene. Two crucial issues are addressed in particular: 1) the emergence in the Early Pleistocene of the archaic variant of Homo that might represent the last common ancestor before the emergence of at least two (more probably three) geographically distinct trajectories; and (2) the evolution of these derived lineages, ultimately leading to the allopatric speciations of the most encephalised species of Homo: H. neanderthalensis and H. sapiens. In this framework, the time window between 1.0 million years ago (Ma) and 500 thousand years ago (ka) is of crucial importance, since it is probable that a new kind of humanity emerged in this period and then spread across a wide area encompassing Africa and Eurasia. These humans are represented by a number of specimens that are included within the single, polymorphic, and widespread species H. heidelbergensis. It is suggested that, in the course of the Middle Pleistocene, this species diversified in a number of incipient species -or subspecies- geographically and phenotypically distinct from one another. The case-study furnished by the calvarium found near Ceprano, in Italy, is of great interest in this regard, since it displays the least derived morphology seen among the hypodigm of H. heidelbergensis, and may represent better than other specimens the ancestral morphotype (i.e., the stem subspecies) of this taxon.

  9. Living in an adaptive world: Genomic dissection of the genus Homo and its immune response.

    PubMed

    Quach, Hélène; Quintana-Murci, Lluis

    2017-04-03

    More than a decade after the sequencing of the human genome, a deluge of genome-wide population data are generating a portrait of human genetic diversity at an unprecedented level of resolution. Genomic studies have provided new insight into the demographic and adaptive history of our species, Homo sapiens, including its interbreeding with other hominins, such as Neanderthals, and the ways in which natural selection, in its various guises, has shaped genome diversity. These studies, combined with functional genomic approaches, such as the mapping of expression quantitative trait loci, have helped to identify genes, functions, and mechanisms of prime importance for host survival and involved in phenotypic variation and differences in disease risk. This review summarizes new findings in this rapidly developing field, focusing on the human immune response. We discuss the importance of defining the genetic and evolutionary determinants driving immune response variation, and highlight the added value of population genomic approaches in settings relevant to immunity and infection.

  10. Human orexin/hypocretin receptors form constitutive homo- and heteromeric complexes with each other and with human CB{sub 1} cannabinoid receptors

    SciTech Connect

    Jäntti, Maria H.; Mandrika, Ilona; Kukkonen, Jyrki P.

    2014-03-07

    Highlights: • OX{sub 1} and OX{sub 2} orexin and CB{sub 1} cannabinoid receptor dimerization was investigated. • Bioluminescence resonance energy transfer method was used. • All receptors readily formed constitutive homo- and heteromeric complexes. - Abstract: Human OX{sub 1} orexin receptors have been shown to homodimerize and they have also been suggested to heterodimerize with CB{sub 1} cannabinoid receptors. The latter has been suggested to be important for orexin receptor responses and trafficking. In this study, we wanted to assess the ability of the other combinations of receptors to also form similar complexes. Vectors for expression of human OX{sub 1}, OX{sub 2} and CB{sub 1} receptors, C-terminally fused with either Renilla luciferase or GFP{sup 2} green fluorescent protein variant, were generated. The constructs were transiently expressed in Chinese hamster ovary cells, and constitutive dimerization between the receptors was assessed by bioluminescence energy transfer (BRET). Orexin receptor subtypes readily formed homo- and hetero(di)mers, as suggested by significant BRET signals. CB{sub 1} receptors formed homodimers, and they also heterodimerized with both orexin receptors. Interestingly, BRET efficiency was higher for homodimers than for almost all heterodimers. This is likely to be due to the geometry of the interaction; the putatively symmetric dimers may place the C-termini in a more suitable orientation in homomers. Fusion of luciferase to an orexin receptor and GFP{sup 2} to CB{sub 1} produced more effective BRET than the opposite fusions, also suggesting differences in geometry. Similar was seen for the OX{sub 1}–OX{sub 2} interaction. In conclusion, orexin receptors have a significant propensity to make homo- and heterodi-/oligomeric complexes. However, it is unclear whether this affects their signaling. As orexin receptors efficiently signal via endocannabinoid production to CB{sub 1} receptors, dimerization could be an effective way

  11. In search of Homo economicus.

    PubMed

    Yamagishi, Toshio; Li, Yang; Takagishi, Haruto; Matsumoto, Yoshie; Kiyonari, Toko

    2014-09-01

    Homo economicus, a model for humans in neoclassical economics, is a rational maximizer of self-interest. However, many social scientists regard such a person as a mere imaginary creature. We found that 31 of 446 residents of relatively wealthy Tokyo suburbs met the behavioral definition of Homo economicus. In several rounds of economic games, participants whose behavior was consistent with this model always apportioned the money endowed by the experimenter to themselves, leaving no share for their partners. These participants had high IQs and a deliberative decision style. An additional 39 participants showed a similar disregard for other people's welfare, although they were slightly more altruistic than those in the Homo economicus group. The psychological composition of these quasi-Homo economicus participants was distinct from that of participants in the Homo economicus group. Although participants in the latter group behaved selfishly on the basis of rational calculations, those in the former group made selfish choices impulsively. The implications of these findings concerning the two types of extreme noncooperators are discussed.

  12. Modern human origins: progress and prospects.

    PubMed Central

    Stringer, Chris

    2002-01-01

    The question of the mode of origin of modern humans (Homo sapiens) has dominated palaeoanthropological debate over the last decade. This review discusses the main models proposed to explain modern human origins, and examines relevant fossil evidence from Eurasia, Africa and Australasia. Archaeological and genetic data are also discussed, as well as problems with the concept of 'modernity' itself. It is concluded that a recent African origin can be supported for H. sapiens, morphologically, behaviourally and genetically, but that more evidence will be needed, both from Africa and elsewhere, before an absolute African origin for our species and its behavioural characteristics can be established and explained. PMID:12028792

  13. A bivariate approach to the widening of the frontal lobes in the genus Homo.

    PubMed

    Bruner, Emiliano; Holloway, Ralph L

    2010-02-01

    Within the genus Homo, the most encephalized taxa (Neandertals and modern humans) show relatively wider frontal lobes than either Homo erectus or australopithecines. The present analysis considers whether these changes are associated with a single size-based or allometric pattern (positive allometry of the width of the anterior endocranial fossa) or with a more specific and non-allometric pattern. The relationship between hemispheric length, maximum endocranial width, and frontal width at Broca's area was investigated in extant and extinct humans. Our results do not support positive allometry for the frontal lobe's width in relation to the main endocranial diameters within modern humans (Homo sapiens). Also, the correlation between frontal width and hemispheric length is lower than the correlation between frontal width and parieto-temporal width. When compared with the australopithecines, the genus Homo could have experienced a non-allometric widening of the brain at the temporo-parietal areas, which is most evident in Neandertals. Modern humans and Neandertals also display a non-allometric widening of the anterior endocranial fossa at the Broca's cap when compared with early hominids, again more prominent in the latter group. Taking into account the contrast between the intra-specific patterns and the between-species differences, the relative widening of the anterior fossa can be interpreted as a definite evolutionary character instead of a passive consequence of brain size increase. This expansion is most likely associated with correspondent increments of the underlying neural mass, or at least with a geometrical reallocation of the frontal cortical volumes. Although different structural changes of the cranial architecture can be related to such variations, the widening of the frontal areas is nonetheless particularly interesting when some neural functions (like language or working memory, decision processing, etc.) and related fronto-parietal cortico

  14. [A new mutation c.422C>G (p.S141C) in homo- and heterozygous forms of the human leptin gene].

    PubMed

    Chekhranova, M K; Karpova, S K; Iatsyshina, S B; Pankov, Iu A

    2008-01-01

    Mutation g.15409C>G, c.422C>G (p.S141C) in homo- and heterozygous forms of the human LEP gene was identified among some patients of the high mountain village of Karaul, Ashkhabad oblast, Turkmenistan, some of which suffer from adiposity. It causes the substitution S120C in the secreted leptin. The mature leptin molecule (146 aa) has only two Cys residues (C96 and C146) forming an S-S bridge, which is important for the hormone function. A third mutation, C120, in the molecule might disturb the correct formation of the S-S bond and could alter the leptin activity.

  15. The foot of Homo naledi

    PubMed Central

    Harcourt-Smith, W. E. H.; Throckmorton, Z.; Congdon, K. A.; Zipfel, B.; Deane, A. S.; Drapeau, M. S. M.; Churchill, S. E.; Berger, L. R.; DeSilva, J. M.

    2015-01-01

    Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo. PMID:26439101

  16. The foot of Homo naledi.

    PubMed

    Harcourt-Smith, W E H; Throckmorton, Z; Congdon, K A; Zipfel, B; Deane, A S; Drapeau, M S M; Churchill, S E; Berger, L R; DeSilva, J M

    2015-10-06

    Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo.

  17. The many mysteries of Homo naledi

    PubMed Central

    2015-01-01

    More than 1500 fossils from the Rising Star cave system in South Africa have been assigned to a new human species, Homo naledi, which displays a unique combination of primitive and derived traits throughout the skeleton. PMID:26354290

  18. Tropical forests and the genus Homo.

    PubMed

    Roberts, Patrick; Boivin, Nicole; Lee-Thorp, Julia; Petraglia, Michael; Stock, Jay

    2016-11-01

    Tropical forests constitute some of the most diverse and complex terrestrial ecosystems on the planet. From the Miocene onward, they have acted as a backdrop to the ongoing evolution of our closest living relatives, the great apes, and provided the cradle for the emergence of early hominins, who retained arboreal physiological adaptations at least into the Late Pliocene. There also now exists growing evidence, from the Late Pleistocene onward, for tool-assisted intensification of tropical forest occupation and resource extraction by our own species, Homo sapiens. However, between the Late Pliocene and Late Pleistocene there is an apparent gap in clear and convincing evidence for the use of tropical forests by hominins, including early members of our own genus. In discussions of Late Pliocene and Early Pleistocene hominin evolution, including the emergence and later expansion of Homo species across the globe, tropical forest adaptations tend to be eclipsed by open, savanna environments. Thus far, it is not clear whether this Early-Middle Pleistocene lacuna in Homo-rainforest interaction is real and representative of an adaptive shift with the emergence of our species or if it is simply reflective of preservation bias.

  19. Paleoneurology of two new neandertal occipitals from El Sidrón (asturias, Spain) in the context of homo endocranial evolution.

    PubMed

    Peña-Melián, Angel; Rosas, Antonio; García-Tabernero, Antonio; Bastir, Markus; De La Rasilla, Marco

    2011-08-01

    The endocranial surface description and comparative analyses of two new neandertal occipital fragments (labelled SD-1149 and SD-370a) from the El Sidrón site (Asturias, Spain) reveal new aspects of neandertal brain morphological asymmetries. The dural sinus drainage pattern, as observed on the sagittal-transverse system, as well as the cerebral occipito-petalias, point out a slightly differential configuration of the neandertal brain when compared to other Homo species, especially H. sapiens. The neandertal dural sinus drainage pattern is organized in a more asymmetric mode, in such a way that the superior sagittal sinus (SSS) drains either to the right or to the left transverse sinuses, but in no case in a confluent mode (i.e. simultaneous continuation of SSS with both right (RTS) and left (LTS) transverse sinuses). Besides, the superior sagittal sinus shows an accentuated deviation from of the mid-sagittal plane in its way to the RTS in 35% of neandertals. This condition, which increases the asymmetry of the system, is almost nonexistent neither in the analyzed Homo fossil species sample nor in that of anatomically modern humans. Regarding the cerebral occipito-petalias, neandertals manifest one of the lowest percentages of left petalia of the Homo sample (including modern H. sapiens). As left occipito-petalia is the predominant pattern in hominins, it seems as if neandertals would have developed a different pattern of brain hemispheres asymmetry. Finally, the relief and position of the the cerebral sulci and gyri impressions observed in the El Sidrón occipital specimens look similar to those observed in modern H. sapiens.

  20. Gamma-ray spectrometric dating of late Homo erectus skulls from Ngandong and Sambungmacan, Central Java, Indonesia.

    PubMed

    Yokoyama, Yuji; Falguères, Christophe; Sémah, François; Jacob, Teuku; Grün, Rainer

    2008-08-01

    Hominid fossils from Ngandong and Sambungmacan, Central Java, Indonesia, are considered to be the most anatomically derived and youngest representatives of Homo erectus. Nondestructive gamma-ray spectrometric dating of three of these Homo erectus skulls showed that all samples underwent uranium leaching. Nevertheless, we could establish minimum age estimates of around 40ka, with an upper age limit of around 60 to 70ka. This means that the Homo erectus of Java very likely survived the Toba eruption and may have been contemporaneous with the earliest Homo sapiens in Southeast Asia and Australasia.

  1. More on the Liang Bua finds and modern human cretins.

    PubMed

    Oxnard, Charles; Obendorf, Peter J; Kefford, Ben J; Dennison, John

    2012-12-01

    Brown (2012: LB1 and LB6 Homo floresiensis are not modern human (Homo sapiens) cretins, Journal of Human Evolution) makes errors of fact, omission and interpretation. Brown's comments refer, among others, to (1) delayed growth and development indicated by unfused epiphyses, (2) postcranial limb proportions: limbs to trunk, between limbs, and within limbs, (3) postcranial bone torsions and angles, (4) postcranial robusticity, real and apparent, (5) skull features, and (6) cretinism on Flores. In each of these areas, much information about cretins is incorrect and much information (Oxnard et al., 2010) comparing the Liang Bua remains with cretins is ignored.

  2. The first archaic Homo from Taiwan

    PubMed Central

    Chang, Chun-Hsiang; Kaifu, Yousuke; Takai, Masanaru; Kono, Reiko T.; Grün, Rainer; Matsu’ura, Shuji; Kinsley, Les; Lin, Liang-Kong

    2015-01-01

    Recent studies of an increasing number of hominin fossils highlight regional and chronological diversities of archaic Homo in the Pleistocene of eastern Asia. However, such a realization is still based on limited geographical occurrences mainly from Indonesia, China and Russian Altai. Here we describe a newly discovered archaic Homo mandible from Taiwan (Penghu 1), which further increases the diversity of Pleistocene Asian hominins. Penghu 1 revealed an unexpectedly late survival (younger than 450 but most likely 190–10 thousand years ago) of robust, apparently primitive dentognathic morphology in the periphery of the continent, which is unknown among the penecontemporaneous fossil records from other regions of Asia except for the mid-Middle Pleistocene Homo from Hexian, Eastern China. Such patterns of geographic trait distribution cannot be simply explained by clinal geographic variation of Homo erectus between northern China and Java, and suggests survival of multiple evolutionary lineages among archaic hominins before the arrival of modern humans in the region. PMID:25625212

  3. Homo- and hetero-dimerization of human UDP-glucuronosyltransferase 2B7 (UGT2B7) wild type and its allelic variants affect zidovudine glucuronidation activity.

    PubMed

    Yuan, Lingmin; Qian, Sainan; Xiao, Yongsheng; Sun, Hongying; Zeng, Su

    2015-05-01

    Most human UDP-glucuronosyltransferase (UGT; EC 2.4.1.17) genes contain non-synonymous single nucleotide polymorphisms (nsSNPs) which cause amino acid substitutions. Allelic variants caused by nsSNPs may exhibit absent or reduced enzyme activity. UGT2B7 is one of the most important UGTs that glucuronidates abundant endobiotics and xenobiotics, such as estriol, morphine, and anticancer drugs. Three nsSNPs, UGT2B7*71S (211G>T), UGT2B7*2 (802C>T) and UGT2B7*5 (1192G>A) are observed in the UGT2B7 gene, and they code for allozymes UGT2B7*71S (A71S), UGT2B7*2 (H268Y), and UGT2B7*5 (D398N). UGT2B7 has been observed to form oligomers that affect its enzymatic activity and in this study, we investigated protein-protein interactions among UGT2B7 allozymes wild type (WT), A71S, H268Y and D398N, by performing a systematic quantitative fluorescence resonance energy transfer (FRET) analysis in combination with co-immunoprecipitation assay. Quantitative FRET analysis revealed that UGT2B7 allozymes formed homo- and hetero-dimers and showed distinct features in donor-acceptor distances. Both codon 71 and codon 268 in the N-terminal domain were involved in the dimeric interaction. Co-immunoprecipitation experiments also proved that UGT2B7 allozymes formed stable dimers. The glucuronidation activities of homo- and hetero-dimers were further tested with zidovudine as the substrate. An increase in activity was observed when WT hetero-dimerized with A71S compared with homo-dimers, while both H268Y and D398N impaired the activity of WT and A71S by forming hetero-dimers. In addition, zidovudine glucuronidation activity is associated with FRET distance. These findings provide insights into the consequences of amino acid substitution in UGT2B7 on zidovudine glucuronidation and the association between protein-protein interaction and glucuronidation activity.

  4. Early stone technology on Flores and its implications for Homo floresiensis.

    PubMed

    Brumm, Adam; Aziz, Fachroel; van den Bergh, Gert D; Morwood, Michael J; Moore, Mark W; Kurniawan, Iwan; Hobbs, Douglas R; Fullagar, Richard

    2006-06-01

    In the Soa Basin of central Flores, eastern Indonesia, stratified archaeological sites, including Mata Menge, Boa Lesa and Kobatuwa (Fig. 1), contain stone artefacts associated with the fossilized remains of Stegodon florensis, Komodo dragon, rat and various other taxa. These sites have been dated to 840-700 kyr bp (thousand years before present). The authenticity of the Soa Basin artefacts and their provenance have been demonstrated by previous work, but to quell lingering doubts, here we describe the context, attributes and production modes of 507 artefacts excavated at Mata Menge. We also note specific similarities, and apparent technological continuity, between the Mata Menge stone artefacts and those excavated from Late Pleistocene levels at Liang Bua cave, 50 km to the west. The latter artefacts, dated to between 95-74 and 12 kyr ago, are associated with the remains of a dwarfed descendent of S. florensis, Komodo dragon, rat and a small-bodied hominin species, Homo floresiensis, which had a brain size of about 400 cubic centimetres. The Mata Menge evidence negates claims that stone artefacts associated with H. floresiensis are so complex that they must have been made by modern humans (Homo sapiens).

  5. [Mitochondrial DNA polymorphisms shared between modern humans and neanderthals: adaptive convergence or evidence for interspecific hybridization?].

    PubMed

    Maliarchuk, B A

    2013-09-01

    An analysis of the variability of the nucleotide sequences in the mitochondrial genome of modern humans, neanderthals, Denisovans, and other primates has shown that there are shared polymorphisms at positions 2758 and 7146 between modern Homo sapiens (in phylogenetic cluster L2'3'4'5'6) and Homo neanderthalensis (in the group of European neanderthals younger than 48000 years). It is suggested that the convergence may be due to adaptive changes in the mitochondrial genomes of modern humans and neanderthals or interspecific hybridization associated with mtDNA recombination.

  6. Extreme mobility in the Late Pleistocene? Comparing limb biomechanics among fossil Homo, varsity athletes and Holocene foragers.

    PubMed

    Shaw, Colin N; Stock, Jay T

    2013-04-01

    Descriptions of Pleistocene activity patterns often derive from comparisons of long bone diaphyseal robusticity across contemporaneous fossilized hominins. The purpose of this study is to augment existing understanding of Pleistocene hominin mobility patterns by interpreting fossil variation through comparisons with a) living human athletes with known activity patterns, and b) Holocene foragers where descriptions of group-level activity patterns are available. Relative tibial rigidity (midshaft tibial rigidity (J)/midshaft humeral rigidity (J)) was compared amongst Levantine and European Neandertals, Levantine and Upper Palaeolithic Homo sapiens, Holocene foragers and living human athletes and controls. Cross-country runners exhibit significantly (p<0.05) greater relative tibial rigidity compared with swimmers, and higher values compared with controls. In contrast, swimmers displayed significantly (p<0.05) lower relative tibial rigidity than both runners and controls. While variation exists among all Holocene H. sapiens, highly terrestrially mobile Later Stone Age (LSA) southern Africans and cross-country runners display the highest relative tibial rigidity, while maritime Andaman Islanders and swimmers display the lowest, with controls falling between. All fossil hominins displayed relative tibial rigidity that exceeded, or was similar to, the highly terrestrially mobile Later Stone Age southern Africans and modern human cross-country runners. The more extreme skeletal structure of most Neandertals and Levantine H. sapiens, as well as the odd Upper Palaeolithic individual, appears to reflect adaptation to intense and/or highly repetitive lower limb (relative to upper limb) loading. This loading may have been associated with bipedal travel, and appears to have been more strenuous than that encountered by even university varsity runners, and Holocene foragers with hunting grounds 2000-3000 square miles in size. Skeletal variation among the athletes and foraging

  7. Bioethics, technology and human dignity: the Roman Catholic viewpoint.

    PubMed

    Zyciński, J

    2006-01-01

    Many important questions dealing with human dignity in medical research are raised by new medical technologies. The paper presents the Roman Catholic approach to the use of new technologies, the research on human embryos, the ethical aspects of studies on human genome. The concept of "human ecology", as proposed by John Paul II, is to reconcile human dignity, the academic freedom of research, the sacredness of life understood as its quality so important for the cultural growth of Homo sapiens. To protect human ecology it is our moral duty to defend human dignity and to recognize the importance of those values that are fundamental in the process of development of human species.

  8. The upper limb of Homo naledi.

    PubMed

    Feuerriegel, Elen M; Green, David J; Walker, Christopher S; Schmid, Peter; Hawks, John; Berger, Lee R; Churchill, Steven E

    2017-03-01

    The evolutionary transition from an ape-like to human-like upper extremity occurred in the context of a behavioral shift from an upper limb predominantly involved in locomotion to one adapted for manipulation. Selection for overarm throwing and endurance running is thought to have further shaped modern human shoulder girdle morphology and its position about the thorax. Homo naledi (Dinaledi Chamber, Rising Star Cave, Cradle of Humankind, South Africa) combines an australopith-like cranial capacity with dental characteristics akin to early Homo. Although the hand, foot, and lower limb display many derived morphologies, the upper limb retains many primitive traits. Here, we describe the H. naledi upper extremity (excluding the hand) in detail and in a comparative context to evaluate the diversity of clavicular, scapular, humeral, radial, and ulnar morphology among early hominins and later Homo. Homo naledi had a scapula with a markedly cranially-oriented glenoid, a humerus with extremely low torsion, and an australopith-like clavicle. These traits indicate that the H. naledi scapula was situated superiorly and laterally on the thorax. This shoulder girdle configuration is more similar to that of Australopithecus and distinct from that of modern humans, whose scapulae are positioned low and dorsally about the thorax. Although early Homo erectus maintains many primitive clavicular and humeral features, its derived scapular morphology suggests a loss of climbing adaptations. In contrast, the H. naledi upper limb is markedly primitive, retaining morphology conducive to climbing while lacking many of the derived features related to effective throwing or running purported to characterize other members of early Homo.

  9. The hand of Homo naledi

    PubMed Central

    Kivell, Tracy L.; Deane, Andrew S.; Tocheri, Matthew W.; Orr, Caley M.; Schmid, Peter; Hawks, John; Berger, Lee R.; Churchill, Steven E.

    2015-01-01

    A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi. PMID:26441219

  10. Finding genes on the X chromosome by which homo may have become sapiens

    SciTech Connect

    Turner, G.

    1996-06-01

    The map of the X chromosome is now littered, from one telomere to the other, with genes for mental handicap, alone or in combination with other features. In this issue of the journal, report such an entity from the Scottish Highlands, which they give the catchy title of {open_quotes}PPM-X syndrome,{close_quotes} denoting the association of pyramidal tract signs, psychosis, and macroorchidism with mental handicap (XLMR). They have localized this to Xq28 and discuss other genes in the same area, which include L1CAM (associated with MASA [mental retardation, aphasia, shuffling gait, and adducted thumbs] and X-linked hydrocephalus) and two genes for nonspecific XLMR-MRX3 and MRX25. It is also the localization of the gene for G6PD deficiency, which, in earlier studies, had demonstrated linkage to bipolar affective disorders, although this has been questioned in more recent studies. There may well be other families with this pattern of abnormalities who have remained undescribed because depression is so often not diagnosed in those with moderate mental handicap. The occurrence, in this family, of mental handicap with a bipolar disorder may be the chance association of two common disorders, or it may a significant association; at this stage, one cannot judge. 8 refs.

  11. Structure of filamin A immunoglobulin-like repeat 10 from Homo sapiens.

    PubMed

    Page, Richard C; Clark, Jeffrey G; Misra, Saurav

    2011-08-01

    Filamin A (FlnA) plays a critical role in cytoskeletal organization, cell motility and cellular signaling. FlnA utilizes different binding sites on a series of 24 immunoglobulin-like domains (Ig repeats) to interact with diverse cytosolic proteins and with cytoplasmic portions of membrane proteins. Mutations in a specific domain, Ig10 (FlnA-Ig10), are correlated with two severe forms of the otopalatodigital syndrome spectrum disorders Melnick-Needles syndrome and frontometaphyseal dysplasia. The crystal structure of FlnA-Ig10 determined at 2.44 Å resolution provides insight into the perturbations caused by these mutations.

  12. Referential understanding of videos in chimpanzees (Pan troglodytes), orangutans (Pongo pygmaeus), and children (Homo sapiens).

    PubMed

    Poss, Sarah R; Rochat, Philippe

    2003-12-01

    Performance on identical search tasks based on cues directly perceived or indirectly perceived through video were compared among a group of 4 adult chimpanzees (Pan troglodytes), a group of 2 adult orangutans (Pongo pygmaeus), and a group of 36 children (between 2 and 3 years of age). Children comprehended directly perceived cues but had difficulty with video cues. In contrast, chimpanzees and 1 orangutan were successful in using video to guide their search for a hidden object. Two follow-up studies with 3-year-old children demonstrated the importance of more distinct perceptual and verbal cues in aiding children's understanding of video as referring to real-world events.

  13. Homology modeling of Homo sapiens Lipoic acid Synthase: substrate docking and insights on its binding mode.

    PubMed

    Krishnamoorthy, Ezhilarasi; Hassan, Sameer; Hanna, Luke Elizabeth; Padmalayam, Indira; Rajaram, Rama; Viswanathan, Vijay

    2016-10-04

    Lipoic acid synthase (LIAS) is an iron-sulfur cluster mitochondrial enzyme which catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. Recently there has been significant interest in its role in metabolic diseases and its deficiency in LIAS expression has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy, suggesting a strong inverse correlation between LIAS reduction and disease status. In this study we use a bioinformatics approach to predict its structure, which would be helpful to understanding its role. A homology model for LIAS protein was generated using X - ray crystallographic structure of Thermosynechococcus elongatus BP-1 (PDB ID: 4U0P). The predicted structure has 93% of the residues in the most favour region of Ramachandran plot. The active site of LIAS protein was mapped and docked with S-Adenosyl Methionine (SAM) using GOLD software. The LIAS - SAM complex was further refined using molecular dynamics simulation within the subsite 1 and subsite 3 of the active site. To the best of our knowledge, this is the first study to report a reliable homology model of LIAS protein. This study will facilitate a better understanding mode of action of the enzyme-substrate complex for future studies in designing drugs that can target LIAS protein.

  14. Geochronology and geochemistry of volcanic glasses associated with early Homo sapiens in Ethiopia.

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Renne, P. R.; Woldegabriel, G.; White, T. D.

    2005-12-01

    In past work at hominid sites in Ethiopia, 40Ar/39Ar dating was used to constrain obsidian from the base of the Upper Herto Member of the Bouri Formation to 160 ± 2 ka. An overlying vitric tuff was then geochemically correlated to one from the Konso region of Ethiopia, which is constrained to be older than 154 ± 7 ka, thus leaving only 6 ± 7 ky between eruption and deposition of the fossils and artifacts at Herto. To continue these studies, we have collected and are currently analyzing obsidian and associated volcanic ashes from Middle Stone Age (MSA) archaeological and paleontological sites in the Middle Awash, Ethiopia. Distinctive geochemical signatures among most obsidian fragments collected (n=20 per site) suggest that obsidian was being derived from a variety of sources. By comparing our geochemical data with that from known obsidian deposits in Ethiopia and elsewhere in East Africa, we hope to determine the source localities for the obsidian and thus gauge the extent of trade networks during the MSA. Thus, by characterizing obsidian using both 40Ar/39Ar geochronology and trace element geochemistry, will make it possible to temporally refine the stratigraphy and prehistory at hominid sites, which in turn improves understanding of hominid behavior and evolution.

  15. Craniofacial morphology of Homo floresiensis: description, taxonomic affinities, and evolutionary implication.

    PubMed

    Kaifu, Yousuke; Baba, Hisao; Sutikna, Thomas; Morwood, Michael J; Kubo, Daisuke; Saptomo, E Wahyu; Jatmiko; Awe, Rokhus Due; Djubiantono, Tony

    2011-12-01

    This paper describes in detail the external morphology of LB1/1, the nearly complete and only known cranium of Homo floresiensis. Comparisons were made with a large sample of early groups of the genus Homo to assess primitive, derived, and unique craniofacial traits of LB1 and discuss its evolution. Principal cranial shape differences between H. floresiensis and Homo sapiens are also explored metrically. The LB1 specimen exhibits a marked reductive trend in its facial skeleton, which is comparable to the H. sapiens condition and is probably associated with reduced masticatory stresses. However, LB1 is craniometrically different from H. sapiens showing an extremely small overall cranial size, and the combination of a primitive low and anteriorly narrow vault shape, a relatively prognathic face, a rounded oval foramen that is greatly separated anteriorly from the carotid canal/jugular foramen, and a unique, tall orbital shape. Whereas the neurocranium of LB1 is as small as that of some Homo habilis specimens, it exhibits laterally expanded parietals, a weak suprameatal crest, a moderately flexed occipital, a marked facial reduction, and many other derived features that characterize post-habilis Homo. Other craniofacial characteristics of LB1 include, for example, a relatively narrow frontal squama with flattened right and left sides, a marked frontal keel, posteriorly divergent temporal lines, a posteriorly flexed anteromedial corner of the mandibular fossa, a bulbous lateral end of the supraorbital torus, and a forward protruding maxillary body with a distinct infraorbital sulcus. LB1 is most similar to early Javanese Homo erectus from Sangiran and Trinil in these and other aspects. We conclude that the craniofacial morphology of LB1 is consistent with the hypothesis that H. floresiensis evolved from early Javanese H. erectus with dramatic island dwarfism. However, further field discoveries of early hominin skeletal remains from Flores and detailed analyses of the

  16. The uptake of hydroxypropyl methacrylamide based homo, random and block copolymers by human multi-drug resistant breast adenocarcinoma cells

    PubMed Central

    Barz, Matthias; Luxenhofer, Robert; Zentel, Rudolf; Kabanov, Alexander V.

    2011-01-01

    A series of well defined, fluorescently labelled homopolymers, random and block copolymers based on N-(2-hydroxypropyl)-methacrylamide was prepared by reversible addition-fragmentation chain transfer polymerization (RAFT-polymerization). The polydispersity indexes for all polymers were in the range of 1.2 to 1.3 and the number average of the molar mass (Mn) for each polymer was set to be in the range of 15 kDa to 30 kDa. The cellular uptake of these polymers was investigated in the human multi-drug resistant breast adenocarcinoma cell line MCF7/ADR. The uptake greatly depended on the polymer molecular mass and structure. Specifically, smaller polymers (approx. 15 kDa) were taken up by the cells at much lower concentrations than larger polymers (approx. 30 kDa). Furthermore, for polymers of the same molar mass, the random copolymers were more easily internalized in cells than block copolymers or homopolymers. This is attributed to the fact that random copolymers form micelle-like aggregates by intra- and interchain interactions, which are smaller and less stable than the block copolymer structures in which the hydrophobic domain is buried and thus prevented from unspecific interaction with the cell membrane. Our findings underline the need for highly defined polymeric carriers and excipients for future applications in the field of nanomedicine. PMID:19631373

  17. African Homo erectus: Old radiometric ages and young Oldowan assemblages in the middle Awash Valley, Ethiopia

    SciTech Connect

    Clark, J.D.; White, T.D.; Selassie, Y.H. ); Heinzelin, J. de ); Schick, K.D. ); Hart, W.K. ); WoldeGabriel, G. ); Walter, R.C. ); Suwa, G. ); Asfaw, B. )

    1994-06-24

    Fossils and artifacts recovered from the middle Awash Valley of Ethiopia's Afar depression sample the Middle Pleistocene transition from Homo erectus to Homo sapiens. Ar/Ar ages, biostratigraphy, and tephrachronology from this area indicate that the Pleistocene Bodo hominid cranium and newer specimens are approximately 0.6 million years old. Only Oldowan chopper and flake assemblages are present in the lower stratigraphic units but Acheulean bifacial artifacts are consistently prevalent and widespread in directly overlying deposits. This technological transition is related to a shift in sedimentary regime, supporting the hypothesis that Middle Pleistocene Oldowan assemblages represent a behavioral facies of the Acheulean industrial complex.

  18. The Sambungmacan 3 Homo erectus calvaria: a comparative morphometric and morphological analysis.

    PubMed

    Delson, E; Harvati, K; Reddy, D; Marcus, L F; Mowbray, K; Sawyer, G J; Jacob, T; Márquez, S

    2001-04-01

    The Sambungmacan (Sm) 3 calvaria, discovered on Java in 1977, was illegally removed from Indonesia in 1998 and appeared in New York City in early 1999 at the Maxilla & Mandible, Ltd. natural history shop. Here we undertake an analysis of its phylogenetic and systematic position using geometric morphometrics and comparative morphology. The coordinates of points in the sagittal plane from glabella to opisthion were resampled to yield "lines" of 50 semi-landmarks. Coordinates of glabella, bregma, lambda, inion, and opisthion were also collected and analyzed separately. Casts of Homo erectus fossils from Indonesia, China, and Kenya and of "archaic H. sapiens" from Kabwe and Petralona, as well as 10 modern human crania, were used as the primary comparative sample. The modern humans were well separated from the fossils in a graphical superimposition of Procrustes-aligned semi-landmarks as well as in principal component and canonical discriminant analyses. In all of these, Sm 3 falls intermediate between the fossil and modern groups. Morphological comparisons of Sm 3 with a selection of Homo erectus fossils revealed its greatest similarity to specimens from Ngandong and the Sm 1 calvaria. Compared to all other H. erectus, Sm 3 was distinctive in its more vertical supratoral plane, less anteriorly projecting glabella and less sharply angled occiput. In these features it was somewhat similar to modern humans. It is not yet possible to determine if this similarity implies an evolutionary relationship or (more likely) individual or local populational variation. Several features of Sm 3 (small size, gracile supraorbital torus and lack of angular torus, and position in principal component analysis) suggest that it was a female. The use of geometric morphometrics provides a means to statistically test the shapes of such fossils in a manner not easily duplicated by other methods. The intermediate position of Sm 3 between fossil and modern samples in several different subanalyses

  19. Tempo and mode in human evolution.

    PubMed Central

    McHenry, H M

    1994-01-01

    The quickening pace of paleontological discovery is matched by rapid developments in geochronology. These new data show that the pattern of morphological change in the hominid lineage was mosaic. Adaptations essential to bipedalism appeared early, but some locomotor features changed much later. Relative to the highly derived postcrania of the earliest hominids, the craniodental complex was quite primitive (i.e., like the reconstructed last common ancestor with the African great apes). The pattern of craniodental change among successively younger species of Hominidae implies extensive parallel evolution between at least two lineages in features related to mastication. Relative brain size increased slightly among successively younger species of Australopithecus, expanded significantly with the appearance of Homo, but within early Homo remained at about half the size of Homo sapiens for almost a million years. Many apparent trends in human evolution may actually be due to the accumulation of relatively rapid shifts in successive species. PMID:8041697

  20. The skull of Homo naledi.

    PubMed

    Laird, Myra F; Schroeder, Lauren; Garvin, Heather M; Scott, Jill E; Dembo, Mana; Radovčić, Davorka; Musiba, Charles M; Ackermann, Rebecca R; Schmid, Peter; Hawks, John; Berger, Lee R; de Ruiter, Darryl J

    2017-03-01

    The species Homo naledi was recently named from specimens recovered from the Dinaledi Chamber of the Rising Star cave system in South Africa. This large skeletal sample lacks associated faunal material and currently does not have a known chronological context. In this paper, we present comprehensive descriptions and metric comparisons of the recovered cranial and mandibular material. We describe 41 elements attributed to Dinaledi Hominin (DH1-DH5) individuals and paratype U.W. 101-377, and 32 additional cranial fragments. The H. naledi material was compared to Plio-Pleistocene fossil hominins using qualitative and quantitative analyses including over 100 linear measurements and ratios. We find that the Dinaledi cranial sample represents an anatomically homogeneous population that expands the range of morphological variation attributable to the genus Homo. Despite a relatively small cranial capacity that is within the range of australopiths and a few specimens of early Homo, H. naledi shares cranial characters with species across the genus Homo, including Homo habilis, Homo rudolfensis, Homo erectus, and Middle Pleistocene Homo. These include aspects of cranial form, facial morphology, and mandibular anatomy. However, the skull of H. naledi is readily distinguishable from existing species of Homo in both qualitative and quantitative assessments. Since H. naledi is currently undated, we discuss the evolutionary implications of its cranial morphology in a range of chronological frameworks. Finally, we designate a sixth Dinaledi Hominin (DH6) individual based on a juvenile mandible.

  1. Recent origin of low trabecular bone density in modern humans.

    PubMed

    Chirchir, Habiba; Kivell, Tracy L; Ruff, Christopher B; Hublin, Jean-Jacques; Carlson, Kristian J; Zipfel, Bernhard; Richmond, Brian G

    2015-01-13

    Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations.

  2. Recent origin of low trabecular bone density in modern humans

    PubMed Central

    Chirchir, Habiba; Kivell, Tracy L.; Ruff, Christopher B.; Hublin, Jean-Jacques; Carlson, Kristian J.; Zipfel, Bernhard; Richmond, Brian G.

    2015-01-01

    Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations. PMID:25535354

  3. Paleoanthropology: Homo erectus and the limits of a paleontological species.

    PubMed

    Hublin, Jean-Jacques

    2014-01-20

    The bushy nature of the human evolutionary tree in the past 3 million years is widely accepted. Yet, a spectacular new fossil of early Homo has prompted some paleoanthropologists to prune our family tree.

  4. Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

    PubMed Central

    Berger, Lee R; Hawks, John; de Ruiter, Darryl J; Churchill, Steven E; Schmid, Peter; Delezene, Lucas K; Kivell, Tracy L; Garvin, Heather M; Williams, Scott A; DeSilva, Jeremy M; Skinner, Matthew M; Musiba, Charles M; Cameron, Noel; Holliday, Trenton W; Harcourt-Smith, William; Ackermann, Rebecca R; Bastir, Markus; Bogin, Barry; Bolter, Debra; Brophy, Juliet; Cofran, Zachary D; Congdon, Kimberly A; Deane, Andrew S; Dembo, Mana; Drapeau, Michelle; Elliott, Marina C; Feuerriegel, Elen M; Garcia-Martinez, Daniel; Green, David J; Gurtov, Alia; Irish, Joel D; Kruger, Ashley; Laird, Myra F; Marchi, Damiano; Meyer, Marc R; Nalla, Shahed; Negash, Enquye W; Orr, Caley M; Radovcic, Davorka; Schroeder, Lauren; Scott, Jill E; Throckmorton, Zachary; Tocheri, Matthew W; VanSickle, Caroline; Walker, Christopher S; Wei, Pianpian; Zipfel, Bernhard

    2015-01-01

    Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa. DOI: http://dx.doi.org/10.7554/eLife.09560.001 PMID:26354291

  5. Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis.

    PubMed

    Henneberg, Maciej; Eckhardt, Robert B; Chavanaves, Sakdapong; Hsü, Kenneth J

    2014-08-19

    Human skeletons from Liang Bua Cave, Flores, Indonesia, are coeval with only Homo sapiens populations worldwide and no other previously known hominins. We report here for the first time to our knowledge the occipitofrontal circumference of specimen LB1. This datum makes it possible to link the 430-mL endocranial volume of LB1 reported by us previously, later confirmed independently by other investigators, not only with other human skeletal samples past and present but also with a large body of clinical data routinely collected on patients with developmental disorders. Our analyses show that the brain size of LB1 is in the range predicted for an individual with Down syndrome (DS) in a normal small-bodied population from the geographic region that includes Flores. Among additional diagnostic signs of DS and other skeletal dysplasiae are abnormally short femora combined with disproportionate flat feet. Liang Bua Cave femora, known only for LB1, match interlimb proportions for DS. Predictions based on corrected LB1 femur lengths show a stature normal for other H. sapiens populations in the region.

  6. Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis

    NASA Astrophysics Data System (ADS)

    Henneberg, Maciej; Eckhardt, Robert B.; Chavanaves, Sakdapong; Hsü, Kenneth J.

    2014-08-01

    Human skeletons from Liang Bua Cave, Flores, Indonesia, are coeval with only Homo sapiens populations worldwide and no other previously known hominins. We report here for the first time to our knowledge the occipitofrontal circumference of specimen LB1. This datum makes it possible to link the 430-mL endocranial volume of LB1 reported by us previously, later confirmed independently by other investigators, not only with other human skeletal samples past and present but also with a large body of clinical data routinely collected on patients with developmental disorders. Our analyses show that the brain size of LB1 is in the range predicted for an individual with Down syndrome (DS) in a normal small-bodied population from the geographic region that includes Flores. Among additional diagnostic signs of DS and other skeletal dysplasiae are abnormally short femora combined with disproportionate flat feet. Liang Bua Cave femora, known only for LB1, match interlimb proportions for DS. Predictions based on corrected LB1 femur lengths show a stature normal for other H. sapiens populations in the region.

  7. Comparative Transcriptomics Reveals Discrete Survival Responses of S. aureus and S. epidermidis to Sapienic Acid

    PubMed Central

    Moran, Josephine C.; Alorabi, Jamal A.; Horsburgh, Malcolm J.

    2017-01-01

    Staphylococcal colonization of human skin is ubiquitous, with particular species more frequent at different body sites. Whereas Staphylococcus epidermidis can be isolated from the skin of every individual tested, Staphylococcus aureus is isolated from <5% of healthy individuals. The factors that drive staphylococcal speciation and niche selection on skin are incompletely defined. Here we show that S. aureus is inhibited to a greater extent than S. epidermidis by the sebaceous lipid sapienic acid, supporting a role for this skin antimicrobial in selection of skin staphylococci. We used RNA-Seq and comparative transcriptomics to identify the sapienic acid survival responses of S. aureus and S. epidermidis. Consistent with the membrane depolarization mode of action of sapienic acid, both species shared a common transcriptional response to counteract disruption of metabolism and transport. The species differed in their regulation of SaeRS and VraRS regulons. While S. aureus upregulated urease operon transcription, S. epidermidis upregulated arginine deiminase, the oxygen-responsive NreABC nitrogen regulation system and the nitrate and nitrite reduction pathways. The role of S. aureus ACME and chromosomal arginine deiminase pathways in sapienic acid resistance was determined through mutational studies. We speculate that ammonia production could contribute to sapienic acid resistance in staphylococci. PMID:28179897

  8. Comparative Transcriptomics Reveals Discrete Survival Responses of S. aureus and S. epidermidis to Sapienic Acid.

    PubMed

    Moran, Josephine C; Alorabi, Jamal A; Horsburgh, Malcolm J

    2017-01-01

    Staphylococcal colonization of human skin is ubiquitous, with particular species more frequent at different body sites. Whereas Staphylococcus epidermidis can be isolated from the skin of every individual tested, Staphylococcus aureus is isolated from <5% of healthy individuals. The factors that drive staphylococcal speciation and niche selection on skin are incompletely defined. Here we show that S. aureus is inhibited to a greater extent than S. epidermidis by the sebaceous lipid sapienic acid, supporting a role for this skin antimicrobial in selection of skin staphylococci. We used RNA-Seq and comparative transcriptomics to identify the sapienic acid survival responses of S. aureus and S. epidermidis. Consistent with the membrane depolarization mode of action of sapienic acid, both species shared a common transcriptional response to counteract disruption of metabolism and transport. The species differed in their regulation of SaeRS and VraRS regulons. While S. aureus upregulated urease operon transcription, S. epidermidis upregulated arginine deiminase, the oxygen-responsive NreABC nitrogen regulation system and the nitrate and nitrite reduction pathways. The role of S. aureus ACME and chromosomal arginine deiminase pathways in sapienic acid resistance was determined through mutational studies. We speculate that ammonia production could contribute to sapienic acid resistance in staphylococci.

  9. Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron Syndrome).

    PubMed

    Hershkovitz, Israel; Kornreich, Liora; Laron, Zvi

    2007-10-01

    Comparison between the skeletal remains of Homo floresiensis and the auxological and roentgenological findings in a large Israeli cohort of patients with Laron Syndrome (LS, primary or classical GH insensitivity or resistance) revealed striking morphological similarities, including extremely small stature and reduced cranial volume. LS is an autosomal recessive disease caused by a molecular defect of the Growth Hormone (GH) receptor or in the post-receptor cascades. Epidemiological studies have shown that LS occurs more often in consanguineous families and isolates, and it has been described in several countries in South East Asia. It is our conclusion that the findings from the island of Flores, which were attributed to a new species of the genus Homo, may in fact represent a local, highly inbred, Homo sapiens population in whom a mutation for the GH receptor had occurred.

  10. The evolutionary relationships and age of Homo naledi: An assessment using dated Bayesian phylogenetic methods.

    PubMed

    Dembo, Mana; Radovčić, Davorka; Garvin, Heather M; Laird, Myra F; Schroeder, Lauren; Scott, Jill E; Brophy, Juliet; Ackermann, Rebecca R; Musiba, Chares M; de Ruiter, Darryl J; Mooers, Arne Ø; Collard, Mark

    2016-08-01

    Homo naledi is a recently discovered species of fossil hominin from South Africa. A considerable amount is already known about H. naledi but some important questions remain unanswered. Here we report a study that addressed two of them: "Where does H. naledi fit in the hominin evolutionary tree?" and "How old is it?" We used a large supermatrix of craniodental characters for both early and late hominin species and Bayesian phylogenetic techniques to carry out three analyses. First, we performed a dated Bayesian analysis to generate estimates of the evolutionary relationships of fossil hominins including H. naledi. Then we employed Bayes factor tests to compare the strength of support for hypotheses about the relationships of H. naledi suggested by the best-estimate trees. Lastly, we carried out a resampling analysis to assess the accuracy of the age estimate for H. naledi yielded by the dated Bayesian analysis. The analyses strongly supported the hypothesis that H. naledi forms a clade with the other Homo species and Australopithecus sediba. The analyses were more ambiguous regarding the position of H. naledi within the (Homo, Au. sediba) clade. A number of hypotheses were rejected, but several others were not. Based on the available craniodental data, Homo antecessor, Asian Homo erectus, Homo habilis, Homo floresiensis, Homo sapiens, and Au. sediba could all be the sister taxon of H. naledi. According to the dated Bayesian analysis, the most likely age for H. naledi is 912 ka. This age estimate was supported by the resampling analysis. Our findings have a number of implications. Most notably, they support the assignment of the new specimens to Homo, cast doubt on the claim that H. naledi is simply a variant of H. erectus, and suggest H. naledi is younger than has been previously proposed.

  11. Postnatal temporal bone ontogeny in Pan, Gorilla, and Homo, and the implications for temporal bone ontogeny in Australopithecus afarensis.

    PubMed

    Terhune, Claire E; Kimbel, William H; Lockwood, Charles A

    2013-08-01

    Assessments of temporal bone morphology have played an important role in taxonomic and phylogenetic evaluations of fossil taxa, and recent three-dimensional analyses of this region have supported the utility of the temporal bone for testing taxonomic and phylogenetic hypotheses. But while clinical analyses have examined aspects of temporal bone ontogeny in humans, the ontogeny of the temporal bone in non-human taxa is less well documented. This study examines ontogenetic allometry of the temporal bone in order to address several research questions related to the pattern and trajectory of temporal bone shape change during ontogeny in the African apes and humans. We further apply these data to a preliminary analysis of temporal bone ontogeny in Australopithecus afarensis. Three-dimensional landmarks were digitized on an ontogenetic series of specimens of Homo sapiens, Pan troglodytes, Pan paniscus, and Gorilla gorilla. Data were analyzed using geometric morphometric methods, and shape changes throughout ontogeny in relation to size were compared. Results of these analyses indicate that, despite broadly similar patterns, African apes and humans show marked differences in development of the mandibular fossa and tympanic portions of the temporal bone. These findings indicate divergent, rather than parallel, postnatal ontogenetic allometric trajectories for temporal bone shape in these taxa. The pattern of temporal bone shape change with size exhibited by A. afarensis showed some affinities to that of humans, but was most similar to extant African apes, particularly Gorilla.

  12. Endurance running and the evolution of Homo.

    PubMed

    Bramble, Dennis M; Lieberman, Daniel E

    2004-11-18

    Striding bipedalism is a key derived behaviour of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages. Although bipedal gaits include walking and running, running is generally considered to have played no major role in human evolution because humans, like apes, are poor sprinters compared to most quadrupeds. Here we assess how well humans perform at sustained long-distance running, and review the physiological and anatomical bases of endurance running capabilities in humans and other mammals. Judged by several criteria, humans perform remarkably well at endurance running, thanks to a diverse array of features, many of which leave traces in the skeleton. The fossil evidence of these features suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human body form.

  13. Spinal cord evolution in early Homo.

    PubMed

    Meyer, Marc R; Haeusler, Martin

    2015-11-01

    The discovery at Nariokotome of the Homo erectus skeleton KNM-WT 15000, with a narrow spinal canal, seemed to show that this relatively large-brained hominin retained the primitive spinal cord size of African apes and that brain size expansion preceded postcranial neurological evolution. Here we compare the size and shape of the KNM-WT 15000 spinal canal with modern and fossil taxa including H. erectus from Dmanisi, Homo antecessor, the European middle Pleistocene hominins from Sima de los Huesos, and Pan troglodytes. In terms of shape and absolute and relative size of the spinal canal, we find all of the Dmanisi and most of the vertebrae of KNM-WT 15000 are within the human range of variation except for the C7, T2, and T3 of KNM-WT 15000, which are constricted, suggesting spinal stenosis. While additional fossils might definitively indicate whether H. erectus had evolved a human-like enlarged spinal canal, the evidence from the Dmanisi spinal canal and the unaffected levels of KNM-WT 15000 show that unlike Australopithecus, H. erectus had a spinal canal size and shape equivalent to that of modern humans. Subadult status is unlikely to affect our results, as spinal canal growth is complete in both individuals. We contest the notion that vertebrae yield information about respiratory control or language evolution, but suggest that, like H. antecessor and European middle Pleistocene hominins from Sima de los Huesos, early Homo possessed a postcranial neurological endowment roughly commensurate to modern humans, with implications for neurological, structural, and vascular improvements over Pan and Australopithecus.

  14. Energetic consequences of being a Homo erectus female.

    PubMed

    Aiello, Leslie C; Key, Cathy

    2002-01-01

    Body size is one of the most important characteristics of any animal because it affects a range of behavioral, ecological, and physiological traits including energy requirements, choice of food, reproductive strategies, predation risk, range size, and locomotor style. This article focuses on the implications of being large bodied for Homo erectus females, estimated to have been over 50% heavier than average australopithecine females. The energy requirements of these hominins are modeled using data on activity patterns, body mass, and life history from living primates. Particular attention is given to the inferred energetic costs of reproduction for Homo erectus females based on chimpanzee and human reproductive scheduling. Daily energy requirements during gestation and lactation would have been significantly higher for Homo erectus females, as would total energetic cost per offspring if the australopithecines and Homo erectus had similar reproductive schedules (gestation and lactation lengths and interbirth intervals). Shortening the interbirth interval could considerably reduce the costs per offspring to Homo erectus and have the added advantage of increasing reproductive output. The mother would, however, incur additional daily costs of caring for the dependent offspring. If Homo erectus females adopted this reproductive strategy, it would necessarily imply a revolution in the way in which females obtained and utilized energy to support their increased energetic requirements. This transformation is likely to have occurred on several levels involving cooperative economic division of labor, locomotor energetics, menopause, organ size, and other physiological mechanisms for reducing the energetic load on females.

  15. Homo-timeric structural model of human microsomal prostaglandin E synthase-1 and characterization of its substrate/inhibitor binding interactions

    NASA Astrophysics Data System (ADS)

    Xing, Li; Kurumbail, Ravi G.; Frazier, Ronald B.; Davies, Michael S.; Fujiwara, Hideji; Weinberg, Robin A.; Gierse, James K.; Caspers, Nicole; Carter, Jeffrey S.; McDonald, Joseph J.; Moore, William M.; Vazquez, Michael L.

    2009-01-01

    Inducible, microsomal prostaglandin E synthase 1 (mPGES-1), the terminal enzyme in the prostaglandin (PG) biosynthetic pathway, constitutes a promising therapeutic target for the development of new anti-inflammatory drugs. To elucidate structure-function relationships and to enable structure-based design, an mPGES-1 homology model was developed using the three-dimensional structure of the closest homologue of the MAPEG family (Membrane Associated Proteins in Eicosanoid and Glutathione metabolism), mGST-1. The ensuing model of mPGES-1 is a homo-trimer, with each monomer consisting of four membrane-spanning segments. Extensive structure refinement revealed an inter-monomer salt bridge (K26-E77) as well as inter-helical interactions within each monomer, including polar hydrogen bonds (e.g. T78-R110-T129) and hydrophobic π-stacking (F82-F103-F106), all contributing to the overall stability of the homo-trimer of mPGES-1. Catalytic co-factor glutathione (GSH) was docked into the mPGES-1 model by flexible optimization of both the ligand and the protein conformations, starting from the initial location ascertained from the mGST-1 structure. Possible binding site for the substrate, prostaglandin H2 (PGH2), was identified by systematically probing the refined molecular structure of mPGES-1. A binding model was generated by induced fit docking of PGH2 in the presence of GSH. The homology model prescribes three potential inhibitor binding sites per mPGES-1 trimer. This was further confirmed experimentally by equilibrium dialysis study which generated a binding stoichiometric ratio of approximately three inhibitor molecules to three mPGES-1 monomers. The structural model that we have derived could serve as a useful tool for structure-guided design of inhibitors for this emergently important therapeutic target.

  16. Tracing the origin of functional and conserved domains in the human proteome: implications for protein evolution at the modular level

    PubMed Central

    Pal, Lipika R; Guda, Chittibabu

    2006-01-01

    Background The functional repertoire of the human proteome is an incremental collection of functions accomplished by protein domains evolved along the Homo sapiens lineage. Therefore, knowledge on the origin of these functionalities provides a better understanding of the domain and protein evolution in human. The lack of proper comprehension about such origin has impelled us to study the evolutionary origin of human proteome in a unique way as detailed in this study. Results This study reports a unique approach for understanding the evolution of human proteome by tracing the origin of its constituting domains hierarchically, along the Homo sapiens lineage. The uniqueness of this method lies in subtractive searching of functional and conserved domains in the human proteome resulting in higher efficiency of detecting their origins. From these analyses the nature of protein evolution and trends in domain evolution can be observed in the context of the entire human proteome data. The method adopted here also helps delineate the degree of divergence of functional families occurred during the course of evolution. Conclusion This approach to trace the evolutionary origin of functional domains in the human proteome facilitates better understanding of their functional versatility as well as provides insights into the functionality of hypothetical proteins present in the human proteome. This work elucidates the origin of functional and conserved domains in human proteins, their distribution along the Homo sapiens lineage, occurrence frequency of different domain combinations and proteome-wide patterns of their distribution, providing insights into the evolutionary solution to the increased complexity of the human proteome. PMID:17090320

  17. Hominid mandibular corpus shape variation and its utility for recognizing species diversity within fossil Homo.

    PubMed

    Lague, Michael R; Collard, Nicole J; Richmond, Brian G; Wood, Bernard A

    2008-12-01

    Mandibular corpora are well represented in the hominin fossil record, yet few studies have rigorously assessed the utility of mandibular corpus morphology for species recognition, particularly with respect to the linear dimensions that are most commonly available. In this study, we explored the extent to which commonly preserved mandibular corpus morphology can be used to: (i) discriminate among extant hominid taxa and (ii) support species designations among fossil specimens assigned to the genus Homo. In the first part of the study, discriminant analysis was used to test for significant differences in mandibular corpus shape at different taxonomic levels (genus, species and subspecies) among extant hominid taxa (i.e. Homo, Pan, Gorilla, Pongo). In the second part of the study, we examined shape variation among fossil mandibles assigned to Homo (including H. habilis sensu stricto, H. rudolfensis, early African H. erectus/H. ergaster, late African H. erectus, Asian H. erectus, H. heidelbergensis, H. neanderthalensis and H. sapiens). A novel randomization procedure designed for small samples (and using group 'distinctness values') was used to determine whether shape variation among the fossils is consistent with conventional taxonomy (or alternatively, whether a priori taxonomic groupings are completely random with respect to mandibular morphology). The randomization of 'distinctness values' was also used on the extant samples to assess the ability of the test to recognize known taxa. The discriminant analysis results demonstrated that, even for a relatively modest set of traditional mandibular corpus measurements, we can detect significant differences among extant hominids at the genus and species levels, and, in some cases, also at the subspecies level. Although the randomization of 'distinctness values' test is more conservative than discriminant analysis (based on comparisons with extant specimens), we were able to detect at least four distinct groups among the

  18. The earliest unequivocally modern humans in southern China.

    PubMed

    Liu, Wu; Martinón-Torres, María; Cai, Yan-jun; Xing, Song; Tong, Hao-wen; Pei, Shu-wen; Sier, Mark Jan; Wu, Xiao-hong; Edwards, R Lawrence; Cheng, Hai; Li, Yi-yuan; Yang, Xiong-xin; de Castro, José María Bermúdez; Wu, Xiu-jie

    2015-10-29

    The hominin record from southern Asia for the early Late Pleistocene epoch is scarce. Well-dated and well-preserved fossils older than ∼45,000 years that can be unequivocally attributed to Homo sapiens are lacking. Here we present evidence from the newly excavated Fuyan Cave in Daoxian (southern China). This site has provided 47 human teeth dated to more than 80,000 years old, and with an inferred maximum age of 120,000 years. The morphological and metric assessment of this sample supports its unequivocal assignment to H. sapiens. The Daoxian sample is more derived than any other anatomically modern humans, resembling middle-to-late Late Pleistocene specimens and even contemporary humans. Our study shows that fully modern morphologies were present in southern China 30,000-70,000 years earlier than in the Levant and Europe. Our data fill a chronological and geographical gap that is relevant for understanding when H. sapiens first appeared in southern Asia. The Daoxian teeth also support the hypothesis that during the same period, southern China was inhabited by more derived populations than central and northern China. This evidence is important for the study of dispersal routes of modern humans. Finally, our results are relevant to exploring the reasons for the relatively late entry of H. sapiens into Europe. Some studies have investigated how the competition with H. sapiens may have caused Neanderthals' extinction (see ref. 8 and references therein). Notably, although fully modern humans were already present in southern China at least as early as ∼80,000 years ago, there is no evidence that they entered Europe before ∼45,000 years ago. This could indicate that H. neanderthalensis was indeed an additional ecological barrier for modern humans, who could only enter Europe when the demise of Neanderthals had already started.

  19. Morphological variation in great ape and modern human mandibles

    PubMed Central

    HUMPHREY, L. T.; DEAN, M. C.; STRINGER, C. B.

    1999-01-01

    Adult mandibles of 317 modern humans and 91 great apes were selected that showed no pathology. Adult mandibles of Pan troglodytes troglodytes, Pongo pygmaeus pygmaeus and Gorilla gorilla gorilla and from 2 modern human populations (Zulu and Europeans from Spitalfields) were reliably sexed. Thirteen measurements were defined and included mandibular height, length and breadth in representative positions. Univariate statistical techniques and multivariate (principal component analysis and discriminant analysis) statistical techniques were used to investigate interspecific variability and sexual dimorphism in human and great ape mandibles, and intraspecific variability among the modern human mandibles. Analysis of interspecific differences revealed some pairs of variables with a tight linear relationship and others where Homo and the great apes pulled apart from one another due to shape differences. Homo and Pan are least sexually dimorphic in the mandible, Pan less so than Homo sapiens, but both the magnitude of sexual dimorphism and the distribution of sexually dimorphic measurements varied both among and between modern humans and great apes. Intraspecific variation among the 10 populations of modern humans was less than that generally reported in studies of crania (74.3% of mandibles were correctly classified into 1 of 10 populations using discriminant functions based on 13 variables as compared with 93% of crania from 17 populations based on 70 variables in one extensive study of crania). A subrecent European population (Poundbury) emerged as more different from a recent European population (Spitalfields) than other more diverse modern populations were from each other, suggesting considerable morphological plasticity in the mandible through time. This study forms a sound basis on which to explore mandibular variation in Neanderthals, early Homo sapiens and other more ancient fossil hominids. PMID:10634689

  20. Homo-Dimers of Vanillin and Apocynin Decrease Metastatic Potential of Human Cancer Cells by Inhibiting the FAK/PI3K/Akt Signaling Pathway.

    PubMed

    Jantaree, Phatcharida; Lirdprapamongkol, Kriengsak; Kaewsri, Wilailak; Thongsornkleeb, Charnsak; Choowongkomon, Kiattawee; Atjanasuppat, Korakot; Ruchirawat, Somsak; Svasti, Jisnuson

    2017-03-01

    The spread of cancer cells to distant organs, in a process called metastasis, is the main factor that contributes to most death in cancer patients. Vanillin, the vanilla flavoring agent, has been shown to suppress metastasis in a mouse model. Here, we evaluated the anti-metastatic potential of the food additive divanillin, the homo-dimer of vanillin, and their structurally related compounds, apocynin and diapocynin, in hepatocellular carcinoma cells. The Transwell invasion assay showed that the dimeric forms exhibited higher potency than vanillin and apocynin in inhibiting invasion, with IC50 values of 23.3±7.4 to 41.3±4.2 μM for the dimers, which are 26-34 fold lower than IC50 values of vanillin and apocynin (p<0.05). Both monomeric and dimeric forms target regulation of the invasion process, by inhibiting phosphorylation of FAK and Akt. Molecular docking studies suggested that the dimers should bind more tightly than vanillin and apocynin to the Y397 pocket of FAK FERM domain. Thus, the food additive divanillin has greater anti-metastatic potential than the flavoring agent vanillin.

  1. From Australopithecus to Homo: the transition that wasn't.

    PubMed

    Kimbel, William H; Villmoare, Brian

    2016-07-05

    Although the transition from Australopithecus to Homo is usually thought of as a momentous transformation, the fossil record bearing on the origin and earliest evolution of Homo is virtually undocumented. As a result, the poles of the transition are frequently attached to taxa (e.g. A. afarensis, at ca 3.0 Ma versus H. habilis or H. erectus, at ca 2.0-1.7 Ma) in which substantial adaptive differences have accumulated over significant spans of independent evolution. Such comparisons, in which temporally remote and adaptively divergent species are used to identify a 'transition', lend credence to the idea that genera should be conceived at once as monophyletic clades and adaptively unified grades. However, when the problem is recast in terms of lineages, rather than taxa per se, the adaptive criterion becomes a problem of subjectively privileging 'key' characteristics from what is typically a stepwise pattern of acquisition of novel characters beginning in the basal representatives of a clade. This is the pattern inferred for species usually included in early Homo, including H. erectus, which has often been cast in the role as earliest humanlike hominin. A fresh look at brain size, hand morphology and earliest technology suggests that a number of key Homo attributes may already be present in generalized species of Australopithecus, and that adaptive distinctions in Homo are simply amplifications or extensions of ancient hominin trends.This article is part of the themed issue 'Major transitions in human evolution'.

  2. A re-examination of the human fossil specimen from Bački Petrovac (Serbia).

    PubMed

    Radović, Predrag; Lindal, Joshua Allan; Roksandic, Mirjana

    2014-08-01

    A fragmented human calotte was discovered during the early 1950s near Bački Petrovac (Serbia), in association with Palaeolithic stone tools. After its initial publication, the fossil specimen remained largely unknown outside of the Serbian academe and no detailed comparative study has ever been carried out. Since the whereabouts of the fossil itself are currently unknown, and given its potential significance for the Pleistocene human evolution, we re-examine the data published by Živanović (1966, 1975). Using the original measurements, mostly taken on the frontal bone, and a wide comparative sample of 68 fossil specimens, the fossil was compared and analyzed by statistical multivariate methods. We also conducted a visual examination of the morphology based on the available photographic material. Our analysis reveals phenetic similarity with Middle Pleistocene archaic Homo from Africa and anatomically modern Homo sapiens. However, the absence of primitive cranial traits in Bački Petrovac indicates a clear modern Homo sapiens designation. Although lost at the moment, there is a chance for the re-discovery of the fossil in the years to come. This would give us an opportunity to acquire absolute dates and to study the specimen in a more detailed manner.

  3. Homo erectus at Trinil on Java used shells for tool production and engraving.

    PubMed

    Joordens, Josephine C A; d'Errico, Francesco; Wesselingh, Frank P; Munro, Stephen; de Vos, John; Wallinga, Jakob; Ankjærgaard, Christina; Reimann, Tony; Wijbrans, Jan R; Kuiper, Klaudia F; Mücher, Herman J; Coqueugniot, Hélène; Prié, Vincent; Joosten, Ineke; van Os, Bertil; Schulp, Anne S; Panuel, Michel; van der Haas, Victoria; Lustenhouwer, Wim; Reijmer, John J G; Roebroeks, Wil

    2015-02-12

    The manufacture of geometric engravings is generally interpreted as indicative of modern cognition and behaviour. Key questions in the debate on the origin of such behaviour are whether this innovation is restricted to Homo sapiens, and whether it has a uniquely African origin. Here we report on a fossil freshwater shell assemblage from the Hauptknochenschicht ('main bone layer') of Trinil (Java, Indonesia), the type locality of Homo erectus discovered by Eugène Dubois in 1891 (refs 2 and 3). In the Dubois collection (in the Naturalis museum, Leiden, The Netherlands) we found evidence for freshwater shellfish consumption by hominins, one unambiguous shell tool, and a shell with a geometric engraving. We dated sediment contained in the shells with (40)Ar/(39)Ar and luminescence dating methods, obtaining a maximum age of 0.54 ± 0.10 million years and a minimum age of 0.43 ± 0.05 million years. This implies that the Trinil Hauptknochenschicht is younger than previously estimated. Together, our data indicate that the engraving was made by Homo erectus, and that it is considerably older than the oldest geometric engravings described so far. Although it is at present not possible to assess the function or meaning of the engraved shell, this discovery suggests that engraving abstract patterns was in the realm of Asian Homo erectus cognition and neuromotor control.

  4. Human origins: Out of Africa

    PubMed Central

    Tattersall, Ian

    2009-01-01

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200–150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was “discovered” via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent. PMID:19805256

  5. Three new human skulls from the Sima de los Huesos Middle Pleistocene site in Sierra de Atapuerca, Spain.

    PubMed

    Arsuaga, J L; Martínez, I; Gracia, A; Carretero, J M; Carbonell, E

    1993-04-08

    Three important fossil hominids were found in July 1992 in the Middle Pleistocene cave site called Sima de los Huesos (Sierra de Atapuerca, Burgos, Northern Spain). One is a complete calvaria (cranium 4), the second a virtually complete cranium (cranium 5), the third represents a more fragmentary cranium of an immature individual (cranium 6). There is a large difference in size between the two adult specimens (for example endocranial volume 1,125 cm3 versus 1,390 cm3). The Atapuerca human remains are dated to > 300,000 years. The Atapuerca cranial sample fits within the 'archaic Homo sapiens' group, but is well differentiated from the Asian Homo erectus group. The extensive Atapuerca human collection is the most complete sample of Middle Pleistocene humans yet discovered from one site, and appears to document an early stage in Neanderthal evolution.

  6. Qualitative and Quantitative analysis of 3D predicted arachidonate 15-lipoxygenase-B (15-LOX-2) from Homo sapiens.

    PubMed

    Arora, Neha; Singh, Vinay Kumar; Shah, Kavita; Pandey-Rai, Shashi

    2012-01-01

    15-Lipoxygenase-2 protein has been reported to play an important role in normal development of prostate, lung, skin, and cornea tissues. It behaves as a suppressor of prostate cancer development by restricting cell cycle progression and implicating a possible protective role against tumor formation. On the basis of the above report, we selected 15-LOX-2 protein to study the structural classification and functional relationship with associated protein network at computational level. Sequence alignment and protein functional study shows that it contains a highly conserved LOX motif. PLAT domain with PF01477 and LH2 domain with PF00305 were successfully observed. Arachidonate 5-lipoxygenase (PDB ID: 3O8Y) was selected as a template with 42% identity. 3D structure was successfully predicted and verified. Qualitative analysis suggests that the predicted model was reliable and stable with best quality. Quantitative study shows that the model contained expected volume and area with best resolution. Predicted and best evaluated model has been successfully deposited to PMDB database with PMDB ID PM0078035. Active site identification revealed GLU(369), ALA(370), LEU(371), THR(372), HIS(373), LEU(374), HIS(376), SER(377), HIS(378), THR(385), LEU(389), HIS(394), PHE(399), LYS(400), LEU(401), ILE(403) and PRO(404) residues may play a major role during protein-protein, protein-drug and protein-cofactor interactions. STRING database result indicated that IL (4), GPX (2 and 4), PPARG, PTGS (1 and 2), CYP (2J2, 2C8, 4A11 and 2B6), PLA (2G2A, 2G4A, 2G1B and 2G6) and A LOX (5, 15, 12 and 12B) members from their respective gene families have network based functional association with 15-LOX-2.

  7. High mutation rates explain low population genetic divergence at copy-number-variable loci in Homo sapiens

    PubMed Central

    Hu, Xin-Sheng; Yeh, Francis C.; Hu, Yang; Deng, Li-Ting; Ennos, Richard A.; Chen, Xiaoyang

    2017-01-01

    Copy-number-variable (CNV) loci differ from single nucleotide polymorphic (SNP) sites in size, mutation rate, and mechanisms of maintenance in natural populations. It is therefore hypothesized that population genetic divergence at CNV loci will differ from that found at SNP sites. Here, we test this hypothesis by analysing 856 CNV loci from the genomes of 1184 healthy individuals from 11 HapMap populations with a wide range of ancestry. The results show that population genetic divergence at the CNV loci is generally more than three times lower than at genome-wide SNP sites. Populations generally exhibit very small genetic divergence (Gst = 0.05 ± 0.049). The smallest divergence is among African populations (Gst = 0.0081 ± 0.0025), with increased divergence among non-African populations (Gst = 0.0217 ± 0.0109) and then among African and non-African populations (Gst = 0.0324 ± 0.0064). Genetic diversity is high in African populations (~0.13), low in Asian populations (~0.11), and intermediate in the remaining 11 populations. Few significant linkage disequilibria (LDs) occur between the genome-wide CNV loci. Patterns of gametic and zygotic LDs indicate the absence of epistasis among CNV loci. Mutation rate is about twice as large as the migration rate in the non-African populations, suggesting that the high mutation rates play dominant roles in producing the low population genetic divergence at CNV loci. PMID:28225073

  8. Hominid mandibular corpus shape variation and its utility for recognizing species diversity within fossil Homo

    PubMed Central

    Lague, Michael R; Collard, Nicole J; Richmond, Brian G; Wood, Bernard A

    2008-01-01

    Mandibular corpora are well represented in the hominin fossil record, yet few studies have rigorously assessed the utility of mandibular corpus morphology for species recognition, particularly with respect to the linear dimensions that are most commonly available. In this study, we explored the extent to which commonly preserved mandibular corpus morphology can be used to: (i) discriminate among extant hominid taxa and (ii) support species designations among fossil specimens assigned to the genus Homo. In the first part of the study, discriminant analysis was used to test for significant differences in mandibular corpus shape at different taxonomic levels (genus, species and subspecies) among extant hominid taxa (i.e. Homo, Pan, Gorilla, Pongo). In the second part of the study, we examined shape variation among fossil mandibles assigned to Homo(including H. habilis sensu stricto, H. rudolfensis, early African H. erectus/H. ergaster, late African H. erectus, Asian H. erectus, H. heidelbergensis, H. neanderthalensis and H. sapiens). A novel randomization procedure designed for small samples (and using group ‘distinctness values’) was used to determine whether shape variation among the fossils is consistent with conventional taxonomy (or alternatively, whether a priori taxonomic groupings are completely random with respect to mandibular morphology). The randomization of ‘distinctness values’ was also used on the extant samples to assess the ability of the test to recognize known taxa. The discriminant analysis results demonstrated that, even for a relatively modest set of traditional mandibular corpus measurements, we can detect significant differences among extant hominids at the genus and species levels, and, in some cases, also at the subspecies level. Although the randomization of ‘distinctness values’ test is more conservative than discriminant analysis (based on comparisons with extant specimens), we were able to detect at least four distinct groups

  9. [Symbol-based communication in non-human primates: a C. S. Peirce's semiotic analysis].

    PubMed

    Queiroz, João

    2003-12-01

    Are (or were) there any other symbolic species? This question has been addressed by researchers from many different fields and is responsible for a historical controversy on the existence of a threshold between "symbolic creatures" vs "simple forms of language creatures". According to the mainstream ethology and comparative psychology only the Homo sapiens is cognitively equiped to produce and interpret symbols. Here, I introduce an empirically testable model of symbolic semiosis ("symbolic action of sign") supported by C.S.Peirce logical-phenomenological theory of categories. I suggest that a specific sign-user pattern of behavior, observed in non-human primate communication, indicate a transition from indexical to symbolic semiosis.

  10. Stature estimation from complete long bones in the Middle Pleistocene humans from the Sima de los Huesos, Sierra de Atapuerca (Spain).

    PubMed

    Carretero, José-Miguel; Rodríguez, Laura; García-González, Rebeca; Arsuaga, Juan-Luis; Gómez-Olivencia, Asier; Lorenzo, Carlos; Bonmatí, Alejandro; Gracia, Ana; Martínez, Ignacio; Quam, Rolf

    2012-02-01

    Systematic excavations at the site of the Sima de los Huesos (SH) in the Sierra de Atapuerca (Burgos, Spain) have allowed us to reconstruct 27 complete long bones of the human species Homo heidelbergensis. The SH sample is used here, together with a sample of 39 complete Homo neanderthalensis long bones and 17 complete early Homo sapiens (Skhul/Qafzeh) long bones, to compare the stature of these three different human species. Stature is estimated for each bone using race- and sex-independent regression formulae, yielding an average stature for each bone within each taxon. The mean length of each long bone from SH is significantly greater (p < 0.05) than the corresponding mean values in the Neandertal sample. The stature has been calculated for male and female specimens separately, averaging both means to calculate a general mean. This general mean stature for the entire sample of long bones is 163.6 cm for the SH hominins, 160.6 cm for Neandertals and 177.4 cm for early modern humans. Despite some overlap in the ranges of variation, all mean values in the SH sample (whether considering isolated bones, the upper or lower limb, males or females or more complete individuals) are larger than those of Neandertals. Given the strong relationship between long bone length and stature, we conclude that SH hominins represent a slightly taller population or species than the Neandertals. However, compared with living European Mediterranean populations, neither the Sima de los Huesos hominins nor the Neandertals should be considered 'short' people. In fact, the average stature within the genus Homo seems to have changed little over the course of the last two million years, since the appearance of Homo ergaster in East Africa. It is only with the emergence of H. sapiens, whose earliest representatives were 'very tall', that a significant increase in stature can be documented.

  11. Quantitative three-dimensional shape analysis of the proximal hallucial metatarsal articular surface in Homo, Pan, Gorilla, and Hylobates.

    PubMed

    Proctor, Daniel J; Broadfield, Douglas; Proctor, Kristopher

    2008-02-01

    Multidimensional morphometrics is used to compare the proximal articular surface of the first metatarsal between Homo, Pan, Gorilla, Hylobates, and the hominin fossils A.L. 333-54 (A. afarensis), SKX 5017 (P. robustus), and OH 8 (H. habilis). Statistically significant differences in articular surface morphology exist between H. sapiens and the apes, and between ape groups. Ape groups are characterized by greater surface depth, an obliquely curved articular surface through the dorso-lateral and medio-plantar regions, and a wider medio-lateral surface relative to the dorso-plantar height. The OH 8 articular surface is indistinguishable from H. sapiens, while A.L. 333-54 and SKX 5017 more closely resemble the apes. P. robustus and A. afarensis exhibit ape-like oblique curvature of the articular surface.

  12. Human basal body basics.

    PubMed

    Vertii, Anastassiia; Hung, Hui-Fang; Hehnly, Heidi; Doxsey, Stephen

    2016-01-01

    In human cells, the basal body (BB) core comprises a ninefold microtubule-triplet cylindrical structure. Distal and subdistal appendages are located at the distal end of BB, where they play indispensable roles in cilium formation and function. Most cells that arrest in the G0 stage of the cell cycle initiate BB docking at the plasma membrane followed by BB-mediated growth of a solitary primary cilium, a structure required for sensing the extracellular environment and cell signaling. In addition to the primary cilium, motile cilia are present in specialized cells, such as sperm and airway epithelium. Mutations that affect BB function result in cilia dysfunction. This can generate syndromic disorders, collectively called ciliopathies, for which there are no effective treatments. In this review, we focus on the features and functions of BBs and centrosomes in Homo sapiens.

  13. Human evolution: taxonomy and paleobiology

    PubMed Central

    WOOD, BERNARD; RICHMOND, BRIAN G.

    2000-01-01

    This review begins by setting out the context and the scope of human evolution. Several classes of evidence, morphological, molecular, and genetic, support a particularly close relationship between modern humans and the species within the genus Pan, the chimpanzee. Thus human evolution is the study of the lineage, or clade, comprising species more closely related to modern humans than to chimpanzees. Its stem species is the so-called ‘common hominin ancestor’, and its only extant member is Homo sapiens. This clade contains all the species more closely-related to modern humans than to any other living primate. Until recently, these species were all subsumed into a family, Hominidae, but this group is now more usually recognised as a tribe, the Hominini. The rest of the review sets out the formal nomenclature, history of discovery, and information about the characteristic morphology, and its behavioural implications, of the species presently included in the human clade. The taxa are considered within their assigned genera, beginning with the most primitive and finishing with Homo. Within genera, species are presented in order of geological age. The entries conclude with a list of the more important items of fossil evidence, and a summary of relevant taxonomic issues. PMID:10999270

  14. Late Pleistocene climate drivers of early human migration

    NASA Astrophysics Data System (ADS)

    Timmermann, Axel; Friedrich, Tobias

    2016-10-01

    On the basis of fossil and archaeological data it has been hypothesized that the exodus of Homo sapiens out of Africa and into Eurasia between ~50-120 thousand years ago occurred in several orbitally paced migration episodes. Crossing vegetated pluvial corridors from northeastern Africa into the Arabian Peninsula and the Levant and expanding further into Eurasia, Australia and the Americas, early H. sapiens experienced massive time-varying climate and sea level conditions on a variety of timescales. Hitherto it has remained difficult to quantify the effect of glacial- and millennial-scale climate variability on early human dispersal and evolution. Here we present results from a numerical human dispersal model, which is forced by spatiotemporal estimates of climate and sea level changes over the past 125 thousand years. The model simulates the overall dispersal of H. sapiens in close agreement with archaeological and fossil data and features prominent glacial migration waves across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. The findings document that orbital-scale global climate swings played a key role in shaping Late Pleistocene global population distributions, whereas millennial-scale abrupt climate changes, associated with Dansgaard-Oeschger events, had a more limited regional effect.

  15. Late Pleistocene climate drivers of early human migration.

    PubMed

    Timmermann, Axel; Friedrich, Tobias

    2016-10-06

    On the basis of fossil and archaeological data it has been hypothesized that the exodus of Homo sapiens out of Africa and into Eurasia between ~50-120 thousand years ago occurred in several orbitally paced migration episodes. Crossing vegetated pluvial corridors from northeastern Africa into the Arabian Peninsula and the Levant and expanding further into Eurasia, Australia and the Americas, early H. sapiens experienced massive time-varying climate and sea level conditions on a variety of timescales. Hitherto it has remained difficult to quantify the effect of glacial- and millennial-scale climate variability on early human dispersal and evolution. Here we present results from a numerical human dispersal model, which is forced by spatiotemporal estimates of climate and sea level changes over the past 125 thousand years. The model simulates the overall dispersal of H. sapiens in close agreement with archaeological and fossil data and features prominent glacial migration waves across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. The findings document that orbital-scale global climate swings played a key role in shaping Late Pleistocene global population distributions, whereas millennial-scale abrupt climate changes, associated with Dansgaard-Oeschger events, had a more limited regional effect.

  16. The thigh and leg of Homo naledi.

    PubMed

    Marchi, Damiano; Walker, Christopher S; Wei, Pianpian; Holliday, Trenton W; Churchill, Steven E; Berger, Lee R; DeSilva, Jeremy M

    2017-03-01

    This paper describes the 108 femoral, patellar, tibial, and fibular elements of a new species of Homo (Homo naledi) discovered in the Dinaledi chamber of the Rising Star cave system in South Africa. Homo naledi possesses a mosaic of primitive, derived, and unique traits functionally indicative of a bipedal hominin adapted for long distance walking and possibly running. Traits shared with australopiths include an anteroposteriorly compressed femoral neck, a mediolaterally compressed tibia, and a relatively circular fibular neck. Traits shared with Homo include a well-marked linea aspera, anteroposteriorly thick patellae, relatively long tibiae, and gracile fibulae with laterally oriented lateral malleoli. Unique features include the presence of two pillars on the superior aspect of the femoral neck and a tubercular distal insertion of the pes anserinus on the tibia. The mosaic morphology of the H. naledi thigh and leg appears most consistent with a species intermediate between Australopithecus spp. and Homo erectus and, accordingly, may offer insight into the nature of the earliest members of genus Homo. These fossils also expand the morphological diversity of the Homo lower limb, perhaps indicative of locomotor diversity in our genus.

  17. The Age of the 20 Meter Solo River Terrace, Java, Indonesia and the Survival of Homo erectus in Asia

    PubMed Central

    Indriati, Etty; Swisher, Carl C.; Lepre, Christopher; Quinn, Rhonda L.; Suriyanto, Rusyad A.; Hascaryo, Agus T.; Grün, Rainer; Feibel, Craig S.; Pobiner, Briana L.; Aubert, Maxime; Lees, Wendy; Antón, Susan C.

    2011-01-01

    Homo erectus was the first human lineage to disperse widely throughout the Old World, the only hominin in Asia through much of the Pleistocene, and was likely ancestral to H. sapiens. The demise of this taxon remains obscure because of uncertainties regarding the geological age of its youngest populations. In 1996, some of us co-published electron spin resonance (ESR) and uranium series (U-series) results indicating an age as young as 35–50 ka for the late H. erectus sites of Ngandong and Sambungmacan and the faunal site of Jigar (Indonesia). If correct, these ages favor an African origin for recent humans who would overlap with H. erectus in time and space. Here, we report 40Ar/39Ar incremental heating analyses and new ESR/U-series age estimates from the “20 m terrace" at Ngandong and Jigar. Both data sets are internally consistent and provide no evidence for reworking, yet they are inconsistent with one another. The 40Ar/39Ar analyses give an average age of 546±12 ka (sd±5 se) for both sites, the first reliable radiometric indications of a middle Pleistocene component for the terrace. Given the technical accuracy and consistency of the analyses, the argon ages represent either the actual age or the maximum age for the terrace and are significantly older than previous estimates. Most of the ESR/U-series results are older as well, but the oldest that meets all modeling criteria is 143 ka+20/−17. Most samples indicated leaching of uranium and likely represent either the actual or the minimum age of the terrace. Given known sources of error, the U-series results could be consistent with a middle Pleistocene age. However, the ESR and 40Ar/39Ar ages preclude one another. Regardless, the age of the sites and hominins is at least bracketed between these estimates and is older than currently accepted. PMID:21738710

  18. The age of the 20 meter Solo River terrace, Java, Indonesia and the survival of Homo erectus in Asia.

    PubMed

    Indriati, Etty; Swisher, Carl C; Lepre, Christopher; Quinn, Rhonda L; Suriyanto, Rusyad A; Hascaryo, Agus T; Grün, Rainer; Feibel, Craig S; Pobiner, Briana L; Aubert, Maxime; Lees, Wendy; Antón, Susan C

    2011-01-01

    Homo erectus was the first human lineage to disperse widely throughout the Old World, the only hominin in Asia through much of the Pleistocene, and was likely ancestral to H. sapiens. The demise of this taxon remains obscure because of uncertainties regarding the geological age of its youngest populations. In 1996, some of us co-published electron spin resonance (ESR) and uranium series (U-series) results indicating an age as young as 35-50 ka for the late H. erectus sites of Ngandong and Sambungmacan and the faunal site of Jigar (Indonesia). If correct, these ages favor an African origin for recent humans who would overlap with H. erectus in time and space. Here, we report (40)Ar/(39)Ar incremental heating analyses and new ESR/U-series age estimates from the "20 m terrace" at Ngandong and Jigar. Both data sets are internally consistent and provide no evidence for reworking, yet they are inconsistent with one another. The (40)Ar/(39)Ar analyses give an average age of 546±12 ka (sd±5 se) for both sites, the first reliable radiometric indications of a middle Pleistocene component for the terrace. Given the technical accuracy and consistency of the analyses, the argon ages represent either the actual age or the maximum age for the terrace and are significantly older than previous estimates. Most of the ESR/U-series results are older as well, but the oldest that meets all modeling criteria is 143 ka+20/-17. Most samples indicated leaching of uranium and likely represent either the actual or the minimum age of the terrace. Given known sources of error, the U-series results could be consistent with a middle Pleistocene age. However, the ESR and (40)Ar/(39)Ar ages preclude one another. Regardless, the age of the sites and hominins is at least bracketed between these estimates and is older than currently accepted.

  19. Human-Specific Cortical Synaptic Connections and Their Plasticity: Is That What Makes Us Human?

    PubMed Central

    Lourenço, Joana; Bacci, Alberto

    2017-01-01

    One outstanding difference between Homo sapiens and other mammals is the ability to perform highly complex cognitive tasks and behaviors, such as language, abstract thinking, and cultural diversity. How is this accomplished? According to one prominent theory, cognitive complexity is proportional to the repetition of specific computational modules over a large surface expansion of the cerebral cortex (neocortex). However, the human neocortex was shown to also possess unique features at the cellular and synaptic levels, raising the possibility that expanding the computational module is not the only mechanism underlying complex thinking. In a study published in PLOS Biology, Szegedi and colleagues analyzed a specific cortical circuit from live postoperative human tissue, showing that human-specific, very powerful excitatory connections between principal pyramidal neurons and inhibitory neurons are highly plastic. This suggests that exclusive plasticity of specific microcircuits might be considered among the mechanisms endowing the human neocortex with the ability to perform highly complex cognitive tasks. PMID:28103228

  20. Glycan structure and site of glycosylation in the ER-resident glycoprotein, uridine 5'-diphosphate-glucose: glycoprotein glucosyltransferases 1 from rat, porcine, bovine, and human.

    PubMed

    Daikoku, Shusaku; Seko, Akira; Ito, Yukishige; Kanie, Osamu

    2014-08-29

    Here we report glycan structures and their position of attachment to a carrier protein, uridine 5'-diphosphate-glucose: glycoprotein glucosyltransferase (UGGT1), as detected using tandem mass spectrometry. UGGT1 acts as a folding sensor of newly synthesized glycosylated polypeptides in the endoplasmic reticulum, and the transferase itself is known to be glycosylated. The structure of glycan attached to UGGT1, however, has not been investigated. In this study, we reveal the site of glycosylation (N269) and the glycan structures (Hex5-8HexNAc2) in UGGT1 obtained from rat (Rattus norvegicus), pig (Sus scrofa), cow (Bos taurus), and human (Homo sapiens).

  1. How We Got Here: Evolutionary Changes in Skull Shape in Humans & Their Ancestors

    ERIC Educational Resources Information Center

    Price, Rebecca M.

    2012-01-01

    This activity uses inquiry to investigate how large changes in shape can evolve from small changes in the timing of development. Students measure skull shape in fetal, infant, juvenile, and adult chimpanzees and compare them to adult skulls of "Homo sapiens," "Homo erectus," and "Australopithecus afarensis." They conclude by re-interpreting their…

  2. Is Homo heidelbergensis a distinct species? New insight on the Mauer mandible.

    PubMed

    Mounier, Aurélien; Marchal, François; Condemi, Silvana

    2009-03-01

    The discovery of new fossils in Africa, Asia, and Europe, and the recognition of a greater diversity in the middle Pleistocene fossil record, has led to a reconsideration of the species Homo heidelbergensis. This nomen, formulated by Schoetensack in 1908 to describe the Mauer jaw (Germany), was almost forgotten during most of the past century. Numerous fossils have been attributed to it but no consensus has arisen concerning their classification. The holotype anatomical traits are still poorly understood, and numerous fossils with no mandibular remains have been placed in the taxon. Some researchers propose H. heidelbergensis as an Afro-European taxon that is ancestral to both modern humans and Neandertals whereas others think it is a strictly European species that is part of the Neandertal lineage. We focus on the validity of H. heidelbergensis, using the traditional basis of species recognition: anatomical description. We provide a comparative morphological analysis using 47 anatomical traits of 36 Pleistocene fossils from Africa, Asia, and Europe and 35 extant human mandibles. We re-examine the mandibular features of Mauer and discuss the specimen's inclusion in H. heidelbergensis, as well as alternative evolutionary theories. To lend objectivity to specimen grouping, we use multiple correspondence analysis associated with hierarchical classification that creates clusters corresponding to phenetic similarities between jaws. Our phenetic and comparative morphological analyses support the validity of H. heidelbergensis as a taxon. A set of morphological features can be statistically identified for the definition of the species. Some traits can be used to delimit H. heidelbergensis in an evolutionary framework (e.g., foramina mentale posteriorly positioned, horizontal retromolar surface). Those traits are also present on African (e.g., Tighenif) and European (e.g., Sima de los Huesos) specimens that show a close relationship with the Mauer mandible. Therefore, the

  3. Evolution and dispersal of the genus Homo: A landscape approach.

    PubMed

    Winder, Isabelle C; Devès, Maud H; King, Geoffrey C P; Bailey, Geoffrey N; Inglis, Robyn H; Meredith-Williams, Matthew

    2015-10-01

    The notion of the physical landscape as an arena of ecological interaction and human evolution is a powerful one, but its implementation at larger geographical and temporal scales is hampered by the challenges of reconstructing physical landscape settings in the geologically active regions where the earliest evidence is concentrated. We argue that the inherently dynamic nature of these unstable landscapes has made them important agents of biological change, creating complex topographies capable of selecting for, stimulating, obstructing or accelerating the latent and emerging properties of the human evolutionary trajectory. We use this approach, drawing on the concepts and methods of active tectonics, to develop a new perspective on the origins and dispersal of the Homo genus. We show how complex topography provides an easy evolutionary pathway to full terrestrialisation in the African context, and would have further equipped members of the genus Homo with a suite of adaptive characteristics that facilitated wide-ranging dispersal across ecological and climatic boundaries into Europe and Asia by following pathways of complex topography. We compare this hypothesis with alternative explanations for hominin dispersal, and evaluate it by mapping the distribution of topographic features at varying scales, and comparing the distribution of early Homo sites with the resulting maps and with other environmental variables.

  4. A new skull of early Homo from Dmanisi, Georgia.

    PubMed

    Vekua, Abesalom; Lordkipanidze, David; Rightmire, G Philip; Agusti, Jordi; Ferring, Reid; Maisuradze, Givi; Mouskhelishvili, Alexander; Nioradze, Medea; De Leon, Marcia Ponce; Tappen, Martha; Tvalchrelidze, Merab; Zollikofer, Christoph

    2002-07-05

    Another hominid skull has been recovered at Dmanisi (Republic of Georgia) from the same strata in which hominid remains have been reported previously. The Dmanisi site dated to approximately 1.75 million years ago has now produced craniofacial portions of several hominid individuals, along with many well-preserved animal fossils and quantities of stone artifacts. Although there are certain anatomical differences among the Dmanisi specimens, the hominids do not clearly represent more than one taxon. We assign the new skull provisionally to Homo erectus (=ergaster). The Dmanisi specimens are the most primitive and small-brained fossils to be grouped with this species or any taxon linked unequivocally with genus Homo and also the ones most similar to the presumed habilis-like stem. We suggest that the ancestors of the Dmanisi population dispersed from Africa before the emergence of humans identified broadly with the H. erectus grade.

  5. The craniomandibular mechanics of being human

    PubMed Central

    Wroe, Stephen; Ferrara, Toni L.; McHenry, Colin R.; Curnoe, Darren; Chamoli, Uphar

    2010-01-01

    Diminished bite force has been considered a defining feature of modern Homo sapiens, an interpretation inferred from the application of two-dimensional lever mechanics and the relative gracility of the human masticatory musculature and skull. This conclusion has various implications with regard to the evolution of human feeding behaviour. However, human dental anatomy suggests a capacity to withstand high loads and two-dimensional lever models greatly simplify muscle architecture, yielding less accurate results than three-dimensional modelling using multiple lines of action. Here, to our knowledge, in the most comprehensive three-dimensional finite element analysis performed to date for any taxon, we ask whether the traditional view that the bite of H. sapiens is weak and the skull too gracile to sustain high bite forces is supported. We further introduce a new method for reconstructing incomplete fossil material. Our findings show that the human masticatory apparatus is highly efficient, capable of producing a relatively powerful bite using low muscle forces. Thus, relative to other members of the superfamily Hominoidea, humans can achieve relatively high bite forces, while overall stresses are reduced. Our findings resolve apparently discordant lines of evidence, i.e. the presence of teeth well adapted to sustain high loads within a lightweight cranium and mandible. PMID:20554545

  6. Vasopressin Gene-Related Products in the Management of Breast Cancer

    DTIC Science & Technology

    1997-10-01

    mRNA, complete cds. ACCESSION AFO17061 NID g2394273 KEYWORDS . SOURCE human. ORGANISM Homo sapiens Eukaryotae; Metazoa; Chordata ... Chordata ; Vertebrata; Mammalia; Eutheria; Primates; Catarrhini; Hominidae; Homo. REFERENCE 1 (bases 1 to 1298) AUTHORS Thibonnier,M., Auzan.C...SOURCE human. ORGANISM Homo sapiens Eukaryotae; Metazoa; Chordata ; Vertebrata; Mammalia; Euthena; Primates; Catarrhini; Hominidae; Homo

  7. Computational interaction analysis of organophosphorus pesticides with different metabolic proteins in humans

    PubMed Central

    Sharma, Amit Kumar; Gaur, Karuna; Tiwari, Rajeev Kumar; Gaur, Mulayam Singh

    2011-01-01

    Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed through the skin, inhalation, eyes and oral mucosa, are most important targets for this interaction study. The crystal structure of five different proteins, PDBIDs: 3LII, 3NXU, 4GTU, 2XJ1 and 1YXA in Homo sapiens (H. sapiens), interact with organophosphorus pesticides at the molecular level. The 3-D structures were found to be of good quality and validated through PROCHECK, ERRAT and ProSA servers. The results show that the binding energy is maximum -45.21 relative units of cytochrome P450 protein with phosmet pesticide. In terms of H-bonding, methyl parathion and parathion with acetylcholinesterase protein, parathion, methylparathion and phosmet with protein kinase C show the highest interaction. We conclude that these organophosphorus pesticides are more toxic and inhibit enzymatic activity by interrupting the metabolic pathways in H. sapiens. PMID:23554709

  8. Decision support system for individualized nursing procedures: SAPIEN-Tx.

    PubMed

    Ito, M; Ramos, M P; Chern, M S; Espósito, S R; Carmagnani, M I; Cunha, I C; Piveta, V M; Nespoulos, E; Iwasa, A T; Anção, M S

    1995-01-01

    The present work proposes a Decision Support System for nursing procedures: SAPIEN-Tx. The discussion includes the acquisition, modeling , and implementation of nursing expertise professionals in Renal Transplant. It was developed to obtain better quality healthcare services, as well as an effective contribution to the nursing professional in the global assistance of their clientele. We used the KADS methodology to develop the system knowledge base. This methodology permitted us to perform the knowledge modeling with quality and organization. In opposition to the old method, errors were detected before the implementation, avoiding possible modification on the whole project structure.

  9. Out of Africa: modern human origins special feature: the spread of modern humans in Europe.

    PubMed

    Hoffecker, John F

    2009-09-22

    The earliest credible evidence of Homo sapiens in Europe is an archaeological proxy in the form of several artifact assemblages (Bohunician) found in South-Central and possibly Eastern Europe, dating to < or =48,000 calibrated radiocarbon years before present (cal BP). They are similar to assemblages probably made by modern humans in the Levant (Emiran) at an earlier date and apparently represent a population movement into the Balkans during a warm climate interval [Greenland Interstadial 12 (GI 12)]. A second population movement may be represented by a diverse set of artifact assemblages (sometimes termed Proto-Aurignacian) found in the Balkans, parts of Southwest Europe, and probably in Eastern Europe, and dating to several brief interstadials (GI 11-GI 9) that preceded the beginning of cold Heinrich Event 4 (HE4) (approximately 40,000 cal BP). They are similar to contemporaneous assemblages made by modern humans in the Levant (Ahmarian). The earliest known human skeletal remains in Europe that may be unequivocally assigned to H. sapiens (Peçstera cu Oase, Romania) date to this time period (approximately 42,000 cal BP) but are not associated with artifacts. After the Campanian Ignimbrite volcanic eruption (40,000 cal BP) and the beginning of HE4, artifact assemblages assigned to the classic Aurignacian, an industry associated with modern human skeletal remains that seems to have developed in Europe, spread throughout the continent.

  10. Nutrigenetics in the light of human evolution.

    PubMed

    Verginelli, Fabio; Aru, Federica; Battista, Pasquale; Mariani-Costantini, Renato

    2009-01-01

    Bio-cultural adaptations to new foods played a key role in human evolution. The fossil record and sequence differences between human and chimpanzee genes point to a major dietary shift at the stem of human evolution. The earliest representatives of the human lineage diverged from the ancestors of chimpanzees because of their better adaptation to hard and abrasive foods. Bipedalism and modifications of the hand, which allowed tool manufacture and use, impacted on dietary flexibility, facilitating access to foods of animal origin. This promoted major anatomic, physiologic and metabolic adaptations. Encephalization, which requires high-quality diet, characterizes the evolutionary sequence that, through the Homo ergaster/erectus stages, led to our species, Homo sapiens, which originated in Africa about 200,000 years ago. At the end of the Ice Age, climatic changes and human impact determined a major food crisis, which triggered the agricultural revolution. This affected nutrition and health, with rapid evolutionary adaptations through the selection of genetic variants that allowed better utilization of new foods, different in relation to geography and culture. Today population growth, globalization and economic pressure powerfully affect diets worldwide. We must take into account our evolutionary past to meet the present nutritional challenges.

  11. Morphological and population genomic evidence that human faces have evolved to signal individual identity

    PubMed Central

    Nachman, Michael W

    2014-01-01

    Facial recognition plays a key role in human interactions, and there has been great interest in understanding the evolution of human abilities for individual recognition and tracking social relationships. Individual recognition requires sufficient cognitive abilities and phenotypic diversity within a population for discrimination to be possible. Despite the importance of facial recognition in humans, the evolution of facial identity has received little attention. Here we demonstrate that faces evolved to signal individual identity under negative frequency-dependent selection. Faces show elevated phenotypic variation and lower between-trait correlations compared to other traits. Regions surrounding face-associated SNPs show elevated diversity consistent with frequency-dependent selection. Genetic variation maintained by identity signaling tends to be shared across populations and, for some loci, predates the origin of Homo sapiens. Studies of human social evolution tend to emphasize cognitive adaptations but we show that social evolution has shaped patterns of human phenotypic and genetic diversity as well. PMID:25226282

  12. Adult Neandertal clavicles from the El Sidrón site (Asturias, Spain) in the context of Homo pectoral girdle evolution.

    PubMed

    Rosas, Antonio; Rodriguez-Perez, Francisco Javier; Bastir, Markus; Estalrrich, Almudena; Huguet, Rosa; García-Tabernero, Antonio; Pastor, Juan Francisco; de la Rasilla, Marco

    2016-06-01

    We undertook a three-dimensional geometric morphometric (3DGM) analysis on 12 new Neandertal clavicle specimens from the El Sidrón site (Spain), dated to 49,000 years ago. The 3DGM methods were applied in a comparative framework in order to improve our understanding of trait polarity in features related to Homo pectoral girdle evolution, using other Neandertals, Homo sapiens, Pan, ATD6-50 (Homo antecessor), and KNM-WT 15000 (Homo ergaster/erectus) in the reference collection. Twenty-nine homologous landmarks were measured for each clavicle. Variation and morphological similarities were assessed through principal component analysis, conducted separately for the complete clavicle and the diaphysis. On average, Neandertal clavicles had significantly larger muscular entheses, double dorsal curvature, clavicle torsion, and cranial orientation of the acromial end than non-Neandertal clavicles; the El Sidrón clavicles fit this pattern. Variation within the samples was large, with extensive overlap between Homo species; only chimpanzee specimens clearly differed from the other specimens in morphometric terms. Taken together, our morphometric analyses are consistent with the following phylogenetic sequence. The primitive condition of the clavicle is manifest in the cranial orientation of both the acromial and sternal ends. The derived condition expressed in the H. sapiens + Neandertal clade is defined by caudal rotation of both the sternal and acromial ends, but with variation in the number of acromia remaining in a certain cranial orientation. Finally, the autapomorphic Neandertal condition is defined by secondarily acquired primitive cranial re-orientation of the acromial end, which varies from individual to individual. These results suggest that the pace of phylogenetic change in the pectoral girdle does not seem to follow that of other postcranial skeletal features.

  13. Direct evidence for the Homo-Pan clade.

    PubMed

    Wimmer, Rainer; Kirsch, Stefan; Rappold, Gudrun A; Schempp, Werner

    2002-01-01

    For a long time, the evolutionary relationship between human and African apes, the 'trichotomy problem', has been debated with strong differences in opinion and interpretation. Statistical analyses of different molecular DNA data sets have been carried out and have primarily supported a Homo-Pan clade. An alternative way to address this question is by the comparison of evolutionarily relevant chromosomal breakpoints. Here, we made use of a P1-derived artificial chromosome (PAC)/bacterial artificial chromosome (BAC) contig spanning approximately 2.8 Mb on the long arm of the human Y chromosome, to comparatively map individual PAC clones to chromosomes from great apes, gibbons, and two species of Old World monkeys by fluorescence in-situ hybridization. During our search for evolutionary breakpoints on the Y chromosome, it transpired that a transposition of an approximately 100-kb DNA fragment from chromosome 1 onto the Y chromosome must have occurred in a common ancestor of human, chimpanzee and bonobo. Only the Y chromosomes of these three species contain the chromosome-1-derived fragment; it could not be detected on the Y chromosomes of gorillas or the other primates examined. Thus, this shared derived (synapomorphic) trait provides clear evidence for a Homo-Pan clade independent of DNA sequence analysis.

  14. Viral and vector zoonotic exploitation of a homo-sociome memetic complex.

    PubMed

    Rupprecht, C E; Burgess, G W

    2015-05-01

    As most newly characterized emerging infectious diseases are considered to be zoonotic, a modern pre-eminence ascribed within this classification lies clearly within the viral taxonomic realm. In particular, RNA viruses deserve special concern given their documented impact on conservation biology, veterinary medicine and public health, with an unprecedented ability to promote an evolutionary host-pathogen arms race from the ultimate infection and immunity perspective. However, besides the requisite molecular/gross anatomical and physiological bases for infectious diseases to transmit from one host to another, both viral pathogens and their reservoirs/vectors exploit a complex anthropological, cultural, historical, psychological and social suite that specifically defines the phylodynamics within Homo sapiens, unlike any other species. Some of these variables include the ecological benefits of living in groups, decisions on hunting and foraging behaviours and dietary preferences, myths and religious doctrines, health economics, travel destinations, population planning, political decisions on agricultural product bans and many others, in a homo-sociome memetic complex. Taken to an extreme, such complexities elucidate the underpinnings of explanations as to why certain viral zoonoses reside in neglected people, places and things, whereas others are chosen selectively and prioritized for active mitigation. Canine-transmitted rabies serves as one prime example of how a neglected viral zoonosis may transition to greater attention on the basis of renewed advocacy, social media, local champions and vested international community engagement. In contrast, certain bat-associated and arboviral diseases suffer from basic ignorance and perpetuated misunderstanding of fundamental reservoir and vector ecology tenets, translated into failed control policies that only exacerbate the underlying environmental conditions of concern. Beyond applied biomedical knowledge, epidemiological

  15. Direct evidence for human reliance on rainforest resources in late Pleistocene Sri Lanka.

    PubMed

    Roberts, Patrick; Perera, Nimal; Wedage, Oshan; Deraniyagala, Siran; Perera, Jude; Eregama, Saman; Gledhill, Andrew; Petraglia, Michael D; Lee-Thorp, Julia A

    2015-03-13

    Human occupation of tropical rainforest habitats is thought to be a mainly Holocene phenomenon. Although archaeological and paleoenvironmental data have hinted at pre-Holocene rainforest foraging, earlier human reliance on rainforest resources has not been shown directly. We applied stable carbon and oxygen isotope analysis to human and faunal tooth enamel from four late Pleistocene-to-Holocene archaeological sites in Sri Lanka. The results show that human foragers relied primarily on rainforest resources from at least ~20,000 years ago, with a distinct preference for semi-open rainforest and rain forest edges. Homo sapiens' relationship with the tropical rainforests of South Asia is therefore long-standing, a conclusion that indicates the time-depth of anthropogenic reliance and influence on these habitats.

  16. Skull diversity in the Homo lineage and the relative position of Homo naledi.

    PubMed

    Schroeder, Lauren; Scott, Jill E; Garvin, Heather M; Laird, Myra F; Dembo, Mana; Radovčić, Davorka; Berger, Lee R; de Ruiter, Darryl J; Ackermann, Rebecca R

    2017-03-01

    The discovery of Homo naledi has expanded the range of phenotypic variation in Homo, leading to new questions surrounding the mosaic nature of morphological evolution. Though currently undated, its unique morphological pattern and possible phylogenetic relationships to other hominin taxa suggest a complex evolutionary scenario. Here, we perform geometric morphometric analyses on H. naledi cranial and mandibular remains to investigate its morphological relationship with species of Homo and Australopithecus. We use Generalized Procrustes analysis to place H. naledi within the pattern of known hominin skull diversity, distributions of Procrustes distances among individuals to compare H. naledi and Homo erectus, and neighbor joining trees to investigate the potential phenetic relationships between groups. Our goal is to address a set of hypotheses relating to the uniqueness of H. naledi, its affinity with H. erectus, and the age of the fossils based on skull morphology. Our results indicate that, cranially, H. naledi aligns with members of the genus Homo, with closest affiliations to H. erectus. The mandibular results are less clear; H. naledi closely associates with a number of taxa, including some australopiths. However, results also show that although H. naledi shares similarities with H. erectus, some distances from this taxon - especially small-brained members of this taxon - are extreme. The neighbor joining trees place H. naledi firmly within Homo. The trees based on cranial morphology again indicate a close relationship between H. naledi and H. erectus, whereas the mandibular tree places H. naledi closer to basal Homo, suggesting a deeper antiquity. Altogether, these results emphasize the unique combination of features (H. erectus-like cranium, less derived mandible) defining H. naledi. Our results also highlight the variability within Homo, calling for a greater focus on the cause of this variability, and emphasizing the importance of using the

  17. Brain size and encephalization in early to Mid-Pleistocene Homo.

    PubMed

    Rightmire, G Philip

    2004-06-01

    Important changes in the brain have occurred during the course of human evolution. Both absolute and relative size increases can be documented for species of Homo, culminating in the appearance of modern humans. One species that is particularly well-represented by fossil crania is Homo erectus. The mean capacity for 30 individuals is 973 cm(3). Within this group there is substantial variation, but brain size increases slightly in specimens from later time periods. Other Middle Pleistocene crania differ from those of Homo erectus. Characters of the facial skeleton, vault, and cranial base suggest that fossils from sites such as Arago Cave in France, the Sima de los Huesos in Spain, Bodo in Ethiopia, Broken Hill in Zambia, and perhaps Dali in China belong to the taxon Homo heidelbergensis. Ten of these mid-Quaternary hominins have brains averaging 1,206 cm(3) in volume, and many fall beyond the limits of size predicted for Homo erectus of equivalent age. When orbit height is used to construct an index of relative brain size, it is apparent that the (significant) increase in volume documented for the Middle Pleistocene individuals is not simply a consequence of larger body mass. Encephalization quotient values confirm this finding. These changes in absolute and relative brain size can be taken as further corroborative evidence for a speciation event, in which Homo erectus produced a daughter lineage. It is probable that Homo heidelbergensis originated in Africa or western Eurasia and then ranged widely across the Old World. Archaeological traces indicate that these populations differed in their technology and behavior from earlier hominins.

  18. Human evolution: humanistic selection and looking to the future.

    PubMed

    Krsiak, Miloslav

    2006-10-01

    Cultural evolution has predominated over biological evolution in modern man (Homo sapiens sapiens). Cultural evolution differs from biological evolution not only by inheritance of acquired characteristics but also, as is proposed in the present essay, by another kind of selection mechanism. Whereas selection in biological evolution is executed according to a criterion of reproductive success (the natural selection), selection in cultural evolution appears to be carried out according to human and humanistic criteria (success or fitness in meeting human needs, interests and humanistic values--"humanistic selection"). Many humanistic needs or values do not seem to be prerequisite for reproductive success, yet some of them (e.g. a need for freedom) seem to be inborn. Innateness, humanistic selection (decisive at a community level) and hierarchy of some human needs, interests and values appear to give cultural evolution a generally upward trend although long periods of stagnation or even regression may occur. Modern humans appear to be still at the early stage of their cultural evolution. A further cultural evolution of man appears to be, in contrast to biological evolution, predictable (with an optimistic outlook) and testable. The problem is that the hopeful result of this test will probably be known only in the fairly remote future provided that this species will not become extinct before that.

  19. Evidence for expansion of the precuneus in human evolution.

    PubMed

    Bruner, Emiliano; Preuss, Todd M; Chen, Xu; Rilling, James K

    2017-03-01

    The evolution of neurocranial morphology in Homo sapiens is characterized by bulging of the parietal region, a feature unique to our species. In modern humans, expansion of the parietal surface occurs during the first year of life, in a morphogenetic stage which is absent in chimpanzees and Neandertals. A similar variation in brain shape among living adult humans is associated with expansion of the precuneus. Using MRI-derived structural brain templates, we compare medial brain morphology between humans and chimpanzees through shape analysis and geometrical modeling. We find that the main spatial difference is a prominent expansion of the precuneus in our species, providing further evidence of evolutionary changes associated with this area. The precuneus is a major hub of brain organization, a central node of the default-mode network, and plays an essential role in visuospatial integration. Together, the comparative neuroanatomical and paleontological evidence suggest that precuneus expansion is a neurological specialization of H. sapiens that evolved in the last 150,000 years that may be associated with recent human cognitive specializations.

  20. Evolution of the RECQ family of helicases: A drosophila homolog, Dmblm, is similar to the human bloom syndrome gene.

    PubMed Central

    Kusano, K; Berres, M E; Engels, W R

    1999-01-01

    Several eukaryotic homologs of the Escherichia coli RecQ DNA helicase have been found. These include the human BLM gene, whose mutation results in Bloom syndrome, and the human WRN gene, whose mutation leads to Werner syndrome resembling premature aging. We cloned a Drosophila melanogaster homolog of the RECQ helicase family, Dmblm (Drosophila melanogaster Bloom), which encodes a putative 1487-amino-acid protein. Phylogenetic and dot plot analyses for the RECQ family, including 10 eukaryotic and 3 prokaryotic genes, indicate Dmblm is most closely related to the Homo sapiens BLM gene, suggesting functional similarity. Also, we found that Dmblm cDNA partially rescued the sensitivity to methyl methanesulfonate of Saccharomyces cerevisiae sgs1 mutant, demonstrating the presence of a functional similarity between Dmblm and SGS1. Our analyses identify four possible subfamilies in the RECQ family: (1) the BLM subgroup (H. sapiens Bloom, D. melanogaster Dmblm, and Caenorhabditis elegans T04A11.6); (2) the yeast RECQ subgroup (S. cerevisiae SGS1 and Schizosaccharomyces pombe rqh1/rad12); (3) the RECQL/Q1 subgroup (H. sapiens RECQL/Q1 and C. elegans K02F3.1); and (4) the WRN subgroup (H. sapiens Werner and C. elegans F18C5.2). This result may indicate that metazoans hold at least three RECQ genes, each of which may have a different function, and that multiple RECQ genes diverged with the generation of multicellular organisms. We propose that invertebrates such as nematodes and insects are useful as model systems of human genetic diseases. PMID:10049920

  1. Unique Dental Morphology of Homo floresiensis and Its Evolutionary Implications

    PubMed Central

    Kaifu, Yousuke; Kono, Reiko T.; Sutikna, Thomas; Saptomo, Emanuel Wahyu; Jatmiko

    2015-01-01

    Homo floresiensis is an extinct, diminutive hominin species discovered in the Late Pleistocene deposits of Liang Bua cave, Flores, eastern Indonesia. The nature and evolutionary origins of H. floresiensis’ unique physical characters have been intensively debated. Based on extensive comparisons using linear metric analyses, crown contour analyses, and other trait-by-trait morphological comparisons, we report here that the dental remains from multiple individuals indicate that H. floresiensis had primitive canine-premolar and advanced molar morphologies, a combination of dental traits unknown in any other hominin species. The primitive aspects are comparable to H. erectus from the Early Pleistocene, whereas some of the molar morphologies are more progressive even compared to those of modern humans. This evidence contradicts the earlier claim of an entirely modern human-like dental morphology of H. floresiensis, while at the same time does not support the hypothesis that H. floresiensis originated from a much older H. habilis or Australopithecus-like small-brained hominin species currently unknown in the Asian fossil record. These results are however consistent with the alternative hypothesis that H. floresiensis derived from an earlier Asian Homo erectus population and experienced substantial body and brain size dwarfism in an isolated insular setting. The dentition of H. floresiensis is not a simple, scaled-down version of earlier hominins. PMID:26624612

  2. Comparison between the SAPIEN S3 and the SAPIEN XT transcatheter heart valves: A single-center experience

    PubMed Central

    Sawaya, Fadi J; Spaziano, Marco; Lefèvre, Thierry; Roy, Andrew; Garot, Phillippe; Hovasse, Thomas; Neylon, Antoinette; Benamer, Hakim; Romano, Mauro; Unterseeh, Thierry; Morice, Marie-Claude; Chevalier, Bernard

    2016-01-01

    AIM To investigate the clinical outcomes of transcatheter aortic valve implantation (TAVI) with the SAPIEN 3 transcatheter heart valve (S3-THV) vs the SAPIEN XT valve (XT-THV). METHODS We retrospectively analyzed 507 patients that underwent TAVI with the XT-THV and 283 patients that received the S3-THV at our institution between March 2010 and December 2015. RESULTS Thirty-day mortality (3.5% vs 8.7%; OR = 0.44, P = 0.21) and 1-year mortality (25.7% vs 20.1%, P = 0.55) were similar in the S3-THV and the XT-THV groups. The rates of both major vascular complication and paravalvular regurgitation (PVR) > 1 were almost 4 times lower in the S3-THV group than the XT-THV group (major vascular complication: 2.8% vs 9.9%, P < 0.0001; PVR > 1: 2.4% vs 9.7%, P < 0.0001). However, the rate of new pacemaker implantation was almost twice as high in the S3-THV group (17.3% vs 9.8%, P = 0.03). In the S3 group, independent predictors of new permanent pacemaker were pre-procedural RBBB (OR = 4.9; P = 0.001), pre-procedural PR duration (OR = 1.14, P = 0.05) and device lack of coaxiality (OR = 1.13; P = 0.05) during deployment. CONCLUSION The S3-THV is associated to lower rates of major vascular complications and PVR but higher rates of new pacemaker compared to the XT-THV. Sub-optimal visualization of the S3-THV in relation to the aortic valvular complex during deployment is a predictor of new permanent pacemaker. PMID:28070241

  3. The vertebrae and ribs of Homo naledi.

    PubMed

    Williams, Scott A; García-Martínez, Daniel; Bastir, Markus; Meyer, Marc R; Nalla, Shahed; Hawks, John; Schmid, Peter; Churchill, Steven E; Berger, Lee R

    2017-03-01

    Hominin evolution featured shifts from a trunk shape suitable for climbing and housing a large gut to a trunk adapted to bipedalism and higher quality diets. Our knowledge regarding the tempo, mode, and context in which these derived traits evolved has been limited, based largely on a small-bodied Australopithecus partial skeleton (A.L. 288-1; "Lucy") and a juvenile Homo erectus skeleton (KNM-WT 15000; "Turkana Boy"). Two recent discoveries, of a large-bodied Australopithecus afarensis (KSD-VP-1/1) and two Australopithecus sediba partial skeletons (MH1 and MH2), have added to our understanding of thorax evolution; however, little is known about thorax morphology in early Homo. Here we describe hominin vertebrae, ribs, and sternal remains from the Dinaledi chamber of the Rising Star cave system attributed to Homo naledi. Although the remains are highly fragmented, the best-preserved specimens-two lower thoracic vertebrae and a lower rib-were found in association and belong to a small-bodied individual. A second lower rib may belong to this individual as well. All four of these individual elements are amongst the smallest known in the hominin fossil record. H. naledi is characterized by robust, relatively uncurved lower ribs and a relatively large spinal canal. We expect that the recovery of additional material from Rising Star Cave will clarify the nature of these traits and shed light on H. naledi functional morphology and phylogeny.

  4. A natural history of the human mind: tracing evolutionary changes in brain and cognition

    PubMed Central

    Sherwood, Chet C; Subiaul, Francys; Zawidzki, Tadeusz W

    2008-01-01

    Since the last common ancestor shared by modern humans, chimpanzees and bonobos, the lineage leading to Homo sapiens has undergone a substantial change in brain size and organization. As a result, modern humans display striking differences from the living apes in the realm of cognition and linguistic expression. In this article, we review the evolutionary changes that occurred in the descent of Homo sapiens by reconstructing the neural and cognitive traits that would have characterized the last common ancestor and comparing these with the modern human condition. The last common ancestor can be reconstructed to have had a brain of approximately 300–400 g that displayed several unique phylogenetic specializations of development, anatomical organization, and biochemical function. These neuroanatomical substrates contributed to the enhancement of behavioral flexibility and social cognition. With this evolutionary history as precursor, the modern human mind may be conceived as a mosaic of traits inherited from a common ancestry with our close relatives, along with the addition of evolutionary specializations within particular domains. These modern human-specific cognitive and linguistic adaptations appear to be correlated with enlargement of the neocortex and related structures. Accompanying this general neocortical expansion, certain higher-order unimodal and multimodal cortical areas have grown disproportionately relative to primary cortical areas. Anatomical and molecular changes have also been identified that might relate to the greater metabolic demand and enhanced synaptic plasticity of modern human brain's. Finally, the unique brain growth trajectory of modern humans has made a significant contribution to our species’ cognitive and linguistic abilities. PMID:18380864

  5. Misconceptions about mitochondria and mammalian fertilization: implications for theories on human evolution.

    PubMed

    Ankel-Simons, F; Cummins, J M

    1996-11-26

    In vertebrates, inheritance of mitochondria is thought to be predominantly maternal, and mitochondrial DNA analysis has become a standard taxonomic tool. In accordance with the prevailing view of strict maternal inheritance, many sources assert that during fertilization, the sperm tail, with its mitochondria, gets excluded from the embryo. This is incorrect. In the majority of mammals-including humans-the midpiece mitochondria can be identified in the embryo even though their ultimate fate is unknown. The "missing mitochondria" story seems to have survived--and proliferated-unchallenged in a time of contention between hypotheses of human origins, because it supports the "African Eve" model of recent radiation of Homo sapiens out of Africa. We will discuss the infiltration of this mistake into concepts of mitochondrial inheritance and human evolution.

  6. Mitochondrial COII sequences and modern human origins.

    PubMed

    Ruvolo, M; Zehr, S; von Dornum, M; Pan, D; Chang, B; Lin, J

    1993-11-01

    The aim of this study is to measure human mitochondrial sequence variability in the relatively slowly evolving mitochondrial gene cytochrome oxidase subunit II (COII) and to estimate when the human common ancestral mitochondrial type existed. New COII gene sequences were determined for five humans (Homo sapiens), including some of the most mitochondrially divergent humans known; for two pygmy chimpanzees (Pan paniscus); and for a common chimpanzee (P. troglodytes). COII sequences were analyzed with those from another relatively slowly evolving mitochondrial region (ND4-5). From class 1 (third codon position) sequence data, a relative divergence date for the human mitochondrial ancestor is estimated as 1/27 th of the human-chimpanzee divergence time. If it is assumed that humans and chimpanzees diverged 6 Mya, this places a human mitochondrial ancestor at 222,000 years, significantly different from 1 Myr (the presumed time of an H. erectus emergence from Africa). The mean coalescent time estimated from all 1,580 sites of combined mitochondrial data, when a 6-Mya human-chimpanzee divergence is assumed, is 298,000 years, with 95% confidence interval of 129,000-536,000 years. Neither estimate is compatible with a 1-Myr-old human mitochondrial ancestor. The mitochondrial DNA sequence data from COII and ND4-5 regions therefore do not support this multiregional hypothesis for the emergence of modern humans.

  7. Starch Catabolism by a Prominent Human Gut Symbiont Is Directed by the Recognition of Amylose Helices

    SciTech Connect

    Koropatkin, Nicole M.; Martens, Eric C.; Gordon, Jeffrey I.; Smith, Thomas J.

    2009-01-12

    The human gut microbiota performs functions that are not encoded in our Homo sapiens genome, including the processing of otherwise undigestible dietary polysaccharides. Defining the structures of proteins involved in the import and degradation of specific glycans by saccharolytic bacteria complements genomic analysis of the nutrient-processing capabilities of gut communities. Here, we describe the atomic structure of one such protein, SusD, required for starch binding and utilization by Bacteroides thetaiotaomicron, a prominent adaptive forager of glycans in the distal human gut microbiota. The binding pocket of this unique {alpha}-helical protein contains an arc of aromatic residues that complements the natural helical structure of starch and imposes this conformation on bound maltoheptaose. Furthermore, SusD binds cyclic oligosaccharides with higher affinity than linear forms. The structures of several SusD/oligosaccharide complexes reveal an inherent ligand recognition plasticity dominated by the three-dimensional conformation of the oligosaccharides rather than specific interactions with the composite sugars.

  8. Human evolution and cognition.

    PubMed

    Tattersall, Ian

    2010-09-01

    Human beings are distinguished from all other organisms by their symbolic way of processing information about the world. This unique cognitive style is qualitatively different from all the earlier hominid cognitive styles, and is not simply an improved version of them. The hominid fossil and archaeological records show clearly that biological and technological innovations have typically been highly sporadic, and totally out of phase, since the invention of stone tools some 2.5 million years ago. They also confirm that this pattern applied in the arrival of modern cognition: the anatomically recognizable species Homo sapiens was well established long before any population of it began to show indications of behaving symbolically. This places the origin of symbolic thought in the realms of exaptation, whereby new structures come into existence before being recruited to new uses, and of emergence, whereby entire new levels of complexity are achieved through new combinations of attributes unremarkable in themselves. Both these phenomena involve entirely routine evolutionary processes; special as we human beings may consider ourselves, there was nothing special about the way we came into existence. Modern human cognition is a very recent acquisition; and its emergence ushered in an entirely new pattern of technological (and other behavioral) innovation, in which constant change results from the ceaseless exploration of the potential inherent in our new capacity.

  9. Synthesis and cytotoxicity of A-homo-lactam derivatives of cholic acid and 7-deoxycholic acid.

    PubMed

    Huang, Yanmin; Chen, Sijing; Cui, Jianguo; Gan, Chunfang; Liu, Zhiping; Wei, Yingliang; Song, Huachan

    2011-06-01

    Using cholic acid and deoxycholic acid as starting materials, a series of 3-aza-A-homo-4-one bile acid and 7-deoxycholic acid derivatives were synthesized by the esterification, oxidation, reduction, oximation and Beckman rearrangement etc. The cytotoxicity of the synthesized compounds against MGC 7901 (human ventriculi carcinoma cell line), hela (human cervical carcinoma cell line), SMMC 7404 (human liver carcinoma cell line) were investigated. The results showed that bile acid and 7-deoxycholic-acid derivatives with 3-aza-A-homo-4-one configuration bearing a 6-hydroximino or 12-hydroximino group displayed a distinct cytotoxicity to Hela tumor cell line. In particular, the IC(50) values of the compounds 6 and 13 were 14.3 and 24.3 μmol/L against Hela human tumor cell line respectively. The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs.

  10. Disproportionate Cochlear Length in Genus Homo Shows a High Phylogenetic Signal during Apes’ Hearing Evolution

    PubMed Central

    Braga, J.; Loubes, J-M.; Descouens, D.; Dumoncel, J.; Thackeray, J. F.; Kahn, J-L.; de Beer, F.; Riberon, A.; Hoffman, K.; Balaresque, P.; Gilissen, E.

    2015-01-01

    Changes in lifestyles and body weight affected mammal life-history evolution but little is known about how they shaped species’ sensory systems. Since auditory sensitivity impacts communication tasks and environmental acoustic awareness, it may have represented a deciding factor during mammal evolution, including apes. Here, we statistically measure the influence of phylogeny and allometry on the variation of five cochlear morphological features associated with hearing capacities across 22 living and 5 fossil catarrhine species. We find high phylogenetic signals for absolute and relative cochlear length only. Comparisons between fossil cochleae and reconstructed ape ancestral morphotypes show that Australopithecus absolute and relative cochlear lengths are explicable by phylogeny and concordant with the hypothetized ((Pan,Homo),Gorilla) and (Pan,Homo) most recent common ancestors. Conversely, deviations of the Paranthropus oval window area from these most recent common ancestors are not explicable by phylogeny and body weight alone, but suggest instead rapid evolutionary changes (directional selection) of its hearing organ. Premodern (Homo erectus) and modern human cochleae set apart from living non-human catarrhines and australopiths. They show cochlear relative lengths and oval window areas larger than expected for their body mass, two features corresponding to increased low-frequency sensitivity more recent than 2 million years ago. The uniqueness of the “hypertrophied” cochlea in the genus Homo (as opposed to the australopiths) and the significantly high phylogenetic signal of this organ among apes indicate its usefulness to identify homologies and monophyletic groups in the hominid fossil record. PMID:26083484

  11. Evolution of Brain Active Gene Promoters in Human Lineage Towards the Increased Plasticity of Gene Regulation.

    PubMed

    Gunbin, Konstantin V; Ponomarenko, Mikhail P; Suslov, Valentin V; Gusev, Fedor; Fedonin, Gennady G; Rogaev, Evgeny I

    2017-02-24

    Adaptability to a variety of environmental conditions is a prominent feature of Homo sapiens. We hypothesize that this feature can be explained by evolutionary changes in gene promoters active in the brain prefrontal cortex leading to a more flexible gene regulation network. The genotype-dependent range of gene expression can be broader in humans than in other higher primates. Thus, we searched for specific signatures of evolutionary changes in promoter architectures of multiple hominid genes, including the genes active in human cortical neurons that may indicate an increase of variability of gene expression rather than just changes in the level of expression, such as downregulation or upregulation of the genes. We performed a whole-genome search for genetic-based alterations that may impact gene regulation "flexibility" in a process of hominids evolution, such as (i) CpG dinucleotide content, (ii) predicted nucleosome-DNA dissociation constant, and (iii) predicted affinities for TATA-binding protein (TBP) in gene promoters. We tested all putative promoter regions across the human genome and especially gene promoters in active chromatin state in neurons of prefrontal cortex, the brain region critical for abstract thinking and social and behavioral adaptation. Our data imply that the origin of modern man has been associated with an increase of flexibility of promoter-driven gene regulation in brain. In contrast, after splitting from the ancestral lineages of H. sapiens, the evolution of ape species is characterized by reduced flexibility of gene promoter functioning, underlying reduced variability of the gene expression.

  12. Human Dispersals Along the African Rift Valley in the Late Quaternary

    NASA Astrophysics Data System (ADS)

    Tryon, C. A.; Faith, J. T.; Peppe, D. J.

    2014-12-01

    Climate- and tectonic-driven environmental dynamics of the East African Rift System (EARS) during the Quaternary played an important role in the demographic history of early Homo sapiens, including expansions of modern humans across and out of Africa. Human forager population size, geographic range, and behaviors such as hunting strategies and residential mobility likely varied in response to changes in the local and regional environment. Throughout the Quaternary, floral and faunal change was linked at least in part to variations in moisture availability, temperature, and atmospheric CO2, which in addition to uplift and faulting, contributed to the expansion and contraction of a number of large lakes that served as biogeographic barriers to many taxa. This is particularly clear for the Lake Victoria basin, where biogeographic, geological, and paleontological evidence documents repeated expansion and contraction of the ranges of species in response to lake level and vegetation change. Across much of eastern Africa, the topography of the rift facilitated north-south dispersals, the timing of which may have depended in part on the expansion and contraction of the equatorial forest belt. Dispersal potential likely increased during the more arid periods of the late Quaternary, when the roles of lakes and forests as dispersal barriers was reduced and the extent of low net primary productivity dry grasslands increased, the latter requiring large home ranges for human foragers, conditions suitable for range expansions within H. sapiens.

  13. The Evolution of Human Longevity: Toward a Biocultural Theory.

    ERIC Educational Resources Information Center

    Mayer, Peter J.

    Homo sapiens is the only extant species for which there exists a significant post-reproductive period in the normal lifespan. Explanations for the evolution of this species-specific trait are possible through "non-deterministic" theories of aging positing "wear and tear" or the failure of nature to eliminate imperfection, or…

  14. Impaired Air Conditioning within the Nasal Cavity in Flat-Faced Homo.

    PubMed

    Nishimura, Takeshi; Mori, Futoshi; Hanida, Sho; Kumahata, Kiyoshi; Ishikawa, Shigeru; Samarat, Kaouthar; Miyabe-Nishiwaki, Takako; Hayashi, Misato; Tomonaga, Masaki; Suzuki, Juri; Matsuzawa, Tetsuro; Matsuzawa, Teruo

    2016-03-01

    We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD) with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved "Out of Africa" to explore the more severe climates of

  15. Impaired Air Conditioning within the Nasal Cavity in Flat-Faced Homo

    PubMed Central

    Nishimura, Takeshi; Mori, Futoshi; Hanida, Sho; Kumahata, Kiyoshi; Ishikawa, Shigeru; Samarat, Kaouthar; Miyabe-Nishiwaki, Takako; Hayashi, Misato; Tomonaga, Masaki; Suzuki, Juri; Matsuzawa, Tetsuro; Matsuzawa, Teruo

    2016-01-01

    We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD) with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved “Out of Africa” to explore the more severe climates of

  16. Evolution of human brain functions: the functional structure of human consciousness.

    PubMed

    Cloninger, C Robert

    2009-11-01

    The functional structure of self-aware consciousness in human beings is described based on the evolution of human brain functions. Prior work on heritable temperament and character traits is extended to account for the quantum-like and holographic properties (i.e. parts elicit wholes) of self-aware consciousness. Cladistic analysis is used to identify the succession of ancestors leading to human beings. The functional capacities that emerge along this lineage of ancestors are described. The ecological context in which each cladogenesis occurred is described to illustrate the shifting balance of evolution as a complex adaptive system. Comparative neuroanatomy is reviewed to identify the brain structures and networks that emerged coincident with the emergent brain functions. Individual differences in human temperament traits were well developed in the common ancestor shared by reptiles and humans. Neocortical development in mammals proceeded in five major transitions: from early reptiles to early mammals, early primates, simians, early Homo, and modern Homo sapiens. These transitions provide the foundation for human self-awareness related to sexuality, materiality, emotionality, intellectuality, and spirituality, respectively. The functional structure of human self-aware consciousness is concerned with the regulation of five planes of being: sexuality, materiality, emotionality, intellectuality, and spirituality. Each plane elaborates neocortical functions organized around one of the five special senses. The interactions among these five planes gives rise to a 5 x 5 matrix of subplanes, which are functions that coarsely describe the focus of neocortical regulation. Each of these 25 neocortical functions regulates each of five basic motives or drives that can be measured as temperaments or basic emotions related to fear, anger, disgust, surprise, and happiness/sadness. The resulting 5 x 5 x 5 matrix of human characteristics provides a general and testable model of the

  17. New magnetostratigraphic dates of Lantian Homo erectus

    NASA Astrophysics Data System (ADS)

    Zhisheng, An; Kun, Ho Chuan

    1989-09-01

    Skeletal remains of Homo erectus found in Pleistocene loess at two sites near Lantian in central China are of greatly different geologic age. The cranium found in the fossil-bearing strata at Gongwangling is about 1.15 myr old whereas the remains found at the Chenjiawo locality in middle Pleistocene loess are about 0.65 myr old. The dating is based on new paleomagnetic polarity determinations and on the lithostratigraphic position of the fossils in the loess-paleosol sequence. Our results confirm that both localities are older than the first occupation of Zhoukoudian. New dates, palaeoenvironmental settings, and morphological features of the hominids from Lantian localities have significant bearing on the understanding of adaptive radiations of the middle and late hominids in Asia.

  18. Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa

    PubMed Central

    Dirks, Paul HGM; Berger, Lee R; Roberts, Eric M; Kramers, Jan D; Hawks, John; Randolph-Quinney, Patrick S; Elliott, Marina; Musiba, Charles M; Churchill, Steven E; de Ruiter, Darryl J; Schmid, Peter; Backwell, Lucinda R; Belyanin, Georgy A; Boshoff, Pedro; Hunter, K Lindsay; Feuerriegel, Elen M; Gurtov, Alia; Harrison, James du G; Hunter, Rick; Kruger, Ashley; Morris, Hannah; Makhubela, Tebogo V; Peixotto, Becca; Tucker, Steven

    2015-01-01

    We describe the physical context of the Dinaledi Chamber within the Rising Star cave, South Africa, which contains the fossils of Homo naledi. Approximately 1550 specimens of hominin remains have been recovered from at least 15 individuals, representing a small portion of the total fossil content. Macro-vertebrate fossils are exclusively H. naledi, and occur within clay-rich sediments derived from in situ weathering, and exogenous clay and silt, which entered the chamber through fractures that prevented passage of coarser-grained material. The chamber was always in the dark zone, and not accessible to non-hominins. Bone taphonomy indicates that hominin individuals reached the chamber complete, with disarticulation occurring during/after deposition. Hominins accumulated over time as older laminated mudstone units and sediment along the cave floor were eroded. Preliminary evidence is consistent with deliberate body disposal in a single location, by a hominin species other than Homo sapiens, at an as-yet unknown date. DOI: http://dx.doi.org/10.7554/eLife.09561.001 PMID:26354289

  19. Malaria infection and human evolution.

    PubMed

    Sabbatani, Sergio; Manfredi, Roberto; Fiorino, Sirio

    2010-03-01

    During the evolution of the genus Homo, with regard to the species habilis, erectus and sapiens, malaria has played a key biological role in influencing human development. The plasmodia causing malaria have evolved in two ways, in biological and phylogenetic terms: Plasmodium vivax, Plasmodium malariae and Plasmodium ovale appear to have either coevolved with human mankind, or encountered human species during the most ancient phases of Homo evolution; on the other hand, Plasmodium falciparum has been transmitted to humans by monkeys in a more recent period, probably between the end of the Mesolithic and the beginning of the Neolithic age. The authors show both direct and indirect biomolecular evidence of malarial infection, detected in buried subjects, dating to ancient times and brought to light in the course of archaeological excavations in major Mediterranean sites. In this review of the literature the authors present scientific evidence confirming the role of malaria in affecting the evolution of populations in Mediterranean countries. The people living in several different Mediterranean regions, the cradle of western civilization, have been progressively influenced by malaria in the course of the spread of this endemic disease in recent millennia. In addition, populations affected by endemic malaria progressively developed cultural, dietary and behavioural adaptation mechanisms, which contributed to diminish the risk of disease. These habits were probably not fully conscious. Nevertheless it may be thought that both these customs and biological modifications, caused by malarial plasmodia, favoured the emergence of groups of people with greater resistance to malaria. All these factors have diminished the unfavourable demographic impact of the disease, also positively influencing the general development and growth of civilization.

  20. Evolution and genomics of the human brain.

    PubMed

    Rosales-Reynoso, M A; Juárez-Vázquez, C I; Barros-Núñez, P

    2015-08-21

    Most living beings are able to perform actions that can be considered intelligent or, at the very least, the result of an appropriate reaction to changing circumstances in their environment. However, the intelligence or intellectual processes of humans are vastly superior to those achieved by all other species. The adult human brain is a highly complex organ weighing approximately 1500g, which accounts for only 2% of the total body weight but consumes an amount of energy equal to that required by all skeletal muscle at rest. Although the human brain displays a typical primate structure, it can be identified by its specific distinguishing features. The process of evolution and humanisation of the Homo sapiens brain resulted in a unique and distinct organ with the largest relative volume of any animal species. It also permitted structural reorganization of tissues and circuits in specific segments and regions. These steps explain the remarkable cognitive abilities of modern humans compared not only with other species in our genus, but also with older members of our own species. Brain evolution required the coexistence of two adaptation mechanisms. The first involves genetic changes that occur at the species level, and the second occurs at the individual level and involves changes in chromatin organisation or epigenetic changes. The genetic mechanisms include: a) genetic changes in coding regions that lead to changes in the sequence and activity of existing proteins; b) duplication and deletion of previously existing genes; c) changes in gene expression through changes in the regulatory sequences of different genes; and d) synthesis of non-coding RNAs. Lastly, this review describes some of the main documented chromosomal differences between humans and great apes. These differences have also contributed to the evolution and humanisation process of the H. sapiens brain.

  1. The evolutionary history of the hominin hand since the last common ancestor of Pan and Homo

    PubMed Central

    Tocheri, Matthew W; Orr, Caley M; Jacofsky, Marc C; Marzke, Mary W

    2008-01-01

    Molecular evidence indicates that the last common ancestor of the genus Pan and the hominin clade existed between 8 and 4 million years ago (Ma). The current fossil record indicates the Pan-Homo last common ancestor existed at least 5 Ma and most likely between 6 and 7 Ma. Together, the molecular and fossil evidence has important consequences for interpreting the evolutionary history of the hand within the tribe Hominini (hominins). Firstly, parsimony supports the hypothesis that the hand of the last common ancestor most likely resembled that of an extant great ape overall (Pan, Gorilla, and Pongo), and that of an African ape in particular. Second, it provides a context for interpreting the derived changes to the hand that have evolved in various hominins. For example, the Australopithecus afarensis hand is likely derived in comparison with that of the Pan–Homo last common ancestor in having shorter fingers relative to thumb length and more proximo-distally oriented joints between its capitate, second metacarpal, and trapezium. This evidence suggests that these derived features evolved prior to the intensification of stone tool-related hominin behaviors beginning around 2.5 Ma. However, a majority of primitive features most likely present in the Pan-Homo last common ancestor are retained in the hands of Australopithecus, Paranthropus/early Homo, and Homo floresiensis. This evidence suggests that further derived changes to the hands of other hominins such as modern humans and Neandertals did not evolve until after 2.5 Ma and possibly even later than 1.5 Ma, which is currently the earliest evidence of Acheulian technology. The derived hands of modern humans and Neandertals may indicate a morphological commitment to tool-related manipulative behaviors beyond that observed in other hominins, including those (e.g. H. floresiensis) which may be descended from earlier tool-making species. PMID:18380869

  2. In silico modification of Zn2+ binding group of suberoylanilide hydroxamic acid (SAHA) by organoselenium compounds as Homo sapiens class II HDAC inhibitor of cervical cancer

    NASA Astrophysics Data System (ADS)

    Sumo Friend Tambunan, Usman; Bakri, Ridla; Aditya Parikesit, Arli; Ariyani, Titin; Dyah Puspitasari, Ratih; Kerami, Djati

    2016-02-01

    Cervical cancer is the most common cancer in women, and ranks seventh of all cancers worldwide, with 529000 cases in 2008 and more than 85% cases occur in developing countries. One way to treat this cancer is through the inhibition of HDAC enzymes which play a strategic role in the regulation of gene expression. Suberoyl Anilide Hydroxamic Acid (SAHA) or Vorinostat is a drug which commercially available to treat the cancer, but still has some side effects. This research present in silico SAHA modification in Zinc Binding Group (ZBG) by organoselenium compound to get ligands which less side effect. From molecular docking simulation, and interaction analysis, there are five best ligands, namely CC27, HA27, HB28, IB25, and KA7. These five ligands have better binding affinity than the standards, and also have interaction with Zn2+ cofactor of inhibited HDAC enzymes. This research is expected to produce more potent HDAC inhibitor as novel drug for cervical cancer treatment.

  3. Crystallization and preliminary X-ray crystallographic investigations on a betagamma-crystallin domain of absent in melanoma 1 (AIM1), a protein from Homo sapiens.

    PubMed

    Aravind, Penmatsa; Rajini, Bheemreddy; Sharma, Yogendra; Sankaranarayanan, Rajan

    2006-03-01

    AIM1g1 is a single betagamma-crystallin domain from the protein absent in melanoma 1 (AIM1), which appears to play a role in the suppression of melanomas. This domain is known to bind calcium and its structure would help in identifying calcium-coordinating sites in vertebrate crystallins, which have hitherto been believed to have lost this ability during evolution. Crystallization of this domain was performed by the hanging-drop vapour-diffusion method. Crystals diffracted to a maximum resolution of 1.86 A and were found to belong to space group P6(1) or P6(5), with unit-cell parameters a = b = 54.98, c = 59.73 A. Solvent-content analysis indicated the presence of one monomer per asymmetric unit.

  4. Sexual dimorphism in Australopithecus afarensis was similar to that of modern humans.

    PubMed

    Reno, Philip L; Meindl, Richard S; McCollum, Melanie A; Lovejoy, C Owen

    2003-08-05

    The substantial fossil record for Australopithecus afarensis includes both an adult partial skeleton [Afar Locality (A.L.) 288-1, "Lucy"] and a large simultaneous death assemblage (A.L. 333). Here we optimize data derived from both to more accurately estimate skeletal size dimorphism. Postcranial ratios derived from A.L. 288-1 enable a significant increase in sample size compared with previous studies. Extensive simulations using modern humans, chimpanzees, and gorillas confirm that this technique is accurate and that skeletal size dimorphism in A. afarensis was most similar to that of contemporary Homo sapiens. These data eliminate some apparent discrepancies between the canine and skeletal size dimorphism in hominoids, imply that the species was not characterized by substantial sexual bimaturation, and greatly increase the probability that the reproductive strategy of A. afarensis was principally monogamy.

  5. Body proportions of Australopithecus afarensis and A. africanus and the origin of the genus Homo.

    PubMed

    McHenry, H M; Berger, L R

    1998-07-01

    New discoveries of A. africanus fossils from Member 4 Sterkfontein reveal a body form quite unlike earlier Australopithecus species. The new adult material consists of over 48 fore- and hindlimb specimens and includes an associated partial skeleton, Stw 431. The forelimbs and relatively large: the average size of their joints corresponds to a modern human with body mass of 53 kg. The hindlimbs are much smaller with an average size matching a modern human of only 33 kg. Analyses of the Stw 431 partial skeleton confirm these results. In contrast, A. afarensis and anamensis more closely approximate a human pattern of forelimb joint size. This is an unanticipated complication in our understanding of early human evolution. In general, craniodental morphology tracks time in species of Australopithecus: A. anamensis (3.5-4.1 Ma) is the the most primitive with a strongly sloping symphysis, large canine roots, etc., A. afarensis (3.0-3.6 Ma) is less primitive, and A. africanus (2.6-3.0 Ma) shares many derived characteristics with early Homo (e.g., expanded brain, reduced canine, bicuspid lower third premolar, reduced prognathism, greater flexion of the cranial base, deeper TMJ). the new postcranial material, however, reveals an apparently primitive morphology of relatively large forelimb and small hindlimb joints resembling more the pongid than the human pattern. More pongid-like proportions are also present in the two known associated partial skeletons of H. habilis (OH 62 KNM-ER 3735). This may imply either (1) that A. africanus and H. habilis evolved craniodental characters in parallel with the lineage leading to later Homo, or (2) that fore- to hindlimb proportions of A. afarensis (and perhaps A. anamensis) evolved independent of the lineage leading to Homo and does not imply a close phylogenetic link with Homo. Both of these explanations or any other phylogeny imply homoplasy.

  6. Evidence of Probabilistic Behaviour in Protein Interaction Networks

    DTIC Science & Technology

    2008-01-31

    Evidence of degree-weighted connectivity in nine PPI networks. a, Homo sapiens (human); b, Drosophila melanogaster (fruit fly); c-e, Saccharomyces...illustrates maps for the networks of Homo sapiens and Dro- sophila melanogaster, while maps for the remaining net- works are provided in Additional file 2. As...protein-protein interaction networks. a, Homo sapiens ; b, Drosophila melanogaster. Distances shown as average shortest path lengths L(k1, k2) between

  7. PELDOR in rotationally symmetric homo-oligomers

    NASA Astrophysics Data System (ADS)

    Giannoulis, Angeliki; Ward, Richard; Branigan, Emma; Naismith, James H.; Bode, Bela E.

    2013-10-01

    Nanometre distance measurements by pulsed electron-electron double resonance (PELDOR) spectroscopy have become an increasingly important tool in structural biology. The theoretical underpinning of the experiment is well defined for systems containing two nitroxide spin-labels (spin pairs); however, recently experiments have been reported on homo-oligomeric membrane proteins consisting of up to eight spin-labelled monomers. We have explored the theory behind these systems by examining model systems based on multiple spins arranged in rotationally symmetric polygons. The results demonstrate that with a rising number of spins within the test molecule, increasingly strong distortions appear in distance distributions obtained from an analysis based on the simple spin pair approach. These distortions are significant over a range of system sizes and remain so even when random errors are introduced into the symmetry of the model. We present an alternative approach to the extraction of distances on such systems based on a minimisation that properly treats multi-spin correlations. We demonstrate the utility of this approach on a spin-labelled mutant of the heptameric Mechanosensitive Channel of Small Conductance of E. coli.

  8. Molar crown inner structural organization in Javanese Homo erectus.

    PubMed

    Zanolli, Clément

    2015-01-01

    This contribution investigates the inner organizational pattern (tooth tissue proportions and enamel-dentine junction morphology) of seven Homo erectus permanent molar crowns from the late Lower-early Middle Pleistocene Kabuh Formation of the Sangiran Dome (Central Java, Indonesia). The previous study of their external characteristics confirmed the degree of time-related structural reduction occurred in Javanese H. erectus, and also revealed a combination of nonmetric features which are rare in the Lower and early Middle Pleistocene dental record, but more frequently found in recent humans. In accordance with their outer occlusal morphology, the specimens exhibit a set of derived internal features, such as thick to hyperthick enamel, an incomplete expression of the crest patterns at the enamel-dentine junction (EDJ) level, a sharp EDJ topography. As a whole, these features differ from those expressed in some penecontemporaneous specimens/samples representing African H. erectus/ergaster and H. heidelbergensis, as well as in Neanderthals, but occur in recent human populations. Further research in virtual dental paleoanthropology to be developed at macroregional scale would clarify the polarity and intensity of the intermittent exchanges between continental and insular Southeast Asia around the Lower to Middle Pleistocene boundary, as well as should shed light on the still poorly understood longitudinal evolutionary dynamics across continental Asia.

  9. Protein Analysis of Sapienic Acid-Treated Porphyromonas gingivalis Suggests Differential Regulation of Multiple Metabolic Pathways

    PubMed Central

    Dawson, Deborah V.; Blanchette, Derek R.; Drake, David R.; Wertz, Philip W.; Brogden, Kim A.

    2015-01-01

    ABSTRACT Lipids endogenous to skin and mucosal surfaces exhibit potent antimicrobial activity against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Our previous work demonstrated the antimicrobial activity of the fatty acid sapienic acid (C16:1Δ6) against P. gingivalis and found that sapienic acid treatment alters both protein and lipid composition from those in controls. In this study, we further examined whole-cell protein differences between sapienic acid-treated bacteria and untreated controls, and we utilized open-source functional association and annotation programs to explore potential mechanisms for the antimicrobial activity of sapienic acid. Our analyses indicated that sapienic acid treatment induces a unique stress response in P. gingivalis resulting in differential expression of proteins involved in a variety of metabolic pathways. This network of differentially regulated proteins was enriched in protein-protein interactions (P = 2.98 × 10−8), including six KEGG pathways (P value ranges, 2.30 × 10−5 to 0.05) and four Gene Ontology (GO) molecular functions (P value ranges, 0.02 to 0.04), with multiple suggestive enriched relationships in KEGG pathways and GO molecular functions. Upregulated metabolic pathways suggest increases in energy production, lipid metabolism, iron acquisition and processing, and respiration. Combined with a suggested preferential metabolism of serine, which is necessary for fatty acid biosynthesis, these data support our previous findings that the site of sapienic acid antimicrobial activity is likely at the bacterial membrane. IMPORTANCE P. gingivalis is an important opportunistic pathogen implicated in periodontitis. Affecting nearly 50% of the population, periodontitis is treatable, but the resulting damage is irreversible and eventually progresses to tooth loss. There is a great need for natural products that can be used to treat and/or prevent the overgrowth of

  10. "H. Sapiens" as Ecologically Special: What Does Language Contribute?

    ERIC Educational Resources Information Center

    Ross, Don

    2007-01-01

    This paper inquires into the extent to which humans are specially constituted relative to other animals by their language. First a principled concept of evolutionary specialness is operationalized. Then it is agreed that humans satisfy the criteria for this sort of specialness in consequence of the kind of cultural evolution in which they have…

  11. Reconstructing recent human evolution.

    PubMed

    Stringer, C B

    1992-08-29

    The two most distinct models of recent human evolution, the multiregional and the recent African origin models, have different retrodictions concerning specific archaic-recent population relationships. The former model infers multiple regional archaic-modern connections and the ancient establishment of regional characteristics, whereas the latter model implies only an African archaic-all modern relationship, with recent (late Pleistocene) development of regionality. In this paper, four late archaic groups from Europe, southwest Asia, Africa and East Asia are compared with various fossil and recent Homo sapiens crania or cranial samples. The results of Penrose shape comparisons narrowly favour a late archaic African-modern special relationship over an East Asian-modern one, with European and southwest Asian Neanderthal groups much more distant. No specific archaic-recent regional relationships are indicated in the shape analyses, nor in separate examinations of patterns of regionality, which indicate a recent origin for present day regionality. The Skhul-Qafzeh sample provides an excellent shape intermediate between the archaic and recent samples.

  12. Evidence for a large double-cruciform DNA structure on the X chromosome of human and chimpanzee.

    PubMed

    Losch, Florian O; Bredenbeck, Anne; Hollstein, Verena M; Walden, Peter; Wrede, Paul

    2007-11-01

    The human X chromosome consists of a high number of large inverted repeat (IR) DNA sequences which fulfill all requirements for formation of cruciform DNA structures. Such alternative DNA structures are suggested to have a great impact in altering the chromatin architecture and function. Our comprehensive analysis of the corresponding orthologous nucleotide sequences of an IR sequence from Homo sapiens and Pan troglodytes revealed that most of the nucleotide differences between the two species are symmetrical to the apex of the IR, and that the spacer region of the orthologous IRs are in reverse orientation. We provide evidence that this IR forms a large non-B DNA structure containing two Holliday junctions, allowing intrastrand nucleotide pairing of the arms and interstrand pairing of the spacer region of the IR. This structure would extrude into a large double-cruciform DNA structure providing the molecular basis of translocation events and regulation of gene expression.

  13. Descriptions of the lower limb skeleton of Homo floresiensis.

    PubMed

    Jungers, W L; Larson, S G; Harcourt-Smith, W; Morwood, M J; Sutikna, T; Due Awe, Rokhus; Djubiantono, T

    2009-11-01

    Bones of the lower extremity have been recovered for up to nine different individuals of Homo floresiensis - LB1, LB4, LB6, LB8, LB9, LB10, LB11, LB13, and LB14. LB1 is represented by a bony pelvis (damaged but now repaired), femora, tibiae, fibulae, patellae, and numerous foot bones. LB4/2 is an immature right tibia lacking epiphyses. LB6 includes a fragmentary metatarsal and two pedal phalanges. LB8 is a nearly complete right tibia (shorter than that of LB1). LB9 is a fragment of a hominin femoral diaphysis. LB10 is a proximal hallucal phalanx. LB11 includes pelvic fragments and a fragmentary metatarsal. LB13 is a patellar fragment, and LB14 is a fragment of an acetabulum. All skeletal remains recovered from Liang Bua were extremely fragile, and some were badly damaged when they were removed temporarily from Jakarta. At present, virtually all fossil materials have been returned, stabilized, and hardened. These skeletal remains are described and illustrated photographically. The lower limb skeleton exhibits a uniquely mosaic pattern, with many primitive-like morphologies; we have been unable to find this combination of ancient and derived (more human-like) features in either healthy or pathological modern humans, regardless of body size. Bilateral asymmetries are slight in the postcranium, and muscle markings are clearly delineated on all bones. The long bones are robust, and the thickness of their cortices is well within the ranges seen in healthy modern humans. LB1 is most probably a female based on the shape of her greater sciatic notch, and the marked degree of lateral iliac flaring recalls that seen in australopithecines such as "Lucy" (AL 288-1). The metatarsus has a human-like robusticity formula, but the proximal pedal phalanges are relatively long and robust (and slightly curved). The hallux is fully adducted, but we suspect that a medial longitudinal arch was absent.

  14. Race and the odd history of human paleontology.

    PubMed

    Schwartz, Jeffrey H

    2006-11-01

    Although the late 17th century witnessed the recognition of fossils as the remains of extinct organisms-because they could be incorporated into the creation story embodied in the Great Chain of Being-acceptance of human antiquity through the indisputable demonstration of the contemporaneity of human bones, stone tools, and accepted fossils was not forthcoming for nearly 2 centuries thereafter. When it did occur, however, ancient humans were not seen as presenting a pattern of diversity similar to that seen in the fossil records of nonhuman organisms. Instead, human evolution then, as now, has typically been interpreted as being unilinear. This belief can be traced to Huxley (1863), who argued that the Feldhofer Grotto Neanderthal skullcap was merely an extension into the past of morphology seen in the Australian Aborigine, whom he took to represent the primitive end of an extreme range of variation he thought characterized Homo sapiens. During the mid-20th century, Mayr and Dobzhansky (mis)used their clout as founders of the evolutionary synthesis to cement in paleoanthropology the idea that human evolutionary history was characterized by nonspeciation. As such, anything that could be interpreted as potentially representing taxic diversity was relegated to the status of individual variation. Lack of understanding of the history of human paleontology, and the biases that constrained its perspective on human evolution, continue to affect the ways in which most paleoanthropologists pigeonhole human fossils.

  15. Shared pattern of endocranial shape asymmetries among great apes, anatomically modern humans, and fossil hominins.

    PubMed

    Balzeau, Antoine; Gilissen, Emmanuel; Grimaud-Hervé, Dominique

    2011-01-01

    Anatomical asymmetries of the human brain are a topic of major interest because of their link with handedness and cognitive functions. Their emergence and occurrence have been extensively explored in human fossil records to document the evolution of brain capacities and behaviour. We quantified for the first time antero-posterior endocranial shape asymmetries in large samples of great apes, modern humans and fossil hominins through analysis of "virtual" 3D models of skull and endocranial cavity and we statistically test for departures from symmetry. Once based on continuous variables, we show that the analysis of these brain asymmetries gives original results that build upon previous analysis based on discrete traits. In particular, it emerges that the degree of petalial asymmetries differs between great apes and hominins without modification of their pattern. We indeed demonstrate the presence of shape asymmetries in great apes, with a pattern similar to modern humans but with a lower variation and a lower degree of fluctuating asymmetry. More importantly, variations in the position of the frontal and occipital poles on the right and left hemispheres would be expected to show some degree of antisymmetry when population distribution is considered, but the observed pattern of variation among the samples is related to fluctuating asymmetry for most of the components of the petalias. Moreover, the presence of a common pattern of significant directional asymmetry for two components of the petalias in hominids implicates that the observed traits were probably inherited from the last common ancestor of extant African great apes and Homo sapiens.These results also have important implications for the possible relationships between endocranial shape asymmetries and functional capacities in hominins. It emphasizes the uncoupling between lateralized activities, some of them well probably distinctive to Homo, and large-scale cerebral lateralization itself, which is not unique

  16. Ontogeny and phylogeny of the pelvis in Gorilla, Pongo, Pan, Australopithecus and Homo.

    PubMed

    Williams, Frank L'engle; Orban, Rosine

    2007-01-01

    To examine the evolutionary differences between hominoid locomotor systems, a number of observations concerning the growth of the pelvis among the great apes as compared to modern and fossil hominids are reported. We are interested in the size and shape of the coxal bones at different developmental stages across species that may elucidate the relationship between ontogeny and phylogeny (i.e., heterochrony) in the hominoid pelvis. Our hypotheses are: (1) do rates of absolute growth differ?, (2) do rates of relative growth differ?, and (3) does heterochrony explain these differences? Bivariate and multivariate analyses of pelvic dimensions demonstrate both the diversity of species-specific ontogenetic patterns among hominoids, and an unequivocal separation of hominids and the great apes. Heterochrony alone fails to account for the ontogenetic differences between hominids and the great apes. Compared to recent Homo,Australopithecus can be described as 'hyper-human' from the relative size of the ischium, and short but broad ilium. Australopithecus afarensis differs from Australopithecus africanus by its relatively long pubis. In multivariate analyses of ilium shape, the most complete coxal bone attributed to Homo erectus, KNM-ER 3228, falls within the range of juvenile and adult Australopithecus, whereas Broken Hill falls within the range of modern Homo, suggesting that the modern human ilium shape arose rather recently. Among the great apes, patterns of pelvic ontogeny do not exclusively separate the African apes from Pongo.

  17. Synthesis and antiproliferative activity of C-homo-lactam derivatives of 7-deoxycholic acid.

    PubMed

    Huang, Yanmin; Cui, Jianguo; Chen, Sijing; Gan, Chunfang; Yao, Qiucui; Lin, Qifu

    2013-04-01

    Using deoxycholic acid as starting materials, a series of 12a-aza-C-homo-12-one 7-deoxycholic acid derivatives were synthesized The antiproliferative activity of the synthesized compounds against some carcinoma cell lines was investigated. The results showed that some 12-oxy-12a-aza-C-homo-7-deoxycholic acid derivatives displayed distinct cytotoxicity to HeLa (human cervical carcinoma) and Tu 686 (laryngocarcinoma) tumor cell lines. In particular, the IC50 values of the compounds 6 and 7 against Tu 686 cells are 16.7 and 19.8 μM/L respectively. The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs.

  18. Characterizing the Evolutionary Path(s) to Early Homo

    PubMed Central

    Schroeder, Lauren; Roseman, Charles C.; Cheverud, James M.; Ackermann, Rebecca R.

    2014-01-01

    Numerous studies suggest that the transition from Australopithecus to Homo was characterized by evolutionary innovation, resulting in the emergence and coexistence of a diversity of forms. However, the evolutionary processes necessary to drive such a transition have not been examined. Here, we apply statistical tests developed from quantitative evolutionary theory to assess whether morphological differences among late australopith and early Homo species in Africa have been shaped by natural selection. Where selection is demonstrated, we identify aspects of morphology that were most likely under selective pressure, and determine the nature (type, rate) of that selection. Results demonstrate that selection must be invoked to explain an Au. africanus—Au. sediba—Homo transition, while transitions from late australopiths to various early Homo species that exclude Au. sediba can be achieved through drift alone. Rate tests indicate that selection is largely directional, acting to rapidly differentiate these taxa. Reconstructions of patterns of directional selection needed to drive the Au. africanus—Au. sediba—Homo transition suggest that selection would have affected all regions of the skull. These results may indicate that an evolutionary path to Homo without Au. sediba is the simpler path and/or provide evidence that this pathway involved more reliance on cultural adaptations to cope with environmental change. PMID:25470780

  19. The stem species of our species: a place for the archaic human cranium from Ceprano, Italy.

    PubMed

    Mounier, Aurélien; Condemi, Silvana; Manzi, Giorgio

    2011-04-20

    One of the present challenges in the study of human evolution is to recognize the hominin taxon that was ancestral to Homo sapiens. Some researchers regard H. heidelbergensis as the stem species involved in the evolutionary divergence leading to the emergence of H. sapiens in Africa, and to the evolution of the Neandertals in Europe. Nevertheless, the diagnosis and hypodigm of H. heidelbergensis still remain to be clarified. Here we evaluate the morphology of the incomplete cranium (calvarium) known as Ceprano whose age has been recently revised to the mid of the Middle Pleistocene, so as to test whether this specimen may be included in H. heidelbergensis. The analyses were performed according to a phenetic routine including geometric morphometrics and the evaluation of diagnostic discrete traits. The results strongly support the uniqueness of H. heidelbergensis on a wide geographical horizon, including both Eurasia and Africa. In this framework, the Ceprano calvarium--with its peculiar combination of archaic and derived traits--may represent, better than other penecontemporaneous specimens, an appropriate ancestral stock of this species, preceding the appearance of regional autapomorphic features.

  20. The Stem Species of Our Species: A Place for the Archaic Human Cranium from Ceprano, Italy

    PubMed Central

    Mounier, Aurélien; Condemi, Silvana; Manzi, Giorgio

    2011-01-01

    One of the present challenges in the study of human evolution is to recognize the hominin taxon that was ancestral to Homo sapiens. Some researchers regard H. heidelbergensis as the stem species involved in the evolutionary divergence leading to the emergence of H. sapiens in Africa, and to the evolution of the Neandertals in Europe. Nevertheless, the diagnosis and hypodigm of H. heidelbergensis still remain to be clarified. Here we evaluate the morphology of the incomplete cranium (calvarium) known as Ceprano whose age has been recently revised to the mid of the Middle Pleistocene, so as to test whether this specimen may be included in H. heidelbergensis. The analyses were performed according to a phenetic routine including geometric morphometrics and the evaluation of diagnostic discrete traits. The results strongly support the uniqueness of H. heidelbergensis on a wide geographical horizon, including both Eurasia and Africa. In this framework, the Ceprano calvarium – with its peculiar combination of archaic and derived traits – may represent, better than other penecontemporaneous specimens, an appropriate ancestral stock of this species, preceding the appearance of regional autapomorphic features. PMID:21533096

  1. A modern human pattern of dental development in lower pleistocene hominids from Atapuerca-TD6 (Spain).

    PubMed

    Bermúdez de Castro, J M; Rosas, A; Carbonell, E; Nicolás, M E; Rodríguez, J; Arsuaga, J L

    1999-03-30

    The study of life history evolution in hominids is crucial for the discernment of when and why humans have acquired our unique maturational pattern. Because the development of dentition is critically integrated into the life cycle in mammals, the determination of the time and pattern of dental development represents an appropriate method to infer changes in life history variables that occurred during hominid evolution. Here we present evidence derived from Lower Pleistocene human fossil remains recovered from the TD6 level (Aurora stratum) of the Gran Dolina site in the Sierra de Atapuerca, northern Spain. These hominids present a pattern of development similar to that of Homo sapiens, although some aspects (e.g., delayed M3 calcification) are not as derived as that of European populations and people of European origin. This evidence, taken together with the present knowledge of cranial capacity of these and other late Early Pleistocene hominids, supports the view that as early as 0.8 Ma at least one Homo species shared with modern humans a prolonged pattern of maturation.

  2. A modern human pattern of dental development in Lower Pleistocene hominids from Atapuerca-TD6 (Spain)

    PubMed Central

    Bermúdez de Castro, J. M.; Rosas, A.; Carbonell, E.; Nicolás, M. E.; Rodríguez, J.; Arsuaga, J. L.

    1999-01-01

    The study of life history evolution in hominids is crucial for the discernment of when and why humans have acquired our unique maturational pattern. Because the development of dentition is critically integrated into the life cycle in mammals, the determination of the time and pattern of dental development represents an appropriate method to infer changes in life history variables that occurred during hominid evolution. Here we present evidence derived from Lower Pleistocene human fossil remains recovered from the TD6 level (Aurora stratum) of the Gran Dolina site in the Sierra de Atapuerca, northern Spain. These hominids present a pattern of development similar to that of Homo sapiens, although some aspects (e.g., delayed M3 calcification) are not as derived as that of European populations and people of European origin. This evidence, taken together with the present knowledge of cranial capacity of these and other late Early Pleistocene hominids, supports the view that as early as 0.8 Ma at least one Homo species shared with modern humans a prolonged pattern of maturation. PMID:10097189

  3. The Hominin Sites and Paleolakes Drilling Project: inferring the environmental context of human evolution from eastern African rift lake deposits

    NASA Astrophysics Data System (ADS)

    Cohen, A.; Campisano, C.; Arrowsmith, R.; Asrat, A.; Behrensmeyer, A. K.; Deino, A.; Feibel, C.; Hill, A.; Johnson, R.; Kingston, J.; Lamb, H.; Lowenstein, T.; Noren, A.; Olago, D.; Owen, R. B.; Potts, R.; Reed, K.; Renaut, R.; Schäbitz, F.; Tiercelin, J.-J.; Trauth, M. H.; Wynn, J.; Ivory, S.; Brady, K.; O'Grady, R.; Rodysill, J.; Githiri, J.; Russell, J.; Foerster, V.; Dommain, R.; Rucina, S.; Deocampo, D.; Russell, J.; Billingsley, A.; Beck, C.; Dorenbeck, G.; Dullo, L.; Feary, D.; Garello, D.; Gromig, R.; Johnson, T.; Junginger, A.; Karanja, M.; Kimburi, E.; Mbuthia, A.; McCartney, T.; McNulty, E.; Muiruri, V.; Nambiro, E.; Negash, E. W.; Njagi, D.; Wilson, J. N.; Rabideaux, N.; Raub, T.; Sier, M. J.; Smith, P.; Urban, J.; Warren, M.; Yadeta, M.; Yost, C.; Zinaye, B.

    2016-02-01

    The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered. We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012-2014 HSPDP coring campaign.

  4. Human occupation of the Arabian Empty Quarter during MIS 5: evidence from Mundafan Al-Buhayrah, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Groucutt, Huw S.; White, Tom S.; Clark-Balzan, Laine; Parton, Ash; Crassard, Rémy; Shipton, Ceri; Jennings, Richard P.; Parker, Adrian G.; Breeze, Paul S.; Scerri, Eleanor M. L.; Alsharekh, Abdullah; Petraglia, Michael D.

    2015-07-01

    The Empty Quarter (or Rub' al Khali) of the Arabian Peninsula is the largest continuous sandy desert in the world. It has been known for several decades that Late Pleistocene and Holocene deposits, representing phases of wetter climate, are preserved there. These sequences have yielded palaeontological evidence in the form of a variety of vertebrate and invertebrate fossils and have been dated using various radiometric techniques. However, evidence for human presence during these wetter phases has until now been ephemeral. Here, we report on the first stratified and dated archaeology from the Empty Quarter, recovered from the site of Mundafan Al-Buhayrah (MDF-61). Human occupation at the site, represented by stone tools, has been dated to the later part of Marine Isotope Stage (MIS) 5 using multiple luminescence dating techniques (multigrain and single grain OSL, TT-OSL). The sequence consists primarily of lacustrine and palustrine sediments, from which evidence for changing local environmental conditions has been obtained through analysis of fossil assemblages (phytoliths and non-marine molluscs and ostracods). The discovery of securely-dated archaeological material at ∼100 to 80 ka in the Empty Quarter has important implications for hypotheses concerning the timing and routes of dispersal of Homo sapiens out of Africa, which have been much debated. Consequently, the data presented here fill a crucial gap in palaeoenvironmental and archaeological understanding of the southern Arabian interior. Fossils of H. sapiens in the Levant, also dated to MIS 5, together with Middle Palaeolithic archaeological sites in Arabia and India are thought to represent the earliest dispersal of our species out of Africa. We suggest that the widespread occurrence of similar lithic technologies across southern Asia, coupled with a growing body of evidence for environmental amelioration across the Saharo-Arabian belt, indicates that occupation of the Levant by H. sapiens during MIS 5

  5. The Edge of Human? The Problem with the Posthuman as the 'Beyond'.

    PubMed

    Lawrence, David R

    2017-03-01

    This article asks whether enhancement can truly lead to something beyond humanity, or whether it is, itself, an inherently human act. The 'posthuman' is an uncertain proposition. What, exactly, would one be? Many commentators suggest it to be an endpoint for the use of enhancement technologies, yet few choose to codify the term outright; which frequently leads to unnecessary confusion. Characterizing and contextualizing the term, particularly its more novel uses, is therefore a valuable enterprise. The abuse of the term 'Human', especially in the context of the enhancement debate and the myriad meanings ascribed to it, could give 'posthuman' very different slants depending on one's assumptions. There are perhaps three main senses in which the term 'human' is employed: the biological, the moral, and the self-idealizing. In the first of these, 'human' is often conflated with Homo sapiens, and used interchangeably to denote species; in the second, 'human' (or 'humanity') generally refers to a community of beings which qualify as having a certain moral value; and the third, the self-idealizing sense, is more descriptive; a label denoting the qualities that make us who we are as beings, or 'what matters about those who matter'. So, what might enhancement make us? A novel species or genus of hominid? Or, perhaps, a morally more valuable being than a regular human? Of course, there's a third option: that a posthuman is a being which embodies our self-ideal more successfully than we do ourselves - one 'more human than human'. Which to choose?

  6. Novelty-seeking DRD4 polymorphisms are associated with human migration distance out-of-Africa after controlling for neutral population gene structure.

    PubMed

    Matthews, Luke J; Butler, Paul M

    2011-07-01

    Numerous lines of evidence suggest that Homo sapiens evolved as a distinct species in Africa by 150,000 years before the present (BP) and began major migrations out-of-Africa ∼50,000 BP. By 20,000 BP, our species had effectively colonized the entire Old World, and by 12,000 BP H. sapiens had a global distribution. We propose that this rapid migration into new habitats selected for individuals with low reactivity to novel stressors. Certain dopamine receptor D4 (DRD4) polymorphisms are associated with low neuronal reactivity and increased exploratory behavior, novelty seeking, and risk taking, collectively considered novelty-seeking trait (NS). One previous report (Chen et al.: Evol Hum Behav 20 (1999) 309-324) demonstrated a correlation between migratory distance and the seven-repeat (7R) VNTR DRD4 allele at exon 3 for human populations. This study, however, failed to account for neutral genetic processes (drift and admixture) that might create such a correlation in the absence of natural selection. Furthermore, additional loci surrounding DRD4 are now recognized to influence NS. Herein we account for neutral genetic structure by modeling the nonindependence of neutral allele frequencies between human populations. We retest the DRD4 exon 3 alleles, and also test two other loci near DRD4 that are associated with NS. We conclude there is an association between migratory distance and DRD4 exon 3 2R and 7R alleles that cannot be accounted for by neutral genetic processes alone.

  7. Radiometric dating of the type-site for Homo heidelbergensis at Mauer, Germany.

    PubMed

    Wagner, Günther A; Krbetschek, Matthias; Degering, Detlev; Bahain, Jean-Jacques; Shao, Qingfeng; Falguères, Christophe; Voinchet, Pierre; Dolo, Jean-Michel; Garcia, Tristan; Rightmire, G Philip

    2010-11-16

    The Mauer mandible, holotype of Homo heidelbergensis, was found in 1907 in fluvial sands deposited by the Neckar River 10 km southeast of Heidelberg, Germany. The fossil is an important key to understanding early human occupation of Europe north of the Alps. Given the associated mammal fauna and the geological context, the find layer has been placed in the early Middle Pleistocene, but confirmatory chronometric evidence has hitherto been missing. Here we show that two independent techniques, the combined electron spin resonance/U-series method used with mammal teeth and infrared radiofluorescence applied to sand grains, date the type-site of Homo heidelbergensis at Mauer to 609 ± 40 ka. This result demonstrates that the mandible is the oldest hominin fossil reported to date from central and northern Europe and raises questions concerning the phyletic relationship of Homo heidelbergensis to more ancient populations documented from southern Europe and in Africa. We address the paleoanthropological significance of the Mauer jaw in light of this dating evidence.

  8. From Darwinian to technological evolution: forgetting the human lottery.

    PubMed

    Tintino, Giorgio

    2014-01-01

    The GRIN technologies (-geno, -robo, -info, -nano) promise to change the inner constitution of human body and its own existence. This transformation involves the structure of our lives and represent a brave new world that we have to explore and to manage. In this sense, the traditional tools of humanism seems very inadequate to think the biotech century and there is a strong demand of a new thought for the evolution and the concrete history of life. The posthuman philosophy tries to take this new path of human existence in all of its novelty since GRIN technologies seem to promise new and unexpected paths of evolution to living beings and, above all, man. For this, the post-human thought, as we see, is a new anthropological overview on the concrete evolution of human being, an overview that involves an epistemological revolution of the categories that humanism uses to conceptualize the journey that divides the Homo sapiens from the man. But, is this right?

  9. The mitochondrial Italian Human Proteome Project initiative (mt-HPP).

    PubMed

    Urbani, Andrea; De Canio, Michele; Palmieri, Ferdinando; Sechi, Salvatore; Bini, Luca; Castagnola, Massimo; Fasano, Mauro; Modesti, Alessandra; Roncada, Paola; Timperio, Anna Maria; Bonizzi, Luigi; Brunori, Maurizio; Cutruzzolà, Francesca; De Pinto, Vito; Di Ilio, Carmine; Federici, Giorgio; Folli, Franco; Foti, Salvatore; Gelfi, Cecilia; Lauro, Davide; Lucacchini, Antonio; Magni, Fulvio; Messana, Irene; Pandolfi, Pier Paolo; Papa, Sergio; Pucci, Piero; Sacchetta, Paolo

    2013-08-01

    Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA), which can be defined as the 25th human chromosome. The chromosome-centric Human Proteome Project (c-HPP) has initially focused its activities addressing the characterization and quantification of the nuclear encoded proteins. Following the last International HUPO Congress in Boston (September 2012) it was clear that however small the mitochondrial chromosome is, it plays an important role in many biological and physiopathological functions. Mutations in the mtDNA have been shown to be associated with dozens of unexplained disorders and the information contained in the mtDNA should be of major relevance to the understanding of many human diseases. Within this paper we describe the Italian initiative of the Human Proteome Project dedicated to mitochondria as part of both programs: chromosome-centric (c-HPP) and Biology/Disease (B/D-HPP). The mt-HPP has finally shifted the attention of the HUPO community outside the nuclear chromosomes with the general purpose to highlight the mitochondrial processes influencing the human health. Following this vision and considering the large interest and evidence collected on the non-Mendelian heredity of Homo sapiens associated with mt-chromosome and with the microbial commensal ecosystem constituting our organism we may speculate that this program will represent an initial step toward other HPP initiatives focusing on human phenotypic heredity.

  10. Taphonomy of the Tianyuandong human skeleton and faunal remains.

    PubMed

    Fernández-Jalvo, Yolanda; Andrews, Peter; Tong, HaoWen

    2015-06-01

    Tianyuan Cave is an Upper Palaeolithic site, 6 km from the core area of the Zhoukoudian Site Complex. Tianyuandong (or Tianyuan Cave) yielded one ancient (though not the earliest) fossil skeleton of Homo sapiens in China (42-39 ka cal BP). Together with the human skeleton, abundant animal remains were found, but no stone tools were recovered. The animal fossil remains are extremely fragmentary, in contrast to human skeletal elements that are, for the most part, complete. We undertook a taphonomic study to investigate the circumstances of preservation of the human skeleton in Tianyuan Cave, and in course of this we considered four hypotheses: funerary ritual, cannibalism, carnivore activity or natural death. Taphonomic results characterize the role of human action in the site and how these agents acted in the past. Because of disturbance of the human skeleton during its initial excavation, it is not known if it was in a grave cut or if there was any funerary ritual. No evidence was found for cannibalism or carnivore activity in relation to the human skeleton, suggesting natural death as the most reasonable possibility.

  11. Gas-phase Dissociation of homo-DNA Oligonucleotides

    NASA Astrophysics Data System (ADS)

    Stucki, Silvan R.; Désiron, Camille; Nyakas, Adrien; Marti, Simon; Leumann, Christian J.; Schürch, Stefan

    2013-12-01

    Synthetic modified oligonucleotides are of interest for diagnostic and therapeutic applications, as their biological stability, pairing selectivity, and binding strength can be considerably increased by the incorporation of unnatural structural elements. Homo-DNA is an oligonucleotide homologue based on dideoxy-hexopyranosyl sugar moieties, which follows the Watson-Crick A-T and G-C base pairing system, but does not hybridize with complementary natural DNA and RNA. Homo-DNA has found application as a bioorthogonal element in templated chemistry applications. The gas-phase dissociation of homo-DNA has been investigated by ESI-MS/MS and MALDI-MS/MS, and mechanistic aspects of its gas-phase dissociation are discussed. Experiments revealed a charge state dependent preference for the loss of nucleobases, which are released either as neutrals or as anions. In contrast to DNA, nucleobase loss from homo-DNA was found to be decoupled from backbone cleavage, thus resulting in stable products. This renders an additional stage of ion activation necessary in order to generate sequence-defining fragment ions. Upon MS3 of the primary base-loss ion, homo-DNA was found to exhibit unspecific backbone dissociation resulting in a balanced distribution of all fragment ion series.

  12. Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain).

    PubMed

    Pablos, Adrián; Martínez, Ignacio; Lorenzo, Carlos; Gracia, Ana; Sala, Nohemi; Arsuaga, Juan Luis

    2013-07-01

    Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site.

  13. The Menengai Tuff: A 36 ka widespread tephra and its chronological relevance to Late Pleistocene human evolution in East Africa

    NASA Astrophysics Data System (ADS)

    Blegen, Nick; Brown, Francis H.; Jicha, Brian R.; Binetti, Katie M.; Faith, J. Tyler; Ferraro, Joseph V.; Gathogo, Patrick N.; Richardson, Jonathan L.; Tryon, Christian A.

    2016-11-01

    The East African Rift preserves the world's richest Middle and Late Pleistocene (∼780-12 ka) geological, archaeological and paleontological archives relevant to the emergence of Homo sapiens. This region also provides unparalleled chronological control for many important sites through tephrochronology, the dating and correlation of volcanic ashes as widespread isochronous markers in the geological record. There are many well-characterized Pliocene-Early Pleistocene tephras that are widespread across East Africa. A comparable framework is lacking for the Middle and Late Pleistocene; a period characterized by spatially and temporally complex patterns of climate change, as well as the emergence of modern Homo sapiens and the dispersal of this species across and out of Africa. Unraveling relationships among these spatial and temporally complex phenomena requires a precise chronology. To this end we report the Menengai Tuff, a widespread volcanic ash produced by the large-scale caldera-forming eruption in Kenya and 40Ar/39Ar dated to 35.62 ± 0.26 ka. Geochemical characterization of 565 glass shards from 36 samples by wavelength-dispersive electron probe microanalysis show the Menengai Tuff was deposited over >115,000 km2 and is found in the Baringo, Chalbi, Elmenteita, Nakuru, Olorgesailie, Turkana, and Victoria basins, all of which preserve rich Late Pleistocene paleoenvironmental and archaeological archives. Correlation and dating of the Menengai Tuff demonstrate that it is the most widespread tephra and largest eruption currently known from the Late Pleistocene of East Africa. As such, it is a valuable marker in establishing a Late Pleistocene chronology for paleoclimatic, archeological, and paleontological records relevant to the study of human evolution.

  14. Heterochronic processes in human evolution: an ontogenetic analysis of the hominid pelvis.

    PubMed

    Berge, C

    1998-04-01

    Changes in pelvic shape in human ontogeny and hominid phylogeny suggest that the heterochronic processes involved differ greatly from the neotenic process traditionally described in the evolution of the skull. The morphology of 150 juvenile and adult pelves of African apes, 60 juvenile and adult pelves of modern humans, two adult pelves and a juvenile hip bone of australopithecines (Sts 14, AL 288, MLD 7) was studied. Multivariate results, ontogenetic allometries, and growth curves confirm that the pelvic growth pattern in humans differs markedly from those of the African apes. The results permit the following conclusions. First, the appearance of a new feature (acetabulo-cristal buttress and cristal tubercle) at the time of human birth allows the addition of traits, such as the attainment of a proportionally narrower pelvis, with more sagittally positioned iliac blades. Pelvic proportions and orientation change progressively in early childhood as bipedalism is practiced. Other changes in pelvic proportions occur later with the adolescent growth spurt. Second, comparison of juvenile and adult australopithecines to modern humans indicates that 1) some pelvic traits of adult Australopithecus resemble those of neonate Homo; 2) the pelvic growth of Australopithecus was probably closer to that of apes, than to that of humans; and 3) prolonged growth in length of hindlimb and pelvis after sexual maturity seems to be a unique feature of Homo. The position of the acetabulo-cristal buttress and of the cristal tubercle on the ilium are similar in adult Australopithecus and neonate Homo suggesting that this feature may have been displaced later during hominid evolution. Progressive displacement of the acetabulo-cristal buttress on the ilium occurs both during hominid evolution (from Australopithecus to Homo sapiens) and human growth (from neonate to adult). This suggests peramorphic evolution of the pelvic morphology of hominids combining three processes of recapitulation

  15. Evolutionary reversals of limb proportions in early hominids? Evidence from KNM-ER 3735 (Homo habilis).

    PubMed

    Haeusler, Martin; McHenry, Henry M

    2007-10-01

    Upper-to-lower limb proportions of Homo habilis are often said to be more ape-like than those of its reputed ancestor, Australopithecus afarensis. Such proportions would either imply multiple evolutionary reversals or parallel development of a relatively short upper limb in A. afarensis and later Homo. However, assessments of limb proportions are complicated by the fragmentary nature of the two known H. habilis skeletons, OH 62 and KNM-ER 3735. Initially, KNM-ER 3735 was compared to A.L. 288-1 (A. afarensis) using a single modern human and chimpanzee as reference. Here, based on a larger comparative sample, we find that the relative size of the distal humerus, radial head, and shaft of both KNM-ER 3735 and A.L. 288-1 lie within the range of variation of modern humans, whereas their sacra are small as is the case for all early hominids. In addition, their manual phalanges are similar in having a gracile base but robust midshaft. Contrary to earlier studies, the fossils are not differentiable from each other statistically with respect to all features listed above. On the other hand, they differ in robusticity of the scapular spine and relative length of the radial neck. An exact randomization test suggests only a very low probability of finding a similar degree of difference within a single species of extant hominoids. In contrast to the consensus view, we conclude that A.L. 288-1 had a short, human-like forearm, whereas KNM-ER 3735 possessed a distinctly longer forearm and more powerful shoulder girdle. This interpretation fits with earlier conclusions that suggested human-like humerofemoral proportions but chimpanzee-like brachial proportions for Homo habilis. Thus, the scenario of a unidirectional, progressive change in limb proportions within the hominid lineage is not supported by our work.

  16. A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis

    PubMed Central

    Baab, Karen L.; Brown, Peter; Falk, Dean; Richtsmeier, Joan T.; Hildebolt, Charles F.; Smith, Kirk; Jungers, William

    2016-01-01

    The Liang Bua hominins from Flores, Indonesia, have been the subject of intense scrutiny and debate since their initial description and classification in 2004. These remains have been assigned to a new species, Homo floresiensis, with the partial skeleton LB1 as the type specimen. The Liang Bua hominins are notable for their short stature, small endocranial volume, and many features that appear phylogenetically primitive relative to modern humans, despite their late Pleistocene age. Recently, some workers suggested that the remains represent members of a small-bodied island population of modern Austro-Melanesian humans, with LB1 exhibiting clinical signs of Down syndrome. Many classic Down syndrome signs are soft tissue features that could not be assessed in skeletal remains. Moreover, a definitive diagnosis of Down syndrome can only be made by genetic analysis as the phenotypes associated with Down syndrome are variable. Most features that contribute to the Down syndrome phenotype are not restricted to Down syndrome but are seen in other chromosomal disorders and in the general population. Nevertheless, we re-evaluated the presence of those phenotypic features used to support this classification by comparing LB1 to samples of modern humans diagnosed with Down syndrome and euploid modern humans using comparative morphometric analyses. We present new data regarding neurocranial, brain, and symphyseal shape in Down syndrome, additional estimates of stature for LB1, and analyses of inter- and intralimb proportions. The presence of cranial sinuses is addressed using CT images of LB1. We found minimal congruence between the LB1 phenotype and clinical descriptions of Down syndrome. We present important differences between the phenotypes of LB1 and individuals with Down syndrome, and quantitative data that characterize LB1 as an outlier compared with Down syndrome and non-Down syndrome groups. Homo floresiensis remains a phenotypically unique, valid species with its roots

  17. A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis.

    PubMed

    Baab, Karen L; Brown, Peter; Falk, Dean; Richtsmeier, Joan T; Hildebolt, Charles F; Smith, Kirk; Jungers, William

    2016-01-01

    The Liang Bua hominins from Flores, Indonesia, have been the subject of intense scrutiny and debate since their initial description and classification in 2004. These remains have been assigned to a new species, Homo floresiensis, with the partial skeleton LB1 as the type specimen. The Liang Bua hominins are notable for their short stature, small endocranial volume, and many features that appear phylogenetically primitive relative to modern humans, despite their late Pleistocene age. Recently, some workers suggested that the remains represent members of a small-bodied island population of modern Austro-Melanesian humans, with LB1 exhibiting clinical signs of Down syndrome. Many classic Down syndrome signs are soft tissue features that could not be assessed in skeletal remains. Moreover, a definitive diagnosis of Down syndrome can only be made by genetic analysis as the phenotypes associated with Down syndrome are variable. Most features that contribute to the Down syndrome phenotype are not restricted to Down syndrome but are seen in other chromosomal disorders and in the general population. Nevertheless, we re-evaluated the presence of those phenotypic features used to support this classification by comparing LB1 to samples of modern humans diagnosed with Down syndrome and euploid modern humans using comparative morphometric analyses. We present new data regarding neurocranial, brain, and symphyseal shape in Down syndrome, additional estimates of stature for LB1, and analyses of inter- and intralimb proportions. The presence of cranial sinuses is addressed using CT images of LB1. We found minimal congruence between the LB1 phenotype and clinical descriptions of Down syndrome. We present important differences between the phenotypes of LB1 and individuals with Down syndrome, and quantitative data that characterize LB1 as an outlier compared with Down syndrome and non-Down syndrome groups. Homo floresiensis remains a phenotypically unique, valid species with its roots

  18. Middle Pleistocene lower back and pelvis from an aged human individual from the Sima de los Huesos site, Spain.

    PubMed

    Bonmatí, Alejandro; Gómez-Olivencia, Asier; Arsuaga, Juan-Luis; Carretero, José Miguel; Gracia, Ana; Martínez, Ignacio; Lorenzo, Carlos; Bérmudez de Castro, José María; Carbonell, Eudald

    2010-10-26

    We report a nearly complete lumbar spine from the Middle Pleistocene site of the Sima de los Huesos (SH) that is assigned to the previously published SH male Pelvis 1 [Arsuaga JL, et al. (1999). Nature 399: 255-258]. The "SH Pelvis 1 individual" is a unique nearly complete lumbo-pelvic complex from the human Middle Pleistocene fossil record, and offers a rare glimpse into the anatomy and past lifeways of Homo heidelbergensis. A revised reconstruction of Pelvis 1, together with the current fossil evidence, confirms our previous hypothesis that the morphology of this pelvis represents the primitive pattern within the genus Homo. Here we argue that this primitive pattern is also characterized by sexual dimorphism in the pelvic canal shape, implying complicated deliveries. In addition, this individual shows signs of lumbar kyphotic deformity, spondylolisthesis, and Baastrup disease. This suite of lesions would have postural consequences and was most likely painful. As a result, the individual's daily physical activities would have been restricted to some extent. Reexamination of the age-at-death agrees with this individual being over 45 y old, relying on the modern human pattern of changes of the articular surfaces of the os coxae. The presence of degenerative pathological lesions and the advanced age-at-death of this individual make it the most ancient postcranial evidence of an aged individual in the human fossil record. Additional nonpathological SH lumbo-pelvic remains are consistent with previous hypotheses, suggesting a less-pronounced sagittal spinal curvature in Neandertals compared with Homo sapiens.

  19. Middle Pleistocene lower back and pelvis from an aged human individual from the Sima de los Huesos site, Spain

    PubMed Central

    Bonmatí, Alejandro; Gómez-Olivencia, Asier; Arsuaga, Juan-Luis; Carretero, José Miguel; Gracia, Ana; Martínez, Ignacio; Lorenzo, Carlos; Bérmudez de Castro, José María; Carbonell, Eudald

    2010-01-01

    We report a nearly complete lumbar spine from the Middle Pleistocene site of the Sima de los Huesos (SH) that is assigned to the previously published SH male Pelvis 1 [Arsuaga JL, et al. (1999). Nature 399: 255–258]. The “SH Pelvis 1 individual” is a unique nearly complete lumbo-pelvic complex from the human Middle Pleistocene fossil record, and offers a rare glimpse into the anatomy and past lifeways of Homo heidelbergensis. A revised reconstruction of Pelvis 1, together with the current fossil evidence, confirms our previous hypothesis that the morphology of this pelvis represents the primitive pattern within the genus Homo. Here we argue that this primitive pattern is also characterized by sexual dimorphism in the pelvic canal shape, implying complicated deliveries. In addition, this individual shows signs of lumbar kyphotic deformity, spondylolisthesis, and Baastrup disease. This suite of lesions would have postural consequences and was most likely painful. As a result, the individual’s daily physical activities would have been restricted to some extent. Reexamination of the age-at-death agrees with this individual being over 45 y old, relying on the modern human pattern of changes of the articular surfaces of the os coxae. The presence of degenerative pathological lesions and the advanced age-at-death of this individual make it the most ancient postcranial evidence of an aged individual in the human fossil record. Additional nonpathological SH lumbo-pelvic remains are consistent with previous hypotheses, suggesting a less-pronounced sagittal spinal curvature in Neandertals compared with Homo sapiens. PMID:20937858

  20. The social side of Homo economicus.

    PubMed

    Rankin, Daniel J

    2011-01-01

    Many recent experiments in the field of behavioural economics appear to demonstrate a willingness of humans to behave altruistically, even when it is not in their interest to do so. This has led to the assertion that humans have evolved a special predisposition towards altruism. Recent studies have questioned this, and demonstrated that selfless cooperation does not hold up in controlled experiments. As I discuss here, this calls for more economic 'field experiments' and highlights the need for greater integration of the evolutionary and economic sciences.

  1. The integration hypothesis of human language evolution and the nature of contemporary languages

    PubMed Central

    Miyagawa, Shigeru; Ojima, Shiro; Berwick, Robert C.; Okanoya, Kazuo

    2014-01-01

    How human language arose is a mystery in the evolution of Homo sapiens. Miyagawa et al. (2013) put forward a proposal, which we will call the Integration Hypothesis of human language evolution, that holds that human language is composed of two components, E for expressive, and L for lexical. Each component has an antecedent in nature: E as found, for example, in birdsong, and L in, for example, the alarm calls of monkeys. E and L integrated uniquely in humans to give rise to language. A challenge to the Integration Hypothesis is that while these non-human systems are finite-state in nature, human language is known to require characterization by a non-finite state grammar. Our claim is that E and L, taken separately, are in fact finite-state; when a grammatical process crosses the boundary between E and L, it gives rise to the non-finite state character of human language. We provide empirical evidence for the Integration Hypothesis by showing that certain processes found in contemporary languages that have been characterized as non-finite state in nature can in fact be shown to be finite-state. We also speculate on how human language actually arose in evolution through the lens of the Integration Hypothesis. PMID:24936195

  2. RNA editing differently affects protein-coding genes in D. melanogaster and H. sapiens.

    PubMed

    Grassi, Luigi; Leoni, Guido; Tramontano, Anna

    2015-07-14

    When an RNA editing event occurs within a coding sequence it can lead to a different encoded amino acid. The biological significance of these events remains an open question: they can modulate protein functionality, increase the complexity of transcriptomes or arise from a loose specificity of the involved enzymes. We analysed the editing events in coding regions that produce or not a change in the encoded amino acid (nonsynonymous and synonymous events, respectively) in D. melanogaster and in H. sapiens and compared them with the appropriate random models. Interestingly, our results show that the phenomenon has rather different characteristics in the two organisms. For example, we confirm the observation that editing events occur more frequently in non-coding than in coding regions, and report that this effect is much more evident in H. sapiens. Additionally, in this latter organism, editing events tend to affect less conserved residues. The less frequently occurring editing events in Drosophila tend to avoid drastic amino acid changes. Interestingly, we find that, in Drosophila, changes from less frequently used codons to more frequently used ones are favoured, while this is not the case in H. sapiens.

  3. RNA editing differently affects protein-coding genes in D. melanogaster and H. sapiens

    PubMed Central

    Grassi, Luigi; Leoni, Guido; Tramontano, Anna

    2015-01-01

    When an RNA editing event occurs within a coding sequence it can lead to a different encoded amino acid. The biological significance of these events remains an open question: they can modulate protein functionality, increase the complexity of transcriptomes or arise from a loose specificity of the involved enzymes. We analysed the editing events in coding regions that produce or not a change in the encoded amino acid (nonsynonymous and synonymous events, respectively) in D. melanogaster and in H. sapiens and compared them with the appropriate random models. Interestingly, our results show that the phenomenon has rather different characteristics in the two organisms. For example, we confirm the observation that editing events occur more frequently in non-coding than in coding regions, and report that this effect is much more evident in H. sapiens. Additionally, in this latter organism, editing events tend to affect less conserved residues. The less frequently occurring editing events in Drosophila tend to avoid drastic amino acid changes. Interestingly, we find that, in Drosophila, changes from less frequently used codons to more frequently used ones are favoured, while this is not the case in H. sapiens. PMID:26169954

  4. [Beyond eugenics: posthumanism as Homo patiens denials].

    PubMed

    Ballesteros Llompart, Jesús

    2012-01-01

    Throughout history there have been attempts to overcome human limitations by means of technique. The novelty of the 20th century has been to try to extirpate all the faults, the suffering, the disease, and even the death. This power has been attributed successively to machines (the futurism), to the genetic information (the eugenism) and to the electronic information (the posthumanism). In all cases, it's unknown the distinction between inevitable faults, ontological deficiencies, as the reality of death, and avoidable ones, sociological deficiencies, as the deaths due to circumstances as lack of drinkable water, of medicaments, wars or any other type of violence. The due way of confronting the human faults is to try to eradicate their avoidable causes and at the same time to understand the sense of those that cannot be avoided, as occasion of the self-overcoming and the opening to the Transcendence.

  5. The posterior border of the sphenoid greater wing and its phylogenetic usefulness in human evolution.

    PubMed

    Braga, J; Crubézy, E; Elyaqtine, M

    1998-12-01

    The elucidation of patterns of cranial skeletal maturation and growth in fossil hominids is possible not only through dental studies but also by mapping different aspects of ossification in both extant African apes and humans. However, knowledge of normal skeletal development in large samples of extant great apes is flimsy. To remedy this situation, this paper offers an extensive survey and thorough discussion of the ossification of the posterior border of the sphenoid greater wing. Indeed, this area provides much information about basicranial skeletal maturation. We investigate three variants: the absence of the foramen spinosum and the position of both the foramen spinosum and the foramen ovale in relation to the sphenosquamosal suture. Providing original data about humans and 1,425 extant great ape skulls and using a sample of 64 fossil hominids, this study aimed to test whether different ossification patterns occurred during the course of human evolution. The incidence of three derived morphologies located on the posterior border of the sphenoid greater wing increases during human evolution at different geological periods. The evolutionary polarity of these three derived morphologies is assessed by outgroup comparison and ontogenetic methods. During human evolution, there is a clear trend for the foramen spinosum to be present and wholly located on the posterior area of the sphenoid greater wing. Moreover, in all the great ape species and in Australopithecus afarensis, the sphenosquamosal suture may split the foramen ovale. Inversely, the foramen ovale always lies wholly within the sphenoid greater wing in Australopithecus africanus, robust australopithecines, early Homo, H. erectus (and/or H. ergaster), and Homo sapiens. From ontogenetic studies in humans, we conclude that, during human evolution, the ossification of the posterior area of the sphenoid greater wing progressively surrounded the middle meningeal artery (passing through the foramen spinosum) and

  6. Deep Haplotype Divergence and Long-Range Linkage Disequilibrium at Xp21.1 Provide Evidence That Humans Descend From a Structured Ancestral Population

    PubMed Central

    Garrigan, Daniel; Mobasher, Zahra; Kingan, Sarah B.; Wilder, Jason A.; Hammer, Michael F.

    2005-01-01

    Fossil evidence links human ancestry with populations that evolved from modern gracile morphology in Africa 130,000–160,000 years ago. Yet fossils alone do not provide clear answers to the question of whether the ancestors of all modern Homo sapiens comprised a single African population or an amalgamation of distinct archaic populations. DNA sequence data have consistently supported a single-origin model in which anatomically modern Africans expanded and completely replaced all other archaic hominin populations. Aided by a novel experimental design, we present the first genetic evidence that statistically rejects the null hypothesis that our species descends from a single, historically panmictic population. In a global sample of 42 X chromosomes, two African individuals carry a lineage of noncoding 17.5-kb sequence that has survived for >1 million years without any clear traces of ongoing recombination with other lineages at this locus. These patterns of deep haplotype divergence and long-range linkage disequilibrium are best explained by a prolonged period of ancestral population subdivision followed by relatively recent interbreeding. This inference supports human evolution models that incorporate admixture between divergent African branches of the genus Homo. PMID:15937130

  7. Human cloning and embryo research: the 2003 John J. Conley Lecture on medical ethics.

    PubMed

    George, Robert P

    2004-01-01

    The author, a member of the U.S. President's Council on Bioethics, discusses ethical issues raised by human cloning, whether for purposes of bringing babies to birth or for research purposes. He first argues that every cloned human embryo is a new, distinct, and enduring organism, belonging to the species Homo sapiens, and directing its own development toward maturity. He then distinguishes between two types of capacities belonging to individual organisms belonging to this species, an immediately exerciseable capacity and a basic natural capacity that develops over time. He argues that it is the second type of capacity that is the ground for full moral respect, and that this capacity (and its concomitant degree of respect) belongs to cloned human embryos no less than to adult human beings. He then considers and rejects counter-arguments to his position, including the suggestion that the capacity of embryos is equivalent to the capacity of somatic cells, that full human rights are afforded only to human organisms with functioning brains, that the possibility of twinning diminishes the moral status of embryos, that the fact that people do not typically mourn the loss of early embryos implies that they have a diminished moral status, that the fact that early spontaneous abortions occur frequently diminishes the moral status of embryos, and that his arguments depend upon a concept of ensoulment. He concludes that if the moral status of cloned human embryos is equivalent to that of adults, then public policy should be based upon this assumption.

  8. Limits to human locomotor performance: phylogenetic origins and comparative perspectives.

    PubMed

    Dudley, R

    2001-09-01

    Studies of human exercise physiology have been conducted from a largely ahistorical perspective. This approach usefully elucidates proximate limits to locomotor performance, but ignores potential sources of biomechanical and physiological variation that derive from adaptation to ancestral environments. Phylogenetic reconstruction suggests that multiple hominoid lineages, including that leading to Homo sapiens, evolved in African highlands at altitudes of 1000-2000 m. The evolution of human locomotor physiology therefore occurred under conditions of hypobaric hypoxia. In contrast to present-day humans running on treadmills or exercising in otherwise rectilinear trajectories, ancestral patterns of hominid locomotion probably involved intermittent knuckle-walking over variable terrain, occasional bouts of arboreality and an evolving capacity for bipedalism. All such factors represent potential axes of locomotor variation at present unstudied in extant hominoid taxa. As with humans, hummingbirds evolved in mid-montane contexts but pose an extreme contrast with respect to body size, locomotor mode and metabolic capacity. Substantial biomechanical and physiological challenges are associated with flight in hypobaria. Nonetheless, hummingbird lineages demonstrate a progressive invasion of higher elevations and a remarkable tolerance to hypoxia during hovering. Upregulation of aerobic capacity and parallel resistance to hypoxia may represent coupled evolutionary adaptations to flight under high-altitude conditions.

  9. Are human embryos Kantian persons?: Kantian considerations in favor of embryonic stem cell research

    PubMed Central

    Manninen, Bertha Alvarez

    2008-01-01

    One argument used by detractors of human embryonic stem cell research (hESCR) invokes Kant's formula of humanity, which proscribes treating persons solely as a means to an end, rather than as ends in themselves. According to Fuat S. Oduncu, for example, adhering to this imperative entails that human embryos should not be disaggregated to obtain pluripotent stem cells for hESCR. Given that human embryos are Kantian persons from the time of their conception, killing them to obtain their cells for research fails to treat them as ends in themselves. This argument assumes two points that are rather contentious given a Kantian framework. First, the argument assumes that when Kant maintains that humanity must be treated as an end in itself, he means to argue that all members of the species Homo sapiens must be treated as ends in themselves; that is, that Kant regards personhood as co-extensive with belonging to the species Homo sapiens. Second, the argument assumes that the event of conception is causally responsible for the genesis of a Kantian person and that, therefore, an embryo is a Kantian person from the time of its conception. In this paper, I will present challenges against these two assumptions by engaging in an exegetical study of some of Kant's works. First, I will illustrate that Kant did not use the term "humanity" to denote a biological species, but rather the capacity to set ends according to reason. Second, I will illustrate that it is difficult given a Kantian framework to denote conception (indeed any biological event) as causally responsible for the creation of a person. Kant ascribed to a dualistic view of human agency, and personhood, according to him, was derived from the supersensible capacity for reason. To argue that a Kantian person is generated due to the event of conception ignores Kant's insistence in various aspects of his work that it is not possible to understand the generation of a person qua a physical operation. Finally, I will end the

  10. Are human embryos Kantian persons?: Kantian considerations in favor of embryonic stem cell research.

    PubMed

    Manninen, Bertha Alvarez

    2008-01-31

    One argument used by detractors of human embryonic stem cell research (hESCR) invokes Kant's formula of humanity, which proscribes treating persons solely as a means to an end, rather than as ends in themselves. According to Fuat S. Oduncu, for example, adhering to this imperative entails that human embryos should not be disaggregated to obtain pluripotent stem cells for hESCR. Given that human embryos are Kantian persons from the time of their conception, killing them to obtain their cells for research fails to treat them as ends in themselves. This argument assumes two points that are rather contentious given a Kantian framework. First, the argument assumes that when Kant maintains that humanity must be treated as an end in itself, he means to argue that all members of the species Homo sapiens must be treated as ends in themselves; that is, that Kant regards personhood as co-extensive with belonging to the species Homo sapiens. Second, the argument assumes that the event of conception is causally responsible for the genesis of a Kantian person and that, therefore, an embryo is a Kantian person from the time of its conception. In this paper, I will present challenges against these two assumptions by engaging in an exegetical study of some of Kant's works. First, I will illustrate that Kant did not use the term "humanity" to denote a biological species, but rather the capacity to set ends according to reason. Second, I will illustrate that it is difficult given a Kantian framework to denote conception (indeed any biological event) as causally responsible for the creation of a person. Kant ascribed to a dualistic view of human agency, and personhood, according to him, was derived from the supersensible capacity for reason. To argue that a Kantian person is generated due to the event of conception ignores Kant's insistence in various aspects of his work that it is not possible to understand the generation of a person qua a physical operation. Finally, I will end the

  11. Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

    PubMed Central

    Bosiocic, Vanya

    2016-01-01

    The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate. PMID:27853608

  12. Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

    NASA Astrophysics Data System (ADS)

    Seymour, Roger S.; Bosiocic, Vanya; Snelling, Edward P.

    2016-08-01

    The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.

  13. Reconstruction and analysis of human liver-specific metabolic network based on CNHLPP data.

    PubMed

    Zhao, Jing; Geng, Chao; Tao, Lin; Zhang, Duanfeng; Jiang, Ying; Tang, Kailin; Zhu, Ruixin; Yu, Hong; Zhang, Weidong; He, Fuchu; Li, Yixue; Cao, Zhiwei

    2010-04-05

    Liver is the largest internal organ in the body that takes central roles in metabolic homeostasis, detoxification of various substances, as well as in the synthesis and storage of nutrients. To fulfill these complex tasks, thousands of biochemical reactions are going on in liver to cope with a wide range of foods and environmental variations, which are densely interconnected into an intricate metabolic network. Here, the first human liver-specific metabolic network was reconstructed according to proteomics data from Chinese Human Liver Proteome Project (CNHLPP), and then investigated in the context of the genome-scale metabolic network of Homo sapiens. Topological analysis shows that this organ-specific metabolic network exhibits similar features as organism-specific networks, such as power-law degree distribution, small-world property, and bow-tie structure. Furthermore, the structure of liver network exhibits a modular organization where the modules are formed around precursors from primary metabolism or hub metabolites from derivative metabolism, respectively. Most of the modules are dominated by one major category of metabolisms, while enzymes within same modules have a tendency of being expressed concertedly at protein level. Network decomposition and comparison suggest that the liver network overlays a predominant area in the global metabolic network of H. sapiens genome; meanwhile the human network may develop extra modules to gain more specialized functionality out of liver. The results of this study would permit a high-level interpretation of the metabolite information flow in human liver and provide a basis for modeling the physiological and pathological metabolic states of liver.

  14. Short faces, big tongues: developmental origin of the human chin.

    PubMed

    Coquerelle, Michael; Prados-Frutos, Juan Carlos; Rojo, Rosa; Mitteroecker, Philipp; Bastir, Markus

    2013-01-01

    During the course of human evolution, the retraction of the face underneath the braincase, and closer to the cervical column, has reduced the horizontal dimension of the vocal tract. By contrast, the relative size of the tongue has not been reduced, implying a rearrangement of the space at the back of the vocal tract to allow breathing and swallowing. This may have left a morphological signature such as a chin (mental prominence) that can potentially be interpreted in Homo. Long considered an autopomorphic trait of Homo sapiens, various extinct hominins show different forms of mental prominence. These features may be the evolutionary by-product of equivalent developmental constraints correlated with an enlarged tongue. In order to investigate developmental mechanisms related to this hypothesis, we compare modern 34 human infants against 8 chimpanzee fetuses, whom development of the mandibular symphysis passes through similar stages. The study sets out to test that the shared ontogenetic shape changes of the symphysis observed in both species are driven by the same factor--space restriction at the back of the vocal tract and the associated arrangement of the tongue and hyoid bone. We apply geometric morphometric methods to extensive three-dimensional anatomical landmarks and semilandmarks configuration, capturing the geometry of the cervico-craniofacial complex including the hyoid bone, tongue muscle and the mandible. We demonstrate that in both species, the forward displacement of the mental region derives from the arrangement of the tongue and hyoid bone, in order to cope with the relative horizontal narrowing of the oral cavity. Because humans and chimpanzees share this pattern of developmental integration, the different forms of mental prominence seen in some extinct hominids likely originate from equivalent ontogenetic constraints. Variations in this process could account for similar morphologies.

  15. Dating the Homo erectus bearing travertine from Kocabaş (Denizli, Turkey) at at least 1.1 Ma

    NASA Astrophysics Data System (ADS)

    Lebatard, Anne-Elisabeth; Alçiçek, M. Cihat; Rochette, Pierre; Khatib, Samir; Vialet, Amélie; Boulbes, Nicolas; Bourlès, Didier L.; Demory, François; Guipert, Gaspard; Mayda, Serdar; Titov, Vadim V.; Vidal, Laurence; de Lumley, Henry

    2014-03-01

    Since its discovery within a travertine quarry, the fragmentary cranium of the only known Turkish Homo erectus, the Kocabaş hominid, has led to conflicting biochronological estimations. First estimated to be ˜500 ka old, the partial skull presents a combination of archaic and evolved features that puts it as an intermediate specimen between the Dmanisi fossils (Homo georgicus) and the Chinese Zhoukoudian skulls (Homo erectus) respectively dated to 1.8 to ˜0.8 Ma. Here we present a multidisciplinary study combining sedimentological, paleontological and paleoanthropological observations together with cosmogenic nuclide concentration and paleomagnetic measurements to provide an absolute chronological framework for the Upper fossiliferous Travertine unit where the Kocabaş hominid and fauna were discovered. The 26Al/10Be burial ages determined on pebbles from conglomeratic levels framing the Upper fossiliferous Travertine unit, which exhibits an inverse polarity, constrains its deposition to before the Cobb Mountain sub-chron, that is between 1.22 and ˜1.5 Ma. The alternative match of the normal polarity recorded above the travertine with the Jaramillo subchron (lower limit 1.07 Ma) may also be marginally compatible with cosmogenic nuclides interpretation, thus the proposed minimum age of 1.1 Ma for the end of massive travertine deposition. The actual age of the fossils is likely to be in the 1.1-1.3 Ma range. This absolute date is in close agreement with the paleoanthropological conclusions based on morphometric comparisons implying that Kocabaş hominid belongs to the Homo erectus s.l. group that includes Chinese and African fossils, and is different from Middle and Upper Pleistocene specimens. Furthermore, this date is confirmed by the large mammal assemblage, typical of the late Villafranchian. Because it attests to the antiquity of human occupation of the Anatolian Peninsula and one of the waves of settlements out of Africa, this work challenges the current

  16. Language and life history: a new perspective on the development and evolution of human language.

    PubMed

    Locke, John L; Bogin, Barry

    2006-06-01

    It has long been claimed that Homo sapiens is the only species that has language, but only recently has it been recognized that humans also have an unusual pattern of growth and development. Social mammals have two stages of pre-adult development: infancy and juvenility. Humans have two additional prolonged and pronounced life history stages: childhood, an interval of four years extending between infancy and the juvenile period that follows, and adolescence, a stage of about eight years that stretches from juvenility to adulthood. We begin by reviewing the primary biological and linguistic changes occurring in each of the four pre-adult ontogenetic stages in human life history. Then we attempt to trace the evolution of childhood and juvenility in our hominin ancestors. We propose that several different forms of selection applied in infancy and childhood; and that, in adolescence, elaborated vocal behaviors played a role in courtship and intrasexual competition, enhancing fitness and ultimately integrating performative and pragmatic skills with linguistic knowledge in a broad faculty of language. A theoretical consequence of our proposal is that fossil evidence of the uniquely human stages may be used, with other findings, to date the emergence of language. If important aspects of language cannot appear until sexual maturity, as we propose, then a second consequence is that the development of language requires the whole of modern human ontogeny. Our life history model thus offers new ways of investigating, and thinking about, the evolution, development, and ultimately the nature of human language.

  17. The Human Semicircular Canals Orientation Is More Similar to the Bonobos than to the Chimpanzees

    PubMed Central

    El Khoury, Marwan; Braga, José; Dumoncel, Jean; Nancy, Javotte; Esclassan, Remi; Vaysse, Frederic

    2014-01-01

    For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Humans and bonobos proved more similarities between themselves than with chimpanzees. This finding did not fit with the well established chimpanzee – bonobo monophyly. One hypothesis was convergent evolution in which bonobos and humans produce independently similar phenotypes possibly in response to similar selective pressures that may be associated with postural adaptations. Another possibility was convergence following a “random walk” (Brownian motion) evolutionary model. A more parsimonious explanation was that the bonobo-human labyrinthine shared morphology more closely retained the ancestral condition with chimpanzees being subsequently derived. Finally, these results might be a consequence of genetic diversity and incomplete lineage sorting. The remarkable symmetry of the Semicircular Canals was the second major finding of this article with possible applications in taphonomy. It has the potential to investigate altered fossils, inferring the probability of post-mortem deformation which can lead to difficulties in understanding taxonomic variation, phylogenetic relationships, and functional morphology. PMID:24710502

  18. Yawn contagion in humans and bonobos: emotional affinity matters more than species

    PubMed Central

    Norscia, Ivan; Demuru, Elisa

    2014-01-01

    In humans and apes, yawn contagion echoes emotional contagion, the basal layer of empathy. Hence, yawn contagion is a unique tool to compare empathy across species. If humans are the most empathic animal species, they should show the highest empathic response also at the level of emotional contagion. We gathered data on yawn contagion in humans (Homo sapiens) and bonobos (Pan paniscus) by applying the same observational paradigm and identical operational definitions. We selected a naturalistic approach because experimental management practices can produce different psychological and behavioural biases in the two species, and differential attention to artificial stimuli. Within species, yawn contagion was highest between strongly bonded subjects. Between species, sensitivity to others’ yawns was higher in humans than in bonobos when involving kin and friends but was similar when considering weakly-bonded subjects. Thus, emotional contagion is not always highest in humans. The cognitive components concur in empowering emotional affinity between individuals. Yet, when they are not in play, humans climb down from the empathic podium to return to the “understory”, which our species shares with apes. PMID:25165630

  19. L'os temporal du Petit-Puymoyen

    NASA Astrophysics Data System (ADS)

    Elyaqtine, Mustapha

    1997-12-01

    The temporal bone discovered by Bœuf within the fauna from the Petit-Puymoyen site is studied. It is attributed to an individual whose age is estimated at 2/4 years and that possesses a mastoid fissure. This characteristic, constant in Homo sapiens neanderthalensis and absent in Homo sapiens sapiens, allows to conclude that it is more likely that this individual be allocated to the Neanderthal lineage rather than to the anatomically modern human one.

  20. Implantation of a SAPIEN 3 Valve in a Patient with Pure Aortic Regurgitation.

    PubMed

    Minol, Jan-Philipp; Veulemans, Verena; Zeus, Tobias; Blehm, Alexander

    2016-07-01

    Transcatheter aortic valve implantation (TAVI) is an emerging treatment for high-risk patients with aortic stenosis. Aortic regurgitation is considered to be a relative contraindication for transcatheter procedures, as a non-calcified aortic annulus poses the risk of an insufficient anchoring of the transcatheter aortic valve prosthesis. Herein is described the case of a patient who suffered from recurrent aortic valve regurgitation after valve-sparing repair, and which was successfully treated by the transcatheter implantation of an Edwards SAPIEN 3™ prosthesis. This case report demonstrated the suitability of this prosthesis to treat pure aortic valve regurgitation, without excessive oversizing of the valve.

  1. A Left-to-Right Shunt After Transfemoral TAVR Using Edwards SAPIEN 3.

    PubMed

    Steffen, Julius; Köhler, Anton; Schwarz, Florian; Sadoni, Sebastian; Hagl, Christian; Massberg, Steffen; Greif, Martin

    2016-07-01

    Transcatheter aortic valve replacement (TAVR) is used for the treatment of aortic stenosis (AS). Besides major bleeding, conduction blocks, stroke or atrial fibrillation, complications include cardiac perforation with possible left-to-right-shunts. Herein is reported the sixth case of a left-to-right shunt in an 87-year-old man who underwent TAVR using a 29 mm Edwards SAPIEN S3 prosthesis to treat AS. Soon after the procedure, a small channel evolving from the right coronary cusp could be detected on echocardiography. The patient was managed medically.

  2. [Scientific ethics and the use of human material or data].

    PubMed

    Valenzuela, Carlos Y

    2012-03-01

    A scientific article censured by superposing obstacles to its reading remembers the censure of Galileo made by the Inquisition. The censure followed the failure to obtain the informed consent (IC) to disclose results of old samples. At present, the use of collected data or samples for a new research needs a new IC, in most ethical protocols. The Helsinki Code allows the research ethics committees the authorization for the use of that information. This norm is founded rather in commercial, legal or protective arguments than in ethical bases. This article criticizes this norm from the Scientific Ethics viewpoint because: i) the ownership of the genome and environment that originate a person is not of such person but of the human society and Homo sapiens species, ii) a person is not the unique owner of that information; laboratories, institutions, health services and research teams add constituents to it, iii) several violations to this norm occurring in medical, labor, legal and social practice show it as biased against science, iv) if this stored information and its use are beneficial for humankind (its proper owner) it is ethically obligatory to use it. It is proposed to create an anonymous World Bank for Human Information with open access and universal transparency. This universal collection of data handled under universal accepted ethical norms should prevent exclusive private use of public information, non-publication of negative results, illicit and unethical use of human data.

  3. [Evolution of human brain and intelligence].

    PubMed

    Lakatos, László; Janka, Zoltán

    2008-07-30

    The biological evolution, including human evolution is mainly driven by environmental changes. Accidental genetic modifications and their innovative results make the successful adaptation possible. As we know the human evolution started 7-8 million years ago in the African savannah, where upright position and bipedalism were significantly advantageous. The main drive of improving manual actions and tool making could be to obtain more food. Our ancestor got more meat due to more successful hunting, resulting in more caloric intake, more protein and essential fatty acid in the meal. The nervous system uses disproportionally high level of energy, so better quality of food was a basic condition for the evolution of huge human brain. The size of human brain was tripled during 3.5 million years, it increased from the average of 450 cm3 of Australopithecinae to the average of 1350 cm3 of Homo sapiens. A genetic change in the system controlling gene expression could happen about 200 000 years ago, which influenced the development of nervous system, the sensorimotor function and learning ability for motor processes. The appearance and stabilisation of FOXP2 gene structure as feature of modern man coincided with the first presence and quick spread of Homo sapiens on the whole Earth. This genetic modification made opportunity for human language, as the basis of abrupt evolution of human intelligence. The brain region being responsible for human language is the left planum temporale, which is much larger in left hemisphere. This shows the most typical human brain asymmetry. In this case the anatomical asymmetry means a clearly defined functional asymmetry as well, where the brain hemispheres act differently. The preference in using hands, the lateralised using of tools resulted in the brain asymmetry, which is the precondition of human language and intelligence. However, it cannot be held anymore, that only humans make tools, because our closest relatives, the chimpanzees are

  4. Australopithecus sediba and the earliest origins of the genus Homo.

    PubMed

    Berger, Lee

    2012-01-01

    Discovered in 2008, the site of Malapa has yielded a remarkable assemblage of early hominin remains attributed to the species Australopithecus sediba. The species shows unexpected and unpredicted mosaicism in its anatomy. Several commentators have questioned the specific status of Au. sediba arguing that it does not exceed the variation of Au. africanus. This opinion however, does not take into account that Au. sediba differs from Au. africanus in both craniodental and postcranial characters to a greater degree than Au.africanus differs from Au. afarensis in these same characters. Au. sediba has also been questioned as a potential ancestor of the genus Homo due to the perception that earlier specimens of the genus have been found than the c198 Ma date of the Malapa sample. This opinion however, does not take into account either the poor condition of these fossils, as well as the numerous problems with both the criteria used to associate them with the genus Homo, nor the questionable provenance of each of these specimens. This argument also does not acknowledge that Malapa is almost certainly not the first chronological appearance of Au. sediba, it is only the first known fossil occurrence. Au. sediba should therefore be considered a strong potential candidate ancestor of the genus Homo until better preserved specimens are discovered that would refute such a hypothesis.

  5. [Human nutrition in the context of evolutionary medicine].

    PubMed

    Ströhle, Alexander; Wolters, Maike; Hahn, Andreas

    2009-01-01

    Evolutionary medicine has gained increasing attention in recent years by implying that a food selection similar to that of the Paleolithic may prevent diseases. This article is an attempt to characterize the food selection during hominid evolution based on current paleontologic research. Hominid evolution can be divided into multiple phases; and the nutrition ecology of the plio-pleistocene hominids can be tentatively characterized. According to new results of isotope analysis, the Australopithecines did ingest small amounts of animal food already 4.5-2.5 million years ago, while consuming a mainly plant based abrasive diet, which was similar to that of recent chimpanzees. Compared to the Australopithecines, the first representatives of Homo such as H. erectus and H. habilis (2.5-1.5 million years before today) were likely to consume a diet providing more energy and nutrients, which might also have been related to the more gracile dentition. Like H. sapiens the members of this species also consumed an omnivore diet. Assumptions about the nutrition ecology of the archaic and the modern H. sapiens are often concluded by analogies based on the living of historic and recent foragers (hunter-gatherers). As the few detailed ethnographic data show, the diet composition of the individual hunter-gatherer groups varied considerably and ranged from a nearly pure animal-based diet to a diet dominated by plants. All in all the eating behaviour of prehistoric humans was, like that of their pleistocene ancestors, very flexible. Except for focussing on an energy and nutrient-rich diet there was neither specialization in certain foods, nor a typical plant-animal ratio nor a defined macronutrient distribution. Correspondingly, it is impossible to justify details given by representatives of evolutionary medicine on "the Paleolithic diet" empirically.

  6. Human skin pigmentation, migration and disease susceptibility

    PubMed Central

    Jablonski, Nina G.; Chaplin, George

    2012-01-01

    Human skin pigmentation evolved as a compromise between the conflicting physiological demands of protection against the deleterious effects of ultraviolet radiation (UVR) and photosynthesis of UVB-dependent vitamin D3. Living under high UVR near the equator, ancestral Homo sapiens had skin rich in protective eumelanin. Dispersals outside of the tropics were associated with positive selection for depigmentation to maximize cutaneous biosynthesis of pre-vitamin D3 under low and highly seasonal UVB conditions. In recent centuries, migrations and high-speed transportation have brought many people into UVR regimes different from those experienced by their ancestors and, accordingly, exposed them to new disease risks. These have been increased by urbanization and changes in diet and lifestyle. Three examples—nutritional rickets, multiple sclerosis (MS) and cutaneous malignant melanoma (CMM)—are chosen to illustrate the serious health effects of mismatches between skin pigmentation and UVR. The aetiology of MS in particular provides insight into complex and contingent interactions of genetic and environmental factors necessary to trigger lethal disease states. Low UVB levels and vitamin D deficiencies produced by changes in location and lifestyle pose some of the most serious disease risks of the twenty-first century. PMID:22312045

  7. Cranial vault thickness in primates: Homo erectus does not have uniquely thick vault bones.

    PubMed

    Copes, Lynn E; Kimbel, William H

    2016-01-01

    Extremely thick cranial vaults have been noted as a diagnostic characteristic of Homo erectus since the first fossil of the species was identified, but relatively little work has been done on elucidating its etiology or variation across fossils, living humans, or extant non-human primates. Cranial vault thickness (CVT) is not a monolithic trait, and the responsiveness of its layers to environmental stimuli is unknown. We obtained measurements of cranial vault thickness in fossil hominins from the literature and supplemented those data with additional measurements taken on African fossil specimens. Total CVT and the thickness of the cortical and diploë layers individually were compared to measures of CVT in extant species measured from more than 500 CT scans of human and non-human primates. Frontal and parietal CVT in fossil primates was compared to a regression of CVT on cranial capacity calculated for extant species. Even after controlling for cranial capacity, African and Asian H. erectus do not have uniquely high frontal or parietal thickness residuals, either among hominins or extant primates. Extant primates with residual CVT thickness similar to or exceeding H. erectus (depending on the sex and bone analyzed) include Nycticebus coucang, Perodicticus potto, Alouatta caraya, Lophocebus albigena, Galago alleni, Mandrillus sphinx, and Propithecus diadema. However, the especially thick vaults of extant non-human primates that overlap with H. erectus values are composed primarily of cortical bone, while H. erectus and other hominins have diploë-dominated vault bones. Thus, the combination of thick vaults comprised of a thickened diploë layer may be a reliable autapomorphy for members of the genus Homo.

  8. New ages for human occupation and climatic change at Lake Mungo, Australia

    NASA Astrophysics Data System (ADS)

    Bowler, James M.; Johnston, Harvey; Olley, Jon M.; Prescott, John R.; Roberts, Richard G.; Shawcross, Wilfred; Spooner, Nigel A.

    2003-02-01

    Australia's oldest human remains, found at Lake Mungo, include the world's oldest ritual ochre burial (Mungo III) and the first recorded cremation (Mungo I). Until now, the importance of these finds has been constrained by limited chronologies and palaeoenvironmental information. Mungo III, the source of the world's oldest human mitochondrial DNA, has been variously estimated at 30 thousand years (kyr) old, 42-45kyr old and 62 +/- 6kyr old, while radiocarbon estimates placed the Mungo I cremation near 20-26kyr ago. Here we report a new series of 25 optical ages showing that both burials occurred at 40 +/- 2kyr ago and that humans were present at Lake Mungo by 50-46kyr ago, synchronously with, or soon after, initial occupation of northern and western Australia. Stratigraphic evidence indicates fluctuations between lake-full and drier conditions from 50 to 40kyr ago, simultaneously with increased dust deposition, human arrival and continent-wide extinction of the megafauna. This was followed by sustained aridity between 40 and 30kyr ago. This new chronology corrects previous estimates for human burials at this important site and provides a new picture of Homo sapiens adapting to deteriorating climate in the world's driest inhabited continent.

  9. New ages for human occupation and climatic change at Lake Mungo, Australia.

    PubMed

    Bowler, James M; Johnston, Harvey; Olley, Jon M; Prescott, John R; Roberts, Richard G; Shawcross, Wilfred; Spooner, Nigel A

    2003-02-20

    Australia's oldest human remains, found at Lake Mungo, include the world's oldest ritual ochre burial (Mungo III) and the first recorded cremation (Mungo I). Until now, the importance of these finds has been constrained by limited chronologies and palaeoenvironmental information. Mungo III, the source of the world's oldest human mitochondrial DNA, has been variously estimated at 30 thousand years (kyr) old, 42-45 kyr old and 62 +/- 6 kyr old, while radiocarbon estimates placed the Mungo I cremation near 20-26 kyr ago. Here we report a new series of 25 optical ages showing that both burials occurred at 40 +/- 2 kyr ago and that humans were present at Lake Mungo by 50-46 kyr ago, synchronously with, or soon after, initial occupation of northern and western Australia. Stratigraphic evidence indicates fluctuations between lake-full and drier conditions from 50 to 40 kyr ago, simultaneously with increased dust deposition, human arrival and continent-wide extinction of the megafauna. This was followed by sustained aridity between 40 and 30 kyr ago. This new chronology corrects previous estimates for human burials at this important site and provides a new picture of Homo sapiens adapting to deteriorating climate in the world's driest inhabited continent.

  10. Upper Pleistocene Human Dispersals out of Africa: A Review of the Current State of the Debate

    PubMed Central

    Beyin, Amanuel

    2011-01-01

    Although there is a general consensus on African origin of early modern humans, there is disagreement about how and when they dispersed to Eurasia. This paper reviews genetic and Middle Stone Age/Middle Paleolithic archaeological literature from northeast Africa, Arabia, and the Levant to assess the timing and geographic backgrounds of Upper Pleistocene human colonization of Eurasia. At the center of the discussion lies the question of whether eastern Africa alone was the source of Upper Pleistocene human dispersals into Eurasia or were there other loci of human expansions outside of Africa? The reviewed literature hints at two modes of early modern human colonization of Eurasia in the Upper Pleistocene: (i) from multiple Homo sapiens source populations that had entered Arabia, South Asia, and the Levant prior to and soon after the onset of the Last Interglacial (MIS-5), (ii) from a rapid dispersal out of East Africa via the Southern Route (across the Red Sea basin), dating to ~74–60 kya. PMID:21716744

  11. Precuneus proportions and cortical folding: A morphometric evaluation on a racially diverse human sample.

    PubMed

    Bruner, Emiliano; Pereira-Pedro, Ana Sofia; Chen, Xu; Rilling, James K

    2017-03-06

    Recent analyses have suggested that the size and proportions of the precuneus are remarkably variable among adult humans, representing a major source of geometrical difference in midsagittal brain morphology. The same area also represents the main midsagittal brain difference between humans and chimpanzees, being more expanded in our species. Enlargement of the upper parietal surface is a specific feature of Homo sapiens, when compared with other fossil hominids, suggesting the involvement of these cortical areas in recent modern human evolution. Here, we provide a survey on midsagittal brain morphology by investigating whether precuneus size represents the largest component of variance within a larger and racially diverse sample of 265 adult humans. Additionally, we investigate the relationship between precuneus shape variation and folding patterns. Precuneus proportions are confirmed to be a major source of human brain variation even when racial variability is considered. Larger precuneus size is associated with additional precuneal gyri, generally in its anterior district. Spatial variation is most pronounced in the dorsal areas, with no apparent differences between hemispheres, between sexes, or among different racial groups. These dorsal areas integrate somatic and visual information together with the lateral elements of the parietal cortex, representing a crucial node for self-centered mental imagery. The histological basis and functional significance of this intra-specific variation in the upper precuneus remains to be evaluated.

  12. Upper Pleistocene Human Dispersals out of Africa: A Review of the Current State of the Debate.

    PubMed

    Beyin, Amanuel

    2011-01-01

    Although there is a general consensus on African origin of early modern humans, there is disagreement about how and when they dispersed to Eurasia. This paper reviews genetic and Middle Stone Age/Middle Paleolithic archaeological literature from northeast Africa, Arabia, and the Levant to assess the timing and geographic backgrounds of Upper Pleistocene human colonization of Eurasia. At the center of the discussion lies the question of whether eastern Africa alone was the source of Upper Pleistocene human dispersals into Eurasia or were there other loci of human expansions outside of Africa? The reviewed literature hints at two modes of early modern human colonization of Eurasia in the Upper Pleistocene: (i) from multiple Homo sapiens source populations that had entered Arabia, South Asia, and the Levant prior to and soon after the onset of the Last Interglacial (MIS-5), (ii) from a rapid dispersal out of East Africa via the Southern Route (across the Red Sea basin), dating to ~74-60 kya.

  13. Who Was Helping? The Scope for Female Cooperative Breeding in Early Homo

    PubMed Central

    Bell, Adrian Viliami; Hinde, Katie; Newson, Lesley

    2013-01-01

    Derived aspects of our human life history, such as short interbirth intervals and altricial newborns, have been attributed to male provisioning of nutrient-rich meat within monogamous relationships. However, many primatologists and anthropologists have questioned the relative importance of pair-bonding and biparental care, pointing to evidence that cooperative breeding better characterizes human reproductive and child-care relationships. We present a mathematical model with empirically-informed parameter ranges showing that natural selection favors cooperation among mothers over a wide range of conditions. In contrast, our analysis provides a far more narrow range of support for selection favoring male coalition-based monogamy over more promiscuous independent males, suggesting that provisioning within monogamous relationships may fall short of explaining the evolution of Homo life history. Rather, broader cooperative networks within and between the sexes provide the primary basis for our unique life history. PMID:24367605

  14. Nasal septal and premaxillary developmental integration: implications for facial reduction in Homo.

    PubMed

    Holton, Nathan E; Franciscus, Robert G; Marshall, Steven D; Southard, Thomas E; Nieves, Mary Ann

    2011-01-01

    The influence of the chondrocranium in craniofacial development and its role in the reduction of facial size and projection in the genus Homo is incompletely understood. As one component of the chondrocranium, the nasal septum has been argued to play a significant role in human midfacial growth, particularly with respect to its interaction with the premaxilla during prenatal and early postnatal development. Thus, understanding the precise role of nasal septal growth on the facial skeleton is potentially informative with respect to the evolutionary change in craniofacial form. In this study, we assessed the integrative effects of the nasal septum and premaxilla by experimentally reducing facial length in Sus scrofa via circummaxillary suture fixation. Following from the nasal septal-traction model, we tested the following hypotheses: (1) facial growth restriction produces no change in nasal septum length; and (2) restriction of facial length produces compensatory premaxillary growth due to continued nasal septal growth. With respect to hypothesis 1, we found no significant differences in septum length (using the vomer as a proxy) in our experimental (n = 10), control (n = 9) and surgical sham (n = 9) trial groups. With respect to hypothesis 2, the experimental group exhibited a significant increase in premaxilla length. Our hypotheses were further supported by multivariate geometric morphometric analysis and support an integrative relationship between the nasal septum and premaxilla. Thus, continued assessment of the growth and integration of the nasal septum and premaxilla is potentially informative regarding the complex developmental mechanisms that underlie facial reduction in genus Homo evolution.

  15. Cytotoxicity and genotoxicity of hexavalent chromium in human and North Atlantic right whale (Eubalaena glacialis) lung cells.

    PubMed

    Li Chen, Tânia; Wise, Sandra S; Holmes, Amie; Shaffiey, Fariba; Wise, John Pierce; Thompson, W Douglas; Kraus, Scott; Wise, John Pierce

    2009-11-01

    Humans and cetaceans are exposed to a wide range of contaminants. In this study, we compared the cytotoxic and genotoxic effects of a metal pollutant, hexavalent chromium [Cr(VI)], which has been shown to cause damage in lung cells from both humans and North Atlantic right whales. Our results show that Cr induces increased cell death and chromosome damage in lung cells from both species with increasing intracellular Cr ion levels. Soluble Cr(VI) induced less of a cytotoxic and genotoxic effect based on administered dose in right whale (Eubalaena glacialis) cells than in human (Homo sapiens) cells. Whereas, particulate Cr(VI) induced a similar cytotoxic effect but less of a genotoxic effect based on administered dose in right whale cells than in human cells. Differences in chromium ion uptake explained soluble chromate-induced cell death but not all of the soluble chromate-induced chromosome damage. Uptake differences of lead ions could explain the differences in particulate chromate-induced toxicity. The data show that both forms of Cr(VI) are less genotoxic to right whale than human lung cells, and that soluble Cr(VI) induces a similar cytotoxic effect in both right whale and human cells, while particulate Cr(VI) is more cytotoxic to right whale lung cells.

  16. Human phylogeography and diversity

    PubMed Central

    Harcourt, Alexander H.

    2016-01-01

    Homo sapiens phylogeography begins with the species’ origin nearly 200 kya in Africa. First signs of the species outside Africa (in Arabia) are from 125 kya. Earliest dates elsewhere are now 100 kya in China, 45 kya in Australia and southern Europe (maybe even 60 kya in Australia), 32 kya in northeast Siberia, and maybe 20 kya in the Americas. Humans reached arctic regions and oceanic islands last—arctic North America about 5 kya, mid- and eastern Pacific islands about 2–1 kya, and New Zealand about 700 y ago. Initial routes along coasts seem the most likely given abundant and easily harvested shellfish there as indicated by huge ancient oyster shell middens on all continents. Nevertheless, the effect of geographic barriers—mountains and oceans—is clear. The phylogeographic pattern of diasporas from several single origins—northeast Africa to Eurasia, southeast Eurasia to Australia, and northeast Siberia to the Americas—allows the equivalent of a repeat experiment on the relation between geography and phylogenetic and cultural diversity. On all continents, cultural diversity is high in productive low latitudes, presumably because such regions can support populations of sustainable size in a small area, therefore allowing a high density of cultures. Of course, other factors operate. South America has an unusually low density of cultures in its tropical latitudes. A likely factor is the phylogeographic movement of peoples from the Old World bringing novel and hence, lethal diseases to the New World, a foretaste, perhaps, of present day global transport of tropical diseases. PMID:27432967

  17. Human phylogeography and diversity.

    PubMed

    Harcourt, Alexander H

    2016-07-19

    Homo sapiens phylogeography begins with the species' origin nearly 200 kya in Africa. First signs of the species outside Africa (in Arabia) are from 125 kya. Earliest dates elsewhere are now 100 kya in China, 45 kya in Australia and southern Europe (maybe even 60 kya in Australia), 32 kya in northeast Siberia, and maybe 20 kya in the Americas. Humans reached arctic regions and oceanic islands last-arctic North America about 5 kya, mid- and eastern Pacific islands about 2-1 kya, and New Zealand about 700 y ago. Initial routes along coasts seem the most likely given abundant and easily harvested shellfish there as indicated by huge ancient oyster shell middens on all continents. Nevertheless, the effect of geographic barriers-mountains and oceans-is clear. The phylogeographic pattern of diasporas from several single origins-northeast Africa to Eurasia, southeast Eurasia to Australia, and northeast Siberia to the Americas-allows the equivalent of a repeat experiment on the relation between geography and phylogenetic and cultural diversity. On all continents, cultural diversity is high in productive low latitudes, presumably because such regions can support populations of sustainable size in a small area, therefore allowing a high density of cultures. Of course, other factors operate. South America has an unusually low density of cultures in its tropical latitudes. A likely factor is the phylogeographic movement of peoples from the Old World bringing novel and hence, lethal diseases to the New World, a foretaste, perhaps, of present day global transport of tropical diseases.

  18. Africa: the next frontier for human disease gene discovery?

    PubMed

    Ramsay, Michèle; Tiemessen, Caroline T; Choudhury, Ananyo; Soodyall, Himla

    2011-10-15

    The populations of Africa harbour the greatest human genetic diversity following an evolutionary history tracing its beginnings on the continent to time before the emergence of Homo sapiens. Signatures of selection are detectable as responses to ancient environments and cultural practices, modulated by more recent events including infectious epidemics, migrations, admixture and, of course, chance. The age of high-throughput biology is not passing Africa by. African-based cohort studies and networks with an African footprint are ideal springboards for disease-related genetic and genomic studies. Initiatives like HapMap, the 1000 Genomes Project, MalariaGEN, the INDEPTH network and Human Heredity and Health in Africa are catalysts to exploring African genetic diversity and its role in the spectrum from health to disease. The challenges are abundant in dissecting biological questions in the light of linguistic, cultural, geographic and political boundaries and their respective roles in shaping health-related profiles. Will studies based on African populations lead to a new wave of discovery of genetic contributors to disease?

  19. Stratigraphic placement and age of modern humans from Kibish, Ethiopia.

    PubMed

    McDougall, Ian; Brown, Francis H; Fleagle, John G

    2005-02-17

    In 1967 the Kibish Formation in southern Ethiopia yielded hominid cranial remains identified as early anatomically modern humans, assigned to Homo sapiens. However, the provenance and age of the fossils have been much debated. Here we confirm that the Omo I and Omo II hominid fossils are from similar stratigraphic levels in Member I of the Kibish Formation, despite the view that Omo I is more modern in appearance than Omo II. 40Ar/39Ar ages on feldspar crystals from pumice clasts within a tuff in Member I below the hominid levels place an older limit of 198 +/- 14 kyr (weighted mean age 196 +/- 2 kyr) on the hominids. A younger age limit of 104 +/- 7 kyr is provided by feldspars from pumice clasts in a Member III tuff. Geological evidence indicates rapid deposition of each member of the Kibish Formation. Isotopic ages on the Kibish Formation correspond to ages of Mediterranean sapropels, which reflect increased flow of the Nile River, and necessarily increased flow of the Omo River. Thus the 40Ar/39Ar age measurements, together with the sapropel correlations, indicate that the hominid fossils have an age close to the older limit. Our preferred estimate of the age of the Kibish hominids is 195 +/- 5 kyr, making them the earliest well-dated anatomically modern humans yet described.

  20. Visuospatial integration and human evolution: the fossil evidence.

    PubMed

    Bruner, Emiliano; Lozano, Marina; Lorenzo, Carlos

    2016-06-20

    Visuospatial integration concerns the ability to coordinate the inner and outer environments, namely the central nervous system and the outer spatial elements, through the interface of the body. This integration is essential for every basic human activity, from locomotion and grasping to speech or tooling. Visuospatial integration is even more fundamental when dealing with theories on extended mind, embodiment, and material engagement. According to the hypotheses on extended cognition, the nervous system, the body and the external objects work as a single integrated unit, and what we call "mind" is the process resulting from such interaction. Because of the relevance of culture and material culture in humans, important changes in such processes were probably crucial for the evolution of Homo sapiens. Much information in this sense can be supplied by considering issues in neuroarchaeology and cognitive sciences. Nonetheless, fossils and their anatomy can also provide evidence according to changes involving physical and body aspects. In this article, we review three sources of morphological information concerning visuospatial management and fossils: evolutionary neuroanatomy, manipulative behaviors, and hand evolution.

  1. The origin and dispersion of human parasitic diseases in the old world (Africa, Europe and Madagascar).

    PubMed

    Nozais, Jean-Pierre

    2003-01-01

    The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani--the dog--has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar

  2. Resequencing data provide no evidence for a human bottleneck in Africa during the penultimate glacial period.

    PubMed

    Sjödin, Per; E Sjöstrand, Agnès; Jakobsson, Mattias; Blum, Michael G B

    2012-07-01

    Based on the accumulation of genetic, climatic, and fossil evidence, a central theory in paleoanthropology stipulates that a demographic bottleneck coincided with the origin of our species Homo Sapiens. This theory proposes that anatomically modern humans--which were only present in Africa at the time--experienced a drastic bottleneck during the penultimate glacial age (130-190 kya) when a cold and dry climate prevailed. Two scenarios have been proposed to describe the bottleneck, which involve either a fragmentation of the range occupied by humans or the survival of one small group of humans. Here, we analyze DNA sequence data from 61 nuclear loci sequenced in three African populations using Approximate Bayesian Computation and numerical simulations. In contrast to the bottleneck theory, we show that a simple model without any bottleneck during the penultimate ice age has the greatest statistical support compared with bottleneck models. Although the proposed bottleneck is ancient, occurring at least 130 kya, we can discard the possibility that it did not leave detectable footprints in the DNA sequence data except if the bottleneck involves a less than a 3-fold reduction in population size. Finally, we confirm that a simple model without a bottleneck is able to reproduce the main features of the observed patterns of genetic variation. We conclude that models of Pleistocene refugium for modern human origins now require substantial revision.

  3. Evolution of human longevity, population pressure and the origins of warfare.

    PubMed

    Holliday, Robin

    2005-01-01

    In a protected environment, humans have the longest lifespan of all primates. However, during the emergence of Homo sapiens from pre-hominids, the expectation of life at birth would have been quite low. On the basis of reasonable assumptions, an average expectation of life of less than 20 years is sufficient to maintain a population of hunter-gatherers. As individuals became better adapted to their environment, the mortality rate would gradually decrease, and this would result in the survival of more offspring to adulthood. Thus, the population will increase, and one of the consequences in human evolution is the migration of human communities to many new habitats. The development of agriculture provided a more reliable source of food, and stimulated further the increase in population size. Villages became towns, and then cities, states and empires arose which had very large populations, and competed for land and other resources. Armies were raised and were often at war. All this was due to population pressure, as Malthus had realised more than 200 years ago. However, neither he, nor any of the others who discussed warfare, understood that the demographic changes that produced large human populations was a steady increase in the expectation of life at birth. This inevitably occurred at the same time as man gradually gained more control over his environment, and achieved far more reproductive success than is seen in hunter-gatherers living in a harsh, stressful environment.

  4. Earliest modern humans in southern Africa dated by isoleucine epimerization in ostrich eggshell

    NASA Astrophysics Data System (ADS)

    Miller, G. H.; Beaumont, P. B.; Deacon, H. J.; Brooks, A. S.; Hare, P. E.; Jull, A. J. T.

    1999-11-01

    The oldest anatomically modern human remains are beyond the range of radiocarbon dating, and associated deposits lack material suitable for most other dating methods. Consequently, age estimates for early human skeletal material and correlative stratigraphic horizons in southern Africa are frequently based on paleoclimatic correlations to the deep-sea record and extrapolated sedimentation rates, both of which incorporate a number of untested assumptions. Here we focus on one substage of the Middle Stone Age of southern Africa, the Howiesons Poort industry, a distinctive culture-stratigraphic marker in sequences south of the Zambezi. Anatomically modern human skeletal material has been found associated with, or even older than the Howiesons Poort layer in stratified deposits at Border Cave and Klasies River main site. We have dated or bracketed the Howiesons Poort horizon at Border Cave, Boomplaas Cave and Apollo 11 Cave, three stratified cave sites in southern Africa, based on the extent of isoleucine epimerization in associated ostrich eggshells. We conclude that the Howiesons Poort lithic industry is bracketed by limiting dates of 56 and 80 ka, and is most likely centered on 66±5 ka. Anatomically modern human remains in deeper levels are more than 100 ka old, lending support to the hypothesis of an African origin for Homo sapiens.

  5. Phylogenetic analysis of the human basic helix-loop-helix proteins

    PubMed Central

    2002-01-01

    Background The basic helix-loop-helix (bHLH) proteins are a large and complex multigene family of transcription factors with important roles in animal development, including that of fruitflies, nematodes and vertebrates. The identification of orthologous relationships among the bHLH genes from these widely divergent taxa allows reconstruction of the putative complement of bHLH genes present in the genome of their last common ancestor. Results We identified 39 different bHLH genes in the worm Caenorhabditis elegans, 58 in the fly Drosophila melanogaster and 125 in human (Homo sapiens). We defined 44 orthologous families that include most of these bHLH genes. Of these, 43 include both human and fly and/or worm genes, indicating that genes from these families were already present in the last common ancestor of worm, fly and human. Only two families contain both yeast and animal genes, and no family contains both plant and animal bHLH genes. We suggest that the diversification of bHLH genes is directly linked to the acquisition of multicellularity, and that important diversification of the bHLH repertoire occurred independently in animals and plants. Conclusions As the last common ancestor of worm, fly and human is also that of all bilaterian animals, our analysis indicates that this ancient ancestor must have possessed at least 43 different types of bHLH, highlighting its genomic complexity. PMID:12093377

  6. Mojokerto revisited: evidence for an intermediate pattern of brain growth in Homo erectus.

    PubMed

    O'Connell, Caitlin A; DeSilva, Jeremy M

    2013-08-01

    Brain development in Homo erectus is a subject of great interest, and the infant calvaria from Mojokerto, Indonesia, has featured prominently in these debates. Some researchers have suggested that the pattern of brain development in H. erectus resembled that of non-human apes, while others argue for a more human-like growth pattern. In this study, we retested hypotheses regarding brain ontogeny in H. erectus using new methods (resampling), and data from additional H. erectus crania. Our results reveal that humans achieve 62% (±10%) and chimpanzees 80% (±9%) of their adult endocranial volume by 0.5-1.5 years of age. Using brain mass data, humans achieve on average 65% and chimpanzees 81% of adult size by 0.5-1.5 years. When compared with adult H. erectus crania (n = 9) from Indonesian sites greater than 1.2 million years old, Mojokerto had reached ∼70% of its adult cranial capacity. Mojokerto thus falls almost directly between the average growth in humans and chimpanzees, and well within the range of both. We therefore suggest that brain development in H. erectus cannot be dichotomized as either ape-like or human-like; it was H. erectus-like. These data indicate that H. erectus may have had a unique developmental pattern that should be considered as an important step along the continuum of brain ontogeny between apes and humans.

  7. Dental topography and diets of Australopithecus afarensis and early Homo.

    PubMed

    Ungar, Peter

    2004-05-01

    Diet is key to understanding the paleoecology of early hominins. We know little about the diets of these fossil taxa, however, in part because of a limited fossil record, and in part because of limitations in methods available to infer their feeding adaptations. This paper applies a new method, dental topographic analysis, to the inference of diet from fossil hominin teeth. This approach uses laser scanning to generate digital 3D models of teeth and geographic information systems software to measure surface attributes, such as slope and occlusal relief. Because it does not rely on specific landmarks that change with wear, dental topographic analysis allows measurement and comparison of variably worn teeth, greatly increasing sample sizes compared with techniques that require unworn teeth. This study involved comparison of occlusal slope and relief of the lower second molars of Australopithecus afarensis (n=15) and early Homo (n=8) with those of Gorilla gorilla gorilla (n=47) and Pan troglodytes troglodytes (n=54). Results indicate that while all groups show reduced slope and relief in progressively more worn specimens, there are consistent differences at given wear stages among the taxa. Early Homo shows steeper slopes and more relief than chimpanzees, whereas A. afarensis shows less slope and relief than any of the other groups. The differences between the two hominin taxa are on the same order as those between the extant apes, suggesting similar degrees of difference in diet. Because these chimpanzees and gorillas differ mostly in fallback foods where they are sympatric, results suggest that the early hominins may likewise have differed mostly in fallback foods, with A. afarensis emphasizing harder, more brittle foods, and early Homo relying on tougher, more elastic foods.

  8. The Dawn of Human Matrilineal Diversity

    PubMed Central

    Behar, Doron M.; Villems, Richard; Soodyall, Himla; Blue-Smith, Jason; Pereira, Luisa; Metspalu, Ene; Scozzari, Rosaria; Makkan, Heeran; Tzur, Shay; Comas, David; Bertranpetit, Jaume; Quintana-Murci, Lluis; Tyler-Smith, Chris; Wells, R. Spencer; Rosset, Saharon

    2008-01-01

    The quest to explain demographic history during the early part of human evolution has been limited because of the scarce paleoanthropological record from the Middle Stone Age. To shed light on the structure of the mitochondrial DNA (mtDNA) phylogeny at the dawn of Homo sapiens, we constructed a matrilineal tree composed of 624 complete mtDNA genomes from sub-Saharan Hg L lineages. We paid particular attention to the Khoi and San (Khoisan) people of South Africa because they are considered to be a unique relic of hunter-gatherer lifestyle and to carry paternal and maternal lineages belonging to the deepest clades known among modern humans. Both the tree phylogeny and coalescence calculations suggest that Khoisan matrilineal ancestry diverged from the rest of the human mtDNA pool 90,000–150,000 years before present (ybp) and that at least five additional, currently extant maternal lineages existed during this period in parallel. Furthermore, we estimate that a minimum of 40 other evolutionarily successful lineages flourished in sub-Saharan Africa during the period of modern human dispersal out of Africa approximately 60,000–70,000 ybp. Only much later, at the beginning of the Late Stone Age, about 40,000 ybp, did introgression of additional lineages occur into the Khoisan mtDNA pool. This process was further accelerated during the recent Bantu expansions. Our results suggest that the early settlement of humans in Africa was already matrilineally structured and involved small, separately evolving isolated populations. PMID:18439549

  9. The Flores speleothem carbon isotope record: vegetation, volcanism and the demise of Homo floresiensis

    NASA Astrophysics Data System (ADS)

    Scroxton, N.; Gagan, M. K.; Ayliffe, L. K.; Hantoro, W. S.; Hellstrom, J. C.; Cheng, H.; Edwards, R. L.; Zhao, J. X.; Suwargadi, B. W.; Scott-Gagan, H.; Cowley, J. A.; Rifai, H.

    2015-12-01

    The last surviving non-human member of the Homo genus: Homo floresiensis, disappeared from the stratigraphic record in Liang Bua cave, Flores, Indonesia, between 17 and 10 kyr BP (Roberts et al. 2009, J. Hum. Evol.). The cause of the disappearance (e.g. climate change, volcanic catastrophe or human competition) has not been established. Here, we present a new 92,000-year long speleothem δ13C record for Liang Luar cave, 800m South of Liang Bua. Our record acts as a proxy for local environmental and vegetation health throughout H. floresiensis' occupation of the area. The Liang Luar speleothem δ13C record is primarily a record of vegetation productivity and soil respiration rates, highlighting local ecological responses to changing regional and global climate forcings such as temperature, atmospheric pCO2 and precipitation amount. Changes in speleothem δ13C can largely be considered an environmental response to climate change. Events that caused significant harm to the local environment and H. floresiensis are likely to be outside the natural range of variability: being quick enough or extreme enough that adaptation to new conditions is not possible. We identify disturbances to the vegetation system using two indicators in the speleothem record. 1) Abrupt positive δ13C excursions which indicate periods of reduced vegetative activity. 2) A loss of correlation between the δ13C and δ18O records, indicating that precipitation is no longer a dominant control on vegetation productivity. The largest (8‰) and longest (7 kyr) abrupt positive excursion, the 68 kyr event, sees positive speleothem δ13C values, due to increased bedrock contribution and/or C4 vegetation at this time. Crucially a H. floresiensis occupation interval dates to this period. The largest abrupt deterioration in vegetation (positive δ13C excursion) between 17 and 10 kyr BP is a 1 in 5kyr occurrence - An event of a magnitude that was likely encountered and survived by H. floresiensis multiple

  10. Structural basis of homo- and heterotrimerization of collagen I

    PubMed Central

    Sharma, Urvashi; Carrique, Loïc; Vadon-Le Goff, Sandrine; Mariano, Natacha; Georges, Rainier-Numa; Delolme, Frederic; Koivunen, Peppi; Myllyharju, Johanna; Moali, Catherine; Aghajari, Nushin; Hulmes, David J. S.

    2017-01-01

    Fibrillar collagen molecules are synthesized as precursors, procollagens, with large propeptide extensions. While a homotrimeric form (three α1 chains) has been reported in embryonic tissues as well as in diseases (cancer, fibrosis, genetic disorders), collagen type I usually occurs as a heterotrimer (two α1 chains and one α2 chain). Inside the cell, the role of the C-terminal propeptides is to gather together the correct combination of three α chains during molecular assembly, but how this occurs for different forms of the same collagen type is so far unknown. Here, by structural and mutagenic analysis, we identify key amino acid residues in the α1 and α2 C-propeptides that determine homo- and heterotrimerization. A naturally occurring mutation in one of these alters the homo/heterotrimer balance. These results show how the C-propeptide of the α2 chain has specifically evolved to permit the appearance of heterotrimeric collagen I, the major extracellular building block among the metazoa. PMID:28281531

  11. Dynamic similarity predicts gait parameters for Homo floresiensis and the Laetoli hominins.

    PubMed

    Vaughan, Christopher L; Blaszczyk, Maria B

    2008-01-01

    Late in 2004, the skeletal remains of a pygmy-sized hominin recovered from a cave on the Indonesian island of Flores were first documented, with the authors concluding that the "postcranial anatomy [was] consistent with human-like obligate bipedalism" (Brown et al. [2004]: Nature 431:1055-1061). We have assumed that Homo floresiensis, who was estimated to be 18,000-years-old, walked with a gait pattern that was dynamically similar to modern man. The dynamic similarity hypothesis was also applied to the Australopithecines that left their footprints at Laetoli 4-million-years ago. According to this hypothesis, dimensionless gait parameters can be used in combination with known leg length or step length to calculate velocity of bipedal locomotion. We have gathered data on 20 extant modern humans to calculate the standard estimates of error when predicting gait parameters. We predict that the Homo floresiensis specimen walked at a velocity of 1.11 +/- 0.14 m/s. For the Laetoli footprints, the velocity for Track 1 was estimated to be 1.03 +/- 0.12 m/s and for Track 2 to be 1.14 +/- 0.12 m/s. These latter values for Australopithecines are greater than prior analyses, but are in good agreement with more recent work based on evolutionary robotics. Since modern man walks at 1.44 +/- 0.14 m/s, our results suggest that, despite their diminutive size, these ancient hominins were capable of ranging across a wide geographical area.

  12. Human Development, Human Evolution.

    ERIC Educational Resources Information Center

    Smillie, David

    One of the truly remarkable events in human evolution is the unprecedented increase in the size of the brain of "Homo" over a brief span of 2 million years. It would appear that some significant selective pressure or opportunity presented itself to this branch of the hominid line and caused a rapid increase in the brain, introducing a…

  13. Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism.

    PubMed

    Fincher, Corey L; Thornhill, Randy; Murray, Damian R; Schaller, Mark

    2008-06-07

    Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behaviour contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies.

  14. Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism

    PubMed Central

    Fincher, Corey L; Thornhill, Randy; Murray, Damian R; Schaller, Mark

    2008-01-01

    Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behaviour contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies. PMID:18302996

  15. Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

    PubMed Central

    Boivin, Nicole L.; Zeder, Melinda A.; Fuller, Dorian Q.; Crowther, Alison; Larson, Greger; Erlandson, Jon M.; Denham, Tim; Petraglia, Michael D.

    2016-01-01

    The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens. A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity—the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences. PMID:27274046

  16. Tempo and mode of ERV-K evolution in human and chimpanzee genomes.

    PubMed

    Romano, C M; Ramalho, R F; Zanotto, P M de A

    2006-11-01

    Several families of endogenous retrovirus (ERV) exist in copious numbers in the genomes of primate species. Therefore, we undertook a systematic search for endogenous retrovirus sequences from the ERV-K family, comparing across both human (Homo sapiens) and chimpanzee (Pan troglodytes) genomes. Using conserved motifs of the ERV-K as query we identified and characterized 76 complete ERV-K elements, 54 in human (HERV-K), 34 of which were described previously, and 21 in the chimpanzee (CERV-K). Phylogenetic analysis using coding regions and LTRs showed the existence of two main branches. Group I was the most heterogeneous and had an average integration time of 18.3 MYBP (million years before present), using rates ranging from 1.5 to 4.0 x 10(-9) s/s/y (substitution per site per year). Group O/N integrated around 19.4 MYBP and nested Group N integrated about 14 MYBP. We found evidence for strong positive selection on the gag, pol and env coding regions and for A/T hypermutation. Our data suggest that the endogenous elements were possibly involved in chromosomal rearrangements and retained a great deal of information from their active stage, most likely as a consequence of host interactions. This study also contributes to the annotation effort of both human and chimpanzee genomes.

  17. No Distinction of Orthology/Paralogy between Human and Chimpanzee Rh Blood Group Genes

    PubMed Central

    Kitano, Takashi; Kim, Choong-Gon; Blancher, Antoine; Saitou, Naruya

    2016-01-01

    On human (Homo sapiens) chromosome 1, there is a tandem duplication encompassing Rh blood group genes (Hosa_RHD and Hosa_RHCE). This duplication occurred in the common ancestor of humans, chimpanzees (Pan troglodytes), and gorillas, after splitting from their common ancestor with orangutans. Although several studies have been conducted on ape Rh blood group genes, the clear genome structures of the gene clusters remain unknown. Here, we determined the genome structure of the gene cluster of chimpanzee Rh genes by sequencing five BAC (Bacterial Artificial Chromosome) clones derived from chimpanzees. We characterized three complete loci (Patr_RHα, Patr_RHβ, and Patr_RHγ). In the Patr_RHβ locus, a short version of the gene, which lacked the middle part containing exons 4–8, was observed. The Patr_RHα and Patr_RHβ genes were located on the locations corresponding to Hosa_RHD and Hosa_RHCE, respectively, and Patr_RHγ was in the immediate vicinity of Patr_RHβ. Sequence comparisons revealed high sequence similarity between Patr_RHβ and Hosa_RHCE, while the chimpanzee Rh gene closest to Hosa_RHD was not Patr_RHα but rather Patr_RHγ. The results suggest that rearrangements and gene conversions frequently occurred between these genes and that the classic orthology/paralogy dichotomy no longer holds between human and chimpanzee Rh blood group genes. PMID:26872772

  18. Femoral morphology and femoropelvic musculoskeletal anatomy of humans and great apes: a comparative virtopsy study.

    PubMed

    Morimoto, Naoki; Ponce de León, Marcia S; Nishimura, Takeshi; Zollikofer, Christoph P E

    2011-09-01

    The proximal femoral morphology of fossil hominins is routinely interpreted in terms of muscular topography and associated locomotor modes. However, the detailed correspondence between hard and soft tissue structures in the proximal femoral region of extant great apes is relatively unknown, because dissection protocols typically do not comprise in-depth osteological descriptions. Here, we use computed tomography and virtopsy (virtual dissection) for non-invasive examination of the femoropelvic musculoskeletal anatomy in Pan troglodytes, P. paniscus, Gorilla gorilla, Pongo pygmaeus, and Homo sapiens. Specifically, we analyze the topographic relationship between muscle attachment sites and surface structures of the proximal femoral shaft such as the lateral spiral pilaster. Our results show that the origin of the vastus lateralis muscle is anterior to the insertion of gluteus maximus in all examined great ape specimens and humans. In gorillas and orangutans, the insertion of gluteus maximus is on the inferior (anterolateral) side of the lateral spiral pilaster. In chimpanzees, however, the maximus insertion is on its superior (posteromedial) side, similar to the situation in modern humans. These findings support the hypothesis that chimpanzees and humans exhibit a shared-derived musculoskeletal topography of the proximal femoral region, irrespective of their different locomotor modes, whereas gorillas and orangutans represent the primitive condition. Caution is thus warranted when inferring locomotor behavior from the surface topography of the proximal femur of fossil hominins, as the morphology of this region may contain a strong phyletic signal that tends to blur locomotor adaptation.

  19. Footprints reveal direct evidence of group behavior and locomotion in Homo erectus

    PubMed Central

    Hatala, Kevin G.; Roach, Neil T.; Ostrofsky, Kelly R.; Wunderlich, Roshna E.; Dingwall, Heather L.; Villmoare, Brian A.; Green, David J.; Harris, John W. K.; Braun, David R.; Richmond, Brian G.

    2016-01-01

    Bipedalism is a defining feature of the human lineage. Despite evidence that walking on two feet dates back 6–7 Ma, reconstructing hominin gait evolution is complicated by a sparse fossil record and challenges in inferring biomechanical patterns from isolated and fragmentary bones. Similarly, patterns of social behavior that distinguish modern humans from other living primates likely played significant roles in our evolution, but it is exceedingly difficult to understand the social behaviors of fossil hominins directly from fossil data. Footprints preserve direct records of gait biomechanics and behavior but they have been rare in the early human fossil record. Here we present analyses of an unprecedented discovery of 1.5-million-year-old footprint assemblages, produced by 20+ Homo erectus individuals. These footprints provide the oldest direct evidence for modern human-like weight transfer and confirm the presence of an energy-saving longitudinally arched foot in H. erectus. Further, print size analyses suggest that these H. erectus individuals lived and moved in cooperative multi-male groups, offering direct evidence consistent with human-like social behaviors in H. erectus. PMID:27403790

  20. Comparative cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in human and sperm whale (Physeter macrocephalus) skin cells.

    PubMed

    Li Chen, Tânia; LaCerte, Carolyne; Wise, Sandra S; Holmes, Amie; Martino, Julieta; Wise, John Pierce; Thompson, W Douglas; Wise, John Pierce

    2012-01-01

    Chromium (Cr) is a global marine pollutant, present in marine mammal tissues. Hexavalent chromium [Cr(VI)] is a known human carcinogen. In this study, we compare the cytotoxic and clastogenic effects of Cr(VI) in human (Homo sapiens) and sperm whale (Physeter macrocephalus) skin fibroblasts. Our data show that increasing concentrations of both particulate and soluble Cr(VI) induce increasing amounts of cytotoxicity and clastogenicity in human and sperm whale skin cells. Furthermore, the data show that sperm whale cells are resistant to these effects exhibiting less cytotoxicity and genotoxicity than the human cells. Differences in Cr uptake accounted for some but not all of the differences in particulate and soluble Cr(VI) genotoxicity, although it did explain the differences in particulate Cr(VI) cytotoxicity. Altogether, the data indicate that Cr(VI) is a genotoxic threat to whales, but also suggest that whales have evolved cellular mechanisms to protect them against the genotoxicity of environmental agents such as Cr(VI).

  1. The Brazilian megamastofauna of the Pleistocene/Holocene transition and its relationship with the early human settlement of the continent

    NASA Astrophysics Data System (ADS)

    Hubbe, Alex; Hubbe, Mark; Neves, Walter A.

    2013-03-01

    One of the most intriguing questions regarding the Brazilian Late Quaternary extinct megafauna and Homo sapiens is to what extent they coexisted and how humans could have contributed to the former's extinction. The aim of this article is to review the chronological and archaeological evidences of their coexistence in Brazil and to evaluate the degree of direct interaction between them. Critical assessment of the Brazilian megafauna chronological data shows that several of the late Pleistoscene/early Holocene dates available so far cannot be considered reliable, but the few that do suggest that at least two species (Catonyx cuvieri, ground sloth; Smilodon populator, saber-toothed cat) survived until the beginning of the Holocene in Southeast Brazil. Archaeological data indicates that the first human groups arrived in Brazil and were inhabiting this region during the last millennia of the Pleistocene and, consequently, they coexisted with the extinct fauna in some parts of Brazil for at least one thousand years. There is no robust evidence favoring any kind of direct interaction between humans and megafauna prior to their extinction. To date, it is not possible to properly judge the indirect influence of humans (landscape transformation, introduction of predators, among others) in this extinction event. Intense and to some extent unique climate changes between the Last Glacial Maximum and the Holocene favors the interpretation that they had a major contribution to the megafauna extinction, although the scarcity of data impedes the proper testing of this hypothesis.

  2. Dynamic control of strand excision during human DNA mismatch repair.

    PubMed

    Jeon, Yongmoon; Kim, Daehyung; Martín-López, Juana V; Lee, Ryanggeun; Oh, Jungsic; Hanne, Jeungphill; Fishel, Richard; Lee, Jong-Bong

    2016-03-22

    Mismatch repair (MMR) is activated by evolutionarily conserved MutS homologs (MSH) and MutL homologs (MLH/PMS). MSH recognizes mismatched nucleotides and form extremely stable sliding clamps that may be bound by MLH/PMS to ultimately authorize strand-specific excision starting at a distant 3'- or 5'-DNA scission. The mechanical processes associated with a complete MMR reaction remain enigmatic. The purified human (Homo sapien or Hs) 5'-MMR excision reaction requires the HsMSH2-HsMSH6 heterodimer, the 5' → 3' exonuclease HsEXOI, and the single-stranded binding heterotrimer HsRPA. The HsMLH1-HsPMS2 heterodimer substantially influences 5'-MMR excision in cell extracts but is not required in the purified system. Using real-time single-molecule imaging, we show that HsRPA or Escherichia coli EcSSB restricts HsEXOI excision activity on nicked or gapped DNA. HsMSH2-HsMSH6 activates HsEXOI by overcoming HsRPA/EcSSB inhibition and exploits multiple dynamic sliding clamps to increase tract length. Conversely, HsMLH1-HsPMS2 regulates tract length by controlling the number of excision complexes, providing a link to 5' MMR.

  3. Evolutionary aspects of human exercise--born to run purposefully.

    PubMed

    Mattson, Mark P

    2012-07-01

    This article is intended to raise awareness of the adaptive value of endurance exercise (particularly running) in the evolutionary history of humans, and the implications of the genetic disposition to exercise for the aging populations of modern technology-driven societies. The genome of Homo sapiens has evolved to support the svelte phenotype of an endurance runner, setting him/her apart from all other primates. The cellular and molecular mechanisms underlying the competitive advantages conferred by exercise capacity in youth can also provide a survival benefit beyond the reproductive period. These mechanisms include up-regulation of genes encoding proteins involved in protecting cells against oxidative stress, disposing of damaged proteins and organelles, and enhancing bioenergetics. Particularly fascinating are the signaling mechanisms by which endurance running changes the structure and functional capabilities of the brain and, conversely, the mechanisms by which the brain integrates metabolic, cardiovascular and behavioral responses to exercise. As an emerging example, I highlight the roles of brain-derived neurotrophic factor (BDNF) as a mediator of the effects of exercise on the brain, and BDNF's critical role in regulating metabolic and cardiovascular responses to endurance running. A better understanding of such 'healthspan-extending' actions of endurance exercise may lead to new approaches for improving quality of life as we advance in the coming decades and centuries.

  4. Evolutionary Aspects of Human Exercise – Born to Run Purposefully

    PubMed Central

    Mattson, Mark P.

    2012-01-01

    This article is intended to raise awareness of the adaptive value of endurance exercise (particularly running) in the evolutionary history of humans, and the implications of the genetic disposition to exercise for the aging populations of modern technology-driven societies. The genome of Homo sapiens has evolved to support the svelte phenotype of an endurance runner, setting him/her apart from all other primates. The cellular and molecular mechanisms underlying the competitive advantages conferred by exercise capacity in youth can also provide a survival benefit beyond the reproductive period. These mechanisms include up-regulation of genes encoding proteins involved in protecting cells against oxidative stress, disposing of damaged proteins and organelles, and enhancing bioenergetics. Particularly fascinating are the signaling mechanisms by which endurance running changes the structure and functional capabilities of the brain and, conversely, the mechanisms by which the brain integrates metabolic, cardiovascular and behavioral responses to exercise. As an emerging example, I highlight the roles of brain-derived neurotrophic factor (BDNF) as a mediator of the effects of exercise on the brain, and BDNF s critical role in regulating metabolic and cardiovascular responses to endurance running. A better understanding of such healthspan-extending actions of endurance exercise may lead to new approaches for improving quality of life as we advance in the coming decades and centuries. PMID:22394472

  5. Continuity or discontinuity in the European Early Pleistocene human settlement: the Atapuerca evidence

    NASA Astrophysics Data System (ADS)

    Bermúdez de Castro, José María; Martinón-Torres, María; Blasco, Ruth; Rosell, Jordi; Carbonell, Eudald

    2013-09-01

    The nature, timing, pattern, favourable circumstances and impediments of the human occupation of the European continent during the Early Pleistocene are hot topics in Quaternary studies. In particular, the problem of the (dis) continuity of the settlement of Europe in this period is an important matter of discussion, which has been approached in the last decade from different points of view. The Gran Dolina (TD) and Sima del Elefante (TE) cave sites in the Sierra de Atapuerca, (Spain) include large and quasi-continuous stratigraphic sequences that stretch back from at least 1.2 million years ago (Ma) to the Matuyama/Brunhes boundary. The archaeological and paleontological record from these sites can help to test different hypotheses about the character of the human settlement in this region and period. Furthermore, the TD6 level has yielded a large collection of human fossil remains attributed to Homo antecessor. According to different geochronological methods, as well as to paleomagnetic and biostratigraphical analyses, these hominins belong to an age range of 0.96-0.80 Ma. Unfortunately, the finding in 2007 of some human fossil remains in the TE9 level, dated to about 1.22 Ma, was not enough to conclude whether H. antecessor had deep roots in the European Early Pleistocene. A set of derived features of H. antecessor shared with both the Neanderthal lineage and modern humans suggests that this species is related, and not far, from the most recent common ancestor (MRCA) of Homo neanderthalensis and Homo sapiens. If we assume that there was a lineal biological relationship between the TE9 and TD6 hominins, we should reconsider many of the conclusions achieved in previous paleontological and genetic studies. In addition, we would be obliged to build a highly complicated paleogeographical scenario for the origin of the MRCA. Although continuity in the settlement of Europe during the entire late Early Pleistocene is not discarded (e.g. in refuge areas), it seems that

  6. Short communication: Traits unique to genus Homo within primates at the cervical spine (C2-C7).

    PubMed

    Rios, Luis; Muñoz, Alexandra; Cardoso, Hugo; Pastor, Francisco

    2014-05-01

    From a comparative study of 222 human and 261 nonhuman primates complete cervical spines, two bony variants associated to the course of the vertebral artery are proposed as unique to genus Homo within primates. First, the opening of the foramen transversarium at C2, a trait present at low frequency in humans (3 to 5.6%). Second, the presence of a bipartite foramen transversarium in the cervical segment C3-C6, a trait that can be observed fully formed in human fetal skeletons, with a clear frequency pattern along the cervical spine (C3>C4>C5>C6human spines studied, practically absent in Strepsirrhini, at low frequency in Platyrrhini, and generalized in Catarrhini. These findings, together with previous data regarding absence and presence of foramina at C1, indicate a pattern of gain and loss of foramina in the transverse process of the cervical vertebrae for genus Homo. The test of a possible explanation of these differences as associated to anatomical changes of the cervical spine due to erect posture and bipedal locomotion needs further research in the morphology and function of the primate cervical spine.

  7. Homo Heuristicus: Less-is-More Effects in Adaptive Cognition

    PubMed Central

    Brighton, Henry; Gigerenzer, Gerd

    2012-01-01

    Heuristics are efficient cognitive processes that ignore information. In contrast to the widely held view that less processing reduces accuracy, the study of heuristics shows that less information, computation, and time can in fact improve accuracy. We discuss some of the major progress made so far, focusing on the discovery of less-is-more effects and the study of the ecological rationality of heuristics which examines in which environments a given strategy succeeds or fails, and why. Homo heuristicus has a biased mind and ignores part of the available information, yet a biased mind can handle uncertainty more efficiently and robustly than an unbiased mind relying on more resource-intensive and general-purpose processing strategies. PMID:23613644

  8. Homo quintadus, computers and ROOMS (repetitive ocular orthopedic motion stress).

    PubMed

    Grant, A H

    1990-04-01

    Inherent conflict exists between computer systems and ocular physiology of Homo quintadus. Adverse ocular side effects of excessive saccades, excyclotorsion, supraduction, excessive field-of-fixation usage, capitas extension, astigmatic changes, otostatic reflex mismatching, and needless orthopedic malfunctions are imposed upon computer operators. Although the orthopedic dysfunctions are commonly grouped under the heading of Repetitive Strain Injuries (RSI), the inextricable linkage to poor ocular-neurological function argues for postulation of a broader schema entitled Repetitive Ocular Orthopedic Motion Stress (ROOMS). Concepts of good tool usage, total tactile familiarity, total proprioceptive familiarity, and visual cone-of-comfort clash with the installed-equipment base and indicate need for an integrated computer work station to facilitate near covisualization of screen/keyboard and to afford freedom-of-choice for optimal hand/eye synchronicity. The advocacy of computer operators' needs by user-welfare groups, universities, labor unions, and government agencies are portents for achieving genuine improvements.

  9. Cranial morphology of Javanese Homo erectus: new evidence for continuous evolution, specialization, and terminal extinction.

    PubMed

    Kaifu, Yousuke; Aziz, Fachroel; Indriati, Etty; Jacob, Teuku; Kurniawan, Iwan; Baba, Hisao

    2008-10-01

    Our current knowledge of the evolution of Homo during the early to middle Pleistocene is far from complete. This is not only because of the small number of fossil samples available, but also due to the scarcity of standardized datasets which are reliable in terms of landmark identification, interobserver error, and other distorting factors. This study aims to accurately describe the cranial morphological changes of H. erectus in Java using a standardized set of measurements taken by the authors from 18 adult crania from Sangiran, Trinil, Sambungmacan, and Ngandong. The identification of some obscure landmarks was aided by the use of micro-CT imaging. While recent studies tend to emphasize evolutionary conservatism in Javanese H. erectus, our results reinforce the theory that chronologically later groups experienced distinct morphological changes in a number of cranial traits. Some of these changes, particularly those related to brain size expansion, are similar to those observed for the genus Homo as a whole, whereas others are apparently unique specializations restricted to Javanese H. erectus. Such morphological specializations in Java include previously undescribed anteroposterior lengthening of the midcranial base and an anterior shift of the posterior temporal muscle, which might have influenced the morphology of the angular torus and supramastoid sulcus. Analyses of morphological variation indicate that the three crania from Sambungmacan variously fill the morphological gap between the chronologically earlier (Bapang-AG, Bapang Formation above the Grenzbank zone in Sangiran) and later (Ngandong) morphotypes of Java. At least one of the Bapang-AG crania, Sangiran 17, also exhibits a few characteristics which potentially indicate evolution toward the Ngandong condition. These strongly suggest the continuous, gradual morphological evolution of Javanese H. erectus from the Bapang-AG to Ngandong periods. The development of some unique features in later Javanese H

  10. On human self-domestication, psychiatry, and eugenics

    PubMed Central

    Brüne, Martin

    2007-01-01

    The hypothesis that anatomically modern homo sapiens could have undergone changes akin to those observed in domesticated animals has been contemplated in the biological sciences for at least 150 years. The idea had already plagued philosophers such as Rousseau, who considered the civilisation of man as going against human nature, and eventually "sparked over" to the medical sciences in the late 19th and early 20th century. At that time, human "self-domestication" appealed to psychiatry, because it served as a causal explanation for the alleged degeneration of the "erbgut" (genetic material) of entire populations and the presumed increase of mental disorders. Consequently, Social Darwinists emphasised preventing procreation by people of "lower genetic value" and positively selecting favourable traits in others. Both tendencies culminated in euthanasia and breeding programs ("Lebensborn") during the Nazi regime in Germany. Whether or not domestication actually plays a role in some anatomical changes since the late Pleistocene period is, from a biological standpoint, contentious, and the currently resurrected debate depends, in part, on the definitional criteria applied. However, the example of human self-domestication may illustrate that scientific ideas, especially when dealing with human biology, are prone to misuse, particularly if "is" is confused with "ought", i.e., if moral principles are deduced from biological facts. Although such naturalistic fallacies appear to be banned, modern genetics may, at least in theory, pose similar ethical problems to medicine, including psychiatry. In times during which studies into the genetics of psychiatric disorders are scientifically more valued than studies into environmental causation of disorders (which is currently the case), the prospects of genetic therapy may be tempting to alter the human genome in patients, probably at costs that no-one can foresee. In the case of "self-domestication", it is proposed that human

  11. A Critical Discourse Analysis of "No Promo Homo" Policies in US Schools

    ERIC Educational Resources Information Center

    Barrett, Brian; Bound, Arron M.

    2015-01-01

    This article presents a critical discourse analysis of "no promo homo" policies and their effects in US schools. "No promo homo"--short for "no promotion of homosexuality" (Eskridge, 2000, p. 1329)--polices have been adopted across nine states and several local school districts in the United States. They direct…

  12. Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia.

    PubMed

    Villmoare, Brian; Kimbel, William H; Seyoum, Chalachew; Campisano, Christopher J; DiMaggio, Erin N; Rowan, John; Braun, David R; Arrowsmith, J Ramón; Reed, Kaye E

    2015-03-20

    Our understanding of the origin of the genus Homo has been hampered by a limited fossil record in eastern Africa between 2.0 and 3.0 million years ago (Ma). Here we report the discovery of a partial hominin mandible with teeth from the Ledi-Geraru research area, Afar Regional State, Ethiopia, that establishes the presence of Homo at 2.80 to 2.75 Ma. This specimen combines primitive traits seen in early Australopithecus with derived morphology observed in later Homo, confirming that dentognathic departures from the australopith pattern occurred early in the Homo lineage. The Ledi-Geraru discovery has implications for hypotheses about the timing and place of origin of the genus Homo.

  13. A Global Comparison of the Human and T. brucei Degradomes Gives Insights about Possible Parasite Drug Targets

    PubMed Central

    Mashiyama, Susan T.; Koupparis, Kyriacos; Caffrey, Conor R.; McKerrow, James H.; Babbitt, Patricia C.

    2012-01-01

    We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups (“M32” and “C51”) that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html. PMID:23236535

  14. Entamoeba lysyl-tRNA synthetase contains a cytokine-like domain with chemokine activity towards human endothelial cells.

    PubMed

    Castro de Moura, Manuel; Miro, Francesc; Han, Jung Min; Kim, Sunghoon; Celada, Antonio; Ribas de Pouplana, Lluís

    2011-11-01

    Immunological pressure encountered by protozoan parasites drives the selection of strategies to modulate or avoid the immune responses of their hosts. Here we show that the parasite Entamoeba histolytica has evolved a chemokine that mimics the sequence, structure, and function of the human cytokine HsEMAPII (Homo sapiens endothelial monocyte activating polypeptide II). This Entamoeba EMAPII-like polypeptide (EELP) is translated as a domain attached to two different aminoacyl-tRNA synthetases (aaRS) that are overexpressed when parasites are exposed to inflammatory signals. EELP is dispensable for the tRNA aminoacylation activity of the enzymes that harbor it, and it is cleaved from them by Entamoeba proteases to generate a standalone cytokine. Isolated EELP acts as a chemoattractant for human cells, but its cell specificity is different from that of HsEMAPII. We show that cell specificity differences between HsEMAPII and EELP can be swapped by site directed mutagenesis of only two residues in the cytokines' signal sequence. Thus, Entamoeba has evolved a functional mimic of an aaRS-associated human cytokine with modified cell specificity.

  15. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

    PubMed

    Mashiyama, Susan T; Koupparis, Kyriacos; Caffrey, Conor R; McKerrow, James H; Babbitt, Patricia C

    2012-01-01

    We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups ("M32" and "C51") that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html.

  16. Purification, crystallization and preliminary crystallographic analysis of human cystathionine β-synthase

    PubMed Central

    Oyenarte, Iker; Majtan, Tomas; Ereño, June; Corral-Rodríguez, María Angeles; Kraus, Jan P.; Martínez-Cruz, Luis Alfonso

    2012-01-01

    Human cystathionine β-synthase (CBS) is a pyridoxal-5′-phosphate-dependent hemeprotein, whose catalytic activity is regulated by S-adenosylmethionine. CBS catalyzes the β-replacement reaction of homocysteine (Hcy) with serine to yield cystathionine. CBS is a key regulator of plasma levels of the thrombogenic Hcy and deficiency in CBS is the single most common cause of homocystinuria, an inherited metabolic disorder of sulfur amino acids. The properties of CBS enzymes, such as domain organization, oligomerization degree or regulatory mechanisms, are not conserved across the eukaryotes. The current body of knowledge is insufficient to understand these differences and their impact on CBS function and physiology. To overcome this deficiency, we have addressed the crystallization and preliminary crystallographic analysis of a protein construct (hCBS516–525) that contains the full-length CBS from Homo sapiens (hCBS) and just lacks amino-acid residues 516–525, which are located in a disordered loop. The human enzyme yielded crystals belonging to space group I222, with unit-cell parameters a = 124.98, b = 136.33, c = 169.83 Å and diffracting X-rays to a resolution of 3.0 Å. The crystal structure appears to contain two molecules in the asymmetric unit which presumably correspond to a dimeric form of the enzyme. PMID:23143240

  17. The contributions of oxytocin and vasopressin pathway genes to human behavior.

    PubMed

    Ebstein, Richard P; Knafo, Ariel; Mankuta, David; Chew, Soo Hong; Lai, Poh San

    2012-03-01

    Arginine vasopressin (AVP) and oxytocin (OXT) are social hormones and mediate affiliative behaviors in mammals and as recently demonstrated, also in humans. There is intense interest in how these simple nonapeptides mediate normal and abnormal behavior, especially regarding disorders of the social brain such as autism that are characterized by deficits in social communication and social skills. The current review examines in detail the behavioral genetics of the first level of human AVP-OXT pathway genes including arginine vasopressin 1a receptor (AVPR1a), oxytocin receptor (OXTR), AVP (AVP-neurophysin II [NPII]) and OXT (OXT neurophysin I [NPI]), oxytocinase/vasopressinase (LNPEP), ADP-ribosyl cyclase (CD38) and arginine vasopressin 1b receptor (AVPR1b). Wherever possible we discuss evidence from a variety of research tracks including molecular genetics, imaging genomics, pharmacology and endocrinology that support the conclusions drawn from association studies of social phenotypes and detail how common polymorphisms in AVP-OXT pathway genes contribute to the behavioral hard wiring that enables individual Homo sapiens to interact successfully with conspecifics. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

  18. Unnatural amino acids increase activity and specificity of synthetic substrates for human and malarial cathepsin C.

    PubMed

    Poreba, Marcin; Mihelic, Marko; Krai, Priscilla; Rajkovic, Jelena; Krezel, Artur; Pawelczak, Malgorzata; Klemba, Michael; Turk, Dusan; Turk, Boris; Latajka, Rafal; Drag, Marcin

    2014-04-01

    Mammalian cathepsin C is primarily responsible for the removal of N-terminal dipeptides and activation of several serine proteases in inflammatory or immune cells, while its malarial parasite ortholog dipeptidyl aminopeptidase 1 plays a crucial role in catabolizing the hemoglobin of its host erythrocyte. In this report, we describe the systematic substrate specificity analysis of three cathepsin C orthologs from Homo sapiens (human), Bos taurus (bovine) and Plasmodium falciparum (malaria parasite). Here, we present a new approach with a tailored fluorogenic substrate library designed and synthesized to probe the S1 and S2 pocket preferences of these enzymes with both natural and a broad range of unnatural amino acids. Our approach identified very efficiently hydrolyzed substrates containing unnatural amino acids, which resulted in the design of significantly better substrates than those previously known. Additionally, in this study significant differences in terms of the structures of optimal substrates for human and malarial orthologs are important from the therapeutic point of view. These data can be also used for the design of specific inhibitors or activity-based probes.

  19. Network thermodynamic curation of human and yeast genome-scale metabolic models.

    PubMed

    Martínez, Verónica S; Quek, Lake-Ee; Nielsen, Lars K

    2014-07-15

    Genome-scale models are used for an ever-widening range of applications. Although there has been much focus on specifying the stoichiometric matrix, the predictive power of genome-scale models equally depends on reaction directions. Two-thirds of reactions in the two eukaryotic reconstructions Homo sapiens Recon 1 and Yeast 5 are specified as irreversible. However, these specifications are mainly based on biochemical textbooks or on their similarity to other organisms and are rarely underpinned by detailed thermodynamic analysis. In this study, a to our knowledge new workflow combining network-embedded thermodynamic and flux variability analysis was used to evaluate existing irreversibility constraints in Recon 1 and Yeast 5 and to identify new ones. A total of 27 and 16 new irreversible reactions were identified in Recon 1 and Yeast 5, respectively, whereas only four reactions were found with directions incorrectly specified against thermodynamics (three in Yeast 5 and one in Recon 1). The workflow further identified for both models several isolated internal loops that require further curation. The framework also highlighted the need for substrate channeling (in human) and ATP hydrolysis (in yeast) for the essential reaction catalyzed by phosphoribosylaminoimidazole carboxylase in purine metabolism. Finally, the framework highlighted differences in proline metabolism between yeast (cytosolic anabolism and mitochondrial catabolism) and humans (exclusively mitochondrial metabolism). We conclude that network-embedded thermodynamics facilitates the specification and validation of irreversibility constraints in compartmentalized metabolic models, at the same time providing further insight into network properties.

  20. The evolution of the human pelvis: changing adaptations to bipedalism, obstetrics and thermoregulation.

    PubMed

    Gruss, Laura Tobias; Schmitt, Daniel

    2015-03-05

    The fossil record of the human pelvis reveals the selective priorities acting on hominin anatomy at different points in our evolutionary history, during which mechanical requirements for locomotion, childbirth and thermoregulation often conflicted. In our earliest upright ancestors, fundamental alterations of the pelvis compared with non-human primates facilitated bipedal walking. Further changes early in hominin evolution produced a platypelloid birth canal in a pelvis that was wide overall, with flaring ilia. This pelvic form was maintained over 3-4 Myr with only moderate changes in response to greater habitat diversity, changes in locomotor behaviour and increases in brain size. It was not until Homo sapiens evolved in Africa and the Middle East 200 000 years ago that the narrow anatomically modern pelvis with a more circular birth canal emerged. This major change appears to reflect selective pressures for further increases in neonatal brain size and for a narrow body shape associated with heat dissipation in warm environments. The advent of the modern birth canal, the shape and alignment of which require fetal rotation during birth, allowed the earliest members of our species to deal obstetrically with increases in encephalization while maintaining a narrow body to meet thermoregulatory demands and enhance locomotor performance.

  1. The evolution of the human pelvis: changing adaptations to bipedalism, obstetrics and thermoregulation

    PubMed Central

    Gruss, Laura Tobias; Schmitt, Daniel

    2015-01-01

    The fossil record of the human pelvis reveals the selective priorities acting on hominin anatomy at different points in our evolutionary history, during which mechanical requirements for locomotion, childbirth and thermoregulation often conflicted. In our earliest upright ancestors, fundamental alterations of the pelvis compared with non-human primates facilitated bipedal walking. Further changes early in hominin evolution produced a platypelloid birth canal in a pelvis that was wide overall, with flaring ilia. This pelvic form was maintained over 3–4 Myr with only moderate changes in response to greater habitat diversity, changes in locomotor behaviour and increases in brain size. It was not until Homo sapiens evolved in Africa and the Middle East 200 000 years ago that the narrow anatomically modern pelvis with a more circular birth canal emerged. This major change appears to reflect selective pressures for further increases in neonatal brain size and for a narrow body shape associated with heat dissipation in warm environments. The advent of the modern birth canal, the shape and alignment of which require fetal rotation during birth, allowed the earliest members of our species to deal obstetrically with increases in encephalization while maintaining a narrow body to meet thermoregulatory demands and enhance locomotor performance. PMID:25602067

  2. The EuroPhysiome, STEP and a roadmap for the virtual physiological human.

    PubMed

    Fenner, J W; Brook, B; Clapworthy, G; Coveney, P V; Feipel, V; Gregersen, H; Hose, D R; Kohl, P; Lawford, P; McCormack, K M; Pinney, D; Thomas, S R; Van Sint Jan, S; Waters, S; Viceconti, M

    2008-09-13

    Biomedical science and its allied disciplines are entering a new era in which computational methods and technologies are poised to play a prevalent role in supporting collaborative investigation of the human body. Within Europe, this has its focus in the virtual physiological human (VPH), which is an evolving entity that has emerged from the EuroPhysiome initiative and the strategy for the EuroPhysiome (STEP) consortium. The VPH is intended to be a solution to common infrastructure needs for physiome projects across the globe, providing a unifying architecture that facilitates integration and prediction, ultimately creating a framework capable of describing Homo sapiens in silico. The routine reliance of the biomedical industry, biomedical research and clinical practice on information technology (IT) highlights the importance of a tailor-made and robust IT infrastructure, but numerous challenges need to be addressed if the VPH is to become a mature technological reality. Appropriate investment will reap considerable rewards, since it is anticipated that the VPH will influence all sectors of society, with implications predominantly for improved healthcare, improved competitiveness in industry and greater understanding of (patho)physiological processes. This paper considers issues pertinent to the development of the VPH, highlighted by the work of the STEP consortium.

  3. The Sima de los Huesos (Burgos, northern Spain): palaeoenvironment and habitats of Homo heidelbergensis during the Middle Pleistocene

    NASA Astrophysics Data System (ADS)

    García, Nuria; Arsuaga, Juan Luis

    2011-06-01

    Interpreting how environmental dynamics respond to global climate change and how this has affected human evolution and dispersal is an on-going topic of debate. During the early Middle Pleistocene (˜0.6-0.4 Ma), as compared to earlier, environmental conditions were relatively more stable, with longer climatic cycles alternating between open and forested landscapes. During this interval, humans spread successfully providing an important number of fossil sites where fossils or tools are reported. The Atapuerca-Sima de los Huesos (Burgos, northern Spain) site (Atapuerca-SH) is one of the earliest localities with hominin evidence in the European Middle Pleistocene, with the most important accumulation of Homo heidelbergensis so far. We have analyzed the abundant faunal record from Sima de los Huesos, which is mainly comprised of carnivores, in order to approach an interpretation of the palaeoenvironmental circumstances where these hominids inhabited within the Sierra. Other sites from Sierra de Atapuerca referred to the same Faunal Unit (FU 6), are roughly contemporaneous, and include important ungulates, which are here analyzed with Atapuerca-SH. Additional information provided by isotopic analysis helps elucidate the ancient ecology of taxa present in Sima de los Huesos allowing for an accurate portrayal of the setting in which humans lived. The timing of the spread of Homo heidelbergensis is dominated by a relative climatic and environmental stability and points to a landscape dominated by savannah-like open woodland.

  4. Tyrosine Phosphorylation Based Homo-dimerization of Arabidopsis RACK1A Proteins Regulates Oxidative Stress Signaling Pathways in Yeast

    PubMed Central

    Sabila, Mercy; Kundu, Nabanita; Smalls, Deana; Ullah, Hemayet

    2016-01-01

    Scaffold proteins are known as important cellular regulators that can interact with multiple proteins to modulate diverse signal transduction pathways. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, plays regulatory roles in diverse signal transduction and stress response pathways. RACK1 in humans has been implicated in myriads of neuropathological diseases including Alzheimer and alcohol addictions. Model plant Arabidopsis thaliana genome maintains three different RACK1 genes termed RACK1A, RACK1B, and RACK1C with a very high (85–93%) sequence identity among them. Loss of function mutation in Arabidopsis indicates that RACK1 proteins regulate diverse environmental stress signaling pathways including drought and salt stress resistance pathway. Recently deduced crystal structure of Arabidopsis RACK1A- very first among all of the RACK1 proteins, indicates that it can potentially be regulated by post-translational modifications, like tyrosine phosphorylations and sumoylation at key residues. Here we show evidence that RACK1A proteins, depending on diverse environmental stresses, are tyrosine phosphorylated. Utilizing site-directed mutagenesis of key tyrosine residues, it is found that tyrosine phosphorylation can potentially dictate the homo-dimerization of RACK1A proteins. The homo-dimerized RACK1A proteins play a role in providing UV-B induced oxidative stress resistance. It is proposed that RACK1A proteins ability to function as scaffold protein may potentially be regulated by the homo-dimerized RACK1A proteins to mediate diverse stress signaling pathways. PMID:26941753

  5. Tyrosine Phosphorylation Based Homo-dimerization of Arabidopsis RACK1A Proteins Regulates Oxidative Stress Signaling Pathways in Yeast.

    PubMed

    Sabila, Mercy; Kundu, Nabanita; Smalls, Deana; Ullah, Hemayet

    2016-01-01

    Scaffold proteins are known as important cellular regulators that can interact with multiple proteins to modulate diverse signal transduction pathways. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, plays regulatory roles in diverse signal transduction and stress response pathways. RACK1 in humans has been implicated in myriads of neuropathological diseases including Alzheimer and alcohol addictions. Model plant Arabidopsis thaliana genome maintains three different RACK1 genes termed RACK1A, RACK1B, and RACK1C with a very high (85-93%) sequence identity among them. Loss of function mutation in Arabidopsis indicates that RACK1 proteins regulate diverse environmental stress signaling pathways including drought and salt stress resistance pathway. Recently deduced crystal structure of Arabidopsis RACK1A- very first among all of the RACK1 proteins, indicates that it can potentially be regulated by post-translational modifications, like tyrosine phosphorylations and sumoylation at key residues. Here we show evidence that RACK1A proteins, depending on diverse environmental stresses, are tyrosine phosphorylated. Utilizing site-directed mutagenesis of key tyrosine residues, it is found that tyrosine phosphorylation can potentially dictate the homo-dimerization of RACK1A proteins. The homo-dimerized RACK1A proteins play a role in providing UV-B induced oxidative stress resistance. It is proposed that RACK1A proteins ability to function as scaffold protein may potentially be regulated by the homo-dimerized RACK1A proteins to mediate diverse stress signaling pathways.

  6. Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo

    PubMed Central

    Roach, Neil T.; Venkadesan, Madhusudhan; Rainbow, Michael J.; Lieberman, Daniel E.

    2013-01-01

    Although some primates, including chimpanzees, throw objects occasionally1,2, only humans regularly throw projectiles with high speed and great accuracy. Darwin noted that humans’ unique throwing abilities, made possible when bipedalism emancipated the arms, enabled foragers to effectively hunt using projectiles3. However, there has been little consideration of the evolution of throwing in the years since Darwin made his observations, in part because of a lack of evidence on when, how, and why hominins evolved the ability to generate high-speed throws4-8. Here, we show using experimental studies of throwers that human throwing capabilities largely result from several derived anatomical features that enable elastic energy storage and release at the shoulder. These features first appear together approximately two million years ago in the species Homo erectus. Given archaeological evidence that suggests hunting activity intensified around this time9, we conclude that selection for throwing in order to hunt likely played an important role in the evolution of the human genus. PMID:23803849

  7. Homo imitans? Seven reasons why imitation couldn't possibly be associative

    PubMed Central

    Heyes, Cecilia

    2016-01-01

    Many comparative and developmental psychologists believe that we are Homo imitans; humans are more skilled and prolific imitators than other animals, because we have a special, inborn ‘intermodal matching’ mechanism that integrates representations of others with representations of the self. In contrast, the associative sequence learning (ASL) model suggests that human infants learn to imitate using mechanisms that they share with other animals, and the rich resources provided by their sociocultural environments. This article answers seven objections to the ASL model: (i) it presents evidence that newborns do not imitate; (ii) argues that infants receive a plentiful supply of the kind of experience necessary for learning to imitate; (iii) suggests that neither infants nor adults can imitate elementally novel actions; (iv) explains why non-human animals have a limited capacity for imitation; (v) discusses the goal-directedness of imitation; (vi) presents evidence that improvement in imitation depends on visual feedback; and (vii) reflects on the view that associative theories steal ‘the soul of imitation’. The empirical success of the ASL model indicates that the mechanisms which make imitation possible, by aligning representations of self with representations of others, have been tweaked by cultural evolution, not built from scratch by genetic evolution. PMID:26644604

  8. The shaping of human diversity: filters, boundaries and transitions

    PubMed Central

    Mirazón Lahr, Marta

    2016-01-01

    The evolution of modern humans was a complex process, involving major changes in levels of diversity through time. The fossils and stone tools that record the spatial distribution of our species in the past form the backbone of our evolutionary history, and one that allows us to explore the different processes—cultural and biological—that acted to shape the evolution of different populations in the face of major climate change. Those processes created a complex palimpsest of similarities and differences, with outcomes that were at times accelerated by sharp demographic and geographical fluctuations. The result is that the population ancestral to all modern humans did not look or behave like people alive today. This has generated questions regarding the evolution of human universal characters, as well as the nature and timing of major evolutionary events in the history of Homo sapiens. The paucity of African fossils remains a serious stumbling block for exploring some of these issues. However, fossil and archaeological discoveries increasingly clarify important aspects of our past, while breakthroughs from genomics and palaeogenomics have revealed aspects of the demography of Late Quaternary Eurasian hominin groups and their interactions, as well as those between foragers and farmers. This paper explores the nature and timing of key moments in the evolution of human diversity, moments in which population collapse followed by differential expansion of groups set the conditions for transitional periods. Five transitions are identified (i) at the origins of the species, 240–200 ka; (ii) at the time of the first major expansions, 130–100 ka; (iii) during a period of dispersals, 70–50 ka; (iv) across a phase of local/regional structuring of diversity, 45–25 ka; and (v) during a phase of significant extinction of hunter–gatherer diversity and expansion of particular groups, such as farmers and later societies (the Holocene Filter), 15–0 ka. This article is

  9. Prehistory: A Teacher's Guide. Education on Site.

    ERIC Educational Resources Information Center

    Corbishley, Mike; Darvill, Tim; Stone, Peter

    Chronologically prehistory accounts for over 99% of the human past. During this time, the earliest human ancestors spread across the world from Africa and changed, modified, and evolved until the species "Homo sapiens sapiens" made its appearance some 200,000 years ago. This teacher's guide provides an outline of the prehistory of the…

  10. Mass spectrometric U-series dating of Huanglong Cave in Hubei Province, Central China: evidence for early presence of modern humans in Eastern Asia.

    PubMed

    Shen, Guanjun; Wu, Xianzhu; Wang, Qian; Tu, Hua; Feng, Yue-xing; Zhao, Jian-xin

    2013-08-01

    Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ∼50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia.

  11. The human nature of culture and education.

    PubMed

    Trevarthen, Colwyn; Gratier, Maya; Osborne, Nigel

    2014-03-01

    Human cultures educate children with different strategies. Ancient hunter-gatherers 200,000 years ago, with bodies and brains like our own, in bands of a hundred well-known individuals or less, depended on spontaneous cooperative practice of knowledge and skills in a natural world. Before creating language, they appreciated beautiful objects and music. Anthropologists observe that similar living cultures accept that children learn in playful 'intent participation'. Large modern industrial states with millions of citizens competing in a global economy aim to instruct young people in scientific concepts and the rules of literacy and numeracy deemed important for employment with elaborate machines. Our psychobiological theories commonly assume that an infant starts with a body needing care and emotional regulation and a mind that assimilates concepts of objects by sensorimotor action and requires school instruction in rational principles after several years of cognitive development. Evidence from archeology and evolutionary anthropology indicates that Homo sapiens are born with an imaginative and convivial brain ready for the pleasure of shared invention and with a natural sense of beauty in handmade objects and music. In short, there are innate predispositions for culture for practicing meaningful habits and artful performances that are playfully inventive and seductive for companionship in traditions, and soon capable of grasping the clever purpose of shared tasks and tools. This knowledge of inventive human nature with esthetic and moral sensibilities has important implications for educational policy in our schools. WIREs Cogn Sci 2014, 5:173-192. doi: 10.1002/wcs.1276 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.

  12. First Homo erectus from Turkey and implications for migrations into temperate Eurasia.

    PubMed

    Kappelman, John; Alçiçek, Mehmet Cihat; Kazanci, Nizamettin; Schultz, Michael; Ozkul, Mehmet; Sen, Sevket

    2008-01-01

    Remains of fossil hominins from temperate regions of the Old World are rare across both time and space, but such specimens are necessary for understanding basic issues in human evolution including linkages between their adaptations and early migration patterns. We report here the remarkable circumstances surrounding the discovery of the first fossil hominin calvaria from Turkey. The specimen was found in the Denizli province of western Turkey and recovered from within a solid block of travertine stone as it was being sawed into tile-sized slabs for the commercial natural stone building market. The new specimen fills an important geographical and temporal gap and displays several anatomical features that are shared with other Middle Pleistocene hominins from both Africa and Asia attributed to Homo erectus. It also preserves an unusual pathology on the endocranial surface of the frontal bone that is consistent with a diagnosis of Leptomeningitis tuberculosa (TB), and this evidence represents the most ancient example of this disease known for a fossil human. TB is exacerbated in dark-skinned peoples living in northern latitudes by a vitamin D deficiency because of reduced levels of ultraviolet radiation (UVR). Evidence for TB in the new specimen supports the thesis that reduced UVR was one of the many climatic variables presenting an adaptive challenge to ancient hominins during their migration into the temperate regions of Europe and Asia.

  13. BLOOD, BULBS, AND BUNODONTS: ON EVOLUTIONARY ECOLOGY AND THE DIETS OF ARDIPITHECUS, AUSTRALOPITHECUS, AND EARLY HOMO

    PubMed Central

    Sayers, Ken; Lovejoy, C. Owen

    2014-01-01

    Beginning with Darwin, some have argued that predation on other vertebrates dates to the earliest stages of hominid evolution, and can explain many uniquely human anatomical and behavioral characters. Other recent workers have focused instead on scavenging, or particular plant foods. Foraging theory suggests that inclusion of any food is influenced by its profitability and distribution within the consumer’s habitat. The morphology and likely cognitive abilities of Ardipithecus, Australopithecus, and early Homo suggest that while hunting and scavenging occurred, their profitability generally would have been considerably lower than in extant primates and/or modern human hunter-gatherers. On the other hand, early hominid diet modelers should not focus solely on plant foods, as this overlooks standard functional interpretations of the early hominid dentition, their remarkable demographic success, and the wide range of available food types within their likely day ranges. Any dietary model focusing too narrowly on any one food type or foraging strategy must be viewed with caution. We argue that early hominid diet can best be elucidated by consideration of their entire habitat-specific resource base, and by quantifying the potential profitability and abundance of likely available foods. PMID:25510078

  14. Blood, bulbs, and bunodonts: on evolutionary ecology and the diets of Ardipithecus, Australopithecus, and early Homo.

    PubMed

    Sayers, Ken; Lovejoy, C Owen

    2014-12-01

    Beginning with Darwin, some have argued that predation on other vertebrates dates to the earliest stages of hominid evolution, and can explain many uniquely human anatomical and behavioral characters. Other recent workers have focused instead on scavenging, or particular plant foods. Foraging theory suggests that inclusion of any food is influenced by its profitability and distribution within the consumer's habitat. The morphology and likely cognitive abilities of Ardipithecus, Australopithecus, and early Homo suggest that while hunting and scavenging occurred, their profitability generally would have been considerably lower than in extant primates and/or modern human hunter-gatherers. On the other hand, early hominid diet modelers should not focus solely on plant foods, as this overlooks standard functional interpretations of the early hominid dentition, their remarkable demographic success, and the wide range of available food types within their likely day ranges. Any dietary model focusing too narrowly on any one food type or foraging strategy must be viewed with caution. We argue that early hominid diet can best be elucidated by consideration of their entire habitat-specific resource base, and by quantifying the potential profitability and abundance of likely available foods.

  15. A potyvirus-based gene vector allows producing active human S-COMT and animal GFP, but not human sorcin, in vector-infected plants.

    PubMed

    Kelloniemi, Jani; Mäkinen, Kristiina; Valkonen, Jari P T

    2006-05-01

    Potato virus A (PVA), a potyvirus with a (+)ssRNA genome translated to a large polyprotein, was engineered and used as a gene vector for expression of heterologous proteins in plants. Foreign genes including jellyfish GFP (Aequorea victoria) encoding the green fluorescent protein (GFP, 27 kDa) and the genes of human origin (Homo sapiens) encoding a soluble resistance-related calcium-binding protein (sorcin, 22 kDa) and the catechol-O-methyltransferase (S-COMT; 25 kDa) were cloned between the cistrons for the viral replicase and coat protein (CP). The inserts caused no adverse effects on viral infectivity and virulence, and the inserted sequences remained intact in progeny viruses in the systemically infected leaves. The heterologous proteins were released from the viral polyprotein following cleavage by the main viral proteinase, NIa, at engineered proteolytic processing sites flanking the insert. Active GFP, as indicated by green fluorescence, and S-COMT with high levels of enzymatic activity were produced. In contrast, no sorcin was detected despite the expected equimolar amounts of the foreign and viral proteins being expressed as a polyprotein. These data reveal inherent differences between heterologous proteins in their suitability for production in plants.

  16. N2 HOMO-1 orbital cross section revealed through high-order-harmonic generation

    NASA Astrophysics Data System (ADS)

    Troß, Jan; Ren, Xiaoming; Makhija, Varun; Mondal, Sudipta; Kumarappan, Vinod; Trallero-Herrero, Carlos A.

    2017-03-01

    We measure multi-orbital contributions to high harmonic generation from aligned nitrogen. We show that the change in revival structure in the cutoff harmonics has a counterpart in the angular distribution when a lower-lying orbital contributes to the harmonic yield. This angular distribution is directly observed in the laboratory without any further deconvolution. Because of the high degree of alignment we are able to distinguish angular contributions of the highest occupied molecular orbital 1 (HOMO-1) orbital from angle-dependent spectroscopic features of the HOMO. In particular, we are able to make a direct comparison with the cross section of the HOMO-1 orbital in the extreme ultraviolet region.

  17. Cloning and characterization of Rep-8 (D8S2298E) in the human chromosome 8p11.2-p12

    SciTech Connect

    Yamabe, Yukako; Ichikawa, Koji; Sugawara, Kahori

    1997-01-15

    A novel human gene referred to as the Rep-8 gene (D8S2298E) was cloned by a combination of exon trapping, thermal asymmetric interlaced-PCR, and screening of a cDNA library. It is located in human chromosome 8p.11.2-p12. The gene consists of eight exons and spans about 20 kb between the glutathione S-reductase and the protein phosphatase 2A beta subunit genes. The full-length Rep-8 gene contains 1483 nucleotides and codes for a protein of 270 amino acids. Southern blot experiments showed that the Rep-8 gene exists as a single copy per haploid. With a zoo blot analysis, human Rep-8 DNA hybridized strongly with the monkey DNA, but only weakly with the DNAs of species other than Homo sapiens. Northern blot analysis showed that it is expressed abundantly in the testis and ovary, suggesting that the Rep-8 gene product may play a role in reproduction. 16 refs., 5 figs., 1 tab.

  18. MicroRNA (miRNA) Signaling in the Human CNS in Sporadic Alzheimer's Disease (AD)-Novel and Unique Pathological Features.

    PubMed

    Zhao, Yuhai; Pogue, Aileen I; Lukiw, Walter J

    2015-12-17

    Of the approximately ~2.65 × 10³ mature microRNAs (miRNAs) so far identified in Homo sapiens, only a surprisingly small but select subset-about 35-40-are highly abundant in the human central nervous system (CNS). This fact alone underscores the extremely high selection pressure for the human CNS to utilize only specific ribonucleotide sequences contained within these single-stranded non-coding RNAs (ncRNAs) for productive miRNA-mRNA interactions and the down-regulation of gene expression. In this article we will: (i) consolidate some of our still evolving ideas concerning the role of miRNAs in the CNS in normal aging and in health, and in sporadic Alzheimer's disease (AD) and related forms of chronic neurodegeneration; and (ii) highlight certain aspects of the most current work in this research field, with particular emphasis on the findings from our lab of a small pathogenic family of six inducible, pro-inflammatory, NF-κB-regulated miRNAs including miRNA-7, miRNA-9, miRNA-34a, miRNA-125b, miRNA-146a and miRNA-155. This group of six CNS-abundant miRNAs significantly up-regulated in sporadic AD are emerging as what appear to be key mechanistic contributors to the sporadic AD process and can explain much of the neuropathology of this common, age-related inflammatory neurodegeneration of the human CNS.

  19. Characterization of a chromosome-specific chimpanzee alpha satellite subset: Evolutionary relationship to subsets on human chromosomes

    SciTech Connect

    Warburton, P.E.; Gosden, J.; Lawson, D.

    1996-04-15

    Alpha satellite DNA is a tandemly repeated DNA family found at the centromeres of all primate chromosomes examined. The fundamental repeat units of alpha satellite DNA are diverged 169- to 172-bp monomers, often found to be organized in chromosome-specific higher-order repeat units. The chromosomes of human (Homo sapiens (HSA)), chimpanzee (Pan troglodytes (PTR) and Pan paniscus), and gorilla (Gorilla gorilla) share a remarkable similarity and synteny. It is of interest to ask if alpha satellite arrays at centromeres of homologous chromosomes between these species are closely related (evolving in an orthologous manner) or if the evolutionary processes that homogenize and spread these arrays within and between chromosomes result in nonorthologous evolution of arrays. By using PCR primers specific for human chromosome 17-specific alpha satellite DNA, we have amplified, cloned, and characterized a chromosome-specific subset from the PTR chimpanzee genome. Hybridization both on Southern blots and in situ as well as sequence analysis show that this subset is most closely related, as expected, to sequences on HSA 17. However, in situ hybridization reveals that this subset is not found on the homologous chromosome in chimpanzee (PTR 19), but instead on PTR 12, which is homologous to HSA 2p. 40 refs., 3 figs.

  20. Root canal morphology of Chalcolithic and early bronze age human populations of El Mirador Cave (Sierra de Atapuerca, Spain).

    PubMed

    Ceperuelo, Dolors; Lozano, Marina; Duran-Sindreu, Fernando; Mercadé, Montse

    2014-12-01

    This study provides a morphological characterization of the inner anatomy of the root canals of permanent first and second molars in Chalcolithic and early Bronze Age human fossils using cone-beam computed tomography. The general evolutionary trend in present-day human dentition is related to morphological simplification. As little is known about when this trend appeared in Homo sapiens populations, the aim of this work is to test the presence of modern radicular morphology 4,400 years ago. Fifty-four permanent first and second maxillary and mandibular molars of 17 individuals were included in the study. All maxillary first and second molars showed three separate roots. Almost all the lower molars analyzed (100% of first molars and 75% of second molars) had two separate roots. More differences in the canal system configuration were documented in the maxillary mesiobuccal roots than in the palatal or distobuccal roots. The most variable tooth in root and canal configuration is the maxillary second molar. It should be pointed out that 12.5% of the teeth analyzed showed a C-shaped root configuration.

  1. Abundant raw material for cis-regulatory evolution in humans.

    PubMed

    Rockman, Matthew V; Wray, Gregory A

    2002-11-01

    Changes in gene expression and regulation--due in particular to the evolution of cis-regulatory DNA sequences--may underlie many evolutionary changes in phenotypes, yet little is known about the distribution of such variation in populations. We present in this study the first survey of experimentally validated functional cis-regulatory polymorphism. These data are derived from more than 140 polymorphisms involved in the regulation of 107 genes in Homo sapiens, the eukaryote species with the most available data. We find that functional cis-regulatory variation is widespread in the human genome and that the consequent variation in gene expression is twofold or greater for 63% of the genes surveyed. Transcription factor-DNA interactions are highly polymorphic, and regulatory interactions have been gained and lost within human populations. On average, humans are heterozygous at more functional cis-regulatory sites (>16,000) than at amino acid positions (<13,000), in part because of an overrepresentation among the former in multiallelic tandem repeat variation, especially (AC)(n) dinucleotide microsatellites. The role of microsatellites in gene expression variation may provide a larger store of heritable phenotypic variation, and a more rapid mutational input of such variation, than has been realized. Finally, we outline the distinctive consequences of cis-regulatory variation for the genotype-phenotype relationship, including ubiquitous epistasis and genotype-by-environment interactions, as well as underappreciated modes of pleiotropy and overdominance. Ordinary small-scale mutations contribute to pervasive variation in transcription rates and consequently to patterns of human phenotypic variation.

  2. Abundant raw material for cis-regulatory evolution in humans

    NASA Technical Reports Server (NTRS)

    Rockman, Matthew V.; Wray, Gregory A.

    2002-01-01

    Changes in gene expression and regulation--due in particular to the evolution of cis-regulatory DNA sequences--may underlie many evolutionary changes in phenotypes, yet little is known about the distribution of such variation in populations. We present in this study the first survey of experimentally validated functional cis-regulatory polymorphism. These data are derived from more than 140 polymorphisms involved in the regulation of 107 genes in Homo sapiens, the eukaryote species with the most available data. We find that functional cis-regulatory variation is widespread in the human genome and that the consequent variation in gene expression is twofold or greater for 63% of the genes surveyed. Transcription factor-DNA interactions are highly polymorphic, and regulatory interactions have been gained and lost within human populations. On average, humans are heterozygous at more functional cis-regulatory sites (>16,000) than at amino acid positions (<13,000), in part because of an overrepresentation among the former in multiallelic tandem repeat variation, especially (AC)(n) dinucleotide microsatellites. The role of microsatellites in gene expression variation may provide a larger store of heritable phenotypic variation, and a more rapid mutational input of such variation, than has been realized. Finally, we outline the distinctive consequences of cis-regulatory variation for the genotype-phenotype relationship, including ubiquitous epistasis and genotype-by-environment interactions, as well as underappreciated modes of pleiotropy and overdominance. Ordinary small-scale mutations contribute to pervasive variation in transcription rates and consequently to patterns of human phenotypic variation.

  3. Human milk oligosaccharides: evolution, structures and bioselectivity as substrates for intestinal bacteria.

    PubMed

    German, J Bruce; Freeman, Samara L; Lebrilla, Carlito B; Mills, David A

    2008-01-01

    Human milk contains a high concentration of diverse soluble oligosaccharides, carbohydrate polymers formed from a small number of monosaccharides. Novel methods combining liquid chromatography with high resolution mass spectrometry have identified approximately 200 unique oligosaccharides structures varying from 3 to 22 sugars. The increasing complexity of oligosaccharides follows the general pattern of mammalian evolution though the concentration and diversity of these structures in homo sapiens are strikingly. There is also diversity among human mothers in oligosaccharides. Milks from randomly selected mothers contain as few as 23 and as many as 130 different oligosaccharides. The functional implications of this diversity are not known. Despite the role of milk to serve as a sole nutrient source for mammalian infants, the oligosaccharides in milk are not digestible by human infants. This apparent paradox raises questions about the functions of these oligosaccharides and how their diverse molecular structures affect their functions. The nutritional function most attributed to milk oligosaccharides is to serve as prebiotics - a form of indigestible carbohydrate that is selectively fermented by desirable gut microflora. This function was tested by purifying human milk oligosaccharides and providing these as the sole carbon source to various intestinal bacteria. Indeed, the selectively of providing the complex mixture of oligosaccharides pooled from human milk samples is remarkable. Among a variety of Bifidobacteria tested only Bifidobacteria longum biovar infantis was able to grow extensively on human milk oligosaccharides as sole carbon source. The genomic sequence of this strain revealed approximately 700 genes that are unique to infantis, including a variety of co-regulated glycosidases, relative to other Bifidobacteria, implying a co-evolution of human milk oligosaccharides and the genetic capability of select intestinal bacteria to utilize them. The goal of

  4. Human chaperonin 60 (Hsp60) stimulates bone resorption: structure/function relationships.

    PubMed

    Meghji, S; Lillicrap, M; Maguire, M; Tabona, P; Gaston, J S H; Poole, S; Henderson, B

    2003-09-01

    It is established that the molecular chaperone, chaperonin 60, from various bacteria and from Homo sapiens has cell-cell signalling activity and is able to induce proinflammatory cytokine synthesis. We previously reported that chaperonin 60 proteins from Gram-negative bacteria, but not mycobacteria, have the capacity to resorb cultured murine calvarial bone. We now report that lipopolysaccharide-low human recombinant chaperonin 60 (Hsp60) is a relatively weak cytokine-inducing agonist but is a potent stimulator of murine calvarial bone resorption. The osteolytic activity of Hsp60 was significantly inhibited by indomethacin, interleukin-1 receptor antagonist, and osteoprotegerin, but 5-lipoxygenase inhibitors were less effective. Analysis of Hsp60 truncation mutants revealed that N-terminal mutants (Delta1-137, Delta1-358, and Delta1-465) retained bone resorbing activity. In contrast, a C-terminal truncation mutant (Delta1-26 + Delta466-573) was inactive. This suggests that the active domain in this protein is found within residues 466-573. It is now established that Hsp60 is present in the blood of the majority of the population with the normal range encompassing levels able to activate bone cells. The possibility exists that this protein could play a role in bone remodelling.

  5. Characterization of the human CUTA isoform2 present in the stably transfected HeLa cells.

    PubMed

    Yang, Jingchun; Yang, Huirong; Yan, Lichong; Yang, Liu; Yu, Long

    2009-01-01

    CUTA, Homo sapiens divalent cation tolerance homolog, has been implicated in anchoring of acetylcholinesterase in neuronal cell membranes. However, a protein highly homologous to CUTA in Rattus norvegicus is structurally similar to the signal transduction protein PII, and this similarity suggests an intriguing role of CUTA in signal transduction. Recent researches indicated that CUTA was one of the 35 key genes responsible for lactation in mammary gland development. However, the physiological role of CUTA is still unclear, so more information of this gene is needed. In this study, the expression profile of CUTA gene in human tissues was examined, and our research revealed that CUTA gene was constitutively expressed in all of the 18 tissues tested. As reported, CUTA gene has five variant transcripts encoding three isoforms with different N terminals. CUTA isoform2 is encoded by three of the five variant transcripts as the common part of the three isoforms. So CUTA isoform2 was chose as representative to characterize the CUTA protein. We constructed a HeLa cell line stably transfected with the encoding sequence of CUTA isoform2 for further study. The subcellular location and oligomeric structure of the CUTA isoform2 was analyzed in the stable cell lines. It was found that the CUTA isoform2 was mainly located in mitochondria as a new potential mitochondrial protein. Furthermore, CUTA isoform2 formed trimers in cell lysate with the possible occurrence of heteropolymers. These findings would be helpful to the further study on the specific function of CUTA protein.

  6. Biogeographic range expansion into South America by Coccidioides immitis mirrors New World patterns of human migration

    PubMed Central

    Fisher, Matthew C.; Koenig, Gina L.; White, Thomas J.; San-Blas, Gioconda; Negroni, Ricardo; Alvarez, Isidro Gutiérrez; Wanke, Bodo; Taylor, John W.

    2001-01-01

    Long-distance population dispersal leaves its characteristic signature in genomes, namely, reduced diversity and increased linkage between genetic markers. This signature enables historical patterns of range expansion to be traced. Herein, we use microsatellite loci from the human pathogen Coccidioides immitis to show that genetic diversity in this fungus is geographically partitioned throughout North America. In contrast, analyses of South American C. immitis show that this population is genetically depauperate and was founded from a single North American population centered in Texas. Variances of allele distributions show that South American C. immitis have undergone rapid population growth, consistent with an epidemic increase in postcolonization population size. Herein, we estimate the introduction into South America to have occurred within the last 9,000–140,000 years. This range increase parallels that of Homo sapiens. Because of known associations between Amerindians and this fungus, we suggest that the colonization of South America by C. immitis represents a relatively recent and rapid codispersal of a host and its pathogen. PMID:11287648

  7. The 'Out of Africa' Hypothesis, Human Genetic Diversity, and Comparative Economic Development

    PubMed Central

    Ashraf, Quamrul; Galor, Oded

    2013-01-01

    This research argues that deep-rooted factors, determined tens of thousands of years ago, had a significant effect on the course of economic development from the dawn of human civilization to the contemporary era. It advances and empirically establishes the hypothesis that, in the course of the exodus of Homo sapiens out of Africa, variation in migratory distance from the cradle of humankind to various settlements across the globe affected genetic diversity and has had a long-lasting effect on the pattern of comparative economic development that is not captured by geographical, institutional, and cultural factors. In particular, the level of genetic diversity within a society is found to have a hump-shaped effect on development outcomes in both the pre-colonial and the modern era, reflecting the trade-off between the beneficial and the detrimental effects of diversity on productivity. While the intermediate level of genetic diversity prevalent among Asian and European populations has been conducive for development, the high degree of diversity among African populations and the low degree of diversity among Native American populations have been a detrimental force in the development of these regions. PMID:25506083

  8. HOCOMOCO: a comprehensive collection of human transcription factor binding sites models

    PubMed Central

    Kulakovskiy, Ivan V.; Medvedeva, Yulia A.; Schaefer, Ulf; Kasianov, Artem S.; Vorontsov, Ilya E.; Bajic, Vladimir B.; Makeev, Vsevolod J.

    2013-01-01

    Transcription factor (TF) binding site (TFBS) models are crucial for computational reconstruction of transcription regulatory networks. In existing repositories, a TF often has several models (also called binding profiles or motifs), obtained from different experimental data. Having a single TFBS model for a TF is more pragmatic for practical applications. We show that integration of TFBS data from various types of experiments into a single model typically results in the improved model quality probably due to partial correction of source specific technique bias. We present the Homo sapiens comprehensive model collection (HOCOMOCO, http://autosome.ru/HOCOMOCO/, http://cbrc.kaust.edu.sa/hocomoco/) containing carefully hand-curated TFBS models constructed by integration of binding sequences obtained by both low- and high-throughput methods. To construct position weight matrices to represent these TFBS models, we used ChIPMunk software in four computational modes, including newly developed periodic positional prior mode associated with DNA helix pitch. We selected only one TFBS model per TF, unless there was a clear experimental evidence for two rather distinct TFBS models. We assigned a quality rating to each model. HOCOMOCO contains 426 systematically curated TFBS models for 401 human TFs, where 172 models are based on more than one data source. PMID:23175603

  9. Mapping and characterization of non-HLA multigene assemblages in the human MHC class I region

    SciTech Connect

    Venditti, C.P.; Harris, J.M.; Geraghty, D.E.

    1994-07-15

    The major histocompatibility complex (MHC) class I region has been shown to be associated with a variety of immune and nonimmune disorders. In an effort to initiate steps designed to identify the idiopathic hemochromatosis disease gene (HFE), the authors have cloned and mapped two expressed messages using probes from the HLA-H subregion that lie immediately distal to the HLA-A9 breakpoint. Although the cDNA clones identify distinct multifragment families that are dispersed throughout the MHC, the gene sequences from which the two cDNA clones derive map centromeric to the HLA-B locus and are absent from the genomes of higher nonhuman primates. This suggests that a syntenic coding segment arose within a highly polymorphic region (TNF to HLA-B interval) as the result of an insertion event following the emergence of Homo sapiens. An additional syntenic cluster exists within a peak of linkage disequilibrium with the HFE gene and may define coding sequences that underlie the defect in genetic iron overload. These data generally support the concept that the class I region is potentially gene-rich and further highlight the possibility that these new coding sequences may play a role in the development of a variety of HLA-linked diseases. The observations presented suggest that interlocus exchanges have played a structural role in the genesis of the human class I region. 46 refs., 6 refs.

  10. Homo-psychologicus: Reactionary behavioural aspects of epidemics.

    PubMed

    Cherif, Alhaji; Barley, Kamal; Hurtado, Marcel

    2016-03-01

    We formulate an in silico model of pathogen avoidance mechanism and investigate its impact on defensive behavioural measures (e.g., spontaneous social exclusions and distancing, crowd avoidance and voluntary vaccination adaptation). In particular, we use SIR(B)S (e.g., susceptible-infected-recovered with additional behavioural component) model to investigate the impact of homo-psychologicus aspects of epidemics. We focus on reactionary behavioural changes, which apply to both social distancing and voluntary vaccination participations. Our analyses reveal complex relationships between spontaneous and uncoordinated behavioural changes, the emergence of its contagion properties, and mitigation of infectious diseases. We find that the presence of effective behavioural changes can impede the persistence of disease. Furthermore, it was found that under perfect effective behavioural change, there are three regions in the response factor (e.g., imitation and/or reactionary) and behavioural scale factor (e.g., global/local) factors ρ-α behavioural space. Mainly, (1) disease is always endemic even in the presence of behavioural change, (2) behavioural-prevalence plasticity is observed and disease can sometimes be eradication, and (3) elimination of endemic disease under permanence of permanent behavioural change is achieved. These results suggest that preventive behavioural changes (e.g., non-pharmaceutical prophylactic measures, social distancing and exclusion, crowd avoidance) are influenced by individual differences in perception of risks and are a salient feature of epidemics. Additionally, these findings indicates that care needs to be taken when considering the effect of adaptive behavioural change in predicting the course of epidemics, and as well as the interpretation and development of the public health measures that account for spontaneous behavioural changes.

  11. Phase identification and quantification in a devitrified glass using homo- and heteronuclear solid-state NMR.

    PubMed

    Tricot, Grégory; Delevoye, Laurent; Palavit, Gérard; Montagne, Lionel

    2005-11-14

    A complex mixture resulting from the devitrification of an aluminophosphate glass has been studied for the first time using a combination of homo- and heteronuclear solid-state NMR sequences that offers the advantage of subsequent quantification.

  12. A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo.

    PubMed

    Lordkipanidze, David; Ponce de León, Marcia S; Margvelashvili, Ann; Rak, Yoel; Rightmire, G Philip; Vekua, Abesalom; Zollikofer, Christoph P E

    2013-10-18

    The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. Here we report on a new cranium from Dmanisi (D4500) that, together with its mandible (D2600), represents the world's first completely preserved adult hominid skull from the early Pleistocene. D4500/D2600 combines a small braincase (546 cubic centimeters) with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.

  13. PALEOANTHROPOLOGY. Comment on "Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia".

    PubMed

    Hawks, John; de Ruiter, Darryl J; Berger, Lee R

    2015-06-19

    Villmoare et al. (Reports, 20 March 2015, p. 1352) report on a hominin mandible from the Ledi-Geraru research area, Ethiopia, which they claim to be the earliest known representative of the genus Homo. However, certain measurements and observations for Australopithecus sediba mandibles presented are incorrect or are not included in critical aspects of the study. When correctly used, these data demonstrate that specimen LD 350-1 cannot be unequivocally assigned to the genus Homo.

  14. Design of homo-organic acid producing strains using multi-objective optimization.

    PubMed

    Kim, Tae Yong; Park, Jong Myoung; Kim, Hyun Uk; Cho, Kwang Myung; Lee, Sang Yup

    2015-03-01

    Production of homo-organic acids without byproducts is an important challenge in bioprocess engineering to minimize operation cost for separation processes. In this study, we used multi-objective optimization to design Escherichia coli strains with the goals of maximally producing target organic acids, while maintaining sufficiently high growth rate and minimizing the secretion of undesired byproducts. Homo-productions of acetic, lactic and succinic acids were targeted as examples. Engineered E. coli strains capable of producing homo-acetic and homo-lactic acids could be developed by taking this systems approach for the minimal identification of gene knockout targets. Also, failure to predict effective gene knockout targets for the homo-succinic acid production suggests that the multi-objective optimization is useful in assessing the suitability of a microorganism as a host strain for the production of a homo-organic acid. The systems metabolic engineering-based approach reported here should be applicable to the production of other industrially important organic acids.

  15. Type I phosphatidylinositol 4-phosphate 5-kinase homo- and heterodimerization determines its membrane localization and activity.

    PubMed

    Lacalle, Rosa Ana; de Karam, Juan C; Martínez-Muñoz, Laura; Artetxe, Ibai; Peregil, Rosa M; Sot, Jesús; Rojas, Ana M; Goñi, Félix M; Mellado, Mario; Mañes, Santos

    2015-06-01

    Type I phosphatidylinositol 4-phosphate 5-kinases (PIP5KIs; α, β, and γ) are a family of isoenzymes that produce phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] using phosphatidylinositol 4-phosphate as substrate. Their structural homology with the class II lipid kinases [type II phosphatidylinositol 5-phosphate 4-kinase (PIP4KII)] suggests that PIP5KI dimerizes, although this has not been formally demonstrated. Neither the hypothetical structural dimerization determinants nor the functional consequences of dimerization have been studied. Here, we used Förster resonance energy transfer, coprecipitation, and ELISA to show that PIP5KIβ forms homo- and heterodimers with PIP5KIγ_i2 in vitro and in live human cells. Dimerization appears to be a general phenomenon for PIP5KI isoenzymes because PIP5KIβ/PIP5KIα heterodimers were also detected by mass spectrometry. Dimerization was independent of actin cytoskeleton remodeling and was also observed using purified proteins. Mutagenesis studies of PIP5KIβ located the dimerization motif at the N terminus, in a region homologous to that implicated in PIP4KII dimerization. PIP5KIβ mutants whose dimerization was impaired showed a severe decrease in PI(4,5)P2 production and plasma membrane delocalization, although their association to lipid monolayers was unaltered. Our results identify dimerization as an integral feature of PIP5K proteins and a central determinant of their enzyme activity.

  16. The type specimen (LB1) of Homo floresiensis did not have Laron syndrome.

    PubMed

    Falk, Dean; Hildebolt, Charles; Smith, Kirk; Jungers, William; Larson, Susan; Morwood, Michael; Sutikna, Thomas; Jatmiko; Saptomo, E Wahyu; Prior, Fred

    2009-09-01

    The type specimen (LB1) of Homo floresiensis has been hypothesized to be a pathological human afflicted with Laron Syndrome (LS), a type of primary growth hormone insensitivity (Hershkovitz et al.: Am J Phys Anthropol 134 [2007] 198-208). Comparing measurements, photographs and three-dimensional, computed-tomography reconstructions of LB1 with data and diagnoses from the literature on LS, we critically evaluate numerous skull and postcranial traits that Hershkovitz et al. identified as being shared by LB1 and patients with LS. The statements regarding most of these traits are new to the clinical literature and lack quantitative support. LB1 and patients with LS differ markedly in the size and shape of the cranium; thickness and pneumatization of cranial bones; morphology of the face, mandible, teeth, and chin; form of the shoulder, wrist, and pelvis; and general body proportions including relative foot size. Claims that patients with LS are similar to LB1 in displaying protracted scapulae, short clavicles, low degrees of humeral torsion, flaring ilia, and curved tibiae are not supported by data or corroborating images. Some points of similarity (e.g., femoral neck-shaft angle, femoral bicondylar angle, and estimated stature) can be found in other hominins, and cannot be considered diagnostic. From our review and analysis, we conclude that LB1 did not suffer from LS.

  17. Experimental studies illuminate the cultural transmission of percussive technologies in Homo and Pan.

    PubMed

    Whiten, Andrew

    2015-11-19

    The complexity of Stone Age tool-making is assumed to have relied upon cultural transmission, but direct evidence is lacking. This paper reviews evidence bearing on this question provided through five related empirical perspectives. Controlled experimental studies offer special power in identifying and dissecting social learning into its diverse component forms, such as imitation and emulation. The first approach focuses on experimental studies that have discriminated social learning processes in nut-cracking by chimpanzees. Second come experiments that have identified and dissected the processes of cultural transmission involved in a variety of other force-based forms of chimpanzee tool use. A third perspective is provided by field studies that have revealed a range of forms of forceful, targeted tool use by chimpanzees, that set percussion in its broader cognitive context. Fourth are experimental studies of the development of flint knapping to make functional sharp flakes by bonobos, implicating and defining the social learning and innovation involved. Finally, new and substantial experiments compare what different social learning processes, from observational learning to teaching, afford good quality human flake and biface manufacture. Together these complementary approaches begin to delineate the social learning processes necessary to percussive technologies within the Pan-Homo clade.

  18. New interpretation of the Gran Dolina-TD6 bearing Homo antecessor deposits through sedimentological analysis

    PubMed Central

    Campaña, I.; Pérez-González, A.; Benito-Calvo, A.; Rosell, J.; Blasco, R.; de Castro, J. M. Bermúdez; Carbonell, E.; Arsuaga, J. L.

    2016-01-01

    Gran Dolina is a cavity infilled by at least 25 m of Pleistocene sediments. This sequence contains the TD6 stratigraphic unit, whose records include around 170 hominin bones that have allowed the definition of a new species, Homo antecessor. This fossil accumulation was studied as a single assemblage and interpreted as a succession of several human home bases. We propose a complete stratigraphic context and sedimentological interpretation for TD6, analyzing the relationships between the sedimentary facies, the clasts and archaeo-palaeontological remains. The TD6 unit has been divided into three sub-units and 13 layers. Nine sedimentary facies have been defined. Hominin remains appear related to three different sedimentary facies: debris flow facies, channel facies and floodplain facies. They show three kinds of distribution: first a group of scattered fossils, then a group with layers of fossils in fluvial facies, and third a group with a layer of fossils in mixed fluvial and gravity flow facies. The results of this work suggest that some of these hominin remains accumulated in the cave by geological processes, coming from the adjacent slope above the cave or the cave entry, as the palaeogeography and sedimentary characteristics of these allochthonous facies suggest. PMID:27713562

  19. New interpretation of the Gran Dolina-TD6 bearing Homo antecessor deposits through sedimentological analysis

    NASA Astrophysics Data System (ADS)

    Campaña, I.; Pérez-González, A.; Benito-Calvo, A.; Rosell, J.; Blasco, R.; de Castro, J. M. Bermúdez; Carbonell, E.; Arsuaga, J. L.

    2016-10-01

    Gran Dolina is a cavity infilled by at least 25 m of Pleistocene sediments. This sequence contains the TD6 stratigraphic unit, whose records include around 170 hominin bones that have allowed the definition of a new species, Homo antecessor. This fossil accumulation was studied as a single assemblage and interpreted as a succession of several human home bases. We propose a complete stratigraphic context and sedimentological interpretation for TD6, analyzing the relationships between the sedimentary facies, the clasts and archaeo-palaeontological remains. The TD6 unit has been divided into three sub-units and 13 layers. Nine sedimentary facies have been defined. Hominin remains appear related to three different sedimentary facies: debris flow facies, channel facies and floodplain facies. They show three kinds of distribution: first a group of scattered fossils, then a group with layers of fossils in fluvial facies, and third a group with a layer of fossils in mixed fluvial and gravity flow facies. The results of this work suggest that some of these hominin remains accumulated in the cave by geological processes, coming from the adjacent slope above the cave or the cave entry, as the palaeogeography and sedimentary characteristics of these allochthonous facies suggest.

  20. Geometric morphometrics and paleoneurology: brain shape evolution in the genus Homo.

    PubMed

    Bruner, Emiliano

    2004-11-01

    Paleoneurology concerns the study and analysis of fossil endocasts. Together with cranial capacity and discrete anatomical features, shape can be analysed to consider the spatial relationships between structures and to investigate the endocranial structural system. A sample of endocasts from fossil specimens of the genus Homo has been analysed using traditional metrics and 2D geometric morphometrics based on lateral projections of endocranial shape. The maximum and frontal widths show a size-related pattern of variation shared by all the taxa considered. Furthermore, as cranial capacity increases in the non-modern morphotypes there is a general endocranial vertical stretching (mainly centred at the anterior ascending circumvolution) with flattening and relative shortening of the parietal areas. This pattern could have involved some structural stress between brain development and vault bones at the parietal midsagittal profile in the heavy encephalised Neandertals. In contrast, modern humans show a species-specific neomorphic hypertrophy of the parietal volumes, leading to a dorsal growth and ventral flexion (convolution) and consequent globularity of the whole structure. Brain tensors such as the falx cerebri have been hypothesised to represent one of the main physical constraints on morphogenetic trajectories, with additional influences from cranial base structures. The neurofunctional inferences discussed here stress the role of the parietal areas in the visuo-spatial coordination and integration, which can be involved in higher cerebral functions and related to conceptual thinking.

  1. Experimental studies illuminate the cultural transmission of percussive technologies in Homo and Pan

    PubMed Central

    Whiten, Andrew

    2015-01-01

    The complexity of Stone Age tool-making is assumed to have relied upon cultural transmission, but direct evidence is lacking. This paper reviews evidence bearing on this question provided through five related empirical perspectives. Controlled experimental studies offer special power in identifying and dissecting social learning into its diverse component forms, such as imitation and emulation. The first approach focuses on experimental studies that have discriminated social learning processes in nut-cracking by chimpanzees. Second come experiments that have identified and dissected the processes of cultural transmission involved in a variety of other force-based forms of chimpanzee tool use. A third perspective is provided by field studies that have revealed a range of forms of forceful, targeted tool use by chimpanzees, that set percussion in its broader cognitive context. Fourth are experimental studies of the development of flint knapping to make functional sharp flakes by bonobos, implicating and defining the social learning and innovation involved. Finally, new and substantial experiments compare what different social learning processes, from observational learning to teaching, afford good quality human flake and biface manufacture. Together these complementary approaches begin to delineate the social learning processes necessary to percussive technologies within the Pan–Homo clade. PMID:26483537

  2. Synthesis of novel homo-N-nucleoside analogs composed of a homo-1,4-dioxane sugar analog and substituted 1,3,5-triazine base equivalents.

    PubMed

    Yu, Qiang; Schwidom, Dirk; Exner, Alexander; Carlsen, Per

    2008-12-10

    Enantioselective syntheses from dimethyl tartrate of 1,3,5-triazine homo-N-nucleoside analogs, containing a 1,4-dioxane moiety replacing the sugar unit in natural nucleosides, were accomplished. The triazine heterocycle in the nucleoside analogs was further substituted with combinations of NH(2), OH and Cl in the 2,4-triazine positions.

  3. Climate, Environment and Early Human Innovation: Stable Isotope and Faunal Proxy Evidence from Archaeological Sites (98-59ka) in the Southern Cape, South Africa.

    PubMed

    Roberts, Patrick; Henshilwood, Christopher S; van Niekerk, Karen L; Keene, Petro; Gledhill, Andrew; Reynard, Jerome; Badenhorst, Shaw; Lee-Thorp, Julia

    2016-01-01

    The Middle Stone Age (MSA) of southern Africa, and in particular its Still Bay and Howiesons Poort lithic traditions, represents a period of dramatic subsistence, cultural, and technological innovation by our species, Homo sapiens. Climate change has frequently been postulated as a primary driver of the appearance of these innovative behaviours, with researchers invoking either climate instability as a reason for the development of buffering mechanisms, or environmentally stable refugia as providing a stable setting for experimentation. Testing these alternative models has proved intractable, however, as existing regional palaeoclimatic and palaeoenvironmental records remain spatially, stratigraphically, and chronologically disconnected from the archaeological record. Here we report high-resolution records of environmental shifts based on stable carbon and oxygen isotopes in ostrich eggshell (OES) fragments, faunal remains, and shellfish assemblages excavated from two key MSA archaeological sequences, Blombos Cave and Klipdrift Shelter. We compare these records with archaeological material remains in the same strata. The results from both sites, spanning the periods 98-73 ka and 72-59 ka, respectively, show significant changes in vegetation, aridity, rainfall seasonality, and sea temperature in the vicinity of the sites during periods of human occupation. While these changes clearly influenced human subsistence strategies, we find that the remarkable cultural and technological innovations seen in the sites cannot be linked directly to climate shifts. Our results demonstrate the need for scale-appropriate, on-site testing of behavioural-environmental links, rather than broader, regional comparisons.

  4. Climate, Environment and Early Human Innovation: Stable Isotope and Faunal Proxy Evidence from Archaeological Sites (98-59ka) in the Southern Cape, South Africa

    PubMed Central

    Keene, Petro; Gledhill, Andrew; Reynard, Jerome; Badenhorst, Shaw

    2016-01-01

    The Middle Stone Age (MSA) of southern Africa, and in particular its Still Bay and Howiesons Poort lithic traditions, represents a period of dramatic subsistence, cultural, and technological innovation by our species, Homo sapiens. Climate change has frequently been postulated as a primary driver of the appearance of these innovative behaviours, with researchers invoking either climate instability as a reason for the development of buffering mechanisms, or environmentally stable refugia as providing a stable setting for experimentation. Testing these alternative models has proved intractable, however, as existing regional palaeoclimatic and palaeoenvironmental records remain spatially, stratigraphically, and chronologically disconnected from the archaeological record. Here we report high-resolution records of environmental shifts based on stable carbon and oxygen isotopes in ostrich eggshell (OES) fragments, faunal remains, and shellfish assemblages excavated from two key MSA archaeological sequences, Blombos Cave and Klipdrift Shelter. We compare these records with archaeological material remains in the same strata. The results from both sites, spanning the periods 98–73 ka and 72–59 ka, respectively, show significant changes in vegetation, aridity, rainfall seasonality, and sea temperature in the vicinity of the sites during periods of human occupation. While these changes clearly influenced human subsistence strategies, we find that the remarkable cultural and technological innovations seen in the sites cannot be linked directly to climate shifts. Our results demonstrate the need for scale-appropriate, on-site testing of behavioural-environmental links, rather than broader, regional comparisons. PMID:27383620

  5. Effects of loading on the biomechanical [correction of biochemical] behavior of molars of Homo, Pan, and Pongo.

    PubMed

    Macho, G A; Spears, I R

    1999-06-01

    In a previous study, we found systematic differences in the biomechanical behavior of modern human molars using finite element stress analyses (FESA), which led us to propose that molars are adapted to differently-directed loads depending on their position within the mouth (Spears and Macho [1998] Am. J. Phys. Anthropol. 106:467-482). While the FESA results thus derived have not been verified experimentally, such an interpretation seemed reasonable. To refine the model previously presented, this study assessed the effects of 1) food particle size on the biomechanical behavior of molars, and those of 2) differences in morphology, particularly enamel thickness, on stress distribution. In order to appraise the evolutionary significance of the findings, the FESA results for modern humans were subsequently compared with those obtained for molars of one individual of Pan and Pongo, respectively. Bearing in mind limitations imposed by the FESA models created and analyzed in this study, constant cleavage-type loads and cuspal tip loads at different directions were employed on all teeth: this facilitated comparisons of patterns of stress distribution across molars and species. In Pan and Homo, cleavage-type loads exerted by big food particles tended to be better dissipated anteriorly than posteriorly, although trends in Pongo were less clear-cut. Furthermore, similar to modern humans, the buccal cusps of mandibular molars appeared to be able to dissipate the loads associated with a pestle-type action, while maxillary molars were better designed to dissipate the loads which would result if they acted as mortars against which the food is crushed/ground. While increases in enamel thickness lowered the overall stress values in teeth only slightly, changes in outer morphology could have a more profound effect on these stress levels. Overall, Pan appeared to be most generalized, while Homo and Pongo showed a number of unique specializations, which are in accordance with what is

  6. The Mobility of the Human Face: More than Just the Musculature.

    PubMed

    Burrows, Anne M; Rogers-Vizena, Carolyn R; Li, Ly; Mendelson, Bryan

    2016-12-01

    The human face has the greatest mobility and facial display repertoire among all primates. However, the variables that account for this are not clear. Humans and other anthropoids have remarkably similar mimetic musculature. This suggests that differences among the mimetic muscles alone may not account for the increased mobility and facial display repertoire seen in humans. Furthermore, anthropoids themselves outpace prosimians in these categories: humans > other anthropoids > prosimians. This study was undertaken to clarify the morphological underpinnings of the increased mobility and display repertoire of the human face by investigating the SMAS (the superficial musculo-aponeurotic system), a connective tissue layer enclosing the mimetic musculature located between the skin and deep fascia/periosteum. Full-thickness samples from the face near the zygoma region from the anthropoids Homo sapiens (humans, N = 3), Pan troglodytes (chimpanzees, N = 3), Hylobates muelleri (gibbons, N = 1), and Macaca mulatta (rhesus macaque, N = 3) and the prosimians Tarsius bancanus (tarsiers, N = 1), and Otolemur crassicaudatus (galagos, N = 2) were used. All samples were processed for paraffin-based histology and stained sections were viewed under light microscopy to determine if a SMAS layer could be identified. Results indicate that a SMAS layer was present in all anthropoid species but neither of the prosimian species. This connective tissue layer may be a factor in the increased facial mobility and facial display repertoire present in these species. Anat Rec, 299:1779-1788, 2016. © 2016 Wiley Periodicals, Inc.

  7. Olfactory Sensitivity for Six Predator Odorants in CD-1 Mice, Human Subjects, and Spider Monkeys

    PubMed Central

    Sarrafchi, Amir; Odhammer, Anna M. E.; Hernandez Salazar, Laura Teresa; Laska, Matthias

    2013-01-01

    Using a conditioning paradigm, we assessed the olfactory sensitivity of six CD-1 mice (Mus musculus) for six sulfur-containing odorants known to be components of the odors of natural predators of the mouse. With all six odorants, the mice discriminated concentrations <0.1 ppm (parts per million) from the solvent, and with five of the six odorants the best-scoring animals were even able to detect concentrations <1 ppt (parts per trillion). Four female spider monkeys (Ateles geoffroyi) and twelve human subjects (Homo sapiens) tested in parallel were found to detect the same six odorants at concentrations <0.01 ppm, and with four of the six odorants the best-scoring animals and subjects even detected concentrations <10 ppt. With all three species, the threshold values obtained here are generally lower than (or in the lower range of) those reported for other chemical classes tested previously, suggesting that sulfur-containing odorants may play a special role in olfaction. Across-species comparisons showed that the mice were significantly more sensitive than the human subjects and the spider monkeys with four of the six predator odorants. However, the human subjects were significantly more sensitive than the mice with the remaining two odorants. Human subjects and spider monkeys significantly differed in their sensitivity with only two of the six odorants. These comparisons lend further support to the notion that the number of functional olfactory receptor genes or the relative or absolute size of the olfactory bulbs are poor predictors of a species’ olfactory sensitivity. Analysis of odor structure–activity relationships showed that in both mice and human subjects the type of alkyl rest attached to a thietane and the type of oxygen moiety attached to a thiol significantly affected olfactory sensitivity. PMID:24278296

  8. The relationship between homosexuality, internalized homo-negativity, and mental health in men who have sex with men.

    PubMed

    Rosser, B R Simon; Bockting, Walter O; Ross, Michael W; Miner, Michael H; Coleman, Eli

    2008-01-01

    Whether homosexuality or internalized homo-negativity is the critical variable affecting the mental health of men who have sex with men has long been debated. As part of a larger study, 422 Midwestern homosexual men completed questionnaires examining degree of homosexuality, internalized homo-negativity, and depression. Logistic regression modeling identified internalized homo-negativity, but not degree of homosexuality, as significantly associated with greater adjustment depression (OR = 1.5), major depression (OR = 2.6), dysthymia (OR = 1.5), and likelihood of being in therapy (OR = 1.4). Internalized homo-negativity was also negatively associated with overall sexual health, psychosexual maturation, comfort with sexual orientation, "outness," and peer socialization. Internalized homo-negativity, not homosexuality, appears associated with negative health outcomes. Providers should promote sexual health and avoid interventions that reinforce internalized homo-negativity.

  9. "Homo Loquens": Language in the Context of Cosmic Education.

    ERIC Educational Resources Information Center

    Stephenson, Margaret E.

    2001-01-01

    Discusses language in the context of human development and civilization, examining a limitless field of studies and observations including the absorbent mind, the acquisition of language and grammatical structure, the linguistic capacity for abstract thought, the power of language and world community, the role of language and human uniqueness, and…

  10. Hydrogen consumption in microbial electrochemical systems (MXCs): the role of homo-acetogenic bacteria.

    PubMed

    Parameswaran, Prathap; Torres, César I; Lee, Hyung-Sool; Rittmann, Bruce E; Krajmalnik-Brown, Rosa

    2011-01-01

    Homo-acetogens in the anode of a microbial electrolysis cell (MEC) fed with H(2) as sole electron donor allowed current densities similar to acetate-fed biofilm anodes (∼10 A/m(2)). Evidence for homo-acetogens included accumulation of acetate at high concentrations (up to 18 mM) in the anode compartment; detection of formate, a known intermediate during reductive acetogenesis by the acetyl-CoA pathway; and detection of formyl tetrahydrofolate synthetase (FTHFS) genes by quantitative real-time PCR. Current production and acetate accumulation increased in parallel in batch and continuous mode, while both values decreased simultaneously at short hydraulic retention times (1h) in the anode compartment, which limited suspended homo-acetogens. Acetate produced by homo-acetogens accounted for about 88% of the current density of 10A/m(2), but the current density was sustained at 4A/m(2) at short hydraulic retention time because of a robust partnership of homo-acetogens and anode respiring bacteria (ARB) in the biofilm anode.

  11. The Importance of Human Ecology at the Threshold of the Next Millennium: How Can Population Growth Be Stopped?

    NASA Astrophysics Data System (ADS)

    Nentwig, W.

    Ecology is defined as the set of complex interactions between the biotic and abiotic environments. Human ecology concerns principally the population ecology "only" of Homo sapiens, but it also includes all aspects of global ecology because humans are the most important species. Human demography is characterized by a recent decline in mortality and fertility rates. These demographic transitions have largely been completed in industrialized countries, but not in the 140 developing countries. Approximately 100 countries are following the same demographic pattern as industrialized countries, however with a time delay of several generations. China has effectively reduced its population increase by means that would be unacceptable in Western democracies. Some 44 developing countries still show increasing population growth and no detectable demographic transition in birth rate. Thus one part of the world shows limited (and, in the long run, shrinking) population growth, and another continues with a strong increase. All populations are limited in their development by their sustainability by their environment, for example, food and energy resources, and the extent of pollution which the use of these resources produces. It is argued that in the case of human population the limits of sustainability have already been reached with the 6 billion humans alive today, since at least 20% of these suffer from hunger, natural resources are overexploited, and biodiversity is threatened. In the coming 200years it is more likely that the total population will substantially oscillate rather than approach the predicted 12 billion. The most important goal of human ecology should therefore be to slow population growth as far as possible.

  12. Out of Africa: the importance of rivers as human migration corridors

    NASA Astrophysics Data System (ADS)

    Ramirez, J. A.; Coulthard, T. J.; Rogerson, M.; Barton, N.; Bruecher, T.

    2013-12-01

    The route and timing of Homo sapiens exiting Africa remains uncertain. Corridors leading out of Africa through the Sahara, the Nile Valley, and the Red Sea coast have been proposed as migration routes for anatomically modern humans 80,000-130,000 years ago. During this time climate conditions in the Sahara were wetter than present day, and monsoon rainfall fed rivers that flowed across the desert landscape. The location and timing of these rivers may have supported human migration northward from central Africa to the Mediterranean coast, and onwards to Europe or Asia. Here, we use palaeoclimate rainfall and a hydrological model to spatially simulate and quantitatively test the existence of three major rivers crossing the Sahara from south to north during the time of human migration. We provide evidence that, given realistic underlying climatology, the well-known Sahabi and Kufrah rivers very likely flowed across modern day Libya and reached the coast. More unexpectedly an additional river crossed the core of the Sahara through Algeria (Irharhar river) and flowed into the Chotts basin. The Irharhar river is unique, because it links locations in central Africa experiencing monsoon climates with temperate coastal Mediterranean environments where food and resources were likely abundant. From an ecological perspective, this little-known corridor may prove to be the most parsimonious migration route. Support for the Irharar as a viable migration corridor is provided by its geographic proximity to middle Stone Age archaeological artefacts found in North Africa. Our new, highly novel approach provides the first quantitative analysis of the likelihood that rivers occurred during the critical period of human migration out of Africa. Simulated probability of surface water in North Africa during the last interglacial and the location of tools and ornaments from the Middle Stone Age.

  13. Stable isotope paleoecology of Late Pleistocene Middle Stone Age humans from the Lake Victoria basin, Kenya.

    PubMed

    Garrett, Nicole D; Fox, David L; McNulty, Kieran P; Faith, J Tyler; Peppe, Daniel J; Van Plantinga, Alex; Tryon, Christian A

    2015-05-01

    Paleoanthropologists have long argued that environmental pressures played a key role in human evolution. However, our understanding of how these pressures mediated the behavioral and biological diversity of early modern humans and their migration patterns within and out of Africa is limited by a lack of archaeological evidence associated with detailed paleoenvironmental data. Here, we present the first stable isotopic data from paleosols and fauna associated with Middle Stone Age (MSA) sites in East Africa. Late Pleistocene (∼100-45 ka, thousands of years ago) sediments on Rusinga and Mfangano Islands in eastern Lake Victoria (Kenya) preserve a taxonomically diverse, non-analog faunal community associated with MSA artifacts. We analyzed the stable carbon and oxygen isotope composition of paleosol carbonate and organic matter and fossil mammalian tooth enamel, including the first analyses for several extinct bovids such as Rusingoryx atopocranion, Damaliscus hypsodon, and an unnamed impala species. Both paleosol carbonate and organic matter data suggest that local habitats associated with human activities were primarily riverine woodland ecosystems. However, mammalian tooth enamel data indicate that most large-bodied mammals consumed a predominantly C4 diet, suggesting an extensive C4 grassland surrounding these riverine woodlands in the region at the time. These data are consistent with other lines of paleoenvironmental evidence that imply a substantially reduced Lake Victoria at this time, and demonstrate that C4 grasslands were significantly expanded into equatorial Africa compared with their present distribution, which could have facilitated dispersal of human populations and other biotic communities. Our results indicate that early populations of Homo sapiens from the Lake Victoria region exploited locally wooded and well-watered habitats within a larger grassland ecosystem.

  14. Nicotinamidase/pyrazinamidase of Mycobacterium tuberculosis forms homo-dimers stabilized by disulfide bonds

    PubMed Central

    Rueda, Daniel; Sheen, Patricia; Gilman, Robert H.; Bueno, Carlos; Santos, Marco; Pando-Robles, Victoria; Batista, Cesar V.; Zimic, Mirko

    2014-01-01

    Recombinant wild-pyrazinamidase from H37Rv M. tuberculosis was analyzed by gel electrophoresis under differential reducing conditions to evaluate its quaternary structure. PZAse was fractionated by size exclusion chromatography under non-reducing conditions. PZAse activity was measured and mass spectrometry analysis was performed to determine the identity of proteins by de novo sequencing and to determine the presence of disulfide bonds. This study confirmed that M. tuberculosis wild type PZAse was able to form homo-dimers in vitro. Homo-dimers showed a slightly lower specific PZAse activity compared to monomeric PZAse. PZAse dimers were dissociated into monomers in response to reducing conditions. Mass spectrometry analysis confirmed the existence of disulfide bonds (C72-C138 and C138-C138) stabilizing the quaternary structure of the PZAse homo-dimer. PMID:25199451

  15. Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

    NASA Astrophysics Data System (ADS)

    McLeod, John A.; Pitman, Amy L.; Kurmaev, Ernst Z.; Finkelstein, Larisa D.; Zhidkov, Ivan S.; Savva, Achilleas; Moewes, Alexander

    2015-12-01

    The electronic structure of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando.

  16. Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton.

    PubMed

    Schiess, Regula; Boeni, Thomas; Rühli, Frank; Haeusler, Martin

    2014-02-01

    Owing to its completeness, the 1.5 million year old Nariokotome boy skeleton KNM-WT 15000 is central for understanding the skeletal biology of Homo erectus. Nevertheless, since the reported asymmetries and distortions of Nariokotome boy's axial skeleton suggest adolescent idiopathic scoliosis, possibly associated with congenital skeletal dysplasia, it is questionable whether it still can be used as a reference for H. erectus. Recently, however, the presence of skeletal dysplasia has been refuted. Here, we present a morphological and morphometric reanalysis of the assertion of idiopathic scoliosis. We demonstrate that unarticulated vertebral columns of non-scoliotic and scoliotic individuals can be distinguished based on the lateral deviation of the spinous process, lateral and sagittal wedging, vertebral body torsion, pedicle thickness asymmetry, and asymmetry of superior and inferior articular facet areas. A principal component analysis of the overall asymmetry of all seven vertebral shape variables groups KNM-WT 15000 within non-scoliotic modern humans. There is, however, an anomaly of vertebrae T1-T2 that is compatible with a short left convex curve at the uppermost thoracic region, possibly due to injury or local growth dysbalance. Asymmetries of the facet joints L3-L5 suggest a local right convex curve in the lower lumbar region that probably resulted from juvenile traumatic disc herniation. This pattern is incompatible with adolescent idiopathic scoliosis or other types of scoliosis, including congenital, neuromuscular or syndromic scoliosis. It is, however, consistent with a recent reanalysis of the rib cage that did not reveal any asymmetry. Except for these possibly trauma-related anomalies, the Nariokotome boy fossil therefore seems to belong to a normal H. erectus youth without evidence for adolescent idiopathic scoliosis or other severe pathologies of the axial skeleton.

  17. Homo erectus and Middle Pleistocene hominins: brain size, skull form, and species recognition.

    PubMed

    Rightmire, G Philip

    2013-09-01

    Hominins that differ from Homo erectus, the Neanderthals, and recent humans are known from Middle Pleistocene localities across the Old World. The taxonomic status of these populations has been clouded by controversy. Perhaps the most critical problem has been an incomplete understanding of variation in skull form. Here, both H. erectus and later mid-Pleistocene hominins are the focus of an investigation aimed at clarifying the relationships among brain volume, basicranial dimensions, neurocranial shape, and certain facial characters. Brain size in H. erectus averages about 950 cm(3), while in a series of Middle Pleistocene crania from Africa and Europe, volume is about 1230 cm(3). If encephalization is the primary mechanism operating in the mid-Pleistocene, then diverse aspects of cranial form cannot all be treated as independent variables. Correlation is utilized to examine the associations among measurements for more than 30 H. erectus crania that are reasonably well preserved. A similar approach is used with the Middle Pleistocene sample. Patterns of covariation are compared in order to assess integration. Next, factor analysis is applied to the H. erectus specimens in an attempt to identify modules, tightly integrated traits that can evolve independently. Studies of the variation within H. erectus are followed by direct comparisons with the Middle Pleistocene population. Discriminant functions facilitate the description of intergroup differences. Traits that vary independently from brain volume include anterior frontal broadening, lateral expansion of the parietal vault, elevation of the lambda-inion chord, and rounding of the sagittal contour of the occipital. This finding helps to resolve the problem of species recognition. Neurocranial proportions as well as characters from the cranial base and face can be incorporated into a differential diagnosis for the mid-Pleistocene sample. Evidence presented here supports arguments for speciation in the Middle

  18. New blue emissive conjugated small molecules with low lying HOMO energy levels for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Trupthi Devaiah, C.; Hemavathi, B.; Ahipa, T. N.

    2017-03-01

    Versatile conjugated small molecules bearing cyanopyridone core (CP1-5), composed of various donor/acceptor moieties at position - 4 and - 6 have been designed, developed and characterized. Their solvatochromic studies were conducted and analyzed using Lippert-Mataga, Kamlet-Taft and Catalan solvent scales and interesting results were obtained. The polarizability/dipolarity of the solvent greatly influenced the spectra. The electrochemical studies were carried out using cyclic voltammetry to calculate the HOMO-LUMO energy levels. The study revealed that the synthesized conjugated small molecules possess low lying HOMO energy levels which can be exploited for application in various fields of optoelectronics.

  19. Late Pliocene Homo and hominid land use from Western Olduvai Gorge, Tanzania.

    PubMed

    Blumenschine, Robert J; Peters, Charles R; Masao, Fidelis T; Clarke, Ronald J; Deino, Alan L; Hay, Richard L; Swisher, Carl C; Stanistreet, Ian G; Ashley, Gail M; McHenry, Lindsay J; Sikes, Nancy E; Van Der Merwe, Nikolaas J; Tactikos, Joanne C; Cushing, Amy E; Deocampo, Daniel M; Njau, Jackson K; Ebert, James I

    2003-02-21

    Excavation in the previously little-explored western portion of Olduvai Gorge indicates that hominid land use of the eastern paleobasin extended at least episodically to the west. Finds included a dentally complete Homo maxilla (OH 65) with lower face, Oldowan stone artifacts, and butchery-marked bones dated to be between 1.84 and 1.79 million years old. The hominid shows strong affinities to the KNM ER 1470 cranium from Kenya (Homo rudolfensis), a morphotype previously unrecognized at Olduvai. ER 1470 and OH 65 can be accommodated in the H. habilis holotype, casting doubt on H. rudolfensis as a biologically valid taxon.

  20. HDJC9, a novel human type C DnaJ/HSP40 member interacts with and cochaperones HSP70 through the J domain

    SciTech Connect

    Han Chaofeng; Chen Taoyong; Li Nan; Yang Mingjin; Wan Tao; Cao Xuetao; E-mail: caoxt@public3.sta.net.cn

    2007-02-09

    HSP40s are a subfamily of heat shock proteins (HSPs) and play important roles in regulation of cell proliferation, survival and apoptosis by serving as chaperones for HSP70s. Up to date hundreds of HSP40 proteins derived from various species ranging from Escherichia coli to homo sapiens have been identified. Here we report the cloning and characterization of a novel human type C DnaJ homologue, HDJC9, containing a typical N-terminal J domain. HDJC9 is upregulated at both mRNA and protein levels upon various stress and mitogenic stimulations. HDJC9 is mainly localized in cell nuclei under normal culture conditions while it is transported into cytoplasm and plasma membrane upon heat shock stress through a non-classical and lipid-dependent pathway. HDJC9 can interact with HSP70s and activate the ATPase activity of HSP70s, both of which are dependent on the J domain. Our data suggest that HDJC9 is a novel cochaperone for HSP70s.

  1. 3D structure prediction of human β1-adrenergic receptor via threading-based homology modeling for implications in structure-based drug designing.

    PubMed

    Ul-Haq, Zaheer; Saeed, Maria; Halim, Sobia Ahsan; Khan, Waqasuddin

    2015-01-01

    Dilated cardiomyopathy is a disease of left ventricular dysfunction accompanied by impairment of the β1-adrenergic receptor (β1-AR) signal cascade. The disturbed β1-AR function may be based on an elevated sympathetic tone observed in patients with heart failure. Prolonged adrenergic stimulation may induce metabolic and electrophysiological disturbances in the myocardium, resulting in tachyarrhythmia that leads to the development of heart failure in human and sudden death. Hence, β1-AR is considered as a promising drug target but attempts to develop effective and specific drug against this tempting pharmaceutical target is slowed down due to the lack of 3D structure of Homo sapiens β1-AR (hsβADR1). This study encompasses elucidation of 3D structural and physicochemical properties of hsβADR1 via threading-based homology modeling. Furthermore, the docking performance of several docking programs including Surflex-Dock, FRED, and GOLD were validated by re-docking and cross-docking experiments. GOLD and Surflex-Dock performed best in re-docking and cross docking experiments, respectively. Consequently, Surflex-Dock was used to predict the binding modes of four hsβADR1 agonists. This study provides clear understanding of hsβADR1 structure and its binding mechanism, thus help in providing the remedial solutions of cardiovascular, effective treatment of asthma and other diseases caused by malfunctioning of the target protein.

  2. The bone morphogenetic protein antagonist gremlin 1 is overexpressed in human cancers and interacts with YWHAH protein

    PubMed Central

    Namkoong, Hong; Shin, Seung Min; Kim, Hyun Kee; Ha, Seon-Ah; Cho, Goang Won; Hur, Soo Young; Kim, Tae Eung; Kim, Jin Woo

    2006-01-01

    Background Basic studies of oncogenesis have demonstrated that either the elevated production of particular oncogene proteins or the occurrence of qualitative abnormalities in oncogenes can contribute to neoplastic cellular transformation. The purpose of our study was to identify an unique gene that shows cancer-associated expression, and characterizes its function related to human carcinogenesis. Methods We used the differential display (DD) RT-PCR method using normal cervical, cervical cancer, metastatic cervical tissues, and cervical cancer cell lines to identify genes overexpressed in cervical cancers and identified gremlin 1 which was overexpressed in cervical cancers. We determined expression levels of gremlin 1 using Northern blot analysis and immunohistochemical study in various types of human normal and cancer tissues. To understand the tumorigenesis pathway of identified gremlin 1 protein, we performed a yeast two-hybrid screen, GST pull down assay, and immunoprecipitation to identify gremlin 1 interacting proteins. Results DDRT-PCR analysis revealed that gremlin 1 was overexpressed in uterine cervical cancer. We also identified a human gremlin 1 that was overexpressed in various human tumors including carcinomas of the lung, ovary, kidney, breast, colon, pancreas, and sarcoma. PIG-2-transfected HEK 293 cells exhibited growth stimulation and increased telomerase activity. Gremlin 1 interacted with homo sapiens tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, eta polypeptide (14-3-3 eta; YWHAH). YWHAH protein binding site for gremlin 1 was located between residues 61–80 and gremlin 1 binding site for YWHAH was found to be located between residues 1 to 67. Conclusion Gremlin 1 may play an oncogenic role especially in carcinomas of the uterine cervix, lung, ovary, kidney, breast, colon, pancreas, and sarcoma. Over-expressed gremlin 1 functions by interaction with YWHAH. Therefore, Gremlin 1 and its binding protein YWHAH could be good

  3. Ecce Homo: Science and Society Need Anthropological Collections.

    PubMed

    Sholts, Sabrina B; Bell, Joshua A; Rick, Torben C

    2016-08-01

    Scientific collections are crucial to understanding the biological and cultural diversity of the Earth. Anthropological collections document the human experience and the interactions between people, ecosystems, and organisms. Unfortunately, anthropological collections are often poorly known by the public and face a variety of threats to their permanent care and conservation.

  4. An Enlarged Parietal Foramen in the Late Archaic Xujiayao 11 Neurocranium from Northern China, and Rare Anomalies among Pleistocene Homo

    PubMed Central

    Xing, Song

    2013-01-01

    We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual’s age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans. PMID:23527224

  5. Structure determination of symmetric homo-oligomers by a complete search of symmetry configuration space, using NMR restraints and van der Waals packing.

    PubMed

    Potluri, Shobha; Yan, Anthony K; Chou, James J; Donald, Bruce R; Bailey-Kellogg, Chris

    2006-10-01

    Structural studies of symmetric homo-oligomers provide mechanistic insights into their roles in essential biological processes, including cell signaling and cellular regulation. This paper presents a novel algorithm for homo-oligomeric structure determination, given the subunit structure, that is both complete, in that it evaluates all possible conformations, and data-driven, in that it evaluates conformations separately for consistency with experimental data and for quality of packing. Completeness ensures that the algorithm does not miss the native conformation, and being data-driven enables it to assess the structural precision possible from data alone. Our algorithm performs a branch-and-bound search in the symmetry configuration space, the space of symmetry axis parameters (positions and orientations) defining all possible C(n) homo-oligomeric complexes for a given subunit structure. It eliminates those symmetry axes inconsistent with intersubunit nuclear Overhauser effect (NOE) distance restraints and then identifies conformations representing any consistent, well-packed structure to within a user-defined similarity level. For the human phospholamban pentamer in dodecylphosphocholine micelles, using the structure of one subunit determined from a subset of the experimental NMR data, our algorithm identifies a diverse set of complex structures consistent with the nine intersubunit NOE restraints. The distribution of determined structures provides an objective characterization of structural uncertainty: backbone RMSD to the previously determined structure ranges from 1.07 to 8.85 A, and variance in backbone atomic coordinates is an average of 12.32 A(2). Incorporating vdW packing reduces structural diversity to a maximum backbone RMSD of 6.24 A and an average backbone variance of 6.80 A(2). By comparing data consistency and packing quality under different assumptions of oligomeric number, our algorithm identifies the pentamer as the most likely oligomeric state

  6. Differential endocytic routing of homo- and hetero-dimeric ErbB tyrosine kinases confers signaling superiority to receptor heterodimers.

    PubMed Central

    Lenferink, A E; Pinkas-Kramarski, R; van de Poll, M L; van Vugt, M J; Klapper, L N; Tzahar, E; Waterman, H; Sela, M; van Zoelen, E J; Yarden, Y

    1998-01-01

    Both homo- and hetero-dimers of ErbB receptor tyrosine kinases mediate signaling by a large group of epidermal growth factor (EGF)-like ligands. However, some ligands are more potent than others, although they bind to the same direct receptor. In addition, signaling by receptor heterodimers is superior to homodimers. We addressed the mechanism underlying these two features of signal tuning by using three ligands: EGF; transforming growth factor alpha (TGFalpha); and their chimera, denoted E4T, which act on cells singly expressing ErbB-1 as a weak, a strong, and a very strong agonist, respectively. Co-expression of ErbB-2, a developmentally important co-receptor whose expression is frequently elevated in human cancers, specifically potentiated EGF signaling to the level achieved by TGFalpha, an effect that was partially mimicked by ErbB-3. Analysis of the mechanism underlying this trans-potentiation implied that EGF-driven homodimers of ErbB-1 are destined for intracellular degradation, whereas the corresponding heterodimers with ErbB-2 or with ErbB-3, dissociate in the early endosome. As a consequence, in the presence of either co-receptor, ErbB-1 is recycled to the cell surface and its signaling is enhanced. This latter route is followed by TGFalpha-driven homodimers of ErbB-1, and also by E4T-bound receptors, whose signaling is further enhanced by repeated cycles of binding and dissociation from the receptors. We conclude that alternative endocytic routes of homo- and hetero-dimeric receptor complexes may contribute to tuning and diversification of signal transduction. In addition, the ability of ErbB-2 to shunt ligand-activated receptors to recycling may explain, in part, its oncogenic potential. PMID:9628875

  7. The (homo)sexual temptation in Milton's Paradise regained.

    PubMed

    Summers, C J

    1997-01-01

    While the sexual temptation of Paradise Regained is tactful, it is also characteristically Miltonic in its daring. Despite its decorous presentation, the temptation is exceedingly bold in that it is not merely a heterosexual temptation but a homosexual one as well. Acknowledgement of the homosexual lure in the brief epic is essential to understanding the dynamics of the celebrated banquet scene and to appreciating the comprehensiveness of Milton's trial of the Son's humanity. Such a recognition also helps place in perspective the alleged misogyny of Paradise Regained, even as it also reveals the complexity of Milton's poetic technique, particularly his ability to work by indirection and implication and to exploit classical and biblical sources. Although Jesus rejects the homosexual temptation (as He does the heterosexual one), He does not condemn homosexuality. Milton's incorporation of a homosexual temptation provides evidence of his sophisticated recognition of the range of fully human sexual responses.

  8. Expression of a tumor-associated gene, LASS2, in the human bladder carcinoma cell lines BIU-87, T24, EJ and EJ-M3

    PubMed Central

    ZHAO, QINGHUA; WANG, HAIFENG; YANG, MINGYING; YANG, DELIN; ZUO, YIGANG; WANG, JIANSONG

    2013-01-01

    Homo sapiens longevity assurance homolog 2 of yeast LAG1 (LASS2), a metastasis suppressor gene of human cancer, is the most abundantly expressed member of the ceramide synthase gene family. Expression of LASS2 has been reported in carcinomas of the prostate, liver and breast. However, there has been no report on the expression of LASS2 in human bladder cancer cell lines. In order to investigate the expression and potential role of this new tumor metastasis supressor gene in human bladder cancer, we compared the proliferation, metastasis and invasion among the BIU-87, T24, EJ and EJ-M3 human bladder cancer cell lines. The mRNA expression levels of the LASS2 gene were examined using real-time quantitative PCR (qPCR). The expression levels of LASS1 and LASS3 mRNA were used as references. The protein expression level of the LASS2 gene was detected using western blotting. The most aggressive of these four human cancer cell lines was observed to be EJ-M3. The expression of LASS2 mRNA was significantly correlated with diverse proliferation, metastasis and invasion. The expression levels of LASS1 and LASS3 mRNA were not correlated with these parameters. At the protein level, we observed that the more aggressive the cancer cell line, the lower the LASS2 protein expression level. Therefore, LASS2 expression may be correlated with the development and progression of human bladder cancer and may be a prognostic indicator for this cancer. PMID:23407876

  9. Progress and Challenges in Developing Metabolic Footprints from Diet in Human Gut Microbial Cometabolism12

    PubMed Central

    Duffy, Linda C; Raiten, Daniel J; Hubbard, Van S; Starke-Reed, Pamela

    2015-01-01

    Homo sapiens harbor trillions of microbes, whose microbial metagenome (collective genome of a microbial community) using omic validation interrogation tools is estimated to be at least 100-fold that of human cells, which comprise 23,000 genes. This article highlights some of the current progress and open questions in nutrition-related areas of microbiome research. It also underscores the metabolic capabilities of microbial fermentation on nutritional substrates that require further mechanistic understanding and systems biology approaches of studying functional interactions between diet composition, gut microbiota, and host metabolism. Questions surrounding bacterial fermentation and degradation of dietary constituents (particularly by Firmicutes and Bacteroidetes) and deciphering how microbial encoding of enzymes and derived metabolites affect recovery of dietary energy by the host are more complex than previously thought. Moreover, it is essential to understand to what extent the intestinal microbiota is subject to dietary control and to integrate these data with functional metabolic signatures and biomarkers. Many lines of research have demonstrated the significant role of the gut microbiota in human physiology and disease. Probiotic and prebiotic products are proliferating in the market in response to consumer demand, and the science and technology around these products are progressing rapidly. With high-throughput molecular technologies driving the science, studying the bidirectional interactions of host-microbial cometabolism, epithelial cell maturation, shaping of innate immune development, normal vs. dysfunctional nutrient absorption and processing, and the complex signaling pathways involved is now possible. Substantiating the safety and mechanisms of action of probiotic/prebiotic formulations is critical. Beneficial modulation of the human microbiota by using these nutritional and biotherapeutic strategies holds considerable promise as next

  10. Homo- and heterofermentative lactobacilli differently affect sugarcane-based fuel ethanol fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antagonism between by yeast and lactobacilli is largely dependent on the initial population of each organism. While homo-fermentative lactobacillus present higher inhibitory effect upon yeast when in equal cell number, in industrial fuel ethanol conditions where high yeast cell densities prevail...

  11. Molecular beacons with a homo-DNA stem: improving target selectivity

    PubMed Central

    Crey-Desbiolles, Caroline; Ahn, Dae-Ro; Leumann, Christian J.

    2005-01-01

    Molecular beacons (MBs) are stem–loop DNA probes used for identifying and reporting the presence and localization of nucleic acid targets in vitro and in vivo via target-dependent dequenching of fluorescence. A drawback of conventional MB design is present in the stem sequence that is necessary to keep the MBs in a closed conformation in the absence of a target, but that can participate in target binding in the open (target-on) conformation, giving rise to the possibility of false-positive results. In order to circumvent these problems, we designed MBs in which the stem was replaced by an orthogonal DNA analog that does not cross-pair with natural nucleic acids. Homo-DNA seemed to be specially suited, as it forms stable adenine-adenine base pairs of the reversed Hoogsteen type, potentially reducing the number of necessary building blocks for stem design to one. We found that MBs in which the stem part was replaced by homo-adenylate residues can easily be synthesized using conventional automated DNA synthesis. As conventional MBs, such hybrid MBs show cooperative hairpin to coil transitions in the absence of a DNA target, indicating stable homo-DNA base pair formation in the closed conformation. Furthermore, our results show that the homo-adenylate stem is excluded from DNA target binding, which leads to a significant increase in target binding selectivity. PMID:15879349

  12. Comment on "A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo".

    PubMed

    Schwartz, Jeffrey H; Tattersall, Ian; Chi, Zhang

    2014-04-25

    Lordkipanidze et al. (Research Article, 18 October 2013, p. 326) conclude, from gross morphological comparisons and geometric-morphometric analysis of general shape, that the five hominid crania from Dmanisi in Georgia represent a single regional variant of Homo erectus. However, dental, mandibular, and cranial morphologies all suggest taxic diversity and, in particular, validate the previously named H. georgicus.

  13. Human nakedness: adaptation against ectoparasites?

    PubMed

    Rantala, M J

    1999-12-01

    Homo sapiens L. has been described as the naked ape, and this nakedness undoubtedly constitutes one of the most striking differences in appearance between man and the apes. Nakedness has been attributed at various times to sexual selection [1], aquatic stage [2], hunting [3], cooling [4], sex [5], neoteny [6] and allometry [7], most proposed explanations logically revealing some aspect of the phenomenon. However, most fail to account for the distinctiveness of man's hairlessness among mammals of the same size. Unfortunately, fossils cannot help us to explain how denudation occurred, and how it helped hominids to survive. In this paper I will present an old hypothesis with a new point of view incorporating more recent evidence.

  14. A high-resolution whole-genome cattle-human comparative map reveals details of mammalian chromosome evolution.

    PubMed

    Everts-van der Wind, Annelie; Larkin, Denis M; Green, Cheryl A; Elliott, Janice S; Olmstead, Colleen A; Chiu, Readman; Schein, Jacqueline E; Marra, Marco A; Womack, James E; Lewin, Harris A

    2005-12-20

    Approximately 3,000 cattle bacterial artificial chromosome (BAC)-end sequences were added to the Illinois-Texas 5,000-rad RH (RH, radiation hybrid) map. The BAC-end sequences selected for mapping are approximately 1 Mbp apart on the human chromosomes as determined by blastn analysis. The map has 3,484 ordered markers, of which 3,204 are anchored in the human genome. Two hundred-and-one homologous synteny blocks (HSBs) were identified, of which 27 are previously undiscovered, 79 are extended, 26 were formed by previously unrecognized breakpoints in 18 previously defined HSBs, and 23 are the result of fusions. The comparative coverage relative to the human genome is approximately 91%, or 97% of the theoretical maximum. The positions of 64% of all cattle centromeres and telomeres were reassigned relative to their positions on the previous map, thus facilitating a more detailed comparative analysis of centromere and telomere evolution. As an example of the utility of the high-resolution map, 22 cattle BAC fingerprint contigs were directly anchored to cattle chromosome 19 [Bos taurus, (BTA) 19]. The order of markers on the cattle RH and fingerprint maps of BTA19 and the sequence-based map of human chromosome 17 [Homo sapiens, (HSA) 17] were found to be highly consistent, with only two minor ordering discrepancies between the RH map and fingerprint contigs. The high-resolution Illinois-Texas 5,000-rad RH and comparative maps will facilitate identification of candidate genes for economically important traits, the phylogenomic analysis of mammalian chromosomes, proofing of the BAC fingerprint map and, ultimately, aid the assembly of cattle whole-genome sequence.

  15. New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo.

    PubMed

    Leakey, Meave G; Spoor, Fred; Dean, M Christopher; Feibel, Craig S; Antón, Susan C; Kiarie, Christopher; Leakey, Louise N

    2012-08-09

    Since its discovery in 1972 (ref. 1), the cranium KNM-ER 1470 has been at the centre of the debate over the number of species of early Homo present in the early Pleistocene epoch of eastern Africa. KNM-ER 1470 stands out among other specimens attributed to early Homo because of its larger size, and its flat and subnasally orthognathic face with anteriorly placed maxillary zygomatic roots. This singular morphology and the incomplete preservation of the fossil have led to different views as to whether KNM-ER 1470 can be accommodated within a single species of early Homo that is highly variable because of sexual, geographical and temporal factors, or whether it provides evidence of species diversity marked by differences in cranial size and facial or masticatory adaptation. Here we report on three newly discovered fossils, aged between 1.78 and 1.95 million years (Myr) old, that clarify the anatomy and taxonomic status of KNM-ER 1470. KNM-ER 62000, a well-preserved face of a late juvenile hominin, closely resembles KNM-ER 1470 but is notably smaller. It preserves previously unknown morphology, including moderately sized, mesiodistally long postcanine teeth. The nearly complete mandible KNM-ER 60000 and mandibular fragment KNM-ER 62003 have a dental arcade that is short anteroposteriorly and flat across the front, with small incisors; these features are consistent with the arcade morphology of KNM-ER 1470 and KNM-ER 62000. The new fossils confirm the presence of two contemporary species of early Homo, in addition to Homo erectus, in the early Pleistocene of eastern Africa.

  16. Mapping and taphonomic analysis of the Homo erectus loci at Locality 1 Zhoukoudian, China.

    PubMed

    Boaz, Noel T; Ciochon, Russell L; Xu, Qinqi; Liu, Jinyi

    2004-05-01

    From a detailed analysis of published and unpublished sources, we constructed a digitized three-dimensional, stratigraphically-controlled excavation grid of Zhoukoudian Locality 1 in order to assess the spatial relationships of the excavated materials. All 15 fossil Homo erectus loci were mapped on the grid. Meter cubes were used in excavation starting in 1934, and Loci H through O, established between 1934 and 1937, were mapped to within 1 m(3)vertical and horizontal provenience. Loci A through G, established between 1921 and 1933, were excavated in the northernmost part of Locality 1 by unmapped quarrying, but their stratigraphic levels were recorded. We could localize Loci A through G on the grid system by utilizing locations of remaining walls, stratigraphic sections, excavation reports, excavation maps, and photographs. Loci contained skeletal elements of Homo erectus individuals scattered over areas of the cave floor of up to 9 m in diameter. Scoring of taphonomic damage on the Homo erectus sample, as observed on casts and originals, demonstrates that 67% of the hominid sample shows bite marks or other modifications ascribed to large mammalian carnivores, particularly the large Pleistocene cave hyena, Pachycrocuta brevirostris. Virtually all of the remaining Homo erectus skeletal assemblage shows breakage consistent with this taphonomic pattern of fragmentation. Bioturbation by digging carnivores is the most likely explanation for a fragment of Homo erectus Skull XI discovered 1 m below its other conjoined portions in Locus L. Carbon on all the Homo erectus fossils from Locus G, a circumscribed area of 1-meter diameter, earlier taken to indicate burning, cooking, and cannibalism, is here interpreted as detrital carbon deposited under water, perhaps the result of hyaenid caching behavior. Locus G records the close stratigraphic and horizontal association of stone artifacts with Homo erectus and other vertebrate skeletal elements, an association that is seen at

  17. An enlarged postcranial sample confirms Australopithecus afarensis dimorphism was similar to modern humans.

    PubMed

    Reno, Philip L; McCollum, Melanie A; Meindl, Richard S; Lovejoy, C Owen

    2010-10-27

    In a previous study, we introduced the template method as a means of enlarging the Australopithecus afarensis postcranial sample to more accurately estimate its skeletal dimorphism. Results indicated dimorphism to be largely comparable to that of Homo sapiens. Some have since argued that our results were biased by artificial homogeneity in our Au. afarensis sample. Here we report the results from inclusion of 12 additional, newly reported, specimens. The results are consistent with those of our original study and with the hypothesis that early hominid demographic success derived from a reproductive strategy involving male provisioning of pair-bonded females.

  18. Transposable element fragments in protein-coding regions and their contributions to human functional proteins.

    PubMed

    Wu, Ming; Li, Li; Sun, Zhirong

    2007-10-15

    Transposable elements (TEs) and their contributions to protein-coding regions are of particular interest. Here we searched for TE fragments in Homo sapiens at both the transcript and protein levels. We found evidence in support of TE exonization and its association with alternative splicing. Despite recent findings that long evolutionary times are required to incorporate TE into proteins, we found many functional proteins with translated TE cassettes derived from young TEs. Analyses of two Bcl-family proteins and Alu-encoded segments suggest the coding and functional potential of TE sequences.

  19. Terra Sapiens: The Role of Science in Fostering a Wisely Managed Earth

    NASA Astrophysics Data System (ADS)

    Grinspoon, D. H.

    2013-12-01

    Carl Sagan was sometimes shunned by the scientific community for his successful popularizations, but another factor was his activism on issues such as nuclear weapons and climate change. The question of whether Earth has entered a new geological epoch characterized by human influence has gained significance beyond the narrow question of stratigraphic nomenclature. The anthropocene has raised new questions about the 'nature of nature', about the false - or at least fluid - dichotomy between wild and managed environments, about what it is that, in a world already profoundly altered by human activities, we should be trying to conserve, and ultimately about how humanity can learn to live comfortably with world-changing technology. It also raises challenging questions about the role of scientists in the public arena. Astrobiology is largely a scientific study of the relationship between planets and life. On Earth this relationship has taken a dramatic new turn - a planetary transformation potentially as significant as the origin of life, the great oxygenation or the Cambrian 'explosion'. We are not the first species to cause catastrophic change in the quest for a new energy source. The cyanobacteria, in perfecting photosynthesis, liberated vast quantities of free oxygen, wreaking havoc on the global biosphere and climate. And yet, obviously, there seems to be something important differentiating us from cyanobacteria. When we try to describe that difference we use poorly defined (some may even say ironic) words like 'intelligence', 'consciousness', 'foresight', 'awareness' and 'responsibility.' Looking at the anthropocene as an event in planetary evolution gives us new perspective on the meaning of these terms. We may also ask if these phenomena could somehow be unique to Earth and if, given the plethora of exponential changes occurring now, they can become part of a stable or long-lived planetary epoch. It can be shown quantitatively that the prospect for successful

  20. Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol.

    PubMed

    Liu, Jianming; Chan, Siu Hung Joshua; Brock-Nannestad, Theis; Chen, Jun; Lee, Sang Yup; Solem, Christian; Jensen, Peter Ruhdal

    2016-07-01

    Biocompatible chemistry is gaining increasing attention because of its potential within biotechnology for expanding the repertoire of biological transformations carried out by enzymes. Here we demonstrate how biocompatible chemistry can be used for synthesizing valuable compounds as well as for linking metabolic pathways to achieve redox balance and rescued growth. By comprehensive rerouting of metabolism, activation of respiration, and finally metal ion catalysis, we successfully managed to convert the homolactic bacterium Lactococcus lactis into a homo-diacetyl producer with high titer (95mM or 8.2g/L) and high yield (87% of the theoretical maximum). Subsequently, the pathway was extended to (S,S)-2,3-butanediol (S-BDO) through efficiently linking two metabolic pathways via chemical catalysis. This resulted in efficient homo-S-BDO production with a titer of 74mM (6.7g/L) S-BDO and a yield of 82%. The diacetyl and S-BDO production rates and yields obtained are the highest ever reported, demonstrating the promising combination of metabolic engineering and biocompatible chemistry as well as the great potential of L. lactis as a new production platform.

  1. Free will and determinism in first Isaiah: secular hermeneutics, the poetics of contingency, and Emile Durkheim's Homo duplex.

    PubMed

    Berlinerblau, Jacques

    2003-01-01

    Are human beings the sovereign authors of their own thoughts and actions? Or are thought and action determined by external forces beyond their comprehension and control? For the biblical document known to exegetes as First Isaiah (chapters 1-39 of the Book of Isaiah) the answer to both queries seems to be yes. In this article various solutions are advanced to explain why this text equivocates on the question of free will and determinism. One possibility is that the document's collective, transhistorical composition may have scrambled its once coherent message beyond all recognition. Following Emile Durkheim's discussions of homo duplex, it will also be suggested that First Isaiah's confusion may be a manifestation of a deeper contradiction inherent to human consciousness-one that thus recurs across sociological time and space. Both solutions are united by their rejection of traditional theological approaches that have been brought to bear on First Isaiah and the Hebrew Bible in general. It is the movement away from such apologetic exegesis that characterizes the inchoate interpretive orientation that I call "secular hermeneutics."

  2. Biased versus unbiased randomness in homo-polymers and copolymers of amino acids in the prebiotic world.

    PubMed

    Mosqueira, Fernando G; Negron, Alicia; Ramos, Sergio; Polanco, Carlos

    2012-01-01

    The polymerization of amino acids under anhydrous prebiotic conditions was first studied several decades ago. Here we use a stochastic model stressing the relevant role of the polarity of amino acids in the formation of oligopeptides in a prebiotic milieu. Our goal is to outline the predominance of co-polypeptides over homo-polypeptides, resulting not only from the randomness, but also from polarity properties of amino acids. Our results conclude that there was a higher probability of the formation of co-polypeptides than of homo-polymers. Besides, we may hypothesize that the former would have a more ample spectrum of possible chemical functions than homo-polypeptides.

  3. Paleoanthropology. Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia.

    PubMed

    DiMaggio, Erin N; Campisano, Christopher J; Rowan, John; Dupont-Nivet, Guillaume; Deino, Alan L; Bibi, Faysal; Lewis, Margaret E; Souron, Ant