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Sample records for early human ancestors

  1. An early modern human from Romania with a recent Neanderthal ancestor

    PubMed Central

    Fu, Qiaomei; Hajdinjak, Mateja; Moldovan, Oana Teodora; Constantin, Silviu; Mallick, Swapan; Skoglund, Pontus; Patterson, Nick; Rohland, Nadin; Lazaridis, Iosif; Nickel, Birgit; Viola, Bence; Prüfer, Kay; Meyer, Matthias; Kelso, Janet; Reich, David; Pääbo, Svante

    2015-01-01

    Neanderthals are thought to have disappeared in Europe ~39,000–41,000 years ago but they have contributed one to three percent of the DNA of present-day people in Eurasia1. Here, we analyze DNA from a 37,000–42,000-year-old2 modern human from Peştera cu Oase, Romania. Although the specimen contains small amounts of human DNA, we use an enrichment strategy to isolate sites that are informative about its relationship to Neanderthals and present-day humans. We find that on the order of six to nine percent of the genome of the Oase individual is derived from Neanderthals, more than any other modern human sequenced to date. Three chromosomal segments of Neanderthal ancestry are over 50 centimorgans in size, indicating that this individual had a Neanderthal ancestor as recently as four to six generations back. However, the Oase individual does not share more alleles with later Europeans than with East Asians, suggesting that the Oase population did not contribute substantially to later humans in Europe. PMID:26098372

  2. An early modern human from Romania with a recent Neanderthal ancestor.

    PubMed

    Fu, Qiaomei; Hajdinjak, Mateja; Moldovan, Oana Teodora; Constantin, Silviu; Mallick, Swapan; Skoglund, Pontus; Patterson, Nick; Rohland, Nadin; Lazaridis, Iosif; Nickel, Birgit; Viola, Bence; Prüfer, Kay; Meyer, Matthias; Kelso, Janet; Reich, David; Pääbo, Svante

    2015-08-13

    Neanderthals are thought to have disappeared in Europe approximately 39,000-41,000 years ago but they have contributed 1-3% of the DNA of present-day people in Eurasia. Here we analyse DNA from a 37,000-42,000-year-old modern human from Peştera cu Oase, Romania. Although the specimen contains small amounts of human DNA, we use an enrichment strategy to isolate sites that are informative about its relationship to Neanderthals and present-day humans. We find that on the order of 6-9% of the genome of the Oase individual is derived from Neanderthals, more than any other modern human sequenced to date. Three chromosomal segments of Neanderthal ancestry are over 50 centimorgans in size, indicating that this individual had a Neanderthal ancestor as recently as four to six generations back. However, the Oase individual does not share more alleles with later Europeans than with East Asians, suggesting that the Oase population did not contribute substantially to later humans in Europe.

  3. Sex-biased dispersal of human ancestors.

    PubMed

    Sugiyama, Yukimaru

    2017-07-01

    Some anthropologists and primatologists have argued that, judging by extant chimpanzees and humans, which are female-biased dispersers, the common ancestors of humans and chimpanzees were also female-biased dispersers. It has been thought that sex-biased dispersal patterns have been genetically transmitted for millions of years. However, this character has changed many times with changes in environment and life-form during human evolution and historical times. I examined life-form and social organization of nonhuman primates, among them gatherers (foragers), hunter-gatherers, agriculturalists, industrialists, and modern and extant humans. I conclude that dispersal patterns changed in response to environmental conditions during primate and human evolution. © 2017 Wiley Periodicals, Inc.

  4. Diet and the evolution of the earliest human ancestors.

    PubMed

    Teaford, M F; Ungar, P S

    2000-12-05

    Over the past decade, discussions of the evolution of the earliest human ancestors have focused on the locomotion of the australopithecines. Recent discoveries in a broad range of disciplines have raised important questions about the influence of ecological factors in early human evolution. Here we trace the cranial and dental traits of the early australopithecines through time, to show that between 4.4 million and 2.3 million years ago, the dietary capabilities of the earliest hominids changed dramatically, leaving them well suited for life in a variety of habitats and able to cope with significant changes in resource availability associated with long-term and short-term climatic fluctuations.

  5. Virtual ancestor reconstruction: Revealing the ancestor of modern humans and Neandertals.

    PubMed

    Mounier, Aurélien; Mirazón Lahr, Marta

    2016-02-01

    The timing and geographic origin of the common ancestor of modern humans and Neandertals remain controversial. A poor Pleistocene hominin fossil record and the evolutionary complexities introduced by dispersals and regionalisation of lineages have fuelled taxonomic uncertainty, while new ancient genomic data have raised completely new questions. Here, we use maximum likelihood and 3D geometric morphometric methods to predict possible morphologies of the last common ancestor of modern humans and Neandertals from a simplified, fully resolved phylogeny. We describe the fully rendered 3D shapes of the predicted ancestors of humans and Neandertals, and assess their similarity to individual fossils or populations of fossils of Pleistocene age. Our results support models of an Afro-European ancestral population in the Middle Pleistocene (Homo heidelbergensis sensu lato) and further predict an African origin for this ancestral population. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Diet and the evolution of the earliest human ancestors

    PubMed Central

    Teaford, Mark F.; Ungar, Peter S.

    2000-01-01

    Over the past decade, discussions of the evolution of the earliest human ancestors have focused on the locomotion of the australopithecines. Recent discoveries in a broad range of disciplines have raised important questions about the influence of ecological factors in early human evolution. Here we trace the cranial and dental traits of the early australopithecines through time, to show that between 4.4 million and 2.3 million years ago, the dietary capabilities of the earliest hominids changed dramatically, leaving them well suited for life in a variety of habitats and able to cope with significant changes in resource availability associated with long-term and short-term climatic fluctuations. PMID:11095758

  7. Stride lengths, speed and energy costs in walking of Australopithecus afarensis: using evolutionary robotics to predict locomotion of early human ancestors

    PubMed Central

    Sellers, William I; Cain, Gemma M; Wang, Weijie; Crompton, Robin H

    2005-01-01

    This paper uses techniques from evolutionary robotics to predict the most energy-efficient upright walking gait for the early human relative Australopithecus afarensis, based on the proportions of the 3.2 million year old AL 288-1 ‘Lucy’ skeleton, and matches predictions against the nearly contemporaneous (3.5–3.6 million year old) Laetoli fossil footprint trails. The technique creates gaits de novo and uses genetic algorithm optimization to search for the most efficient patterns of simulated muscular contraction at a variety of speeds. The model was first verified by predicting gaits for living human subjects, and comparing costs, stride lengths and speeds to experimentally determined values for the same subjects. Subsequent simulations for A. afarensis yield estimates of the range of walking speeds from 0.6 to 1.3 m s−1 at a cost of 7.0 J kg−1 m−1 for the lowest speeds, falling to 5.8 J kg−1 m−1 at 1.0 m s−1, and rising to 6.2 J kg−1 m−1 at the maximum speed achieved. Speeds previously estimated for the makers of the Laetoli footprint trails (0.56 or 0.64 m s−1 for Trail 1, 0.72 or 0.75 m s−1 for Trail 2/3) may have been underestimated, substantially so for Trail 2/3, with true values in excess of 0.7 and 1.0 m s−1, respectively. The predictions conflict with suggestions that A. afarensis used a ‘shuffling’ gait, indicating rather that the species was a fully competent biped. PMID:16849203

  8. Stride lengths, speed and energy costs in walking of Australopithecus afarensis: using evolutionary robotics to predict locomotion of early human ancestors.

    PubMed

    Sellers, William I; Cain, Gemma M; Wang, Weijie; Crompton, Robin H

    2005-12-22

    This paper uses techniques from evolutionary robotics to predict the most energy-efficient upright walking gait for the early human relative Australopithecus afarensis, based on the proportions of the 3.2 million year old AL 288-1 'Lucy' skeleton, and matches predictions against the nearly contemporaneous (3.5-3.6 million year old) Laetoli fossil footprint trails. The technique creates gaits de novo and uses genetic algorithm optimization to search for the most efficient patterns of simulated muscular contraction at a variety of speeds. The model was first verified by predicting gaits for living human subjects, and comparing costs, stride lengths and speeds to experimentally determined values for the same subjects. Subsequent simulations for A. afarensis yield estimates of the range of walking speeds from 0.6 to 1.3 m s-1 at a cost of 7.0 J kg-1 m-1 for the lowest speeds, falling to 5.8 J kg-1 m-1 at 1.0 m s-1, and rising to 6.2 J kg-1 m-1 at the maximum speed achieved. Speeds previously estimated for the makers of the Laetoli footprint trails (0.56 or 0.64 m s-1 for Trail 1, 0.72 or 0.75 m s-1 for Trail 2/3) may have been underestimated, substantially so for Trail 2/3, with true values in excess of 0.7 and 1.0 m s-1, respectively. The predictions conflict with suggestions that A. afarensis used a 'shuffling' gait, indicating rather that the species was a fully competent biped.

  9. Transmission between Archaic and Modern Human Ancestors during the Evolution of the Oncogenic Human Papillomavirus 16.

    PubMed

    Pimenoff, Ville N; de Oliveira, Cristina Mendes; Bravo, Ignacio G

    2017-01-01

    Every human suffers through life a number of papillomaviruses (PVs) infections, most of them asymptomatic. A notable exception are persistent infections by Human papillomavirus 16 (HPV16), the most oncogenic infectious agent for humans and responsible for most infection-driven anogenital cancers. Oncogenic potential is not homogeneous among HPV16 lineages, and genetic variation within HPV16 exhibits some geographic structure. However, an in-depth analysis of the HPV16 evolutionary history was still wanting. We have analyzed extant HPV16 diversity and compared the evolutionary and phylogeographical patterns of humans and of HPV16. We show that codivergence with modern humans explains at most 30% of the present viral geographical distribution. The most explanatory scenario suggests that ancestral HPV16 already infected ancestral human populations and that viral lineages co-diverged with the hosts in parallel with the split between archaic Neanderthal-Denisovans and ancestral modern human populations, generating the ancestral HPV16A and HPV16BCD viral lineages, respectively. We propose that after out-of-Africa migration of modern human ancestors, sexual transmission between human populations introduced HPV16A into modern human ancestor populations. We hypothesize that differential coevolution of HPV16 lineages with different but closely related ancestral human populations and subsequent host-switch events in parallel with introgression of archaic alleles into the genomes of modern human ancestors may be largely responsible for the present-day differential prevalence and association with cancers for HPV16 variants.

  10. Evolution of life history and behavior in Hominidae: towards phylogenetic reconstruction of the chimpanzee-human last common ancestor.

    PubMed

    Duda, Pavel; Zrzavý, Jan

    2013-10-01

    The origin of the fundamental behavioral differences between humans and our closest living relatives is one of the central issues of evolutionary anthropology. The prominent, chimpanzee-based referential model of early hominin behavior has recently been challenged on the basis of broad multispecies comparisons and newly discovered fossil evidence. Here, we argue that while behavioral data on extant great apes are extremely relevant for reconstruction of ancestral behaviors, these behaviors should be reconstructed trait by trait using formal phylogenetic methods. Using the widely accepted hominoid phylogenetic tree, we perform a series of character optimization analyses using 65 selected life-history and behavioral characters for all extant hominid species. This analysis allows us to reconstruct the character states of the last common ancestors of Hominoidea, Hominidae, and the chimpanzee-human last common ancestor. Our analyses demonstrate that many fundamental behavioral and life-history attributes of hominids (including humans) are evidently ancient and likely inherited from the common ancestor of all hominids. However, numerous behaviors present in extant great apes represent their own terminal autapomorphies (both uniquely derived and homoplastic). Any evolutionary model that uses a single extant species to explain behavioral evolution of early hominins is therefore of limited use. In contrast, phylogenetic reconstruction of ancestral states is able to provide a detailed suite of behavioral, ecological and life-history characters for each hypothetical ancestor. The living great apes therefore play an important role for the confident identification of the traits found in the chimpanzee-human last common ancestor, some of which are likely to represent behaviors of the fossil hominins. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Inbreeding, Pedigree Size, and the Most Recent Common Ancestor of Humanity

    PubMed Central

    Lachance, Joseph

    2009-01-01

    How many generations ago did the common ancestor of all present-day individuals live, and how does inbreeding affect this estimate? The number of ancestors within family trees determines the timing of the most recent common ancestor of humanity. However, mating is often non-random and inbreeding is ubiquitous in natural populations. Rates of pedigree growth are found for multiple types of inbreeding. This data is then combined with models of global population structure to estimate biparental coalescence times. When pedigrees for regular systems of mating are constructed, the growth rates of inbred populations contain Fibonacci n-step constants. The timing of the most recent common ancestor depends on global population structure, the mean rate of pedigree growth, mean fitness, and current population size. Inbreeding reduces the number of ancestors in a pedigree, pushing back global common ancestry times. These results are consistent with the remarkable findings of previous studies: all humanity shares common ancestry in the recent past. PMID:19679139

  12. Scapular shape of extant hominoids and the African ape/modern human last common ancestor.

    PubMed

    Green, David J; Spiewak, Ted A; Seitelman, Brielle; Gunz, Philipp

    2016-05-01

    Newly discovered early hominin fossil scapulae have bolstered investigations of scapular shape, which have long been used to interpret behavioral variation among primates. However, unexpected similarities between Pongo and Homo - particularly in scapular spine orientation - have raised questions about the functional utility of scapular morphology and its phylogenetic context in the hominin lineage. Not surprisingly, significant disagreement surrounds disparate morphological reconstructions of the modern human/African ape last common ancestor (LCA). Our study utilizes geometric morphometric (GM) approaches - two employing homologous, anatomical landmarks and a "spine-free" alternative using 98 sliding semilandmarks along the boundary of the subscapular fossa. The landmark-based "wireframe" GM analysis principally sorted groups by spine orientation: Homo and Pongo were similar to one another with more transversely-oriented spines as compared to Hylobates and the African apes. In contrast, Homo and Gorilla clustered together in our semilandmark analysis with superoinferiorly broad blades. Pan scapulae were similar, but had more mediolaterally compressed blades and laterally-positioned superior angles. Hylobates was superoinferiorly narrow, yet obliquely expanded relative to the vertebral border. Pongo scapulae were unique among hominoids in being nearly as broad as they were long. Previously documented 'convergence' of Homo and Pongo scapulae appears to be principally driven by similarities in spine orientation, rather than overall blade shape. Therefore, we contend that it is more parsimonious to reconstruct the African ape/Homo LCA scapula as being Gorilla-like, especially in light of similar characterizations of certain fossil hominin scapulae. Accordingly, the evolution of Pan (highly oblique spine and laterally-situated superior angle) and Homo (transversely-oriented spine) scapular morphology would have involved relatively minor shifts from this ancestral

  13. Intolerable human suffering and the role of the ancestor: literary criticism as a means of analysis.

    PubMed

    Harrison, E

    2000-09-01

    Intolerable human suffering and the role of the ancestor: literary criticism as a means of analysis This essay explores the experience of intolerable human suffering in Toni Cade Bambara's novel, The Salt Eaters. The method of analysis is literary criticism, a technique that shares many of the same goals as other types of inquiry. It employs close reading to illuminate the novel's meaning(s), thereby revealing information about the nature of intolerable human suffering. Morrison's characteristics of black art is the literary and cultural framework that guides the analysis of Bambara's novel. The paradigm has broad application for nursing. The purpose of this analysis was to describe the role of the ancestral system as a predictor of the trajectory of suffering. The results extend Morrison's paradigm and her notion of ancestor to include traditions and other non-corporeal factors that are essential for well-being and survival. The protagonist in Bambara's novel, Velma Henry, is the patient and exemplar who does not succumb to intolerable suffering because of its cumulative weight, but because she has lost touch with the traditions of her people, an essential component of her ancestral system. The ancestral system is a rich and complex network of individuals, groups, customs and beliefs that are instructive, protective and benevolent. Ancestors are also timeless and provide wisdom, but when the ancestral system is weak or absent, the trajectory of suffering is not favourable. Nurses must learn to recognize intolerable human suffering, to identify the patient's ancestral system, and to work within that system to keep suffering patients from harm.

  14. Fossil hominin shoulders support an African ape-like last common ancestor of humans and chimpanzees.

    PubMed

    Young, Nathan M; Capellini, Terence D; Roach, Neil T; Alemseged, Zeresenay

    2015-09-22

    Reconstructing the behavioral shifts that drove hominin evolution requires knowledge of the timing, magnitude, and direction of anatomical changes over the past ∼6-7 million years. These reconstructions depend on assumptions regarding the morphotype of the Homo-Pan last common ancestor (LCA). However, there is little consensus for the LCA, with proposed models ranging from African ape to orangutan or generalized Miocene ape-like. The ancestral state of the shoulder is of particular interest because it is functionally associated with important behavioral shifts in hominins, such as reduced arboreality, high-speed throwing, and tool use. However, previous morphometric analyses of both living and fossil taxa have yielded contradictory results. Here, we generated a 3D morphospace of ape and human scapular shape to plot evolutionary trajectories, predict ancestral morphologies, and directly test alternative evolutionary hypotheses using the hominin fossil evidence. We show that the most parsimonious model for the evolution of hominin shoulder shape starts with an African ape-like ancestral state. We propose that the shoulder evolved gradually along a single morphocline, achieving modern human-like configuration and function within the genus Homo. These data are consistent with a slow, progressive loss of arboreality and increased tool use throughout human evolution.

  15. Fossil hominin shoulders support an African ape-like last common ancestor of humans and chimpanzees

    PubMed Central

    Young, Nathan M.; Capellini, Terence D.; Roach, Neil T.; Alemseged, Zeresenay

    2015-01-01

    Reconstructing the behavioral shifts that drove hominin evolution requires knowledge of the timing, magnitude, and direction of anatomical changes over the past ∼6–7 million years. These reconstructions depend on assumptions regarding the morphotype of the Homo–Pan last common ancestor (LCA). However, there is little consensus for the LCA, with proposed models ranging from African ape to orangutan or generalized Miocene ape-like. The ancestral state of the shoulder is of particular interest because it is functionally associated with important behavioral shifts in hominins, such as reduced arboreality, high-speed throwing, and tool use. However, previous morphometric analyses of both living and fossil taxa have yielded contradictory results. Here, we generated a 3D morphospace of ape and human scapular shape to plot evolutionary trajectories, predict ancestral morphologies, and directly test alternative evolutionary hypotheses using the hominin fossil evidence. We show that the most parsimonious model for the evolution of hominin shoulder shape starts with an African ape-like ancestral state. We propose that the shoulder evolved gradually along a single morphocline, achieving modern human-like configuration and function within the genus Homo. These data are consistent with a slow, progressive loss of arboreality and increased tool use throughout human evolution. PMID:26351685

  16. No known hominin species matches the expected dental morphology of the last common ancestor of Neanderthals and modern humans

    PubMed Central

    Gómez-Robles, Aida; Bermúdez de Castro, José María; Arsuaga, Juan-Luis; Carbonell, Eudald; Polly, P. David

    2013-01-01

    A central problem in paleoanthropology is the identity of the last common ancestor of Neanderthals and modern humans ([N-MH]LCA). Recently developed analytical techniques now allow this problem to be addressed using a probabilistic morphological framework. This study provides a quantitative reconstruction of the expected dental morphology of the [N-MH]LCA and an assessment of whether known fossil species are compatible with this ancestral position. We show that no known fossil species is a suitable candidate for being the [N-MH]LCA and that all late Early and Middle Pleistocene taxa from Europe have Neanderthal dental affinities, pointing to the existence of a European clade originated around 1 Ma. These results are incongruent with younger molecular divergence estimates and suggest at least one of the following must be true: (i) European fossils and the [N-MH]LCA selectively retained primitive dental traits; (ii) molecular estimates of the divergence between Neanderthals and modern humans are underestimated; or (iii) phenotypic divergence and speciation between both species were decoupled such that phenotypic differentiation, at least in dental morphology, predated speciation. PMID:24145426

  17. The facial skeleton of the chimpanzee-human last common ancestor

    PubMed Central

    Cobb, Samuel N

    2008-01-01

    This review uses the current morphological evidence to evaluate the facial morphology of the hypothetical last common ancestor (LCA) of the chimpanzee/bonobo (panin) and human (hominin) lineages. Some of the problems involved in reconstructing ancestral morphologies so close to the formation of a lineage are discussed. These include the prevalence of homoplasy and poor phylogenetic resolution due to a lack of defining derived features. Consequently the list of hypothetical features expected in the face of the LCA is very limited beyond its hypothesized similarity to extant Pan. It is not possible to determine with any confidence whether the facial morphology of any of the current candidate LCA taxa (Ardipithecus kadabba, Ardipithecus ramidus, Orrorin tugenensis and Sahelanthropus tchadensis) is representative of the LCA, or a stem hominin, or a stem panin or, in some cases, a hominid predating the emergence of the hominin lineage. The major evolutionary trends in the hominin lineage subsequent to the LCA are discussed in relation to the dental arcade and dentition, subnasal morphology and the size, position and prognathism of the facial skeleton. PMID:18380866

  18. The facial skeleton of the chimpanzee-human last common ancestor.

    PubMed

    Cobb, Samuel N

    2008-04-01

    This review uses the current morphological evidence to evaluate the facial morphology of the hypothetical last common ancestor (LCA) of the chimpanzee/bonobo (panin) and human (hominin) lineages. Some of the problems involved in reconstructing ancestral morphologies so close to the formation of a lineage are discussed. These include the prevalence of homoplasy and poor phylogenetic resolution due to a lack of defining derived features. Consequently the list of hypothetical features expected in the face of the LCA is very limited beyond its hypothesized similarity to extant Pan. It is not possible to determine with any confidence whether the facial morphology of any of the current candidate LCA taxa (Ardipithecus kadabba, Ardipithecus ramidus, Orrorin tugenensis and Sahelanthropus tchadensis) is representative of the LCA, or a stem hominin, or a stem panin or, in some cases, a hominid predating the emergence of the hominin lineage. The major evolutionary trends in the hominin lineage subsequent to the LCA are discussed in relation to the dental arcade and dentition, subnasal morphology and the size, position and prognathism of the facial skeleton.

  19. Maize Domestication and Anti-Herbivore Defences: Leaf-Specific Dynamics during Early Ontogeny of Maize and Its Wild Ancestors

    PubMed Central

    Maag, Daniel; Erb, Matthias; Bernal, Julio S.; Wolfender, Jean-Luc; Turlings, Ted C. J.; Glauser, Gaétan

    2015-01-01

    As a consequence of artificial selection for specific traits, crop plants underwent considerable genotypic and phenotypic changes during the process of domestication. These changes may have led to reduced resistance in the cultivated plant due to shifts in resource allocation from defensive traits to increased growth rates and yield. Modern maize (Zea mays ssp. mays) was domesticated from its ancestor Balsas teosinte (Z. mays ssp. parviglumis) approximately 9000 years ago. Although maize displays a high genetic overlap with its direct ancestor and other annual teosintes, several studies show that maize and its ancestors differ in their resistance phenotypes with teosintes being less susceptible to herbivore damage. However, the underlying mechanisms are poorly understood. Here we addressed the question to what extent maize domestication has affected two crucial chemical and one physical defence traits and whether differences in their expression may explain the differences in herbivore resistance levels. The ontogenetic trajectories of 1,4-benzoxazin-3-ones, maysin and leaf toughness were monitored for different leaf types across several maize cultivars and teosinte accessions during early vegetative growth stages. We found significant quantitative and qualitative differences in 1,4-benzoxazin-3-one accumulation in an initial pairwise comparison, but we did not find consistent differences between wild and cultivated genotypes during a more thorough examination employing several cultivars/accessions. Yet, 1,4-benzoxazin-3-one levels tended to decline more rapidly with plant age in the modern maize cultivars. Foliar maysin levels and leaf toughness increased with plant age in a leaf-specific manner, but were also unaffected by domestication. Based on our findings we suggest that defence traits other than the ones that were investigated are responsible for the observed differences in herbivore resistance between teosinte and maize. Furthermore, our results indicate

  20. Maize Domestication and Anti-Herbivore Defences: Leaf-Specific Dynamics during Early Ontogeny of Maize and Its Wild Ancestors.

    PubMed

    Maag, Daniel; Erb, Matthias; Bernal, Julio S; Wolfender, Jean-Luc; Turlings, Ted C J; Glauser, Gaétan

    2015-01-01

    As a consequence of artificial selection for specific traits, crop plants underwent considerable genotypic and phenotypic changes during the process of domestication. These changes may have led to reduced resistance in the cultivated plant due to shifts in resource allocation from defensive traits to increased growth rates and yield. Modern maize (Zea mays ssp. mays) was domesticated from its ancestor Balsas teosinte (Z. mays ssp. parviglumis) approximately 9000 years ago. Although maize displays a high genetic overlap with its direct ancestor and other annual teosintes, several studies show that maize and its ancestors differ in their resistance phenotypes with teosintes being less susceptible to herbivore damage. However, the underlying mechanisms are poorly understood. Here we addressed the question to what extent maize domestication has affected two crucial chemical and one physical defence traits and whether differences in their expression may explain the differences in herbivore resistance levels. The ontogenetic trajectories of 1,4-benzoxazin-3-ones, maysin and leaf toughness were monitored for different leaf types across several maize cultivars and teosinte accessions during early vegetative growth stages. We found significant quantitative and qualitative differences in 1,4-benzoxazin-3-one accumulation in an initial pairwise comparison, but we did not find consistent differences between wild and cultivated genotypes during a more thorough examination employing several cultivars/accessions. Yet, 1,4-benzoxazin-3-one levels tended to decline more rapidly with plant age in the modern maize cultivars. Foliar maysin levels and leaf toughness increased with plant age in a leaf-specific manner, but were also unaffected by domestication. Based on our findings we suggest that defence traits other than the ones that were investigated are responsible for the observed differences in herbivore resistance between teosinte and maize. Furthermore, our results indicate

  1. The universal ancestor

    NASA Technical Reports Server (NTRS)

    Woese, C.

    1998-01-01

    A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when "genetic temperatures" were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell "crystallized," i.e., became refractory to lateral gene transfer, at different stages of "cooling," with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result.

  2. The universal ancestor

    NASA Technical Reports Server (NTRS)

    Woese, C.

    1998-01-01

    A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when "genetic temperatures" were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell "crystallized," i.e., became refractory to lateral gene transfer, at different stages of "cooling," with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result.

  3. The Universal Ancestor

    NASA Astrophysics Data System (ADS)

    Woese, Carl

    1998-06-01

    A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when ``genetic temperatures'' were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell ``crystallized,'' i.e., became refractory to lateral gene transfer, at different stages of ``cooling,'' with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result.

  4. The universal ancestor.

    PubMed

    Woese, C

    1998-06-09

    A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when "genetic temperatures" were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell "crystallized," i.e., became refractory to lateral gene transfer, at different stages of "cooling," with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result.

  5. Lampetra fluviatilis neurotrophin homolog, descendant of a neurotrophin ancestor, discloses the early molecular evolution of neurotrophins in the vertebrate subphylum.

    PubMed

    Hallböök, F; Lundin, L G; Kullander, K

    1998-11-01

    We have isolated a neurotrophin from the lamprey that permitted us to perform a phylogenetic analysis of the neurotrophin gene family that dates back more than 460 million years to the early vertebrate ancestors. The results show that the neurotrophin gene family was originally formed by two subsequent duplications. The duplication that formed nerve growth factor, neurotrophin-3, brain-derived neurotrophic factor, and neurotrophin-4/5 occurred after the split of lampreys but before the split of cartilaginous fish from the main vertebrate lineage. Compilation of chromosomal gene maps around the neurotrophins shows that they are located in paralogous regions, suggesting that the genes were formed at major duplication events possibly by complete genome doubling. Analysis of two isolated Trk receptor sequences shows similar results as for the lamprey neurotrophin. Multiple neurotrophin and Trk genes, including neurotrophin-6 and -7, have been found in bony fish, and we suggest that the extra genes were formed by an additional duplication in the bony fish lineage. Analysis of lamprey Trk mRNA expression in the adult brain shows that the genes are expressed in all regions analyzed so far. Together, the results suggest that the duplications of ancestral neurotrophin and Trk genes at an early vertebrate stage have permitted evolution to bring about differential neurotrophin and Trk expression, thereby allowing the formation of specific functions in selective neuronal populations.

  6. Phylogenomic Analyses Indicate that Early Fungi Evolved Digesting Cell Walls of Algal Ancestors of Land Plants.

    PubMed

    Chang, Ying; Wang, Sishuo; Sekimoto, Satoshi; Aerts, Andrea L; Choi, Cindy; Clum, Alicia; LaButti, Kurt M; Lindquist, Erika A; Yee Ngan, Chew; Ohm, Robin A; Salamov, Asaf A; Grigoriev, Igor V; Spatafora, Joseph W; Berbee, Mary L

    2015-05-14

    As decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant-fungus association. We analyzed 40 fungal genomes, three of which, including Gonapodya prolifera, were sequenced for this study. In the organismal phylogeny from 136 housekeeping loci, Rozella diverged first from all other fungi. Gonapodya prolifera was included among the flagellated, predominantly aquatic fungal species in Chytridiomycota. Sister to Chytridiomycota were the predominantly terrestrial fungi including zygomycota I and zygomycota II, along with the ascomycetes and basidiomycetes that comprise Dikarya. The Gonapodya genome has 27 genes representing five of the seven classes of pectin-specific enzymes known from fungi. Most of these share a common ancestry with pectinases from Dikarya. Indicating functional and sequence similarity, Gonapodya, like many Dikarya, can use pectin as a carbon source for growth in pure culture. Shared pectinases of Dikarya and Gonapodya provide evidence that even ancient aquatic fungi had adapted to extract nutrients from the plants in the green lineage. This implies that 750 million years, the estimated maximum age of origin of the pectin-containing streptophytes represents a maximum age for the divergence of Chytridiomycota from the lineage including Dikarya.

  7. Phylogenomic Analyses Indicate that Early Fungi Evolved Digesting Cell Walls of Algal Ancestors of Land Plants

    PubMed Central

    Chang, Ying; Wang, Sishuo; Sekimoto, Satoshi; Aerts, Andrea L.; Choi, Cindy; Clum, Alicia; LaButti, Kurt M.; Lindquist, Erika A.; Yee Ngan, Chew; Ohm, Robin A.; Salamov, Asaf A.; Grigoriev, Igor V.; Spatafora, Joseph W.; Berbee, Mary L.

    2015-01-01

    As decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant–fungus association. We analyzed 40 fungal genomes, three of which, including Gonapodya prolifera, were sequenced for this study. In the organismal phylogeny from 136 housekeeping loci, Rozella diverged first from all other fungi. Gonapodya prolifera was included among the flagellated, predominantly aquatic fungal species in Chytridiomycota. Sister to Chytridiomycota were the predominantly terrestrial fungi including zygomycota I and zygomycota II, along with the ascomycetes and basidiomycetes that comprise Dikarya. The Gonapodya genome has 27 genes representing five of the seven classes of pectin-specific enzymes known from fungi. Most of these share a common ancestry with pectinases from Dikarya. Indicating functional and sequence similarity, Gonapodya, like many Dikarya, can use pectin as a carbon source for growth in pure culture. Shared pectinases of Dikarya and Gonapodya provide evidence that even ancient aquatic fungi had adapted to extract nutrients from the plants in the green lineage. This implies that 750 million years, the estimated maximum age of origin of the pectin-containing streptophytes represents a maximum age for the divergence of Chytridiomycota from the lineage including Dikarya. PMID:25977457

  8. The universal ancestor

    PubMed Central

    Woese, Carl

    1998-01-01

    A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when “genetic temperatures” were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell “crystallized,” i.e., became refractory to lateral gene transfer, at different stages of “cooling,” with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result. PMID:9618502

  9. The Distribution and Most Recent Common Ancestor of the 17q21 Inversion in Humans

    PubMed Central

    Donnelly, Michael P.; Paschou, Peristera; Grigorenko, Elena; Gurwitz, David; Mehdi, Syed Qasim; Kajuna, Sylvester L.B.; Barta, Csaba; Kungulilo, Selemani; Karoma, N.J.; Lu, Ru-Band; Zhukova, Olga V.; Kim, Jong-Jin; Comas, David; Siniscalco, Marcello; New, Maria; Li, Peining; Li, Hui; Manolopoulos, Vangelis G.; Speed, William C.; Rajeevan, Haseena; Pakstis, Andrew J.; Kidd, Judith R.; Kidd, Kenneth K.

    2010-01-01

    The polymorphic inversion on 17q21, sometimes called the microtubular associated protein tau (MAPT) inversion, is an ∼900 kb inversion found primarily in Europeans and Southwest Asians. We have identified 21 SNPs that act as markers of the inverted, i.e., H2, haplotype. The inversion is found at the highest frequencies in Southwest Asia and Southern Europe (frequencies of ∼30%); elsewhere in Europe, frequencies vary from < 5%, in Finns, to 28%, in Orcadians. The H2 inversion haplotype also occurs at low frequencies in Africa, Central Asia, East Asia, and the Americas, though the East Asian and Amerindian alleles may be due to recent gene flow from Europe. Molecular evolution analyses indicate that the H2 haplotype originally arose in Africa or Southwest Asia. Though the H2 inversion has many fixed differences across the ∼900 kb, short tandem repeat polymorphism data indicate a very recent date for the most recent common ancestor, with dates ranging from 13,600 to 108,400 years, depending on assumptions and estimation methods. This estimate range is much more recent than the 3 million year age estimated by Stefansson et al. in 2005.1 PMID:20116045

  10. Hairless mutation: a driving force of humanization from a human–ape common ancestor by enforcing upright walking while holding a baby with both hands

    PubMed Central

    Sutou, Shizuyo

    2012-01-01

    Three major characteristics distinguish humans from other primates: bipedality, practical nakedness, and the family as a social unit. A hairless mutation introduced into the chimpanzee/human last common ancestor (CLCA) 6 million years ago (Mya) diverged hairless human and hairy chimpanzee lineages. All primates except humans can carry their babies without using their hands. A hairless mother would be forced to stand and walk upright. Her activities would be markedly limited. The male partner would have to collect food and carry it to her by hand to keep her and their baby from starving; irresponsible and selfish males could not have left their offspring. The mother would have sexually accepted her partner at any time as a reward for food. Sexual relations irrespective of estrus cycles might have strengthened the pair bond. Molecular and paleontological dating indicates that CLCA existed 6 Mya, and early hominin fossils show that they were bipeds, indicating that humanization from CLCA occurred rapidly. A single mutation in animals with scalp hair is known to induce hairless phenotype (ectodermal dysplasia). Bipedalism and hairlessness are disadvantageous traits; only those who could survive trials and tribulations in cooperation with family members must have been able to evolve as humans. PMID:22404045

  11. Modern African ape populations as genetic and demographic models of the last common ancestor of humans, chimpanzees, and gorillas.

    PubMed

    Jensen-Seaman, M I; Deinard, A S; Kidd, K K

    2001-01-01

    In order to fully understand human evolutionary history through the use of molecular data, it is essential to include our closest relatives as a comparison. We provide here estimates of nucleotide diversity and effective population size of modern African ape species using data from several independent noncoding nuclear loci, and use these estimates to make predictions about the nature of the ancestral population that eventually gave rise to the living species of African apes, including humans. Chimpanzees, bonobos, and gorillas possess two to three times more nucleotide diversity than modern humans. We hypothesize that the last common ancestor (LCA) of these species had an effective population size more similar to modern apes than modern humans. In addition, estimated dates for the divergence of the Homo, Pan, and Gorilla lineages suggest that the LCA may have had stronger geographic structuring to its mtDNA than its nuclear DNA, perhaps indicative of strong female philopatry or a dispersal system analogous to gorillas, where females disperse only short distances from their natal group. Synthesizing different classes of data, and the inferences drawn from them, allows us to predict some of the genetic and demographic properties of the LCA of humans, chimpanzees, and gorillas.

  12. Human Diversity and the Genealogy of Languages: Noah as the Founding Ancestor of the Chinese

    ERIC Educational Resources Information Center

    Hutton, Christopher

    2008-01-01

    The characteristics which were held to define the Chinese language within the Western intellectual tradition placed it for a time at the centre in discussions of the genealogy of mankind. The dominant premodern paradigm for the explanation of human linguistic diversity was Biblical exegesis, as discussed and elaborated within the framework of…

  13. Human Diversity and the Genealogy of Languages: Noah as the Founding Ancestor of the Chinese

    ERIC Educational Resources Information Center

    Hutton, Christopher

    2008-01-01

    The characteristics which were held to define the Chinese language within the Western intellectual tradition placed it for a time at the centre in discussions of the genealogy of mankind. The dominant premodern paradigm for the explanation of human linguistic diversity was Biblical exegesis, as discussed and elaborated within the framework of…

  14. Ancient horizontal transfers of retrotransposons between birds and ancestors of human pathogenic nematodes

    PubMed Central

    Suh, Alexander; Witt, Christopher C.; Menger, Juliana; Sadanandan, Keren R.; Podsiadlowski, Lars; Gerth, Michael; Weigert, Anne; McGuire, Jimmy A.; Mudge, Joann; Edwards, Scott V.; Rheindt, Frank E.

    2016-01-01

    Parasite host switches may trigger disease emergence, but prehistoric host ranges are often unknowable. Lymphatic filariasis and loiasis are major human diseases caused by the insect-borne filarial nematodes Brugia, Wuchereria and Loa. Here we show that the genomes of these nematodes and seven tropical bird lineages exclusively share a novel retrotransposon, AviRTE, resulting from horizontal transfer (HT). AviRTE subfamilies exhibit 83–99% nucleotide identity between genomes, and their phylogenetic distribution, paleobiogeography and invasion times suggest that HTs involved filarial nematodes. The HTs between bird and nematode genomes took place in two pantropical waves, >25–22 million years ago (Myr ago) involving the Brugia/Wuchereria lineage and >20–17 Myr ago involving the Loa lineage. Contrary to the expectation from the mammal-dominated host range of filarial nematodes, we hypothesize that these major human pathogens may have independently evolved from bird endoparasites that formerly infected the global breadth of avian biodiversity. PMID:27097561

  15. Ancient wolf genome reveals an early divergence of domestic dog ancestors and admixture into high-latitude breeds.

    PubMed

    Skoglund, Pontus; Ersmark, Erik; Palkopoulou, Eleftheria; Dalén, Love

    2015-06-01

    The origin of domestic dogs is poorly understood [1-15], with suggested evidence of dog-like features in fossils that predate the Last Glacial Maximum [6, 9, 10, 14, 16] conflicting with genetic estimates of a more recent divergence between dogs and worldwide wolf populations [13, 15, 17-19]. Here, we present a draft genome sequence from a 35,000-year-old wolf from the Taimyr Peninsula in northern Siberia. We find that this individual belonged to a population that diverged from the common ancestor of present-day wolves and dogs very close in time to the appearance of the domestic dog lineage. We use the directly dated ancient wolf genome to recalibrate the molecular timescale of wolves and dogs and find that the mutation rate is substantially slower than assumed by most previous studies, suggesting that the ancestors of dogs were separated from present-day wolves before the Last Glacial Maximum. We also find evidence of introgression from the archaic Taimyr wolf lineage into present-day dog breeds from northeast Siberia and Greenland, contributing between 1.4% and 27.3% of their ancestry. This demonstrates that the ancestry of present-day dogs is derived from multiple regional wolf populations.

  16. Enzymes, embryos, and ancestors.

    PubMed

    Gerhart, John

    2010-01-01

    In the 1950s, cellular regulatory mechanisms were newly recognized; with Arthur Pardee I investigated the initial enzyme of pyrimidine biosynthesis, which he discovered is controlled by feedback inhibition. The protein proved unusual in having separate but interacting sites for substrates and regulators. Howard Schachman and I dissociated the protein into different subunits, one binding regulators and one substrates. The enzyme became an early prime example of allostery. In developmental biology I studied the egg of the frog, Xenopus laevis, characterizing early processes of axis formation. My excellent students and I described cortical rotation, a 30° movement of the egg's cortex over tracks of parallel microtubules anchored to the underlying cytoplasmic core, and we perturbed it to alter Spemann's organizer and effect spectacular phenotypes. The entire sequence of events has been elucidated by others at the molecular level, making Xenopus a prime example of vertebrate axis formation. Marc Kirschner, Christopher Lowe, and I then compared hemichordate (half-chordate) and chordate early development. Despite anatomical-physiological differences, these groups share numerous steps of axis formation, ones that were probably already in use in their pre-Cambrian ancestor. I've thoroughly enjoyed exploring these areas during a 50-year period of great advances in biological sciences by the worldwide research community.

  17. Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor.

    PubMed

    Kivell, Tracy L; Schmitt, Daniel

    2009-08-25

    Despite decades of debate, it remains unclear whether human bipedalism evolved from a terrestrial knuckle-walking ancestor or from a more generalized, arboreal ape ancestor. Proponents of the knuckle-walking hypothesis focused on the wrist and hand to find morphological evidence of this behavior in the human fossil record. These studies, however, have not examined variation or development of purported knuckle-walking features in apes or other primates, data that are critical to resolution of this long-standing debate. Here we present novel data on the frequency and development of putative knuckle-walking features of the wrist in apes and monkeys. We use these data to test the hypothesis that all knuckle-walking apes share similar anatomical features and that these features can be used to reliably infer locomotor behavior in our extinct ancestors. Contrary to previous expectations, features long-assumed to indicate knuckle-walking behavior are not found in all African apes, show different developmental patterns across species, and are found in nonknuckle-walking primates as well. However, variation among African ape wrist morphology can be clearly explained if we accept the likely independent evolution of 2 fundamentally different biomechanical modes of knuckle-walking: an extended wrist posture in an arboreal environment (Pan) versus a neutral, columnar hand posture in a terrestrial environment (Gorilla). The presence of purported knuckle-walking features in the hominin wrist can thus be viewed as evidence of arboreality, not terrestriality, and provide evidence that human bipedalism evolved from a more arboreal ancestor occupying the ecological niche common to all living apes.

  18. The effective population sizes of the anthropoid ancestors of the human-chimpanzee lineage provide insights on the historical biogeography of the great apes.

    PubMed

    Schrago, Carlos G

    2014-01-01

    The recent development of methods that apply coalescent theory to phylogenetic problems has enabled the study of the population-level phenomena that drove the diversification of anthropoid primates. Effective population size, Ne, is one of the main parameters that constitute the theoretical underpinning of these new analytical approaches. For this reason, the ancestral N(e) of selected primate lineages has been thoroughly investigated. However, for some of these lineages, the estimates of ancestral N(e) reported in several studies present significant variation. This is the case for the common ancestor of humans and chimpanzees. Moreover, several ancestral anthropoid lineages have been ignored in the studies conducted so far. Because N(e) is fundamental to understand historic species demography, it is a crucial component of a complete description of the historical scenario of primate evolution. It also provides information that is helpful for differentiating between competing biogeographical hypotheses. In this study, the effective population sizes of the anthropoid ancestors of the human-chimp lineage are inferred using data sets of coding and noncoding sequences. A general pattern of a serial decline of population sizes is found between the ancestral lineage of Anthropoidea and that of Homo and Pan. When the theoretical distribution of gene trees was derived from the parametric estimates obtained, it closely corresponded to the empirical frequency of inferred gene trees along the genome. The most abrupt decrease of N(e) was found between the ancestors of all great apes and those of the African great apes alone. This suggests the occurrence of a genetic bottleneck during the evolution of Homininae, which corroborates the origin of African apes from a Eurasian ancestor.

  19. Ancient gene flow from early modern humans into Eastern Neanderthals.

    PubMed

    Kuhlwilm, Martin; Gronau, Ilan; Hubisz, Melissa J; de Filippo, Cesare; Prado-Martinez, Javier; Kircher, Martin; Fu, Qiaomei; Burbano, Hernán A; Lalueza-Fox, Carles; de la Rasilla, Marco; Rosas, Antonio; Rudan, Pavao; Brajkovic, Dejana; Kucan, Željko; Gušic, Ivan; Marques-Bonet, Tomas; Andrés, Aida M; Viola, Bence; Pääbo, Svante; Meyer, Matthias; Siepel, Adam; Castellano, Sergi

    2016-02-25

    It has been shown that Neanderthals contributed genetically to modern humans outside Africa 47,000-65,000 years ago. Here we analyse the genomes of a Neanderthal and a Denisovan from the Altai Mountains in Siberia together with the sequences of chromosome 21 of two Neanderthals from Spain and Croatia. We find that a population that diverged early from other modern humans in Africa contributed genetically to the ancestors of Neanderthals from the Altai Mountains roughly 100,000 years ago. By contrast, we do not detect such a genetic contribution in the Denisovan or the two European Neanderthals. We conclude that in addition to later interbreeding events, the ancestors of Neanderthals from the Altai Mountains and early modern humans met and interbred, possibly in the Near East, many thousands of years earlier than previously thought.

  20. Ancient gene flow from early modern humans into Eastern Neanderthals

    PubMed Central

    Kuhlwilm, Martin; Gronau, Ilan; Hubisz, Melissa J.; de Filippo, Cesare; Prado-Martinez, Javier; Kircher, Martin; Fu, Qiaomei; Burbano, Hernán A.; Lalueza-Fox, Carles; de la Rasilla, Marco; Rosas, Antonio; Rudan, Pavao; Brajkovic, Dejana; Kucan, Željko; Gušic, Ivan; Marques-Bonet, Tomas; Andrés, Aida M.; Viola, Bence; Pääbo, Svante; Meyer, Matthias; Siepel, Adam; Castellano, Sergi

    2016-01-01

    It has been shown that Neanderthals contributed genetically to modern humans outside Africa 47,000–65,000 years ago. Here, we analyze the genomes of a Neanderthal and a Denisovan from the Altai Mountains in Siberia together with the sequences of chromosome 21 of two Neanderthals from Spain and Croatia. We find that a population that diverged early from other modern humans in Africa contributed genetically to the ancestors of Neanderthals from the Altai Mountains roughly 100,000 years ago. By contrast, we do not detect such a genetic contribution in the Denisovan or the two European Neanderthals. We conclude that in addition to later interbreeding events, the ancestors of Neanderthals from the Altai Mountains and of modern humans met and interbred, possibly in the Near East, many thousands of years earlier than previously reported. PMID:26886800

  1. Non-Darwinian estimation: My ancestors, my genes' ancestors

    PubMed Central

    Weiss, Kenneth M.; Long, Jeffrey C.

    2009-01-01

    There is widespread interest in characterizing the organization of human genetic variation around the world from a population perspective. Related to this are attempts to describe the pattern of genetic variation in the human species generally, including “recreational” genomics, the genome-based estimation of the ancestry of individuals. These approaches rest on subtle concepts of variation, time, and ancestry that are perhaps not widely appreciated. They share the idea that there are, or were, discrete panmictic human populations such that every person is either a member of such a population or is an admixed descendant of them. Ancestry fraction estimation is biased by assumptions about past and present human population structure, as when we trace ancestry to hypothetical unmixed ancestral populations, or assign an individual's ancestry to continental populations that are indistinguishable from classical “races.” Attempts to identify even individuals' local subpopulations are less precise than most (geneticists included) expect, because that is usually based on a small portion of a person's ancestry, relative to the much larger pool of comparably related ancestors. It is easier to show that two people have some relationship than to show who or where the actual ancestor was. There is an important distinction between individuals' demographic ancestry and the ancestry of their genes. Despite superficial appearances, these interpretations of genetic data are often based on typological rather than Darwinian thinking, raising important issues about the questions that are actually being asked. PMID:19411595

  2. The deuterostome ancestor.

    PubMed

    Gerhart, John

    2006-12-01

    Hemichordates, the phylum of bilateral animals closest to chordates, can illuminate the evolutionary origins of various chordate traits to determine whether these were already present in a shared ancestor (the deuterostome ancestor) or were evolved within the chordate line. We find that an anteroposterior map of gene expression domains, representing 42 genes of neural patterning, is closely similar in hemichordates and chordates, though it is restricted to the neural ectoderm in chordates whereas in hemichordates, which have a diffuse nervous system, it encircles the whole body. This map allows an accurate alignment of the anterioposterior axes of members of the two groups. We propose that this map dates back at least to the deuterostome ancestor. The map of dorsoventral expression domains, organized along a Bmp-Chordin developmental axis, is also similar in the two groups in terms of many gene expression domains and for the placement of the gill slits, heart, and post-anal tail. The two groups, however, differ in two major respects along this axis. The nervous system and epidermis are not segregated into distinct territories in hemichordates, as they are in chordates, and furthermore, the mouth is on the Chordin side in hemichordates but the Bmp side in chordates. The dorsoventral dimension has undergone extensive modification in the chordate line, including centralization of the nervous system, segregation of epidermis, derivation of the notochord, perhaps from the gut midline, and relocation of the mouth. Based on the shared domain maps, speculations can be made for the remodeling of the body axis in the chordate line.

  3. The galaxy ancestor problem

    NASA Astrophysics Data System (ADS)

    Disney, M. J.; Lang, R. H.

    2012-11-01

    The Hubble Space Telescope (HST) findsgalaxies whose Tolman dimming exceeds 10 mag. Could evolution alone explain these as our ancestor galaxies or could they be representatives of quite a different dynasty whose descendants are no longer prominent today? We explore the latter hypothesis and argue that surface brightness selection effects naturally bring into focus quite different dynasties from different redshifts. Thus, the HST z = 7 galaxies could be examples of galaxies whose descendants are both too small and too choked with dust to be recognizable in our neighbourhood easily today. Conversely, the ancestors of the Milky Way and its obvious neighbours would have completely sunk below the sky at z > 1.2, unless they were more luminous in the past, although their diffused light could account for the missing re-ionization flux. This Succeeding Prominent Dynasties Hypothesis (SPDH) fits the existing observations both naturally and well even without evolution, including the bizarre distributions of galaxy surface brightness found in deep fields, the angular size ˜(1 + z)-1 law, 'downsizing' which turns out to be an 'illusion' in the sense that it does not imply evolution, 'infant mortality', that is, the discrepancy between stars born and stars seen, the existence of 'red nuggets', and finally the recently discovered and unexpected excess of quasar absorption line damped Lyα systems at high redshift. If galaxies were not significantly brighter in the past and the SPDH were true, then a large proportion of galaxies could remain sunk from sight, possibly at all redshifts, and these sunken galaxies could supply the missing re-ionization flux. We show that fishing these sunken galaxies out of the sky by their optical emissions alone is practically impossible, even when they are nearby. More ingenious methods are needed to detect them. It follows that disentangling galaxy evolution through studying ever higher redshift galaxies may be a forlorn hope because one could

  4. Construction and immunogenicity study of a 297-bp humanized HIV V3 DNA of an approximated last common ancestor in mice.

    PubMed

    Sirivichayakul, Sunee; Tirawatnapong, Thaweesak; Ruxrungtham, Kiat; Oelrichs, Robert; Lorenzen, Sven-Lver; Xin, Ke-Qin; Okuda, Kenji; Phanuphak, Praphan

    2004-03-01

    DNA immunization represents one of the promising HIV-1 vaccine approaches. To overcome the obstacle of genetic variation, we used the last common ancestor (LCA) or "center-of-the-tree" approach to study a DNA fragment of the HIV-1 envelope surrounding the V3 region. A humanized codon of the 297-bp consensus ancestral sequence of the HIV-1 envelope (codons 291-391) was derived from the 80 most recent HIV-1 isolates from the 8 circulating HIV-1 subtypes worldwide. This 297-bp humanized "multi-clade" V3 DNA was amplified by a PCR-based technique. The PCR product was well expressed in vitro whereas the corresponding non-humanized V3 DNA (subtype A/E) could not be expressed. However, both V3 DNA constructs as well as the full-length HIV-1 envelope construct (A/E) were found to be immunogenic in mice by the footpad-swelling assay. Moreover, intracellular and extracellular interferon-gamma could be detected upon in vitro stimulation of spleen cells although the response was relatively weak. Further improvement of our humanized V3 DNA is needed.

  5. Ontogeny of the maxilla in Neanderthals and their ancestors.

    PubMed

    Lacruz, Rodrigo S; Bromage, Timothy G; O'Higgins, Paul; Arsuaga, Juan-Luis; Stringer, Chris; Godinho, Ricardo Miguel; Warshaw, Johanna; Martínez, Ignacio; Gracia-Tellez, Ana; de Castro, José María Bermúdez; Carbonell, Eudald

    2015-12-07

    Neanderthals had large and projecting (prognathic) faces similar to those of their putative ancestors from Sima de los Huesos (SH) and different from the retracted modern human face. When such differences arose during development and the morphogenetic modifications involved are unknown. We show that maxillary growth remodelling (bone formation and resorption) of the Devil's Tower (Gibraltar 2) and La Quina 18 Neanderthals and four SH hominins, all sub-adults, show extensive bone deposition, whereas in modern humans extensive osteoclastic bone resorption is found in the same regions. This morphogenetic difference is evident by ∼5 years of age. Modern human faces are distinct from those of the Neanderthal and SH fossils in part because their postnatal growth processes differ markedly. The growth remodelling identified in these fossil hominins is shared with Australopithecus and early Homo but not with modern humans suggesting that the modern human face is developmentally derived.

  6. Ontogeny of the maxilla in Neanderthals and their ancestors

    PubMed Central

    Lacruz, Rodrigo S.; Bromage, Timothy G.; O'Higgins, Paul; Arsuaga, Juan-Luis; Stringer, Chris; Godinho, Ricardo Miguel; Warshaw, Johanna; Martínez, Ignacio; Gracia-Tellez, Ana; de Castro, José María Bermúdez; Carbonell, Eudald

    2015-01-01

    Neanderthals had large and projecting (prognathic) faces similar to those of their putative ancestors from Sima de los Huesos (SH) and different from the retracted modern human face. When such differences arose during development and the morphogenetic modifications involved are unknown. We show that maxillary growth remodelling (bone formation and resorption) of the Devil's Tower (Gibraltar 2) and La Quina 18 Neanderthals and four SH hominins, all sub-adults, show extensive bone deposition, whereas in modern humans extensive osteoclastic bone resorption is found in the same regions. This morphogenetic difference is evident by ∼5 years of age. Modern human faces are distinct from those of the Neanderthal and SH fossils in part because their postnatal growth processes differ markedly. The growth remodelling identified in these fossil hominins is shared with Australopithecus and early Homo but not with modern humans suggesting that the modern human face is developmentally derived. PMID:26639346

  7. Structure of the human type XIX collagen (COL19A1) gene, which suggests it has arisen from an ancestor gene of the FACIT family.

    PubMed

    Khaleduzzaman, M; Sumiyoshi, H; Ueki, Y; Inoguchi, K; Ninomiya, Y; Yoshioka, H

    1997-10-15

    Type XIX collagen is a newly discovered member of the FACIT (fibril-associated collagens with interrupted triple helices) group of extracellular matrix proteins. Based on the primary structure, type XIX collagen is thought to act as a cross-bridge between fibrils and other extracellular matrix molecules. Here we describe the complete exon/intron organization of COL19A1 and show that it contains 51 exons, spanning more than 250 kb of genomic DNA. The comparison of exon structures of COL19A1 and other FACIT family genes revealed several similarities among these genes. The structure of exons encoding the noncollagenous (NC) 1-collagenous (COL) 1-NC 2-COL 2-NC 3-COL 3-NC 4 domain of the alpha1(XIX) chain is similar to that of the NC 1-COL 1-NC 2-COL 3-NC 3 domain of the alpha2(IX) chain except for the NC 3 domain of alpha1(XIX). The exons encoding the COL 5-NC 6 domain of alpha1(XIX) are also similar to those of the COL 3-NC 4 domain of alpha1(IX) chain. Previously, COL19A1 was mapped to human chromosome 6q12-q14, where COL9A1 is also located. Likewise, the present work shows that the mouse Col19a1 gene is located on mouse chromosome 1, region A3, where Col9a1 has also been mapped. Taken together, the data suggest that COL19A1 and COL9A1 (Col19a1 and Col9a1) were duplicated from the same ancestor gene of the FACIT family. Three CA repeat markers with high heterozygosity were found in COL19A1. These markers may be useful for linkage analysis of age-related inheritable diseases involved in eyes and/or brain.

  8. Aping our ancestors

    NASA Astrophysics Data System (ADS)

    Ennos, Roland

    2014-08-01

    Roland Ennos argues that the abilities of the great apes to cope in the dangerous mechanical environment of the forest canopy are part of the human species' intellectual inheritance and are intimately connected with our abilities as physicists.

  9. Origin of Clothing Lice Indicates Early Clothing Use by Anatomically Modern Humans in Africa

    PubMed Central

    Toups, Melissa A.; Kitchen, Andrew; Light, Jessica E.; Reed, David L.

    2011-01-01

    Clothing use is an important modern behavior that contributed to the successful expansion of humans into higher latitudes and cold climates. Previous research suggests that clothing use originated anywhere between 40,000 and 3 Ma, though there is little direct archaeological, fossil, or genetic evidence to support more specific estimates. Since clothing lice evolved from head louse ancestors once humans adopted clothing, dating the emergence of clothing lice may provide more specific estimates of the origin of clothing use. Here, we use a Bayesian coalescent modeling approach to estimate that clothing lice diverged from head louse ancestors at least by 83,000 and possibly as early as 170,000 years ago. Our analysis suggests that the use of clothing likely originated with anatomically modern humans in Africa and reinforces a broad trend of modern human developments in Africa during the Middle to Late Pleistocene. PMID:20823373

  10. Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa.

    PubMed

    Toups, Melissa A; Kitchen, Andrew; Light, Jessica E; Reed, David L

    2011-01-01

    Clothing use is an important modern behavior that contributed to the successful expansion of humans into higher latitudes and cold climates. Previous research suggests that clothing use originated anywhere between 40,000 and 3 Ma, though there is little direct archaeological, fossil, or genetic evidence to support more specific estimates. Since clothing lice evolved from head louse ancestors once humans adopted clothing, dating the emergence of clothing lice may provide more specific estimates of the origin of clothing use. Here, we use a Bayesian coalescent modeling approach to estimate that clothing lice diverged from head louse ancestors at least by 83,000 and possibly as early as 170,000 years ago. Our analysis suggests that the use of clothing likely originated with anatomically modern humans in Africa and reinforces a broad trend of modern human developments in Africa during the Middle to Late Pleistocene.

  11. Early depictions of the human anterior nasal septum.

    PubMed

    Pirsig, Wolfgang; Sokiranski, Roman

    2006-06-01

    In the literature, remarks on the depiction of the anterior nasal septum in prehistoric times cannot be found. Studying works of art from some archaeological sites of Asia, Asia Minor, Near East, Egypt, and Southeastern Europe the anatomical depiction of the columella and the nostrils in human figures are shown. These figures or heads, partly appearing as masks, were made of ivory, stone, marble, terracotta, steatite, reeds and clay, or of burned limestone. Faces and figures sculpted in the time between the Upper Palaeolithic (30,000 - 25,000 BC) and the Early Bronze Age (3,300 - 2,400 BC) are presented as examples of our ancestors' outstanding skill to create works of art with an astonishing ability to observe anatomical details. The tendency to create a human nose in a natural manner can already be recognized in the figurines of the Upper Palaeolithic.

  12. The universal ancestor and the ancestor of bacteria were hyperthermophiles.

    PubMed

    Di Giulio, Massimo

    2003-12-01

    The definition of the node of the last universal common ancestor (LUCA) is justified in a topology of the unrooted universal tree. This definition allows previous analyses based on paralogous proteins to be extended to orthologous ones. In particular, the use of a thermophily index (based on the amino acids' propensity to enter the [hyper] thermophile proteins more frequently) and its correlation with the optimal growth temperature of the various organisms allow inferences to be made on the habitat in which the LUCA lived. The reconstruction of ancestral sequences by means of the maximum likelihood method and their attribution to the set of mesophilic or hyperthermophilic sequences have led to the following conclusions: the LUCA was a hyperthermophile "organism," as were the ancestors of the Archaea and Bacteria domains, while the ancestor of the Eukarya domain was a mesophile. These conclusions are independent of the presence of hyperthermophile bacteria in the sample of sequences used in the analysis and are therefore independent of whether or not these are the first lines of divergence in the Bacteria domain, as observed in the topology of the universal tree of ribosomal RNA. These conclusions are thus more easily understood under the hypothesis that the origin of life took place at a high temperature.

  13. 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

  14. The last common bilaterian ancestor

    NASA Technical Reports Server (NTRS)

    Erwin, Douglas H.; Davidson, Eric H.

    2002-01-01

    Many regulatory genes appear to be utilized in at least superficially similar ways in the development of particular body parts in Drosophila and in chordates. These similarities have been widely interpreted as functional homologies, producing the conventional view of the last common protostome-deuterostome ancestor (PDA) as a complex organism that possessed some of the same body parts as modern bilaterians. Here we discuss an alternative view, in which the last common PDA had a less complex body plan than is frequently conceived. This reconstruction alters expectations for Neoproterozoic fossil remains that could illustrate the pathways of bilaterian evolution.

  15. Ancestors of modern plant crops.

    PubMed

    Salse, Jérôme

    2016-04-01

    Recent accumulation of plant genomic resources offers the opportunity to compare modern genomes and model their evolutionary history from their reconstructed Most Recent Common Ancestors (MRCAs) that can be used as a guide to unveil the forces driving the evolutionary success of angiosperms and ultimately to perform applied translational research from models to crops. This article reviews the current state of art of recent structural comparative genomics studies through ancestral genome reconstruction, that is, the field of in silico paleogenomics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. The last common bilaterian ancestor

    NASA Technical Reports Server (NTRS)

    Erwin, Douglas H.; Davidson, Eric H.

    2002-01-01

    Many regulatory genes appear to be utilized in at least superficially similar ways in the development of particular body parts in Drosophila and in chordates. These similarities have been widely interpreted as functional homologies, producing the conventional view of the last common protostome-deuterostome ancestor (PDA) as a complex organism that possessed some of the same body parts as modern bilaterians. Here we discuss an alternative view, in which the last common PDA had a less complex body plan than is frequently conceived. This reconstruction alters expectations for Neoproterozoic fossil remains that could illustrate the pathways of bilaterian evolution.

  17. Windmills: Ancestors of the wind power generation

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Russo, Flavio; Savino, Sergio

    2017-09-01

    A brief description of the windmills from the second millennium BC to the Renaissance is presented. This survey is a part of several studies conducted by the authors on technology in the ancient world. The windmills are the first motor, other than human muscles, and are the ancestors of the modern wind turbines. Some authors' virtual reconstructions of old windmills are also presented. The paper shows that the operating principle of many modern machines had already been conceived in the ancient times by using a technology that was more advanced than expected, but with two main differences, as follows: Similar tasks were accomplished by using much less energy; and the environmental impact was nil or very low. Modern designers should sometimes consider simplicity rather than the use of a large amount of energy.

  18. Windmills: Ancestors of the wind power generation

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Russo, Flavio; Savino, Sergio

    2016-12-01

    A brief description of the windmills from the second millennium BC to the Renaissance is presented. This survey is a part of several studies conducted by the authors on technology in the ancient world. The windmills are the first motor, other than human muscles, and are the ancestors of the modern wind turbines. Some authors' virtual reconstructions of old windmills are also presented. The paper shows that the operating principle of many modern machines had already been conceived in the ancient times by using a technology that was more advanced than expected, but with two main differences, as follows: Similar tasks were accomplished by using much less energy; and the environmental impact was nil or very low. Modern designers should sometimes consider simplicity rather than the use of a large amount of energy.

  19. Transcriptome Encyclopedia of Early Human Development.

    PubMed

    Sahakyan, Anna; Plath, Kathrin

    2016-05-05

    Our understanding of human pre-implantation development is limited by the availability of human embryos and cannot completely rely on mouse studies. Petropoulos et al. now provide an extensive transcriptome analysis of a large number of human pre-implantation embryos at single-cell resolution, revealing previously unrecognized features unique to early human development.

  20. [Luca: the last universal common ancestor].

    PubMed

    Forterre, Patrick; Gribaldo, Simonetta; Brochier, Céline

    2005-10-01

    One of the most important outcomes of modern biology has been the demonstration of the unity of life. All living beings are in fact descendants of a unique ancestor commonly referred to as Luca (the Last universal common ancestor). The discovery - nearly 30 years ago by Carl Woese - that present-day life on our planet can be assigned to only three domains: two of prokaryotic nature (Archaea and Bacteria), and one eukaryoyic (Eucarya), has given birth to a new field of investigation aimed at determining the nature of Luca. Today, thanks to the accumulation of genomic data, we can loop back into the past and infer a few characters of Luca by comparing what present-day organisms have in common. For example, it is now clear that Luca was a cellular organism provided with a cytoplasmic membrane, and that it harboured already a quite sophisticated translation apparatus. However, the inference of other characters of Luca from comparative genomics is less straightforward: for instance, a few key molecular mechanisms for DNA replication are non-homologous across the three domains and their distribution is often puzzling. This evidence has been embraced by proponents of the hypothesis that Luca harboured an RNA genome and that its replacement by DNA and the appearance of the corresponding molecular systems would have occurred independently in the three life domains after their divergence. However, an equally likely scenario would be that of a Luca with a DNA genome and of a subsequent replacement of its DNA-replication systems by non-homologous counterparts either in the bacterial or in the archaeal/eukaroytic branch. Nevertheless, including the viral world into the picture of the tree of life may thus provide us with precious insights into our most distant past since the invention and spread potential of viruses may have played a key role in early evolution.

  1. The Evolution of Brains from Early Mammals to Humans

    PubMed Central

    Kaas, Jon H.

    2012-01-01

    The large size and complex organization of the human brain makes it unique among primate brains. In particular, the neocortex constitutes about 80% of the brain, and this cortex is subdivided into a large number of functionally specialized regions, the cortical areas. Such a brain mediates accomplishments and abilities unmatched by any other species. How did such a brain evolve? Answers come from comparative studies of the brains of present-day mammals and other vertebrates in conjunction with information about brain sizes and shapes from the fossil record, studies of brain development, and principles derived from studies of scaling and optimal design. Early mammals were small, with small brains, an emphasis on olfaction, and little neocortex. Neocortex was transformed from the single layer of output pyramidal neurons of the dorsal cortex of earlier ancestors to the six layers of all present-day mammals. This small cap of neocortex was divided into 20–25 cortical areas, including primary and some of the secondary sensory areas that characterize neocortex in nearly all mammals today. Early placental mammals had a corpus callosum connecting the neocortex of the two hemispheres, a primary motor area, M1, and perhaps one or more premotor areas. One line of evolution, Euarchontoglires, led to present-day primates, tree shrews, flying lemurs, rodents and rabbits. Early primates evolved from small-brained, nocturnal, insect-eating mammals with an expanded region of temporal visual cortex. These early nocturnal primates were adapted to the fine branch niche of the tropical rainforest by having an even more expanded visual system that mediated visually guided reaching and grasping of insects, small vertebrates, and fruits. Neocortex was greatly expanded, and included an array of cortical areas that characterize neocortex of all living primates. Specializations of the visual system included new visual areas that contributed to a dorsal stream of visuomotor processing in a

  2. The Hunt for Dwarf Galaxies' Ancestors

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Dwarf galaxies are typically very faint, and are therefore hard to find. Given that, what are our chances of finding their distant ancestors, located billions of light-years away? A recent study aims to find out.Ancient CounterpartsDwarf galaxies are a hot topic right now, especially as we discover more and more of them nearby. Besides being great places to investigate a variety of astrophysical processes, local group dwarf galaxies are also representative of the most common type of galaxy in the universe. For many of these dwarf galaxies, their low masses and typically old stellar populations suggest that most of their stars were formed early in the universes history, and further star formation was suppressed when the universe was reionized at redshifts of z ~ 610. If this is true, most dwarf galaxies are essentially fossils: theyve evolved little since that point.To test this theory, wed like to find counterparts to our local group dwarf galaxies at these higher redshifts of z = 6 or 7. But dwarf galaxies, since they dont exhibit lots of active star formation, have very low surface brightnesses making them very difficult to detect. What are the chances that current or future telescope sensitivities will allow us to detect these? Thats the question Anna Patej and Abraham Loeb, two theorists at Harvard University, have addressed in a recent study.Entering a New RegimeThe surface brightness vs. size for 73 local dwarf galaxies scaled back to redshifts of z=6 (top) and z=7 (bottom). So far weve been able to observe high-redshift galaxies within the boxed region of the parameter space. JWST will open the shaded region of the parameter space, which includes some of the dwarf galaxies. [Patej Loeb 2015]Starting from observational data for 87 Local-Group dwarf galaxies, Patej and Loeb used a stellar population synthesis code to evolve the galaxies backward in time to redshifts of z = 6 and 7. Next, they narrowed this sample to only those dwarfs for which most star

  3. The Five Ancestors--Book 1: Tiger

    ERIC Educational Resources Information Center

    Stone, Jeff

    2004-01-01

    Losing a job is an awfully low point--until it turns into the opportunity to pursue writing full time, and a book like "The Five Ancestors: Tiger" results. Jeff Stone looks back to his own experience as a young reader and taps that experience to help frame his own writing. An intriguing snapshot of his new book follows.

  4. Apparatus Named after Our Academic Ancestors, III

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2014-01-01

    My academic ancestors in physics have called on me once more to tell you about the apparatus that they devised, and that many of you have used in your demonstrations and labs. This article is about apparatus named after François Arago, Heinrich Helmholtz, Leon Foucault, and James Watt.

  5. Apparatus Named After Our Academic Ancestors, III

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2014-09-01

    My academic ancestors in physics have called on me once more to tell you about the apparatus that they devised, and that many of you have used in your demonstrations and labs. This article is about apparatus named after François Arago, Heinrich Helmholtz, Leon Foucault, and James Watt.

  6. Apparatus Named after Our Academic Ancestors, III

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2014-01-01

    My academic ancestors in physics have called on me once more to tell you about the apparatus that they devised, and that many of you have used in your demonstrations and labs. This article is about apparatus named after François Arago, Heinrich Helmholtz, Leon Foucault, and James Watt.

  7. Gazing Back: Communing with Our Ancestors

    ERIC Educational Resources Information Center

    Osorio, Jonathan Kay Kamakawiwo'ole

    2004-01-01

    This article is a poignant commentary on the connection of the Native Hawaiian people with the past, the present, and the future. In this article, the author positions himself within the histories of his people. He talks about putting faces to his ancestors by linking them with the people of his day, and he talks about reconstructing the…

  8. The Five Ancestors--Book 1: Tiger

    ERIC Educational Resources Information Center

    Stone, Jeff

    2004-01-01

    Losing a job is an awfully low point--until it turns into the opportunity to pursue writing full time, and a book like "The Five Ancestors: Tiger" results. Jeff Stone looks back to his own experience as a young reader and taps that experience to help frame his own writing. An intriguing snapshot of his new book follows.

  9. Environment and Climate of Early Human Evolution

    NASA Astrophysics Data System (ADS)

    Levin, Naomi E.

    2015-05-01

    Evaluating the relationships between climate, the environment, and human traits is a key part of human origins research because changes in Earth's atmosphere, oceans, landscapes, and ecosystems over the past 10 Myr shaped the selection pressures experienced by early humans. In Africa, these relationships have been influenced by a combination of high-latitude ice distributions, sea surface temperatures, and low-latitude orbital forcing that resulted in large oscillations in vegetation and moisture availability that were modulated by local basin dynamics. The importance of both climate and tectonics in shaping African landscapes means that integrated views of the ecological, environmental, and tectonic histories of a region are necessary in order to understand the relationships between climate and human evolution.

  10. Microdosing for early biokinetic studies in humans.

    PubMed

    Stenström, K; Sydoff, M; Mattsson, S

    2010-01-01

    Microdosing is a new concept in drug development that--if implemented in the pharmaceutical industry--would mean that new drugs can be tested earlier in humans than done today. The human microdosing concept--or 'Phase 0'--may offer improved candidate selection, reduced failure rates in the drug development line and a reduction in the use of laboratory animals in early drug development, factors which will help to speed up drug development and also reduce the costs. Microdosing utilises sub-pharmacological amounts of the substance to open opportunities for early studies in man. Three technologies are used for microdosing: accelerator mass spectrometry (AMS), positron emission tomography and liquid chromatography-tandem mass spectrometry. This paper focuses on the principle of AMS and discusses the current status of microdosing with AMS.

  11. In pursuit of our ancestors' hand laterality.

    PubMed

    Bargalló, Amèlia; Mosquera, Marina; Lozano, Sergi

    2017-10-01

    The aim of this paper is to apply a previously published method (Bargalló and Mosquera, 2014) to the archaeological record, allowing us to identify the hand laterality of our ancestors and determine when and how this feature, which is exhibited most strongly in humans, appeared in our evolutionary history. The method focuses on identifying handedness by looking at the technical features of the flakes produced by a single knapper, and discovering how many flakes are required to ascertain their hand preference. This method can potentially be applied to the majority of archaeological sites, since flakes are the most abundant stone tools, and stone tools are the most widespread and widely-preserved remains from prehistory. For our study, we selected two Spanish sites: Gran Dolina-TD10.1 (Atapuerca) and Abric Romaní (Barcelona), which were occupied by pre-Neanderthal and Neanderthal populations, respectively. Our analyses indicate that a minimum number of eight flakes produced by the same knapper is required to ascertain their hand preference. Even though this figure is relatively low, it is quite difficult to obtain from many archaeological sites. In addition, there is no single technical feature that provides information about handedness, instead there is a combination of eight technical features, localised on the striking platforms and ventral surfaces. The raw material is not relevant where good quality rocks are used, in this case quartzite and flint, since most of them retain the technical features required for the analysis. Expertise is not an issue either, since the technical features analysed here only correlate with handedness (Bargalló and Mosquera, 2014). Our results allow us to tentatively identify one right-handed knapper among the pre-Neanderthals of level TD10.1 at Gran Dolina (Atapuerca), while four of the five Neanderthals analysed from Abric Romaní were right-handed. The hand preference of the fifth knapper from that location (AR5) remains unclear

  12. Magnetochronology of early humans in China

    NASA Astrophysics Data System (ADS)

    Deng, C.; Zhu, R.; Pan, Y.

    2009-12-01

    China is a key area for probing into human occupation in the Old World after the initial expansion of early humans out of Africa. Chronology of Chinese Paleolithic/hominin sites in different paleoclimatic and paleoenvironmental settings is paramount for understanding early human migration and adaptation. In recent years, we conducted detailed magnetostratigraphic investigations on the Nihewan Basin in temperate northern China and the Yuanmou Basin in subtropical southern China, both of which contained abundant sites of early humans and mammalian faunas. The age of the sedimentary sequence of the eastern Nihewan Basin can be magnetostratigraphically constrained to an interval from late Pliocene to late Pleistocene. The basal age of the Nihewan Formation in the eastern basin is constrained just prior to the Gauss-Matuyama geomagnetic reversal, that is, between ~2.6 Ma and ~3.0 Ma. The fluvio-lacustrine sequences in this basin were deposited from the late Gauss chron into the late Brunhes chron, and are capped by the last interglacial soil and the last glacial loess , or by the late Pleistocene or Holocene loess sediments. As a result, the Nihewan faunas (sensu lato) can be placed between the Matuyama-Brunhes geomagnetic reversal and the onset of the Olduvai subchron (0.78-1.95 Ma), and a robust chronological sequence of early human colonization in this basin has been established: Maliang (0.8 Ma), Huojiadi (1.0 Ma), Donggutuo and Cenjiawan (1.1 Ma), Feiliang (1.2 Ma), Banshan (1.32 Ma), Xiaochangliang and Xiantai (1.36 Ma), MJG-I (1.55 Ma), MJG-II (1.64 Ma), and MJG-III (1.66 Ma). The age of the sedimentary sequence of the Yuanmou Basin can be magnetostratigraphically constrained to an interval from early Pliocene to Pleistocene. The basal age of this basin sedimentary sequence is constrained just prior to the onset of the Sidufjall subchron, that is, ~4.9 Ma. Accumulation of the Yuanmou sequence was terminated during the Matuyama chron bracketed by the Olduvai and

  13. An unexpected recent ancestor of unisexual Ambystoma.

    PubMed

    Robertson, Alexander V; Ramsden, Cadhla; Niedzwiecki, John; Fu, Jinzhong; Bogart, James P

    2006-10-01

    Previous research has shown that members of the unisexual hybrid complex of the genus Ambystoma possess a mitochondrial genome that is unrelated to their nuclear parental species, but the origin of this mitochondrion has remained unclear. We used a 744-bp fragment of the mitochondrial gene cytochrome b within a comparative phylogenetic framework to infer the maternal ancestor of this unisexual lineage. By examining a broader range of species than has previously been compared, we were able to uncover a recent maternal ancestor to this complex. Unexpectedly, Ambystoma barbouri, a species whose nuclear DNA has not been identified in the unisexuals, was found to be the recent maternal ancestor of the individuals examined through the discovery of a shared mtDNA haplotype between the unisexuals and A. barbouri. Based on a combination of sequence data and glacial patterning, we estimate that the unisexual lineage probably originated less than 25 000 years ago. In addition, all unisexuals examined showed extremely similar mtDNA sequences and the resultant phylogeny was consistent with a single origin for this lineage. These results confirm previous suggestions that the unisexual Ambystoma complex was formed from a hybridization event in which the nuclear DNA of the original maternal species was subsequently lost.

  14. Redeeming the lost voice of the ancestors.

    PubMed

    Troudart, Michal

    2012-09-01

    The Holocaust of the Jews in World War II involved not only the murder of 6 million Jews but also the traumatic destruction and wipe-out of whole communities, with their rich culture and tradition which had existed for centuries. In places where no one survived, it was almost impossible to reconstruct the collective memory of those communities. The voice of the ancestors was lost. As a daughter of Holocaust survivors, I have always felt the strong presence of the loss, not only of the murdered family members but also of the ancient colourful world of Eastern European Jews. I have always felt compelled to link back to that lost world. In the past three years, my journey to the pre-war past has become more intense. This article describes the double role of my journey: it is both an attempt to reconstruct, redeem and preserve the memory of the lost ancestors, and a personal journey to the echoes of my ancestors' voices within my soul.

  15. Magnetostratigraphic dating of early humans in China

    NASA Astrophysics Data System (ADS)

    Zhu, Rixiang; An, Zhisheng; Potts, Richard; Hoffman, Kenneth A.

    2003-06-01

    China is a key area for research into human occupation in the Old World after the initial expansion of early humans out of Africa. Reliable age determinations are pivotal for assessing the patterns of human evolution and dispersal in this region. This paper reviews magnetostratigraphic studies of some early Pleistocene strata bearing hominin remains and/or artifact stone tools from northern to southern China. The quality and reliability of the paleomagnetic dates are also evaluated. New magnetostratigraphic results for the Xihoudu Paleolithic site in north-central China are also presented. Among the few hominin or Paleolithic sites in China from the early Pleistocene, five have been well investigated. Three of these are in northern China at Xiaochangliang, Donggutuo and Gongwangling; the remaining two in southern China at Longgupo and Yuanmou. Considerable progress has been made during the past three decades towards paleomagnetically dating these sites. Indeed, the age estimates at Xiaochangliang and Gongwangling have been widely accepted. Magnetostratigraphic consensus about the age of the Donggutuo site has also been reached. However, the age determination for the two sites in southern China is still contested. The integration of rock-magnetic stratigraphy with magnetic polarity stratigraphy has resulted in a determined age of 1.36 Ma for a stone tool-containing layer of lacustrine sediments at the Xiaochangliang site in the Nihewan Basin. Lithostratigraphic constraints have significantly contributed to determining the age of Lantian Homo erectus at Gongwangling, which occurred in a loess-paleosol sequence of the southern Loess Plateau. Its age, paleomagnetically derived, is about 1.15 Ma. These two paleomagnetic ages suggest an expansion and flourishing of human groups from northern to north-central China during the early Pleistocene. This suggestion has been reinforced by our new magnetostratigraphic age estimate of about 1.27 Ma for the Xihoudu site as will be

  16. Skeletal variation among early Holocene North American humans: implications for origins and diversity in the Americas.

    PubMed

    Auerbach, Benjamin M

    2012-12-01

    The movement of humans into the Americas remains a major topic of debate among scientific disciplines. Central to this discussion is ascertaining the timing and migratory routes of the earliest colonizers, in addition to understanding their ancestry. Molecular studies have recently argued that the colonizing population was isolated from other Asian populations for an extended period before proceeding to colonize the Americas. This research has suggested that Beringia was the location of this "incubation," though archaeological and skeletal data have not yet supported this hypothesis. This study employs the remains of the five most complete North American male early Holocene skeletons to examine patterns of human morphology at the earliest observable time period. Stature, body mass, body breadth, and limb proportions are examined in the context of male skeletal samples representing the range of morphological variation in North America in the last two millennia of the Holocene. These are also compared with a global sample. Results indicate that early Holocene males have variable postcranial morphologies, but all share the common trait of wide bodies. This trait, which is retained in more recent indigenous North American groups, is associated with adaptations to cold climates. Peoples from the Americas exhibit wider bodies than other populations sampled globally. This pattern suggests the common ancestral population of all of these indigenous American groups had reduced morphological variation in this trait. Furthermore, this provides support for a single, possibly high latitude location for the genetic isolation of ancestors of the human colonizers of the Americas.

  17. The last universal common ancestor (LUCA) and the ancestors of archaea and bacteria were progenotes.

    PubMed

    Di Giulio, Massimo

    2011-01-01

    The tRNA split genes of Nanoarchaeum equitans and the Met-tRNA(fMet) → fMet-tRNA(fMet) pathway, identifiable as ancestral traits, and the late appearance of DNA are used to understand the evolutionary stage at which the progenote → genote transition took place. The arguments are such as to impose that not only was the last universal common ancestor (LUCA) a progenote, but the ancestors of Archaea and Bacteria were too. Therefore, the progenote → genote transition took place in a very advanced stage of the evolution of the tree of life, and only when the ancestors of Archaea and Bacteria were already defined. These conclusions are in disagreement with commonly held beliefs.

  18. Punctuated emergences of genetic and phenotypic innovations in eumetazoan, bilaterian, euteleostome, and hominidae ancestors.

    PubMed

    Wenger, Yvan; Galliot, Brigitte

    2013-01-01

    Phenotypic traits derive from the selective recruitment of genetic materials over macroevolutionary times, and protein-coding genes constitute an essential component of these materials. We took advantage of the recent production of genomic scale data from sponges and cnidarians, sister groups from eumetazoans and bilaterians, respectively, to date the emergence of human proteins and to infer the timing of acquisition of novel traits through metazoan evolution. Comparing the proteomes of 23 eukaryotes, we find that 33% human proteins have an ortholog in nonmetazoan species. This premetazoan proteome associates with 43% of all annotated human biological processes. Subsequently, four major waves of innovations can be inferred in the last common ancestors of eumetazoans, bilaterians, euteleostomi (bony vertebrates), and hominidae, largely specific to each epoch, whereas early branching deuterostome and chordate phyla show very few innovations. Interestingly, groups of proteins that act together in their modern human functions often originated concomitantly, although the corresponding human phenotypes frequently emerged later. For example, the three cnidarians Acropora, Nematostella, and Hydra express a highly similar protein inventory, and their protein innovations can be affiliated either to traits shared by all eumetazoans (gut differentiation, neurogenesis); or to bilaterian traits present in only some cnidarians (eyes, striated muscle); or to traits not identified yet in this phylum (mesodermal layer, endocrine glands). The variable correspondence between phenotypes predicted from protein enrichments and observed phenotypes suggests that a parallel mechanism repeatedly produce similar phenotypes, thanks to novel regulatory events that independently tie preexisting conserved genetic modules.

  19. Punctuated Emergences of Genetic and Phenotypic Innovations in Eumetazoan, Bilaterian, Euteleostome, and Hominidae Ancestors

    PubMed Central

    Wenger, Yvan; Galliot, Brigitte

    2013-01-01

    Phenotypic traits derive from the selective recruitment of genetic materials over macroevolutionary times, and protein-coding genes constitute an essential component of these materials. We took advantage of the recent production of genomic scale data from sponges and cnidarians, sister groups from eumetazoans and bilaterians, respectively, to date the emergence of human proteins and to infer the timing of acquisition of novel traits through metazoan evolution. Comparing the proteomes of 23 eukaryotes, we find that 33% human proteins have an ortholog in nonmetazoan species. This premetazoan proteome associates with 43% of all annotated human biological processes. Subsequently, four major waves of innovations can be inferred in the last common ancestors of eumetazoans, bilaterians, euteleostomi (bony vertebrates), and hominidae, largely specific to each epoch, whereas early branching deuterostome and chordate phyla show very few innovations. Interestingly, groups of proteins that act together in their modern human functions often originated concomitantly, although the corresponding human phenotypes frequently emerged later. For example, the three cnidarians Acropora, Nematostella, and Hydra express a highly similar protein inventory, and their protein innovations can be affiliated either to traits shared by all eumetazoans (gut differentiation, neurogenesis); or to bilaterian traits present in only some cnidarians (eyes, striated muscle); or to traits not identified yet in this phylum (mesodermal layer, endocrine glands). The variable correspondence between phenotypes predicted from protein enrichments and observed phenotypes suggests that a parallel mechanism repeatedly produce similar phenotypes, thanks to novel regulatory events that independently tie preexisting conserved genetic modules. PMID:24065732

  20. Mitochondrial lineage M1 traces an early human backflow to Africa

    PubMed Central

    González, Ana M; Larruga, José M; Abu-Amero, Khaled K; Shi, Yufei; Pestano, José; Cabrera, Vicente M

    2007-01-01

    Background The out of Africa hypothesis has gained generalized consensus. However, many specific questions remain unsettled. To know whether the two M and N macrohaplogroups that colonized Eurasia were already present in Africa before the exit is puzzling. It has been proposed that the east African clade M1 supports a single origin of haplogroup M in Africa. To test the validity of that hypothesis, the phylogeographic analysis of 13 complete mitochondrial DNA (mtDNA) sequences and 261 partial sequences belonging to haplogroup M1 was carried out. Results The coalescence age of the African haplogroup M1 is younger than those for other M Asiatic clades. In contradiction to the hypothesis of an eastern Africa origin for modern human expansions out of Africa, the most ancestral M1 lineages have been found in Northwest Africa and in the Near East, instead of in East Africa. The M1 geographic distribution and the relative ages of its different subclades clearly correlate with those of haplogroup U6, for which an Eurasian ancestor has been demonstrated. Conclusion This study provides evidence that M1, or its ancestor, had an Asiatic origin. The earliest M1 expansion into Africa occurred in northwestern instead of eastern areas; this early spread reached the Iberian Peninsula even affecting the Basques. The majority of the M1a lineages found outside and inside Africa had a more recent eastern Africa origin. Both western and eastern M1 lineages participated in the Neolithic colonization of the Sahara. The striking parallelism between subclade ages and geographic distribution of M1 and its North African U6 counterpart strongly reinforces this scenario. Finally, a relevant fraction of M1a lineages present today in the European Continent and nearby islands possibly had a Jewish instead of the commonly proposed Arab/Berber maternal ascendance. PMID:17620140

  1. The existence and abundance of ghost ancestors in biparental populations.

    PubMed

    Gravel, Simon; Steel, Mike

    2015-05-01

    In a randomly-mating biparental population of size N there are, with high probability, individuals who are genealogical ancestors of every extant individual within approximately log2(N) generations into the past. We use this result of J. Chang to prove a curious corollary under standard models of recombination: there exist, with high probability, individuals within a constant multiple of log2(N) generations into the past who are simultaneously (i) genealogical ancestors of each of the individuals at the present, and (ii) genetic ancestors to none of the individuals at the present. Such ancestral individuals-ancestors of everyone today that left no genetic trace-represent 'ghost' ancestors in a strong sense. In this short note, we use simple analytical argument and simulations to estimate how many such individuals exist in finite Wright-Fisher populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. The Last Common Ancestor of Most Bilaterian Animals Possessed at Least Nine Opsins.

    PubMed

    Ramirez, M Desmond; Pairett, Autum N; Pankey, M Sabrina; Serb, Jeanne M; Speiser, Daniel I; Swafford, Andrew J; Oakley, Todd H

    2016-12-01

    The opsin gene family encodes key proteins animals use to sense light and has expanded dramatically as it originated early in animal evolution. Understanding the origins of opsin diversity can offer clues to how separate lineages of animals have repurposed different opsin paralogs for different light-detecting functions. However, the more we look for opsins outside of eyes and from additional animal phyla, the more opsins we uncover, suggesting we still do not know the true extent of opsin diversity, nor the ancestry of opsin diversity in animals. To estimate the number of opsin paralogs present in both the last common ancestor of the Nephrozoa (bilaterians excluding Xenoacoelomorpha), and the ancestor of Cnidaria + Bilateria, we reconstructed a reconciled opsin phylogeny using sequences from 14 animal phyla, especially the traditionally poorly-sampled echinoderms and molluscs. Our analysis strongly supports a repertoire of at least nine opsin paralogs in the bilaterian ancestor and at least four opsin paralogs in the last common ancestor of Cnidaria + Bilateria. Thus, the kernels of extant opsin diversity arose much earlier in animal history than previously known. Further, opsins likely duplicated and were lost many times, with different lineages of animals maintaining different repertoires of opsin paralogs. This phylogenetic information can inform hypotheses about the functions of different opsin paralogs and can be used to understand how and when opsins were incorporated into complex traits like eyes and extraocular sensors.

  3. The Last Common Ancestor of Most Bilaterian Animals Possessed at Least Nine Opsins

    PubMed Central

    Pairett, Autum N.; Pankey, M. Sabrina; Serb, Jeanne M.; Speiser, Daniel I.; Swafford, Andrew J.

    2016-01-01

    Abstract The opsin gene family encodes key proteins animals use to sense light and has expanded dramatically as it originated early in animal evolution. Understanding the origins of opsin diversity can offer clues to how separate lineages of animals have repurposed different opsin paralogs for different light-detecting functions. However, the more we look for opsins outside of eyes and from additional animal phyla, the more opsins we uncover, suggesting we still do not know the true extent of opsin diversity, nor the ancestry of opsin diversity in animals. To estimate the number of opsin paralogs present in both the last common ancestor of the Nephrozoa (bilaterians excluding Xenoacoelomorpha), and the ancestor of Cnidaria + Bilateria, we reconstructed a reconciled opsin phylogeny using sequences from 14 animal phyla, especially the traditionally poorly-sampled echinoderms and molluscs. Our analysis strongly supports a repertoire of at least nine opsin paralogs in the bilaterian ancestor and at least four opsin paralogs in the last common ancestor of Cnidaria + Bilateria. Thus, the kernels of extant opsin diversity arose much earlier in animal history than previously known. Further, opsins likely duplicated and were lost many times, with different lineages of animals maintaining different repertoires of opsin paralogs. This phylogenetic information can inform hypotheses about the functions of different opsin paralogs and can be used to understand how and when opsins were incorporated into complex traits like eyes and extraocular sensors. PMID:28172965

  4. 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

  5. Disseminated Histoplasmosis in Early Human Immunodeficiency Virus Infection.

    PubMed

    Bagla, Prabhava; Sarria, Juan C

    2017-03-01

    Early human immunodeficiency virus (HIV) infection leads to transient immunosuppression followed by a quasi-homeostatic state with slow progression towards AIDS. Histoplasmosis has never been reported in early HIV. We present a case of disseminated histoplasmosis with documented recent seroconversion and review the literature regarding other opportunistic infections in early HIV. Copyright © 2017 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

  6. Teleoperation support for early human planetary missions.

    PubMed

    Genta, Giancarlo; Perino, Maria Antonietta

    2005-12-01

    A renewed interest in human exploration is flourishing among all the major spacefaring nations. In fact, in the complex scene of planned future space activities, the development of a Moon base and the human exploration of Mars might have the potential to renew the enthusiasm in expanding the human presence beyond the boundaries of Earth. Various initiatives have been undertaken to define scenarios and identify the required infrastructures and related technology innovations. The typical proposed approach follows a multistep strategy, starting with a series of precursor robotic missions to acquire further knowledge of the planet and to select the best potential landing sites, and evolving toward more demanding missions for the development of a surface infrastructure necessary to sustain human presence. The technologies involved in such a demanding enterprise range from typical space technologies, like transportation and propulsion, automation and robotics, rendezvous and docking, entry/reentry, aero-braking, navigation, and deep space communications, to human-specific issues like physiology, psychology, behavioral aspects, and nutritional science for long-duration exposure, that go beyond the traditional boundaries of space activities. Among the required elements to support planetary exploration, both for the precursor robotic missions and to sustain human exploration, rovers and trucks play a key role. A robust level of autonomy will need to be secured to perform preplanned operations, particularly for the surface infrastructure development, and a teleoperated support, either from Earth or from a local base, will enhance the in situ field exploration capability.

  7. Algal ancestor of land plants was preadapted for symbiosis.

    PubMed

    Delaux, Pierre-Marc; Radhakrishnan, Guru V; Jayaraman, Dhileepkumar; Cheema, Jitender; Malbreil, Mathilde; Volkening, Jeremy D; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Melkonian, Michael; Pokorny, Lisa; Rothfels, Carl J; Sederoff, Heike Winter; Stevenson, Dennis W; Surek, Barbara; Zhang, Yong; Sussman, Michael R; Dunand, Christophe; Morris, Richard J; Roux, Christophe; Wong, Gane Ka-Shu; Oldroyd, Giles E D; Ané, Jean-Michel

    2015-10-27

    Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis.

  8. The physiology and habitat of the last universal common ancestor.

    PubMed

    Weiss, Madeline C; Sousa, Filipa L; Mrnjavac, Natalia; Neukirchen, Sinje; Roettger, Mayo; Nelson-Sathi, Shijulal; Martin, William F

    2016-07-25

    The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life's origin, yet information about how and where LUCA lived is lacking. We investigated all clusters and phylogenetic trees for 6.1 million protein coding genes from sequenced prokaryotic genomes in order to reconstruct the microbial ecology of LUCA. Among 286,514 protein clusters, we identified 355 protein families (∼0.1%) that trace to LUCA by phylogenetic criteria. Because these proteins are not universally distributed, they can shed light on LUCA's physiology. Their functions, properties and prosthetic groups depict LUCA as anaerobic, CO2-fixing, H2-dependent with a Wood-Ljungdahl pathway, N2-fixing and thermophilic. LUCA's biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosyl methionine-dependent methylations. The 355 phylogenies identify clostridia and methanogens, whose modern lifestyles resemble that of LUCA, as basal among their respective domains. LUCA inhabited a geochemically active environment rich in H2, CO2 and iron. The data support the theory of an autotrophic origin of life involving the Wood-Ljungdahl pathway in a hydrothermal setting.

  9. Mexican papita viroid: putative ancestor of crop viroids.

    PubMed Central

    Martínez-Soriano, J P; Galindo-Alonso, J; Maroon, C J; Yucel, I; Smith, D R; Diener, T O

    1996-01-01

    The potato spindle tuber disease was first observed early in the 20th century in the northeastern United States and shown, in 1971, to be incited by a viroid, potato spindle tuber viroid (PSTVd). No wild-plant PSTVd reservoirs have been identified; thus, the initial source of PSTVd infecting potatoes has remained a mystery. Several variants of a novel viroid, designated Mexican papita viroid (MPVd), have now been isolated from Solanum cardiophyllum Lindl. (papita güera, cimantli) plants growing wild in the Mexican state of Aguascalientes. MPVd's nucleotide sequence is most closely related to those of the tomato planta macho viroid (TPMVd) and PSTVd. From TPMVd, MPVd may be distinguished on the basis of biological properties, such as replication and symptom formation in certain differential hosts. Phylogenetic and ecological data indicate that MPVd and certain viroids now affecting crop plants, such as TPMVd, PSTVd, and possibly others, have a common ancestor. We hypothesize that commercial potatoes grown in the United States have become viroid-infected by chance transfer of MPVd or a similar viroid from endemically infected wild solanaceous plants imported from Mexico as germplasm, conceivably from plants known to have been introduced from Mexico to the United States late in the 19th century in efforts to identify genetic resistance to the potato late blight fungus, Phytophthora infestans. Images Fig. 1 PMID:8790341

  10. Algal ancestor of land plants was preadapted for symbiosis

    PubMed Central

    Delaux, Pierre-Marc; Radhakrishnan, Guru V.; Jayaraman, Dhileepkumar; Cheema, Jitender; Malbreil, Mathilde; Volkening, Jeremy D.; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Melkonian, Michael; Pokorny, Lisa; Rothfels, Carl J.; Sederoff, Heike Winter; Stevenson, Dennis W.; Surek, Barbara; Zhang, Yong; Sussman, Michael R.; Dunand, Christophe; Morris, Richard J.; Roux, Christophe; Wong, Gane Ka-Shu; Oldroyd, Giles E. D.; Ané, Jean-Michel

    2015-01-01

    Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis. PMID:26438870

  11. Extensive intron gain in the ancestor of placental mammals.

    PubMed

    Kordiš, Dušan

    2011-11-23

    Genome-wide studies of intron dynamics in mammalian orthologous genes have found convincing evidence for loss of introns but very little for intron turnover. Similarly, large-scale analysis of intron dynamics in a few vertebrate genomes has identified only intron losses and no gains, indicating that intron gain is an extremely rare event in vertebrate evolution. These studies suggest that the intron-rich genomes of vertebrates do not allow intron gain. The aim of this study was to search for evidence of de novo intron gain in domesticated genes from an analysis of their exon/intron structures. A phylogenomic approach has been used to analyse all domesticated genes in mammals and chordates that originated from the coding parts of transposable elements. Gain of introns in domesticated genes has been reconstructed on well established mammalian, vertebrate and chordate phylogenies, and examined as to where and when the gain events occurred. The locations, sizes and amounts of de novo introns gained in the domesticated genes during the evolution of mammals and chordates has been analyzed. A significant amount of intron gain was found only in domesticated genes of placental mammals, where more than 70 cases were identified. De novo gained introns show clear positional bias, since they are distributed mainly in 5' UTR and coding regions, while 3' UTR introns are very rare. In the coding regions of some domesticated genes up to 8 de novo gained introns have been found. Intron densities in Eutheria-specific domesticated genes and in older domesticated genes that originated early in vertebrates are lower than those for normal mammalian and vertebrate genes. Surprisingly, the majority of intron gains have occurred in the ancestor of placentals. This study provides the first evidence for numerous intron gains in the ancestor of placental mammals and demonstrates that adequate taxon sampling is crucial for reconstructing intron evolution. The findings of this comprehensive

  12. Extensive intron gain in the ancestor of placental mammals

    PubMed Central

    2011-01-01

    Background Genome-wide studies of intron dynamics in mammalian orthologous genes have found convincing evidence for loss of introns but very little for intron turnover. Similarly, large-scale analysis of intron dynamics in a few vertebrate genomes has identified only intron losses and no gains, indicating that intron gain is an extremely rare event in vertebrate evolution. These studies suggest that the intron-rich genomes of vertebrates do not allow intron gain. The aim of this study was to search for evidence of de novo intron gain in domesticated genes from an analysis of their exon/intron structures. Results A phylogenomic approach has been used to analyse all domesticated genes in mammals and chordates that originated from the coding parts of transposable elements. Gain of introns in domesticated genes has been reconstructed on well established mammalian, vertebrate and chordate phylogenies, and examined as to where and when the gain events occurred. The locations, sizes and amounts of de novo introns gained in the domesticated genes during the evolution of mammals and chordates has been analyzed. A significant amount of intron gain was found only in domesticated genes of placental mammals, where more than 70 cases were identified. De novo gained introns show clear positional bias, since they are distributed mainly in 5' UTR and coding regions, while 3' UTR introns are very rare. In the coding regions of some domesticated genes up to 8 de novo gained introns have been found. Intron densities in Eutheria-specific domesticated genes and in older domesticated genes that originated early in vertebrates are lower than those for normal mammalian and vertebrate genes. Surprisingly, the majority of intron gains have occurred in the ancestor of placentals. Conclusions This study provides the first evidence for numerous intron gains in the ancestor of placental mammals and demonstrates that adequate taxon sampling is crucial for reconstructing intron evolution. The

  13. The universal ancestor and the ancestors of Archaea and Bacteria were anaerobes whereas the ancestor of the Eukarya domain was an aerobe.

    PubMed

    Di Giulio, M

    2007-03-01

    The use of an oxyphobic index (OI) based on the propensity of amino acids to enter more frequently the proteins of anaerobes makes it possible to make inferences on the environment in which the last universal common ancestor (LUCA) lived. The reconstruction of the ancestral sequences of proteins using a method based on maximum likelihood and their attribution by means of the OI to the set of aerobe or anaerobe sequences has led to the following conclusions: the LUCA was an anaerobic 'organism', as were the ancestors of Archaea and Bacteria, whereas the ancestor of Eukarya was an aerobe. These observations seem to falsify the hypothesis that the LUCA was an aerobe and help to identify better the environment in which the first organisms lived.

  14. Young Children's Enactments of Human Rights in Early Childhood Education

    ERIC Educational Resources Information Center

    Quennerstedt, Ann

    2016-01-01

    This paper explores ways in which human rights become part of and affect young children's everyday practices in early childhood education and, more particularly, how very young children enact human rights in the preschool setting. The study is conducted in a Swedish preschool through observations of the everyday practices of a group of children…

  15. Young Children's Enactments of Human Rights in Early Childhood Education

    ERIC Educational Resources Information Center

    Quennerstedt, Ann

    2016-01-01

    This paper explores ways in which human rights become part of and affect young children's everyday practices in early childhood education and, more particularly, how very young children enact human rights in the preschool setting. The study is conducted in a Swedish preschool through observations of the everyday practices of a group of children…

  16. The Neurobiological Toll of Early Human Deprivation.

    PubMed

    Nelson, Charles A; Bos, Karen; Gunnar, Megan R; Sonuga-Barke, Edmund J S

    2011-12-01

    Children raised in institutions frequently suffer from a variety of behavioral, emotional, and neuropsychological sequelae, including deficits in attention, executive functions, disorders of attachment and in some cases a syndrome that mimics autism. The extent and severity of these disorders appears to be mediated, in part, by the age at which the child entered and, in some cases, left the institution. Here we review the neurobiological literature on early institutionalization that may account for the psychological and neurological sequelae discussed in other chapters in this volume.

  17. RNase MRP and the RNA processing cascade in the eukaryotic ancestor

    PubMed Central

    Woodhams, Michael D; Stadler, Peter F; Penny, David; Collins, Lesley J

    2007-01-01

    Background Within eukaryotes there is a complex cascade of RNA-based macromolecules that process other RNA molecules, especially mRNA, tRNA and rRNA. An example is RNase MRP processing ribosomal RNA (rRNA) in ribosome biogenesis. One hypothesis is that this complexity was present early in eukaryotic evolution; an alternative is that an initial simpler network later gained complexity by gene duplication in lineages that led to animals, fungi and plants. Recently there has been a rapid increase in support for the complexity-early theory because the vast majority of these RNA-processing reactions are found throughout eukaryotes, and thus were likely to be present in the last common ancestor of living eukaryotes, herein called the Eukaryotic Ancestor. Results We present an overview of the RNA processing cascade in the Eukaryotic Ancestor and investigate in particular, RNase MRP which was previously thought to have evolved later in eukaryotes due to its apparent limited distribution in fungi and animals and plants. Recent publications, as well as our own genomic searches, find previously unknown RNase MRP RNAs, indicating that RNase MRP has a wide distribution in eukaryotes. Combining secondary structure and promoter region analysis of RNAs for RNase MRP, along with analysis of the target substrate (rRNA), allows us to discuss this distribution in the light of eukaryotic evolution. Conclusion We conclude that RNase MRP can now be placed in the RNA-processing cascade of the Eukaryotic Ancestor, highlighting the complexity of RNA-processing in early eukaryotes. Promoter analyses of MRP-RNA suggest that regulation of the critical processes of rRNA cleavage can vary, showing that even these key cellular processes (for which we expect high conservation) show some species-specific variability. We present our consensus MRP-RNA secondary structure as a useful model for further searches. PMID:17288571

  18. Major fungal lineages are derived from lichen symbiotic ancestors.

    PubMed

    Lutzoni, F; Pagel, M; Reeb, V

    2001-06-21

    About one-fifth of all known extant fungal species form obligate symbiotic associations with green algae, cyanobacteria or with both photobionts. These symbioses, known as lichens, are one way for fungi to meet their requirement for carbohydrates. Lichens are widely believed to have arisen independently on several occasions, accounting for the high diversity and mixed occurrence of lichenized and non-lichenized (42 and 58%, respectively) fungal species within the Ascomycota. Depending on the taxonomic classification chosen, 15-18 orders of the Ascomycota include lichen-forming taxa, and 8-11 of these orders (representing about 60% of the Ascomycota species) contain both lichenized and non-lichenized species. Here we report a phylogenetic comparative analysis of the Ascomycota, a phylum that includes greater than 98% of known lichenized fungal species. Using a Bayesian phylogenetic tree sampling methodology combined with a statistical model of trait evolution, we take into account uncertainty about the phylogenetic tree and ancestral state reconstructions. Our results show that lichens evolved earlier than believed, and that gains of lichenization have been infrequent during Ascomycota evolution, but have been followed by multiple independent losses of the lichen symbiosis. As a consequence, major Ascomycota lineages of exclusively non-lichen-forming species are derived from lichen-forming ancestors. These species include taxa with important benefits and detriments to humans, such as Penicillium and Aspergillus.

  19. Locomotion and posture from the common hominoid ancestor to fully modern hominins, with special reference to the last common panin/hominin ancestor

    PubMed Central

    Crompton, R H; Vereecke, E E; Thorpe, S K S

    2008-01-01

    Based on our knowledge of locomotor biomechanics and ecology we predict the locomotion and posture of the last common ancestors of (a) great and lesser apes and their close fossil relatives (hominoids); (b) chimpanzees, bonobos and modern humans (hominines); and (c) modern humans and their fossil relatives (hominins). We evaluate our propositions against the fossil record in the context of a broader review of evolution of the locomotor system from the earliest hominoids of modern aspect (crown hominoids) to early modern Homo sapiens. While some early East African stem hominoids were pronograde, it appears that the adaptations which best characterize the crown hominoids are orthogrady and an ability to abduct the arm above the shoulder – rather than, as is often thought, manual suspension sensu stricto. At 7–9 Ma (not much earlier than the likely 4–8 Ma divergence date for panins and hominins, see Bradley, 2008) there were crown hominoids in southern Europe which were adapted to moving in an orthograde posture, supported primarily on the hindlimb, in an arboreal, and possibly for Oreopithecus, a terrestrial context. By 7 Ma, Sahelanthropus provides evidence of a Central African hominin, panin or possibly gorilline adapted to orthogrady, and both orthogrady and habitually highly extended postures of the hip are evident in the arboreal East African protohominin Orrorin at 6 Ma. If the traditional idea that hominins passed through a terrestrial ‘knuckle-walking’ phase is correct, not only does it have to be explained how a quadrupedal gait typified by flexed postures of the hindlimb could have preadapted the body for the hominin acquisition of straight-legged erect bipedality, but we would have to accept a transition from stem-hominoid pronogrady to crown hominoid orthogrady, back again to pronogrady in the African apes and then back to orthogrady in hominins. Hand-assisted arboreal bipedality, which is part of a continuum of orthograde behaviours, is used by

  20. Palmitic Acid in Early Human Development.

    PubMed

    Innis, Sheila M

    2016-09-09

    Palmitic acid (16:0) is a saturated fatty acid present in the diet and synthesized endogenously. Although often considered to have adverse effects on chronic disease in adults, 16:0 is an essential component of membrane, secretory, and transport lipids, with crucial roles in protein palmitoylation and signal molecules. At birth, the term infant is 13-15% body fat, with 45-50% 16:0, much of which is derived from endogenous synthesis in the fetus. After birth, the infant accumulates adipose tissue at high rates, reaching 25% body weight as fat by 4-5 months age. Over this time, human milk provides 10% dietary energy as 16:0, but in unusual triglycerides with 16:0 on the glycerol center carbon. This paper reviews the synthesis and oxidation of 16:0 and possible reasons why the infant is endowed with large amounts of fat and 16:0. The marked deviations in tissues with displacement of 16:0 that can occur in infants fed vegetable oil formulas is introduced. Assuming fetal fatty acid synthesis and the unusual delivery of 16:0 in human milk evolved to afford survival advantage to the neonate, it is timely to question if 16:0 is an essential component of tissue lipids whereby both deficiency and excess are detrimental.

  1. Human sexual size dimorphism in early pregnancy.

    PubMed

    Bukowski, Radek; Smith, Gordon C S; Malone, Fergal D; Ball, Robert H; Nyberg, David A; Comstock, Christine H; Hankins, Gary D V; Berkowitz, Richard L; Gross, Susan J; Dugoff, Lorraine; Craigo, Sabrina D; Timor-Tritsch, Ilan E; Carr, Stephen R; Wolfe, Honor M; D'Alton, Mary E

    2007-05-15

    Sexual size dimorphism is thought to contribute to the greater mortality and morbidity of men compared with women. However, the timing of onset of sexual size dimorphism remains uncertain. The authors determined whether human fetuses exhibit sexual size dimorphism in the first trimester of pregnancy. Using a prospective cohort study, conducted in 1999-2002 in the United States, they identified 27,655 women who conceived spontaneously and 1,008 whose conception was assisted by in vitro fertilization or intrauterine insemination and for whom a first-trimester measurement of fetal crown-rump length was available. First-trimester size was expressed as the difference between the observed and expected size of the fetus, expressed as equivalence to days of gestational age. The authors evaluated the association between fetal sex, first-trimester size, and birth weight. Eight to 12 weeks after conception, males were larger than females (mean difference: assisted conception = 0.4 days, 95% confidence interval (CI): 0.1, 0.7, p = 0.008; spontaneous conception = 0.3 days, 95% CI: 0.2, 0.4, p < 0.00001). The size discrepancy remained significant at birth (mean birth weight difference: assisted conception = 90 g, 95% CI: 22, 159, p = 0.009; spontaneous conception = 120 g, 95% CI: 107, 132, p < 0.00001). These data demonstrate that human fetuses exhibit sexual size dimorphism in the first trimester of pregnancy.

  2. Early NACA human computers at work

    NASA Technical Reports Server (NTRS)

    1949-01-01

    The women of the Computer Department at NACA High-Speed Flight Research Station are shown busy with test flight calculations. The computers under the direction of Roxanah Yancey were responsible for accurate calculations on the research test flights made at the Station. There were no mechanical computers at the station in 1949, but data was reduced by human computers. Shown in this photograph starting at the left are: Geraldine Mayer and Mary (Tut) Hedgepeth with Friden calculators on the their desks; Emily Stephens conferring with engineer John Mayer; Gertrude (Trudy) Valentine is working on an oscillograph recording reducing the data from a flight. Across the desk is Dorothy Clift Hughes using a slide rule to complete data calculations. Roxanah Yancey completes the picture as she fills out engineering requests for further data.

  3. Indigenous Ways--Fruits of Our Ancestors

    ERIC Educational Resources Information Center

    Cohn, Itamar

    2011-01-01

    In this paper the human-nature relationship is recognized as a major field of interest and a platform of ideas linked with it is explored. A "new" source to inform an alternative paradigm for outdoor education is proposed; it is millennia old, has roots all over the globe and is a living, breathing, and evolving tradition--indigenous ways. While…

  4. Neurochemical Changes Within Human Early Blind Occipital Cortex

    PubMed Central

    Weaver, Kurt E.; Richards, Todd L.; Saenz, Melissa; Petropoulos, Helen; Fine, Ione

    2015-01-01

    Early blindness results in occipital cortex neurons responding to a wide range of auditory and tactile stimuli. These changes in tuning properties are accompanied by an extensive reorganization of occipital cortex that includes alterations in anatomical structure, neurochemical and metabolic pathways. Although it has been established in animal models that neurochemical pathways are heavily affected by early visual deprivation, the effects of blindness on these pathways in humans is still not well characterized. Here, using 1H magnetic resonance spectroscopy in nine early blind and normally sighted subjects, we find that early blindness is associated with higher levels of creatine, choline and myo-Inositol and indications of lower levels of GABA within occipital cortex. These results suggest that the cross-modal responses associated with early blindness may, at least in part, be driven by changes within occipital biochemical pathways. PMID:23954804

  5. Proposed Ancestors of Phage Nucleic Acid Packaging Motors (and Cells)

    PubMed Central

    Serwer, Philip

    2011-01-01

    I present a hypothesis that begins with the proposal that abiotic ancestors of phage RNA and DNA packaging systems (and cells) include mobile shells with an internal, molecule-transporting cavity. The foundations of this hypothesis include the conjecture that current nucleic acid packaging systems have imprints from abiotic ancestors. The abiotic shells (1) initially imbibe and later also bind and transport organic molecules, thereby providing a means for producing molecular interactions that are links in the chain of events that produces ancestors to the first molecules that are both information carrying and enzymatically active, and (2) are subsequently scaffolds on which proteins assemble to form ancestors common to both shells of viral capsids and cell membranes. Emergence of cells occurs via aggregation and merger of shells and internal contents. The hypothesis continues by using proposed imprints of abiotic and biotic ancestors to deduce an ancestral thermal ratchet-based DNA packaging motor that subsequently evolves to integrate a DNA packaging ATPase that provides a power stroke. PMID:21994778

  6. Sequencing Y Chromosomes Resolves Discrepancy in Time to Common Ancestor of Males versus Females

    PubMed Central

    Poznik, G. David; Henn, Brenna M.; Yee, Muh-Ching; Sliwerska, Elzbieta; Euskirchen, Ghia M.; Lin, Alice A.; Snyder, Michael; Quintana-Murci, Lluis; Kidd, Jeffrey M.; Underhill, Peter A.; Bustamante, Carlos D.

    2014-01-01

    The Y chromosome and the mitochondrial genome (mtDNA) have been used to estimate when the common patrilineal and matrilineal ancestors of humans lived. We sequenced the genomes of 69 males from nine populations, including two in which we find basal branches of the Y chromosome tree. We identify ancient phylogenetic structure within African haplogroups and resolve a long-standing ambiguity deep within the tree. Applying equivalent methodologies to the Y and mtDNA, we estimate the time to the most recent common ancestor (TMRCA) of the Y chromosome to be 120–156 thousand years and the mtDNA TMRCA to be 99–148 ky. Our findings suggest that, contrary to prior claims, male lineages do not coalesce significantly more recently than female lineages. PMID:23908239

  7. Distribution of repetitions of ancestors in genealogical trees

    NASA Astrophysics Data System (ADS)

    Derrida, Bernard; Manrubia, Susanna C.; Zanette, Damián H.

    2000-06-01

    We calculate the probability distribution of repetitions of ancestors in a genealogical tree for simple neutral models of a closed population with sexual reproduction and non-overlapping generations. Each ancestor at generation g in the past has a weight w which is (up to a normalization) the number of times this ancestor appears in the genealogical tree of an individual at present. The distribution Pg( w) of these weights reaches a stationary shape P∞( w), for large g, i.e., for a large number of generations back in the past. For small w, P ∞(w) is a power law ( P∞( w)∼ wβ), with a non-trivial exponent β which can be computed exactly using a standard procedure of the renormalization group approach. Some extensions of the model are discussed and the effect of these variants on the shape of P∞( w) are analysed.

  8. Population Dynamics of Early Human Migration in Britain

    PubMed Central

    Vahia, Mayank N.; Ladiwala, Uma; Mahathe, Pavan; Mathur, Deepak

    2016-01-01

    Background Early human migration is largely determined by geography and human needs. These are both deterministic parameters when small populations move into unoccupied areas where conflicts and large group dynamics are not important. The early period of human migration into the British Isles provides such a laboratory which, because of its relative geographical isolation, may allow some insights into the complex dynamics of early human migration and interaction. Method and Results We developed a simulation code based on human affinity to habitable land, as defined by availability of water sources, altitude, and flatness of land, in choosing the path of migration. Movement of people on the British island over the prehistoric period from their initial entry points was simulated on the basis of data from the megalithic period. Topographical and hydro-shed data from satellite databases was used to define habitability, based on distance from water bodies, flatness of the terrain, and altitude above sea level. We simulated population movement based on assumptions of affinity for more habitable places, with the rate of movement tempered by existing populations. We compared results of our computer simulations with genetic data and show that our simulation can predict fairly accurately the points of contacts between different migratory paths. Such comparison also provides more detailed information about the path of peoples’ movement over ~2000 years before the present era. Conclusions We demonstrate an accurate method to simulate prehistoric movements of people based upon current topographical satellite data. Our findings are validated by recently-available genetic data. Our method may prove useful in determining early human population dynamics even when no genetic information is available. PMID:27148959

  9. Population Dynamics of Early Human Migration in Britain.

    PubMed

    Vahia, Mayank N; Ladiwala, Uma; Mahathe, Pavan; Mathur, Deepak

    2016-01-01

    Early human migration is largely determined by geography and human needs. These are both deterministic parameters when small populations move into unoccupied areas where conflicts and large group dynamics are not important. The early period of human migration into the British Isles provides such a laboratory which, because of its relative geographical isolation, may allow some insights into the complex dynamics of early human migration and interaction. We developed a simulation code based on human affinity to habitable land, as defined by availability of water sources, altitude, and flatness of land, in choosing the path of migration. Movement of people on the British island over the prehistoric period from their initial entry points was simulated on the basis of data from the megalithic period. Topographical and hydro-shed data from satellite databases was used to define habitability, based on distance from water bodies, flatness of the terrain, and altitude above sea level. We simulated population movement based on assumptions of affinity for more habitable places, with the rate of movement tempered by existing populations. We compared results of our computer simulations with genetic data and show that our simulation can predict fairly accurately the points of contacts between different migratory paths. Such comparison also provides more detailed information about the path of peoples' movement over ~2000 years before the present era. We demonstrate an accurate method to simulate prehistoric movements of people based upon current topographical satellite data. Our findings are validated by recently-available genetic data. Our method may prove useful in determining early human population dynamics even when no genetic information is available.

  10. Early development of synchrony in cortical activations in the human

    PubMed Central

    Koolen, N.; Dereymaeker, A.; Räsänen, O.; Jansen, K.; Vervisch, J.; Matic, V.; Naulaers, G.; De Vos, M.; Van Huffel, S.; Vanhatalo, S.

    2016-01-01

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates. PMID:26876605

  11. Phylogenomic Reconstruction Indicates Mitochondrial Ancestor Was an Energy Parasite

    PubMed Central

    Wang, Zhang; Wu, Martin

    2014-01-01

    Reconstruction of mitochondrial ancestor has great impact on our understanding of the origin of mitochondria. Previous studies have largely focused on reconstructing the last common ancestor of all contemporary mitochondria (proto-mitochondria), but not on the more informative pre-mitochondria (the last common ancestor of mitochondria and their alphaproteobacterial sister clade). Using a phylogenomic approach and leveraging on the increased taxonomic sampling of alphaproteobacterial and eukaryotic genomes, we reconstructed the metabolisms of both proto-mitochondria and pre-mitochondria. Our reconstruction depicts a more streamlined proto-mitochondrion than these predicted by previous studies, and revealed several novel insights into the mitochondria-derived eukaryotic metabolisms including the lipid metabolism. Most strikingly, pre-mitochondrion was predicted to possess a plastid/parasite type of ATP/ADP translocase that imports ATP from the host, which posits pre-mitochondrion as an energy parasite that directly contrasts with the current role of mitochondria as the cell’s energy producer. In addition, pre-mitochondrion was predicted to encode a large number of flagellar genes and several cytochrome oxidases functioning under low oxygen level, strongly supporting the previous finding that the mitochondrial ancestor was likely motile and capable of oxidative phosphorylation under microoxic condition. PMID:25333787

  12. The Ancestor Project: Aboriginal Computer Education through Storytelling

    ERIC Educational Resources Information Center

    Weston, Marla; Biin, Dianne

    2013-01-01

    The goal of the ANCESTOR program is to use digital storytelling as a means of promoting an interest in technology careers for Aboriginal learners, as well as increasing cultural literacy. A curriculum was developed and first tested with Aboriginal students at the LÁU,WELNEW Tribal School near Victoria, British Columbia, Canada. Based on feedback…

  13. Lost human capital from early-onset chronic depression.

    PubMed

    Berndt, E R; Koran, L M; Finkelstein, S N; Gelenberg, A J; Kornstein, S G; Miller, I M; Thase, M E; Trapp, G A; Keller, M B

    2000-06-01

    Chronic depression starts at an early age for many individuals and could affect their accumulation of "human capital" (i.e., education, higher amounts of which can broaden occupational choice and increase earnings potential). The authors examined the impact, by gender, of early- (before age 22) versus late-onset major depressive disorder on educational attainment. They also determined whether the efficacy and sustainability of antidepressant treatments and psychosocial outcomes vary by age at onset and quantified the impact of early- versus late-onset, as well as never-occurring, major depressive disorder on expected lifetime earnings. The authors used logistic and multivariate regression methods to analyze data from a three-phase, multicenter, double-blind, randomized trial that compared sertraline and imipramine treatment of 531 patients with chronic depression aged 30 years and older. These data were integrated with U.S. Census Bureau data on 1995 earnings by age, educational attainment, and gender. Early-onset major depressive disorder adversely affected the educational attainment of women but not of men. No significant difference in treatment responsiveness by age at onset was observed after 12 weeks of acute treatment or, for subjects rated as having responded, after 76 weeks of maintenance treatment. A randomly selected 21-year-old woman with early-onset major depressive disorder in 1995 could expect future annual earnings that were 12%-18% lower than those of a randomly selected 21-year-old woman whose onset of major depressive disorder occurred after age 21 or not at all. Early-onset major depressive disorder causes substantial human capital loss, particularly for women. Detection and effective treatment of early-onset major depressive disorder may have substantial economic benefits.

  14. Origins and early development of human body knowledge.

    PubMed

    Slaughter, Virginia; Heron, Michelle

    2004-01-01

    As a knowable object, the human body is highly complex. Evidence from several converging lines of research, including psychological studies, neuroimaging and clinical neuropsychology, indicates that human body knowledge is widely distributed in the adult brain, and is instantiated in at least three partially independent levels of representation. Sensorimotor body knowledge is responsible for on-line control and movement of one's own body and may also contribute to the perception of others' moving bodies; visuo-spatial body knowledge specifies detailed structural descriptions of the spatial attributes of the human body; and lexical-semantic body knowledge contains language-based knowledge about the human body. In the first chapter of this Monograph, we outline the evidence for these three hypothesized levels of human body knowledge, then review relevant literature on infants' and young children's human body knowledge in terms of the three-level framework. In Chapters II and III, we report two complimentary series of studies that specifically investigate the emergence of visuo-spatial body knowledge in infancy. Our technique is to compare infants'responses to typical and scrambled human bodies, in order to evaluate when and how infants acquire knowledge about the canonical spatial layout of the human body. Data from a series of visual habituation studies indicate that infants first discriminate scrambled from typical human body picture sat 15 to 18 months of age. Data from object examination studies similarly indicate that infants are sensitive to violations of three-dimensional human body stimuli starting at 15-18 months of age. The overall pattern of data supports several conclusions about the early development of human body knowledge: (a) detailed visuo-spatial knowledge about the human body is first evident in the second year of life, (b) visuo-spatial knowledge of human faces and human bodies are at least partially independent in infancy and (c) infants' initial

  15. The great divides: Ardipithecus ramidus reveals the postcrania of our last common ancestors with African apes.

    PubMed

    Lovejoy, C Owen; Suwa, Gen; Simpson, Scott W; Matternes, Jay H; White, Tim D

    2009-10-02

    Genomic comparisons have established the chimpanzee and bonobo as our closest living relatives. However, the intricacies of gene regulation and expression caution against the use of these extant apes in deducing the anatomical structure of the last common ancestor that we shared with them. Evidence for this structure must therefore be sought from the fossil record. Until now, that record has provided few relevant data because available fossils were too recent or too incomplete. Evidence from Ardipithecus ramidus now suggests that the last common ancestor lacked the hand, foot, pelvic, vertebral, and limb structures and proportions specialized for suspension, vertical climbing, and knuckle-walking among extant African apes. If this hypothesis is correct, each extant African ape genus must have independently acquired these specializations from more generalized ancestors who still practiced careful arboreal climbing and bridging. African apes and hominids acquired advanced orthogrady in parallel. Hominoid spinal invagination is an embryogenetic mechanism that reoriented the shoulder girdle more laterally. It was unaccompanied by substantial lumbar spine abbreviation, an adaptation restricted to vertical climbing and/or suspension. The specialized locomotor anatomies and behaviors of chimpanzees and gorillas therefore constitute poor models for the origin and evolution of human bipedality.

  16. Telomerase Activity is Downregulated Early During Human Brain Development

    PubMed Central

    Ishaq, Abbas; Hanson, Peter S.; Morris, Christopher M.; Saretzki, Gabriele

    2016-01-01

    Changes in hTERT splice variant expression have been proposed to facilitate the decrease of telomerase activity during fetal development in various human tissues. Here, we analyzed the expression of telomerase RNA (hTR), wild type and α-spliced hTERT in developing human fetal brain (post conception weeks, pcw, 6–19) and in young and old cortices using qPCR and correlated it to telomerase activity measured by TRAP assay. Decrease of telomerase activity occurred early during brain development and correlated strongest to decreased hTR expression. The expression of α-spliced hTERT increased between pcw 10 and 19, while that of wild type hTERT remained unchanged. Lack of expression differences between young and old cortices suggests that most changes seem to occur early during human brain development. Using in vitro differentiation of neural precursor stem cells (NPSCs) derived at pcw 6 we found a decrease in telomerase activity but no major expression changes in telomerase associated genes. Thus, they do not seem to model the mechanisms for the decrease in telomerase activity in fetal brains. Our results suggest that decreased hTR levels, as well as transient increase in α-spliced hTERT, might both contribute to downregulation of telomerase activity during early human brain development between 6 and 17 pcw. PMID:27322326

  17. The evolutionary history of protein fold families and proteomes confirms that the archaeal ancestor is more ancient than the ancestors of other superkingdoms.

    PubMed

    Kim, Kyung Mo; Caetano-Anollés, Gustavo

    2012-01-27

    The entire evolutionary history of life can be studied using myriad sequences generated by genomic research. This includes the appearance of the first cells and of superkingdoms Archaea, Bacteria, and Eukarya. However, the use of molecular sequence information for deep phylogenetic analyses is limited by mutational saturation, differential evolutionary rates, lack of sequence site independence, and other biological and technical constraints. In contrast, protein structures are evolutionary modules that are highly conserved and diverse enough to enable deep historical exploration. Here we build phylogenies that describe the evolution of proteins and proteomes. These phylogenetic trees are derived from a genomic census of protein domains defined at the fold family (FF) level of structural classification. Phylogenomic trees of FF structures were reconstructed from genomic abundance levels of 2,397 FFs in 420 proteomes of free-living organisms. These trees defined timelines of domain appearance, with time spanning from the origin of proteins to the present. Timelines are divided into five different evolutionary phases according to patterns of sharing of FFs among superkingdoms: (1) a primordial protein world, (2) reductive evolution and the rise of Archaea, (3) the rise of Bacteria from the common ancestor of Bacteria and Eukarya and early development of the three superkingdoms, (4) the rise of Eukarya and widespread organismal diversification, and (5) eukaryal diversification. The relative ancestry of the FFs shows that reductive evolution by domain loss is dominant in the first three phases and is responsible for both the diversification of life from a universal cellular ancestor and the appearance of superkingdoms. On the other hand, domain gains are predominant in the last two phases and are responsible for organismal diversification, especially in Bacteria and Eukarya. The evolution of functions that are associated with corresponding FFs along the timeline reveals

  18. Evidence in hand: recent discoveries and the early evolution of human manual manipulation.

    PubMed

    Kivell, Tracy L

    2015-11-19

    For several decades, it was largely assumed that stone tool use and production were abilities limited to the genus Homo. However, growing palaeontological and archaeological evidence, comparative extant primate studies, as well as results from methodological advancements in biomechanics and morphological analyses, have been gradually accumulating and now provide strong support for more advanced manual manipulative abilities and tool-related behaviours in pre-Homo hominins than has been traditionally recognized. Here, I review the fossil evidence related to early hominin dexterity, including the recent discoveries of relatively complete early hominin hand skeletons, and new methodologies that are providing a more holistic interpretation of hand function, and insight into how our early ancestors may have balanced the functional requirements of both arboreal locomotion and tool-related behaviours.

  19. Evidence in hand: recent discoveries and the early evolution of human manual manipulation

    PubMed Central

    Kivell, Tracy L.

    2015-01-01

    For several decades, it was largely assumed that stone tool use and production were abilities limited to the genus Homo. However, growing palaeontological and archaeological evidence, comparative extant primate studies, as well as results from methodological advancements in biomechanics and morphological analyses, have been gradually accumulating and now provide strong support for more advanced manual manipulative abilities and tool-related behaviours in pre-Homo hominins than has been traditionally recognized. Here, I review the fossil evidence related to early hominin dexterity, including the recent discoveries of relatively complete early hominin hand skeletons, and new methodologies that are providing a more holistic interpretation of hand function, and insight into how our early ancestors may have balanced the functional requirements of both arboreal locomotion and tool-related behaviours. PMID:26483538

  20. On the tool use behavior of the bonobo-chimpanzee last common ancestor, and the origins of hominine stone tool use.

    PubMed

    Haslam, Michael

    2014-10-01

    The last common ancestor (LCA) shared by chimpanzees (Pan troglodytes) and bonobos (P. paniscus) was an Early Pleistocene African ape, which, based on the behavior of modern chimpanzees, may be assumed to be a tool-using animal. However, the character of tool use in the Pan lineage prior to the 20th century is largely unknown. Here, I use available data on wild bonobo tool use and emerging molecular estimates of demography during Pan evolution to hypothesise the plausible tool use behavior of the bonobo-chimpanzee LCA (or "Pancestor") at the start of the Pleistocene, over 2 million years ago. This method indicates that the common ancestor of living Pan apes likely used plant tools for probing, sponging, and display, but it did not use stone tools. Instead, stone tool use appears to have been independently invented by Western African chimpanzees (P. t. verus) during the Middle Pleistocene in the region of modern Liberia-Ivory Coast-Guinea, possibly as recently as 200,000-150,000 years ago. If this is the case, then the LCA of humans and chimpanzees likely also did not use stone tools, and this trait probably first emerged among hominins in Pliocene East Africa. This review also suggests that the consistently higher population sizes of Central African chimpanzees (P. t. troglodytes) over the past million years may have contributed to the increased complexity of wild tool use seen in this sub-species today.

  1. Autophagy in Normal and Abnormal Early Human Pregnancies.

    PubMed

    Avagliano, Laura; Terraneo, Laura; Virgili, Eleonora; Martinelli, Carla; Doi, Patrizia; Samaja, Michele; Bulfamante, Gaetano Pietro; Marconi, Anna Maria

    2015-07-01

    Autophagy is an inducible catabolic process by which cells degrade and recycle materials to survive stress, starvation, and hypoxia. The aim of this study was to evaluate autophagy at the fetal-maternal interface, to assess autophagy involvement during the early phase of human gestation, and to explore autophagic modification in case of early abnormal pregnancy outcome. Specimens were collected from first-trimester normal gestations undergoing legal termination of pregnancy and first-trimester sporadic spontaneous miscarriages. Autophagy was studied in villous and decidual samples by transmission electron microscopy, immunohistochemistry, immunofluorescence, and Western blotting. Autophagy markers were found in cytotrophoblast, syncytiotrophoblast, extravillous trophoblast, and decidual stromal cells. Autophagy is physiologically involved in early normal gestation. Compared with normal pregnancy, spontaneous miscarriage presents an increase in autophagy expression in villous specimens due to an increment in concentration of autophagic vacuole in syncytiotrophoblast, suggesting a cytoprotective mechanism of the cells to respond to microenvironmental challenge. © The Author(s) 2014.

  2. The DNA methylation landscape of human early embryos.

    PubMed

    Guo, Hongshan; Zhu, Ping; Yan, Liying; Li, Rong; Hu, Boqiang; Lian, Ying; Yan, Jie; Ren, Xiulian; Lin, Shengli; Li, Junsheng; Jin, Xiaohu; Shi, Xiaodan; Liu, Ping; Wang, Xiaoye; Wang, Wei; Wei, Yuan; Li, Xianlong; Guo, Fan; Wu, Xinglong; Fan, Xiaoying; Yong, Jun; Wen, Lu; Xie, Sunney X; Tang, Fuchou; Qiao, Jie

    2014-07-31

    DNA methylation is a crucial element in the epigenetic regulation of mammalian embryonic development. However, its dynamic patterns have not been analysed at the genome scale in human pre-implantation embryos due to technical difficulties and the scarcity of required materials. Here we systematically profile the methylome of human early embryos from the zygotic stage through to post-implantation by reduced representation bisulphite sequencing and whole-genome bisulphite sequencing. We show that the major wave of genome-wide demethylation is complete at the 2-cell stage, contrary to previous observations in mice. Moreover, the demethylation of the paternal genome is much faster than that of the maternal genome, and by the end of the zygotic stage the genome-wide methylation level in male pronuclei is already lower than that in female pronuclei. The inverse correlation between promoter methylation and gene expression gradually strengthens during early embryonic development, reaching its peak at the post-implantation stage. Furthermore, we show that active genes, with the trimethylation of histone H3 at lysine 4 (H3K4me3) mark at the promoter regions in pluripotent human embryonic stem cells, are essentially devoid of DNA methylation in both mature gametes and throughout pre-implantation development. Finally, we also show that long interspersed nuclear elements or short interspersed nuclear elements that are evolutionarily young are demethylated to a milder extent compared to older elements in the same family and have higher abundance of transcripts, indicating that early embryos tend to retain higher residual methylation at the evolutionarily younger and more active transposable elements. Our work provides insights into the critical features of the methylome of human early embryos, as well as its functional relation to the regulation of gene expression and the repression of transposable elements.

  3. Early stress and human behavioral development: emerging evolutionary perspectives.

    PubMed

    Del Giudice, M

    2014-08-01

    Stress experienced early in life exerts a powerful, lasting influence on development. Converging empirical findings show that stressful experiences become deeply embedded in the child's neurobiology, with an astonishing range of long-term effects on cognition, emotion, and behavior. In contrast with the prevailing view that such effects are the maladaptive outcomes of 'toxic' stress, adaptive models regard them as manifestations of evolved developmental plasticity. In this paper, I offer a brief introduction to adaptive models of early stress and human behavioral development, with emphasis on recent theoretical contributions and emerging concepts in the field. I begin by contrasting dysregulation models of early stress with their adaptive counterparts; I then introduce life history theory as a unifying framework, and review recent work on predictive adaptive responses (PARs) in human life history development. In particular, I discuss the distinction between forecasting the future state of the environment (external prediction) and forecasting the future state of the organism (internal prediction). Next, I present the adaptive calibration model, an integrative model of individual differences in stress responsivity based on life history concepts. I conclude by examining how maternal-fetal conflict may shape the physiology of prenatal stress and its adaptive and maladaptive effects on postnatal development. In total, I aim to show how theoretical work from evolutionary biology is reshaping the way we think about the role of stress in human development, and provide researchers with an up-to-date conceptual map of this fascinating and rapidly evolving field.

  4. European early modern humans and the fate of the Neandertals

    PubMed Central

    Trinkaus, Erik

    2007-01-01

    A consideration of the morphological aspects of the earliest modern humans in Europe (more than ≈33,000 B.P.) and the subsequent Gravettian human remains indicates that they possess an anatomical pattern congruent with the autapomorphic (derived) morphology of the earliest (Middle Paleolithic) African modern humans. However, they exhibit a variable suite of features that are either distinctive Neandertal traits and/or plesiomorphic (ancestral) aspects that had been lost among the African Middle Paleolithic modern humans. These features include aspects of neurocranial shape, basicranial external morphology, mandibular ramal and symphyseal form, dental morphology and size, and anteroposterior dental proportions, as well as aspects of the clavicles, scapulae, metacarpals, and appendicular proportions. The ubiquitous and variable presence of these morphological features in the European earlier modern human samples can only be parsimoniously explained as a product of modest levels of assimilation of Neandertals into early modern human populations as the latter dispersed across Europe. This interpretation is in agreement with current analyses of recent and past human molecular data. PMID:17452632

  5. Cortisol levels and very early pregnancy loss in humans

    PubMed Central

    Nepomnaschy, Pablo A.; Welch, Kathleen B.; McConnell, Daniel S.; Low, Bobbi S.; Strassmann, Beverly I.; England, Barry G.

    2006-01-01

    Maternal stress is commonly cited as an important risk factor for spontaneous abortion. For humans, however, there is little physiological evidence linking miscarriage to stress. This lack of evidence may be attributable to a paucity of research on maternal stress during the earliest gestational stages. Most human studies have focused on “clinical” pregnancy (>6 weeks after the last menstrual period). The majority of miscarriages, however, occur earlier, within the first 3 weeks after conception (≈5 weeks after the last menstrual period). Studies focused on clinical pregnancy thus miss the most critical period for pregnancy continuance. We examined the association between miscarriage and levels of maternal urinary cortisol during the first 3 weeks after conception. Pregnancies characterized by increased maternal cortisol during this period (within participant analyses) were more likely to result in spontaneous abortion (P < 0.05). This evidence links increased levels in this stress marker with a higher risk of early pregnancy loss in humans. PMID:16495411

  6. Modulation of early human preadipocyte differentiation by glucocorticoids.

    PubMed

    Tomlinson, Julianna J; Boudreau, Adèle; Wu, Dongmei; Atlas, Ella; Haché, Robert J G

    2006-11-01

    Glucocorticoids provide an adipogenic stimulus that is most obvious in the truncal obesity of patients with Cushing's syndrome. Glucocorticoid treatment also strongly potentiates the differentiation of human preadipocytes in culture. However, the molecular basis of these stimulatory effects remains to be defined. In this study, we provide a detailed analysis of the specific contribution of glucocorticoid treatment to the differentiation of primary human preadipocytes cultured in chemically defined medium. Contrary to previous descriptions of glucocorticoids being required throughout the course of differentiation, our results show that glucocorticoid treatment is stimulatory only during the first 48 h of differentiation. Furthermore, stimulation by glucocorticoids and the peroxisome proliferator activator receptor-gamma agonist troglitazone is mediated sequentially. Several details of the early events in the differentiation of human preadipocytes and the contribution of steroid to these events differ from the responses observed previously in murine preadipocyte models. First, glucocorticoid treatment stimulated the early accumulation of CCAAT enhancer binding protein-beta (C/EBPbeta) in primary human preadipocytes. Second, induction of C/EBPalpha in primary human preadipocytes was noted within 4 h of adipogenic stimulus, whereas C/EBPalpha induction is not detected until 24-48 h in the murine 3T3 L1 preadipocyte model. Remarkably, by contrast to human primary preadipocytes, which do not undergo postconfluent mitosis, 3T3 L1 murine preadipocytes stimulated to differentiate under chemically defined conditions required glucocorticoids to survive the clonal expansion that precedes terminal differentiation, revealing a novel signal imparted by glucocorticoids in this immortalized murine cell system.

  7. Deciding Termination for Ancestor Match- Bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2005-01-01

    Termination of a string rewriting system can be characterized by termination on suitable recursively defined languages. This kind of termination criteria has been criticized for its lack of automation. In an earlier paper we have shown how to construct an automated termination criterion if the recursion is aligned with the rewrite relation. We have demonstrated the technique with Dershowitz's forward closure criterion. In this paper we show that a different approach is suitable when the recursion is aligned with the inverse of the rewrite relation. We apply this idea to Kurth's ancestor graphs and obtain ancestor match-bounded string rewriting systems. Termination is shown to be decidable for this class. The resulting method improves upon those based on match-boundedness or inverse match-boundedness.

  8. Hypoxia: a critical regulator of early human tendinopathy.

    PubMed

    Millar, Neal L; Reilly, James H; Kerr, Shauna C; Campbell, Abigail L; Little, Kevin J; Leach, William J; Rooney, Brian P; Murrell, George A C; McInnes, Iain B

    2012-02-01

    To seek evidence for the role of hypoxia in early human tendinopathy, and thereafter to explore mechanisms whereby tissue hypoxia may regulate apoptosis, inflammatory mediator expression and matrix regulation in human tenocytes. Fifteen torn supraspinatus tendon (established pathology) and matched intact subscapularis tendon (representing 'early pathology') biopsies were collected from patients undergoing arthroscopic shoulder surgery. Control samples of the subscapularis tendon were collected from 10 patients undergoing arthroscopic stabilisation surgery. Markers of hypoxia were quantified by immunohistochemical methods. Human tendon-derived primary cells were derived from hamstring tendon tissue obtained during hamstring tendon anterior cruciate ligament reconstruction. The impact of hypoxia upon tenocyte biology ex vivo was measured using quantitative real-time PCR, multiplex cytokine assays, apoptotic proteomic profiling, immunohistochemistry and annexin V fluorescence-activated cell sorter staining. Increased expression of hypoxia-inducible factor 1α, Bcl-2 and clusterin was detected in subscapularis tendon samples compared with both matched torn samples and non-matched control samples (p<0.01). Hypoxic tenocytes exhibited increased production of proinflammatory cytokines (p<0.001), altered matrix regulation (p<0.01) with increased production of collagen type III operating through a mitogen-activated protein kinase-dependent pathway. Finally, hypoxia increased the expression of several mediators of apoptosis and thereby promoted tenocyte apoptosis. Hypoxia promotes the expression of proinflammatory cytokines, key apoptotic mediators and drives matrix component synthesis towards a collagen type III profile by human tenocytes. The authors propose hypoxic cell injury as a critical pathophysiological mechanism in early tendinopathy offering novel therapeutic opportunities in the management of tendon disorders.

  9. Early enteral feeding with human milk for VLBW infants.

    PubMed

    De Nisi, G; Berti, M; De Nisi, M; Bertino, E

    2012-01-01

    In a NICU early enteral feeding is usually possible only when the newborn clinical conditions permit it. Because of the frequent need of umbilical/central catheters, they usually start with parenteral feeding and/or with minimal enteral feeding (trophic feeding). This kind of management is even more frequent in VLBWIs, in which the risk of NEC is very high. In this work we describe a model of early enteral exclusive feeding (EEEF) based on the use of banking human milk followed by mother milk. In the Centre of Neonatology of Trento, as in other Centers, the newborns weighing less than 750g or with a GE< 27 weeks, are treated with parenteral nutrition and minimal enteral feeding. The newborn weighing 750-1249g and with GE > 26 weeks define a group in which we find critical neonates, who can not be treated with enteral feeding, and neonates whose clinical conditions permit EEEF. In particular, in a period of 16 years (1994-2009) in Trento, 308 newborns weighing 750-1249 g and GE > than 26 weeks were admitted. The 90,9 % has been treated with prenatal steroids, the 91,9 % was inborn, the 96,1% survived. In the 59,1 % of the cases (175) we gave EEEF. We could continue with a complete EEEF in the 40,2 % of the total (119 cases). The characteristics of these neonates and our centre management, based mainly on early use of banking human milk and mother milk, are detailed described.

  10. Early human settlements in the southern Qinling Mountains, central China

    NASA Astrophysics Data System (ADS)

    Sun, Xuefeng; Lu, Huayu; Wang, Shejiang; Yi, Liang; Li, Yongxiang; Bahain, Jean Jacques; Voinchet, Pierre; Hu, Xuzhi; Zeng, Lin; Zhang, Wenchao; Zhuo, Haixin

    2017-05-01

    China is a key area of early human settlement in East Asia, with numerous Paleolithic localities indicating an early Pleistocene presence of hominins in northern and southern China. Considerable research has been devoted to determining possible migration routes for hominins linking the two areas. In this paper, we report the discovery of several loess-covered Paleolithic sites in the Hanzhong and Ankang Basins along the Hanjiang River in the southern piedmont of the Qinling Mountains (QLM) in central China. A chronology is developed for these sections using a combination of detailed optically stimulated luminescence dating, magnetostratigraphic analyses, and pedostratigraphic correlation with the well-dated loess-paleosol sequence of the central Chinese Loess Plateau. The results indicate that the age of the oldest lithic assemblage at the Longgangsi locality 3 Paleolithic site in Hanzhong Basin is ∼1.20 Ma, thus making this locality as one of the oldest sites in central China. Our work also indicates that hominins occupied the Hanjiang valley at several times: ∼1.2, 0.9, ∼0.6, and ∼0.1 Ma. We propose that the Hanjiang River Valley was a probable hominin routeway through the QLM because many sites corresponding to these different phases were also discovered to the north of the QLM. Future study on the Hanjiang River Valley is important for verifying the hypothesis of an early human migration route between southern and northern China.

  11. Ancestor reverence and mental health in South Africa.

    PubMed

    Berg, Astrid

    2003-06-01

    The great majority of South Africa's people consult traditional healers. The deeper meaning of much traditional healing centres on ancestor reverence. This belief system and its accompanying rituals may positively influence the mental health of the individual and the community. Among traditional Xhosa-speaking peoples, the relationship with the ancestors is given expression in life cycle rituals that have much in common with Western psychotherapeutic principles and practices. The common thread that underpins many rituals is that of making links via concrete, literal means. Examples include the participation of the community in the healing of the individual; the linking of body and mind through dancing and drumming. Dreams form an essential connection between conscious life and the unconscious. Understanding the psychological depth of these practices is important so that a respectful relationship between Western-trained professionals and traditional healers can develop. Analytical psychology, with its notion of the collective unconscious has a particular contribution to make to cross-cultural understanding. The ancestors may be understood as archetypal representations of the collective unconscious.

  12. Aplacophoran Mollusks Evolved from Ancestors with Polyplacophoran-like Features

    PubMed Central

    Scherholz, Maik; Redl, Emanuel; Wollesen, Tim; Todt, Christiane; Wanninger, Andreas

    2013-01-01

    Summary Mollusca is an animal phylum with vast morphological diversity and includes worm-shaped aplacophorans, snails, bivalves, and the complex cephalopods [1]. The interrelationships of these class-level taxa are still contentious [2, 3], but recent phylogenomic analyses suggest a dichotomy at the base of Mollusca, resulting in a monophyletic Aculifera (comprising the shell-less, sclerite-bearing aplacophorans and the eight-shelled polyplacophorans) and Conchifera (all other, primarily univalved groups) [4, 5]. The Aculifera concept has recently gained support via description of the fossil Kulindroplax, which shows both aplacophoran- and polyplacophoran-like features and suggests that the aplacophorans originated from a shelled ancestor [6], but the overall morphology of the last common aculiferan ancestor remains obscure. Here we show that larvae of the aplacophoran Wirenia argentea have several sets of muscles previously known only from polyplacophoran mollusks. Most of these are lost during metamorphosis, and we interpret them as ontogenetic remnants of an ancestor with a complex, polyplacophoran-like musculature. Moreover, we find that the first seven pairs of dorsoventral muscles develop synchronously in Wirenia, similar to juvenile polyplacophorans [7], which supports the conclusions based on the seven-shelled Kulindroplax. Accordingly, we argue that the simple body plan of recent aplacophorans is the result of simplification and does not represent a basal molluscan condition. PMID:24139743

  13. Diversity of the Human Skin Microbiome Early in Life

    PubMed Central

    Capone, Kimberly A; Dowd, Scot E; Stamatas, Georgios N; Nikolovski, Janeta

    2011-01-01

    Within days after birth, rapid surface colonization of infant skin coincides with significant functional changes. Gradual maturation of skin function, structure, and composition continues throughout the first years of life. Recent reports have revealed topographical and temporal variations in the adult skin microbiome. Here we address the question of how the human skin microbiome develops early in life. We show that the composition of cutaneous microbial communities evolves over the first year of life, showing increasing diversity with age. Although early colonization is dominated by Staphylococci, their significant decline contributes to increased population evenness by the end of the first year. Similar to what has been shown in adults, the composition of infant skin microflora appears to be site specific. In contrast to adults, we find that Firmicutes predominate on infant skin. Timely and proper establishment of healthy skin microbiome during this early period might have a pivotal role in denying access to potentially infectious microbes and could affect microbiome composition and stability extending into adulthood. Bacterial communities contribute to the establishment of cutaneous homeostasis and modulate inflammatory responses. Early microbial colonization is therefore expected to critically affect the development of the skin immune function. PMID:21697884

  14. Diversity of the human skin microbiome early in life.

    PubMed

    Capone, Kimberly A; Dowd, Scot E; Stamatas, Georgios N; Nikolovski, Janeta

    2011-10-01

    Within days after birth, rapid surface colonization of infant skin coincides with significant functional changes. Gradual maturation of skin function, structure, and composition continues throughout the first years of life. Recent reports have revealed topographical and temporal variations in the adult skin microbiome. Here we address the question of how the human skin microbiome develops early in life. We show that the composition of cutaneous microbial communities evolves over the first year of life, showing increasing diversity with age. Although early colonization is dominated by Staphylococci, their significant decline contributes to increased population evenness by the end of the first year. Similar to what has been shown in adults, the composition of infant skin microflora appears to be site specific. In contrast to adults, we find that Firmicutes predominate on infant skin. Timely and proper establishment of healthy skin microbiome during this early period might have a pivotal role in denying access to potentially infectious microbes and could affect microbiome composition and stability extending into adulthood. Bacterial communities contribute to the establishment of cutaneous homeostasis and modulate inflammatory responses. Early microbial colonization is therefore expected to critically affect the development of the skin immune function.

  15. Ecosystem variability and early human habitats in eastern Africa

    PubMed Central

    Magill, Clayton R.; Ashley, Gail M.; Freeman, Katherine H.

    2013-01-01

    The role of savannas during the course of early human evolution has been debated for nearly a century, in part because of difficulties in characterizing local ecosystems from fossil and sediment records. Here, we present high-resolution lipid biomarker and isotopic signatures for organic matter preserved in lake sediments at Olduvai Gorge during a key juncture in human evolution about 2.0 Ma—the emergence and dispersal of Homo erectus (sensu lato). Using published data for modern plants and soils, we construct a framework for ecological interpretations of stable carbon-isotope compositions (expressed as δ13C values) of lipid biomarkers from ancient plants. Within this framework, δ13C values for sedimentary leaf lipids and total organic carbon from Olduvai Gorge indicate recurrent ecosystem variations, where open C4 grasslands abruptly transitioned to closed C3 forests within several hundreds to thousands of years. Carbon-isotopic signatures correlate most strongly with Earth’s orbital geometry (precession), and tropical sea-surface temperatures are significant secondary predictors in partial regression analyses. The scale and pace of repeated ecosystem variations at Olduvai Gorge contrast with long-held views of directional or stepwise aridification and grassland expansion in eastern Africa during the early Pleistocene and provide a local perspective on environmental hypotheses of human evolution. PMID:23267092

  16. Early human symbolic behavior in the Late Pleistocene of Wallacea.

    PubMed

    Brumm, Adam; Langley, Michelle C; Moore, Mark W; Hakim, Budianto; Ramli, Muhammad; Sumantri, Iwan; Burhan, Basran; Saiful, Andi Muhammad; Siagian, Linda; Suryatman; Sardi, Ratno; Jusdi, Andi; Abdullah; Mubarak, Andi Pampang; Hasliana; Hasrianti; Oktaviana, Adhi Agus; Adhityatama, Shinatria; van den Bergh, Gerrit D; Aubert, Maxime; Zhao, Jian-Xin; Huntley, Jillian; Li, Bo; Roberts, Richard G; Saptomo, E Wahyu; Perston, Yinika; Grün, Rainer

    2017-04-18

    Wallacea, the zone of oceanic islands separating the continental regions of Southeast Asia and Australia, has yielded sparse evidence for the symbolic culture of early modern humans. Here we report evidence for symbolic activity 30,000-22,000 y ago at Leang Bulu Bettue, a cave and rock-shelter site on the Wallacean island of Sulawesi. We describe hitherto undocumented practices of personal ornamentation and portable art, alongside evidence for pigment processing and use in deposits that are the same age as dated rock art in the surrounding karst region. Previously, assemblages of multiple and diverse types of Pleistocene "symbolic" artifacts were entirely unknown from this region. The Leang Bulu Bettue assemblage provides insight into the complexity and diversification of modern human culture during a key period in the global dispersal of our species. It also shows that early inhabitants of Sulawesi fashioned ornaments from body parts of endemic animals, suggesting modern humans integrated exotic faunas and other novel resources into their symbolic world as they colonized the biogeographically unique regions southeast of continental Eurasia.

  17. Ecosystem variability and early human habitats in eastern Africa.

    PubMed

    Magill, Clayton R; Ashley, Gail M; Freeman, Katherine H

    2013-01-22

    The role of savannas during the course of early human evolution has been debated for nearly a century, in part because of difficulties in characterizing local ecosystems from fossil and sediment records. Here, we present high-resolution lipid biomarker and isotopic signatures for organic matter preserved in lake sediments at Olduvai Gorge during a key juncture in human evolution about 2.0 Ma--the emergence and dispersal of Homo erectus (sensu lato). Using published data for modern plants and soils, we construct a framework for ecological interpretations of stable carbon-isotope compositions (expressed as δ(13)C values) of lipid biomarkers from ancient plants. Within this framework, δ(13)C values for sedimentary leaf lipids and total organic carbon from Olduvai Gorge indicate recurrent ecosystem variations, where open C(4) grasslands abruptly transitioned to closed C(3) forests within several hundreds to thousands of years. Carbon-isotopic signatures correlate most strongly with Earth's orbital geometry (precession), and tropical sea-surface temperatures are significant secondary predictors in partial regression analyses. The scale and pace of repeated ecosystem variations at Olduvai Gorge contrast with long-held views of directional or stepwise aridification and grassland expansion in eastern Africa during the early Pleistocene and provide a local perspective on environmental hypotheses of human evolution.

  18. The Human Microbiome. Early Life Determinant of Health Outcomes

    PubMed Central

    2014-01-01

    The development of new technologies to isolate and identify microbial genomes has markedly increased our understanding of the role of microbiomes in health and disease. The idea, first proposed as part of the hygiene hypothesis, that environmental microbes influence the developmental trajectories of the immune system in early life, has now been considerably extended and refined. The abundant microbiota present in mucosal surfaces, especially the gut, is actively selected by the host through complex receptor systems that respond differentially depending on the molecular patterns presented to mucosal cells. Germ-free mice are more likely to develop allergic airway inflammation and show alterations in normal motor control and anxiety. These effects can be reversed by neonatal microbial recolonization but remain unchanged if recolonization occurs in adults. What emerges from these recent studies is the discovery of a complex, major early environmental determinant of lifetime human phenotypes. To change the natural course of asthma, obesity, and other chronic inflammatory conditions, active manipulation of the extensive bacterial, phage, and fungal metagenomes present in mucosal surfaces may be required, specifically during the developing years. Domesticating the human microbiome and adapting it to our health needs may be a challenge akin to, but far more complex than, the one faced by humanity when a few dozen species of plants and animals were domesticated during the transition between hunter-gatherer and sedentary societies after the end of the Pleistocene era. PMID:24437411

  19. An early history of human breast cancer: West meets East.

    PubMed

    Yan, Shou-He

    2013-09-01

    Cancer has been increasingly recognized as a global issue. This is especially true in countries like China, where cancer incidence has increased likely because of changes in environment and lifestyle. However, cancer is not a modern disease; early cases have been recorded in ancient medical books in the West and in China. Here, we provide a brief history of cancer, focusing on cancer of the breast, and review the etymology of ai, the Chinese character for cancer. Notable findings from both Western and Chinese traditional medicine are presented to give an overview of the most important, early contributors to our evolving understanding of human breast cancer. We also discuss the earliest historical documents to record patients with breast cancer.

  20. An early history of human breast cancer: West meets East

    PubMed Central

    Yan, Shou-He

    2013-01-01

    Cancer has been increasingly recognized as a global issue. This is especially true in countries like China, where cancer incidence has increased likely because of changes in environment and lifestyle. However, cancer is not a modern disease; early cases have been recorded in ancient medical books in the West and in China. Here, we provide a brief history of cancer, focusing on cancer of the breast, and review the etymology of ai, the Chinese character for cancer. Notable findings from both Western and Chinese traditional medicine are presented to give an overview of the most important, early contributors to our evolving understanding of human breast cancer. We also discuss the earliest historical documents to record patients with breast cancer. PMID:23958056

  1. Four queries concerning the metaphysics of early human embryogenesis.

    PubMed

    Howsepian, A A

    2008-04-01

    In this essay, I attempt to provide answers to the following four queries concerning the metaphysics of early human embryogenesis. (1) Following its first cellular fission, is it coherent to claim that one and only one of two "blastomeric" twins of a human zygote is identical with that zygote? (2) Following the fusion of two human pre-embryos, is it coherent to claim that one and only one pre-fusion pre-embryo is identical with that postfusion pre-embryo? (3) Does a live human being come into existence only when its brain comes into existence? (4) At implantation, does a pre-embryo become a mere part of its mother? I argue that either if things have quidditative properties or if criterialism is false, then queries (1) and (2) can be answered in the affirmative; that in light of recent developments in theories of human death and in light of a more "functional" theory of brains, query (3) can be answered in the negative; and that plausible mereological principles require a negative answer to query (4).

  2. An early modern human from Tianyuan Cave, Zhoukoudian, China

    PubMed Central

    Shang, Hong; Tong, Haowen; Zhang, Shuangquan; Chen, Fuyou; Trinkaus, Erik

    2007-01-01

    Thirty-four elements of an early modern human (EMH) were found in Tianyuan Cave, Zhoukoudian, China in 2003. Dated to 42,000–39,000 calendrical years before present by using direct accelerator mass spectrometry radiocarbon, the Tianyuan 1 skeleton is among the oldest directly dated EMHs in eastern Eurasia. Morphological comparison shows Tianyuan 1 to have a series of derived modern human characteristics, including a projecting tuber symphyseos, a high anterior symphyseal angle, a broad scapular glenoid fossa, a reduced hamulus, a gluteal buttress, and a pilaster on the femora. Other features of Tianyuan 1 that are more common among EMHs are its modest humeral pectoralis major tuberosities, anteriorly rotated radial tuberosity, reduced radial curvature, and modest talar trochlea. It also lacks several mandibular features common among western Eurasian late archaic humans, including mandibular foramen bridging, mandibular notch asymmetry, and a large superior medial pterygoid tubercle. However, Tianyuan 1 exhibits several late archaic human features, such as its anterior to posterior dental proportions, a large hamulus length, and a broad and rounded distal phalangeal tuberosity. This morphological pattern implies that a simple spread of modern humans from Africa is unlikely. PMID:17416672

  3. Developmental Changes in the Human Sleep EEG During Early Adolescence

    PubMed Central

    Tarokh, Leila; Carskadon, Mary A.

    2010-01-01

    Study Objectives: To use time-frequency analysis to characterize developmental changes in the human sleep electroencephalogram (EEG) across early adolescence. Design: Sleep EEG was recorded when children were 9/10 years old and 1 to 3 years later after sleeping at home on a fixed schedule for at least one week. Setting: A 4-bed sleep laboratory. Participants: Fourteen (5 girls) healthy children ages 9/10 (mean = 10.13, SD = ± 0.51) years at initial and 11 to 13 (mean = 12.28, SD = ± 0.62) years at follow-up. Interventions: N/A. Measurements and Results: All-night polysomnography was performed at each assessment and sleep stages were scored with Rechtschaffen and Kales criteria. Slow wave sleep minutes decreased from the initial to the follow-up session by 29%, while minutes of stage 2 increased by 17%. NREM and REM sleep EEG spectra from two central and two occipital leads were examined for developmental changes. All-night analyses showed a significant decrease of EEG power from the initial to follow-up session across a range of frequencies during NREM and REM sleep. This decline occurred across leads and states in the delta/theta bands (3.8 – 7 Hz). Time-frequency analyses indicated that this effect was consistent across the night. The decline in power with age was most pronounced in the left central and right occipital leads. The frequency of greatest power in the sigma band (11 – 16 Hz) was significantly higher at follow-up. Conclusions: This longitudinal analysis highlights asymmetrical frequency-specific declines in sleep EEG spectral power with early adolescent maturation, which may reflect early signs of the cortical synaptic pruning in the healthy adolescent. Citation: Tarokh L; Carskadon MA. Developmental changes in the human sleep EEG during early adolescence. SLEEP 2010;33(6):801-809. PMID:20550021

  4. A unique chromatin signature uncovers early developmental enhancers in humans.

    PubMed

    Rada-Iglesias, Alvaro; Bajpai, Ruchi; Swigut, Tomek; Brugmann, Samantha A; Flynn, Ryan A; Wysocka, Joanna

    2011-02-10

    Cell-fate transitions involve the integration of genomic information encoded by regulatory elements, such as enhancers, with the cellular environment. However, identification of genomic sequences that control human embryonic development represents a formidable challenge. Here we show that in human embryonic stem cells (hESCs), unique chromatin signatures identify two distinct classes of genomic elements, both of which are marked by the presence of chromatin regulators p300 and BRG1, monomethylation of histone H3 at lysine 4 (H3K4me1), and low nucleosomal density. In addition, elements of the first class are distinguished by the acetylation of histone H3 at lysine 27 (H3K27ac), overlap with previously characterized hESC enhancers, and are located proximally to genes expressed in hESCs and the epiblast. In contrast, elements of the second class, which we term 'poised enhancers', are distinguished by the absence of H3K27ac, enrichment of histone H3 lysine 27 trimethylation (H3K27me3), and are linked to genes inactive in hESCs and instead are involved in orchestrating early steps in embryogenesis, such as gastrulation, mesoderm formation and neurulation. Consistent with the poised identity, during differentiation of hESCs to neuroepithelium, a neuroectoderm-specific subset of poised enhancers acquires a chromatin signature associated with active enhancers. When assayed in zebrafish embryos, poised enhancers are able to direct cell-type and stage-specific expression characteristic of their proximal developmental gene, even in the absence of sequence conservation in the fish genome. Our data demonstrate that early developmental enhancers are epigenetically pre-marked in hESCs and indicate an unappreciated role of H3K27me3 at distal regulatory elements. Moreover, the wealth of new regulatory sequences identified here provides an invaluable resource for studies and isolation of transient, rare cell populations representing early stages of human embryogenesis.

  5. Water, plants, and early human habitats in eastern Africa

    PubMed Central

    Magill, Clayton R.; Ashley, Gail M.; Freeman, Katherine H.

    2013-01-01

    Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as δD values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa—Olduvai Gorge. We convert sedimentary leaf- and algal-lipid δD values into estimates for ancient source-water δD values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water–lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water δD values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative δD values, occur in association with stable carbon-isotopic evidence for open, C4-dominated grassland ecosystems. Wetter conditions, indicated by lower δD values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation δD values, range between approximately 250 and 700 mm·y−1 and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change. PMID:23267102

  6. Water, plants, and early human habitats in eastern Africa.

    PubMed

    Magill, Clayton R; Ashley, Gail M; Freeman, Katherine H

    2013-01-22

    Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as δD values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa--Olduvai Gorge. We convert sedimentary leaf- and algal-lipid δD values into estimates for ancient source-water δD values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water-lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water δD values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative δD values, occur in association with stable carbon-isotopic evidence for open, C(4)-dominated grassland ecosystems. Wetter conditions, indicated by lower δD values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation δD values, range between approximately 250 and 700 mm · y(-1) and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change.

  7. Debatable questions of Siberia settlement by early humans

    NASA Astrophysics Data System (ADS)

    Kuzmin, Ya. V.; Kazanskii, A. Yu.

    2015-01-01

    Data on the age and natural environment of earliest archaeological sites in Siberia are critically analyzed. Particular attention is paid to the Karama site in the Altai Mountains, whose age was earlier estimated at about 1.77-1.95 Ma. The combination of geological, geomorphological, sedimentological, palynological, and paleomagnetic data makes it possible to determine the lower limit of the age of this object at only about 800 ka. Judging by the results of a preliminary study of the Zasukhino site in Trans-Baikal, early humans could have appeared in Siberia about 1 million years ago, but additional research is required in order to obtain reliable information.

  8. Facilitated early cortical processing of nude human bodies.

    PubMed

    Alho, Jussi; Salminen, Nelli; Sams, Mikko; Hietanen, Jari K; Nummenmaa, Lauri

    2015-07-01

    Functional brain imaging has identified specialized neural systems supporting human body perception. Responses to nude vs. clothed bodies within this system are amplified. However, it remains unresolved whether nude and clothed bodies are processed by same cerebral networks or whether processing of nude bodies recruits additional affective and arousal processing areas. We recorded simultaneous MEG and EEG while participants viewed photographs of clothed and nude bodies. Global field power revealed a peak ∼145ms after stimulus onset to both clothed and nude bodies, and ∼205ms exclusively to nude bodies. Nude-body-sensitive responses were centered first (100-200ms) in the extrastriate and fusiform body areas, and subsequently (200-300ms) in affective-motivational areas including insula and anterior cingulate cortex. We conclude that visibility of sexual features facilitates early cortical processing of human bodies, the purpose of which is presumably to trigger sexual behavior and ultimately ensure reproduction.

  9. Environmental Adaptation from the Origin of Life to the Last Universal Common Ancestor

    NASA Astrophysics Data System (ADS)

    Cantine, Marjorie D.; Fournier, Gregory P.

    2017-07-01

    Extensive fundamental molecular and biological evolution took place between the prebiotic origins of life and the state of the Last Universal Common Ancestor (LUCA). Considering the evolutionary innovations between these two endpoints from the perspective of environmental adaptation, we explore the hypothesis that LUCA was temporally, spatially, and environmentally distinct from life's earliest origins in an RNA world. Using this lens, we interpret several molecular biological features as indicating an environmental transition between a cold, radiation-shielded origin of life and a mesophilic, surface-dwelling LUCA. Cellularity provides motility and permits Darwinian evolution by connecting genetic material and its products, and thus establishing heredity and lineage. Considering the importance of compartmentalization and motility, we propose that the early emergence of cellularity is required for environmental dispersal and diversification during these transitions. Early diversification and the emergence of ecology before LUCA could be an important pre-adaptation for life's persistence on a changing planet.

  10. Environmental Adaptation from the Origin of Life to the Last Universal Common Ancestor.

    PubMed

    Cantine, Marjorie D; Fournier, Gregory P

    2017-07-06

    Extensive fundamental molecular and biological evolution took place between the prebiotic origins of life and the state of the Last Universal Common Ancestor (LUCA). Considering the evolutionary innovations between these two endpoints from the perspective of environmental adaptation, we explore the hypothesis that LUCA was temporally, spatially, and environmentally distinct from life's earliest origins in an RNA world. Using this lens, we interpret several molecular biological features as indicating an environmental transition between a cold, radiation-shielded origin of life and a mesophilic, surface-dwelling LUCA. Cellularity provides motility and permits Darwinian evolution by connecting genetic material and its products, and thus establishing heredity and lineage. Considering the importance of compartmentalization and motility, we propose that the early emergence of cellularity is required for environmental dispersal and diversification during these transitions. Early diversification and the emergence of ecology before LUCA could be an important pre-adaptation for life's persistence on a changing planet.

  11. 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.

  12. 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.

  13. Buds from the tree of life: linking compartmentalized prokaryotes and eukaryotes by a non-hyperthermophile common ancestor and implications for understanding Archaean microbial communities

    NASA Astrophysics Data System (ADS)

    Fuerst, John A.; Nisbet, Euan G.

    2004-07-01

    The origin of the first nucleated eukaryote and the nature of the last common ancestor of the three domains of life are major questions in the evolutionary biology of cellular life on Earth, the solutions to which may be linked. Planctomycetes are unusual compartmentalized bacteria that include a membrane-bounded nucleoid. The possibility that they constitute a very deep branch of the domain Bacteria suggests a model for the evolution of the three domains of life from a last common ancestor that was a mesophile or moderate thermophile with a compartmentalized eukaryote-like cell plan. Planctomycetes and some members of the domain Archaea may have retained cell compartmentalization present in an original eukaryote-like last common ancestor of the three domains of life. The implications of this model for possible habitats of the early evolution of domains of cellular life and for interpretation of geological evidence relating to those habitats and the early emergence of life are examined here.

  14. Life cycle evolution: was the eumetazoan ancestor a holopelagic, planktotrophic gastraea?

    PubMed Central

    2013-01-01

    Background Two theories for the origin of animal life cycles with planktotrophic larvae are now discussed seriously: The terminal addition theory proposes a holopelagic, planktotrophic gastraea as the ancestor of the eumetazoans with addition of benthic adult stages and retention of the planktotrophic stages as larvae, i.e. the ancestral life cycles were indirect. The intercalation theory now proposes a benthic, deposit-feeding gastraea as the bilaterian ancestor with a direct development, and with planktotrophic larvae evolving independently in numerous lineages through specializations of juveniles. Results Information from the fossil record, from mapping of developmental types onto known phylogenies, from occurrence of apical organs, and from genetics gives no direct information about the ancestral eumetazoan life cycle; however, there are plenty of examples of evolution from an indirect development to direct development, and no unequivocal example of evolution in the opposite direction. Analyses of scenarios for the two types of evolution are highly informative. The evolution of the indirect spiralian life cycle with a trochophora larva from a planktotrophic gastraea is explained by the trochophora theory as a continuous series of ancestors, where each evolutionary step had an adaptational advantage. The loss of ciliated larvae in the ecdysozoans is associated with the loss of outer ciliated epithelia. A scenario for the intercalation theory shows the origin of the planktotrophic larvae of the spiralians through a series of specializations of the general ciliation of the juvenile. The early steps associated with the enhancement of swimming seem probable, but the following steps which should lead to the complicated downstream-collecting ciliary system are without any advantage, or even seem disadvantageous, until the whole structure is functional. None of the theories account for the origin of the ancestral deuterostome (ambulacrarian) life cycle. Conclusions All

  15. Life cycle evolution: was the eumetazoan ancestor a holopelagic, planktotrophic gastraea?

    PubMed

    Nielsen, Claus

    2013-08-16

    Two theories for the origin of animal life cycles with planktotrophic larvae are now discussed seriously: The terminal addition theory proposes a holopelagic, planktotrophic gastraea as the ancestor of the eumetazoans with addition of benthic adult stages and retention of the planktotrophic stages as larvae, i.e. the ancestral life cycles were indirect. The intercalation theory now proposes a benthic, deposit-feeding gastraea as the bilaterian ancestor with a direct development, and with planktotrophic larvae evolving independently in numerous lineages through specializations of juveniles. Information from the fossil record, from mapping of developmental types onto known phylogenies, from occurrence of apical organs, and from genetics gives no direct information about the ancestral eumetazoan life cycle; however, there are plenty of examples of evolution from an indirect development to direct development, and no unequivocal example of evolution in the opposite direction. Analyses of scenarios for the two types of evolution are highly informative. The evolution of the indirect spiralian life cycle with a trochophora larva from a planktotrophic gastraea is explained by the trochophora theory as a continuous series of ancestors, where each evolutionary step had an adaptational advantage. The loss of ciliated larvae in the ecdysozoans is associated with the loss of outer ciliated epithelia. A scenario for the intercalation theory shows the origin of the planktotrophic larvae of the spiralians through a series of specializations of the general ciliation of the juvenile. The early steps associated with the enhancement of swimming seem probable, but the following steps which should lead to the complicated downstream-collecting ciliary system are without any advantage, or even seem disadvantageous, until the whole structure is functional. None of the theories account for the origin of the ancestral deuterostome (ambulacrarian) life cycle. All the available information is

  16. Carbon cycle and climate commitments from early human interference

    NASA Astrophysics Data System (ADS)

    Zickfeld, K.; Solomon, S.

    2015-12-01

    According to the early anthropogenic hypothesis proposed by Ruddiman (2003), human influence on Earth's climate began several thousand years before the beginning of the industrial era. Agriculture and deforestation starting around 8000 years before present (BP) and slowly increasing over the Holocene, would have led to an increase in atmospheric methane (CH4) and carbon dioxide (CO2) concentration, preventing a natural cooling of Earth's climate. Here, the emphasis is not on testing Ruddiman's hypothesis, but rather on exploring the carbon cycle and climate commitment from potential early CH4 and CO2 emissions. In contrast to modern greenhouse gas emissions, early emissions occurred over millennia, allowing the climate system to come to near-equilibrium with the applied forcing. We perform two transient Holocene simulations with an Earth system model of intermediate complexity - the University of Victoria Earth System Climate Model (UVic ESCM). The first simulation is a standard transient Holocene simulation, forced with reconstructed changes in CO2 and CH4 concentrations and orbital and volcanic forcing. The second simulation is forced with CO2 and CH4 concentrations corrected for the net anthropogenic contribution postulated by Ruddiman (2007), with other forcings evolving as in the standard simulation. The difference in diagnosed emissions between the two simulations allows us to determine the anthropogenic emissions. After year 1850, anthropogenic CO2 and CH4 emissions are set to zero and the simulations continued for several hundred years. In this paper, we analyze the carbon cycle and climate response to the applied forcings, and quantify the resulting (post 1850) commitment from early anthropogenic interference.

  17. Ancient horizontal gene transfer and the last common ancestors.

    PubMed

    Fournier, Gregory P; Andam, Cheryl P; Gogarten, Johann Peter

    2015-04-22

    The genomic history of prokaryotic organismal lineages is marked by extensive horizontal gene transfer (HGT) between groups of organisms at all taxonomic levels. These HGT events have played an essential role in the origin and distribution of biological innovations. Analyses of ancient gene families show that HGT existed in the distant past, even at the time of the organismal last universal common ancestor (LUCA). Most gene transfers originated in lineages that have since gone extinct. Therefore, one cannot assume that the last common ancestors of each gene were all present in the same cell representing the cellular ancestor of all extant life. Organisms existing as part of a diverse ecosystem at the time of LUCA likely shared genetic material between lineages. If these other lineages persisted for some time, HGT with the descendants of LUCA could have continued into the bacterial and archaeal lineages. Phylogenetic analyses of aminoacyl-tRNA synthetase protein families support the hypothesis that the molecular common ancestors of the most ancient gene families did not all coincide in space and time. This is most apparent in the evolutionary histories of seryl-tRNA synthetase and threonyl-tRNA synthetase protein families, each containing highly divergent "rare" forms, as well as the sparse phylogenetic distributions of pyrrolysyl-tRNA synthetase, and the bacterial heterodimeric form of glycyl-tRNA synthetase. These topologies and phyletic distributions are consistent with horizontal transfers from ancient, likely extinct branches of the tree of life. Of all the organisms that may have existed at the time of LUCA, by definition only one lineage is survived by known progeny; however, this lineage retains a genomic record of heterogeneous genetic origins. The evolutionary histories of aminoacyl-tRNA synthetases (aaRS) are especially informative in detecting this signal, as they perform primordial biological functions, have undergone several ancient HGT events, and

  18. Gene content of LUCA, the last universal common ancestor.

    PubMed

    Mushegian, Arcady

    2008-05-01

    Comparative genomics and modern phylogenetic approaches allow us to infer the gene content of LUCA, the Last Universal Common Ancestor of all known currently living cellular organisms. Most of the estimates produce a putative LUCA with 500-1000 protein-coding genes and biochemically coherent metabolism, if the average rates of gene gains (gene emergence plus horizontal gene transfer) and gene losses per family are allowed to be close to each other. This estimate is not strongly sensitive to the topology of the Tree of Life, but the identity of the genes that are placed in LUCA may depend on the position of the deep branches and the root of the tree.

  19. Phylogenetic reconstruction of parental-care systems in the ancestors of birds.

    PubMed Central

    Tullberg, Birgitta S; Ah-King, Malin; Temrin, Hans

    2002-01-01

    Due to the controversy surrounding incipient avian parental care, ancestral parental care systems were reconstructed in a phylogeny including major extant amniote lineages. Using two different resolutions for the basal avian branches, transitions between the states no care, female care, biparental care and male care were inferred for the most basal branches of the tree. Uniparental female care was inferred for the lineage to birds and crocodiles. Using a phylogeny where ratites and tinamous branch off early and an ordered character-state assumption, a transition to biparental care was inferred for the ancestor of birds. This ancestor could be any organism along the lineage leading from the crocodile-bird split up to modern birds, not necessarily the original bird. We discuss the support for alternative avian phylogenies and the homology in parental care between crocodiles and birds. We suggest that the phylogenetic pattern should be used as a starting point for a more detailed analysis of parental care systems in birds and their relatives. PMID:11958694

  20. The Nature (and Nurture?) of Plasticity in Early Human Development.

    PubMed

    Belsky, Jay; Pluess, Michael

    2009-07-01

    The effect of early experience is a long-standing concern in developmental psychology. Gaining further insight into the nature of human plasticity is central to efforts to prevent problems in development from arising and promote positive functioning. Evolutionary reasoning suggests that children should vary in their susceptibility to environmental influences, including parenting. Evidence indicates that rather than some children, such as those with negatively emotional temperaments or certain genotypes, being simply more vulnerable to the adverse effects of negative experiences, as commonly assumed, they may actually be more susceptible to both positive and negative experiences. In addition to raising questions about the nature of plasticity in human development, this article highlights unknowns regarding the role of nature and nurture in shaping individual differences in plasticity, including whether recent research linking maternal stress during pregnancy with child behavior problems illuminates a process whereby fetal programming shapes the child's susceptibility to postnatal environmental influences. Throughout this article, we raise concern about the potentially distorting influence that psychology's disproportionate focus on the adverse effect of negative experiences on developmental problems has on our understanding of human plasticity, and we propose that researchers should pay more attention to the positive side of the plasticity equation. © 2009 Association for Psychological Science.

  1. UVA phototransduction drives early melanin synthesis in human melanocytes.

    PubMed

    Wicks, Nadine L; Chan, Jason W; Najera, Julia A; Ciriello, Jonathan M; Oancea, Elena

    2011-11-22

    Exposure of human skin to solar ultraviolet radiation (UVR), a powerful carcinogen [1] comprising ~95% ultraviolet A (UVA) and ~5% ultraviolet B (UVB) at the Earth's surface, promotes melanin synthesis in epidermal melanocytes [2, 3], which protects skin from DNA damage [4, 5]. UVB causes DNA lesions [6] that lead to transcriptional activation of melanin-producing enzymes, resulting in delayed skin pigmentation within days [7]. In contrast, UVA causes primarily oxidative damage [8] and leads to immediate pigment darkening (IPD) within minutes, via an unknown mechanism [9, 10]. No receptor protein directly mediating phototransduction in skin has been identified. Here we demonstrate that exposure of primary human epidermal melanocytes (HEMs) to UVA causes calcium mobilization and early melanin synthesis. Calcium responses were abolished by treatment with G protein or phospholipase C (PLC) inhibitors or by depletion of intracellular calcium stores. We show that the visual photopigment rhodopsin [11] is expressed in HEMs and contributes to UVR phototransduction. Upon UVR exposure, significant melanin production was measured within one hour; cellular melanin continued to increase in a retinal- and calcium-dependent manner up to 5-fold after 24 hr. Our findings identify a novel UVA-sensitive signaling pathway in melanocytes that leads to calcium mobilization and melanin synthesis and may underlie the mechanism of IPD in human skin.

  2. Archaeal ancestors of eukaryotes: not so elusive any more.

    PubMed

    Koonin, Eugene V

    2015-10-05

    The origin of eukaryotes is one of the hardest problems in evolutionary biology and sometimes raises the ominous specter of irreducible complexity. Reconstruction of the gene repertoire of the last eukaryotic common ancestor (LECA) has revealed a highly complex organism with a variety of advanced features but no detectable evolutionary intermediates to explain their origin. Recently, however, genome analysis of diverse archaea led to the discovery of apparent ancestral versions of several signature eukaryotic systems, such as the actin cytoskeleton and the ubiquitin network, that are scattered among archaea. These findings inspired the hypothesis that the archaeal ancestor of eukaryotes was an unusually complex form with an elaborate intracellular organization. The latest striking discovery made by deep metagenomic sequencing vindicates this hypothesis by showing that in phylogenetic trees eukaryotes fall within a newly identified archaeal group, the Lokiarchaeota, which combine several eukaryotic signatures previously identified in different archaea. The discovery of complex archaea that are the closest living relatives of eukaryotes is most compatible with the symbiogenetic scenario for eukaryogenesis.

  3. Fire as an engineering tool of early modern humans.

    PubMed

    Brown, Kyle S; Marean, Curtis W; Herries, Andy I R; Jacobs, Zenobia; Tribolo, Chantal; Braun, David; Roberts, David L; Meyer, Michael C; Bernatchez, Jocelyn

    2009-08-14

    The controlled use of fire was a breakthrough adaptation in human evolution. It first provided heat and light and later allowed the physical properties of materials to be manipulated for the production of ceramics and metals. The analysis of tools at multiple sites shows that the source stone materials were systematically manipulated with fire to improve their flaking properties. Heat treatment predominates among silcrete tools at approximately 72 thousand years ago (ka) and appears as early as 164 ka at Pinnacle Point, on the south coast of South Africa. Heat treatment demands a sophisticated knowledge of fire and an elevated cognitive ability and appears at roughly the same time as widespread evidence for symbolic behavior.

  4. An Organismal CNV Mutator Phenotype Restricted to Early Human Development.

    PubMed

    Liu, Pengfei; Yuan, Bo; Carvalho, Claudia M B; Wuster, Arthur; Walter, Klaudia; Zhang, Ling; Gambin, Tomasz; Chong, Zechen; Campbell, Ian M; Coban Akdemir, Zeynep; Gelowani, Violet; Writzl, Karin; Bacino, Carlos A; Lindsay, Sarah J; Withers, Marjorie; Gonzaga-Jauregui, Claudia; Wiszniewska, Joanna; Scull, Jennifer; Stankiewicz, Paweł; Jhangiani, Shalini N; Muzny, Donna M; Zhang, Feng; Chen, Ken; Gibbs, Richard A; Rautenstrauss, Bernd; Cheung, Sau Wai; Smith, Janice; Breman, Amy; Shaw, Chad A; Patel, Ankita; Hurles, Matthew E; Lupski, James R

    2017-02-23

    De novo copy number variants (dnCNVs) arising at multiple loci in a personal genome have usually been considered to reflect cancer somatic genomic instabilities. We describe a multiple dnCNV (MdnCNV) phenomenon in which individuals with genomic disorders carry five to ten constitutional dnCNVs. These CNVs originate from independent formation incidences, are predominantly tandem duplications or complex gains, exhibit breakpoint junction features reminiscent of replicative repair, and show increased de novo point mutations flanking the rearrangement junctions. The active CNV mutation shower appears to be restricted to a transient perizygotic period. We propose that a defect in the CNV formation process is responsible for the "CNV-mutator state," and this state is dampened after early embryogenesis. The constitutional MdnCNV phenomenon resembles chromosomal instability in various cancers. Investigations of this phenomenon may provide unique access to understanding genomic disorders, structural variant mutagenesis, human evolution, and cancer biology.

  5. Evolutionary and ecological aspects of early brain malnutrition in humans.

    PubMed

    Lukas, W D; Campbell, B C

    2000-03-01

    This article reviews the effects of malnutrition on early brain development using data generated from animal experiments and human clinical studies. Three related processes, each with their own functional consequences, are implicated in the alteration of brain development. (1) Maternal undernutrition at the start of pregnancy results in reduced transfer of nutrients across the placenta, allowing the conservation of effort for future reproductive episodes. (2) Differential allocation to growing organs by the fetus in response to nutritional stress spares the brain to a large though still limited degree, reflecting the organ's relative contribution to survival and reproductive success. (3) Prenatal malnutrition disrupts developing neurotransmitter systems, which results in the expression of specific cognitive and affective traits. It is argued that the increasing size and therefore cost of the brain, in conjunction with increasing ecological instability and marginality, reinforced selection for maternally controlled growth suppression of offspring, reallocation of organ growth rates by offspring, and behavioral changes related to development of neurotransmitter systems.

  6. Metabolic gene profile in early human fetal heart development.

    PubMed

    Iruretagoyena, J I; Davis, W; Bird, C; Olsen, J; Radue, R; Teo Broman, A; Kendziorski, C; Splinter BonDurant, S; Golos, T; Bird, I; Shah, D

    2014-07-01

    The primitive cardiac tube starts beating 6-8 weeks post fertilization in the developing embryo. In order to describe normal cardiac development during late first and early second trimester in human fetuses this study used microarray and pathways analysis and created a corresponding 'normal' database. Fourteen fetal hearts from human fetuses between 10 and 18 weeks of gestational age (GA) were prospectively collected at the time of elective termination of pregnancy. RNA from recovered tissues was used for transcriptome analysis with Affymetrix 1.0 ST microarray chip. From the amassed data we investigated differences in cardiac development within the 10-18 GA period dividing the sample by GA in three groups: 10-12 (H1), 13-15 (H2) and 16-18 (H3) weeks. A fold change of 2 or above adjusted for a false discovery rate of 5% was used as initial cutoff to determine differential gene expression for individual genes. Test for enrichment to identify functional groups was carried out using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Array analysis correctly identified the cardiac specific genes, and transcripts reported to be differentially expressed were confirmed by qRT-PCR. Single transcript and Ontology analysis showed first trimester heart expression of myosin-related genes to be up-regulated >5-fold compared with second trimester heart. In contrast the second trimester hearts showed further gestation-related increases in many genes involved in energy production and cardiac remodeling. In conclusion, fetal heart development during the first trimester was dominated by heart-specific genes coding for myocardial development and differentiation. During the second trimester, transcripts related to energy generation and cardiomyocyte communication for contractile coordination/proliferation were more dominant. Transcripts related to fatty acid metabolism can be seen as early as 10 weeks and clearly increase as the heart matures. Retinol

  7. Early Human Testing Initiative Phase 1 Regenerative Life Support Systems

    NASA Image and Video Library

    1995-08-08

    Early Human Testing (EHT) Initiative Phase 1 Regenerative Life Support Systems Laboratory (RLSSL). Nigel Packham activities in the Variable Pressure Growth Chamber which he lived inside for 15 days. A crowd of well-wishers outside the test chamber, at the console are John Lewis, Ed Mohr and Marybeth Edeen (15577). Packham exiting the chamber (15578-81). Packham is the focus of television cameras and reporters (15582-3). Don Henninger interviewed by reporters (15584). Packham is presented with a jacket after his stay in the chamber (15585). Packham inside the wheat growth chamber checking the condition of the plants (15586-7, 15597). Packham exercising on a recumbant bicycle (15588, 15592). Packham, through the window into the growth chamber, displays a handful of wheat plants to console monitor Dan Barta (15589-90). Group portrait of the team conducting the Early Human Testing Initiative Phase 1 Regenerative Life Support Systems test and include, front row, from left: Jeff Dominick and Don Overton and back row, from left, unidentified member, Marybeth Edeen, Nigel Packham, John Lewis, Ed Mohr, Dan Barta and Tim Monk (15591). Harry Halford prepares to send a package through the airlock to Packham (15593). Packham displays a handful of wheat plants (15594). Packham fixes himself a bowl of cereal (15595) and retrieves a carton of milk from the refrigerator (15596). Packham retrieves a package from the airlock (15598). Packham packs up trash in plastic bag (15599-600) and sends it back through the airlock (15601). Packham gets a cup of water (15602) and heats it in the microwave (15603).

  8. Ovarian control of pituitary hormone secretion in early human pregnancy.

    PubMed

    Emmi, A M; Skurnick, J; Goldsmith, L T; Gagliardi, C L; Schmidt, C L; Kleinberg, D; Weiss, G

    1991-06-01

    To determine the influence of ovarian relaxin on the secretion of pituitary GH and PRL in vivo, we evaluated circulating serum hormone levels in 17 pregnant patients with functional corpora lutea (group I) and compared them to levels in 10 patients with premature ovarian failure (POF; group II) who became pregnant with egg donation and did not have corpora lutea. Group II patients had exogenous hormonal support. Serum relaxin (RLX), GH, PRL, estradiol (E2), and progesterone levels were measured weekly by RIA from weeks 4-8 of pregnancy. Analysis of variance and covariance were used to determine hormonal relationships. Serum RLX was present in the natural pregnancy group, with a mean of 1.94 micrograms/L over the study period. Serum RLX was undetectable in the POF patients (less than 0.16 micrograms/L). No significant difference in PRL or progesterone levels between the two groups was noted. E2 levels showed an upward trend in both groups with time and were significantly higher in patients of the POF group than in group I women (P = 0.001). GH levels were significantly higher in the natural cycle patients (P = 0.02) despite lower E2 levels. These data provide additional support for the concept that RLX production in early pregnancy originates from the corpus luteum. They suggest that a luteal product, probably RLX, stimulates GH secretion in early pregnancy. This is a previously undescribed role for RLX in pituitary physiology during human pregnancy.

  9. Analyzing the rate at which languages lose the influence of a common ancestor.

    PubMed

    Rafferty, Anna N; Griffiths, Thomas L; Klein, Dan

    2014-01-01

    Analyzing the rate at which languages change can clarify whether similarities across languages are solely the result of cognitive biases or might be partially due to descent from a common ancestor. To demonstrate this approach, we use a simple model of language evolution to mathematically determine how long it should take for the distribution over languages to lose the influence of a common ancestor and converge to a form that is determined by constraints on language learning. We show that modeling language learning as Bayesian inference of n binary parameters or the ordering of n constraints results in convergence in a number of generations that is on the order of n log n. We relax some of the simplifying assumptions of this model to explore how different assumptions about language evolution affect predictions about the time to convergence; in general, convergence time increases as the model becomes more realistic. This allows us to characterize the assumptions about language learning (given the models that we consider) that are sufficient for convergence to have taken place on a timescale that is consistent with the origin of human languages. These results clearly identify the consequences of a set of simple models of language evolution and show how analysis of convergence rates provides a tool that can be used to explore questions about the relationship between accounts of language learning and the origins of similarities across languages. © 2014 Cognitive Science Society, Inc.

  10. The early fetal development of human neocortical GABAergic interneurons.

    PubMed

    Al-Jaberi, Nahidh; Lindsay, Susan; Sarma, Subrot; Bayatti, Nadhim; Clowry, Gavin J

    2015-03-01

    GABAergic interneurons are crucial to controlling the excitability and responsiveness of cortical circuitry. Their developmental origin may differ between rodents and human. We have demonstrated the expression of 12 GABAergic interneuron-associated genes in samples from human neocortex by quantitative rtPCR from 8 to 12 postconceptional weeks (PCW) and shown a significant anterior to posterior expression gradient, confirmed by in situ hybridization or immunohistochemistry for GAD1 and 2, DLX1, 2, and 5, ASCL1, OLIG2, and CALB2. Following cortical plate (CP) formation from 8 to 9 PCW, a proportion of cells were strongly stained for all these markers in the CP and presubplate. ASCL1 and DLX2 maintained high expression in the proliferative zones and showed extensive immunofluorescent double-labeling with the cell division marker Ki-67. CALB2-positive cells increased steadily in the SVZ/VZ from 10 PCW but were not double-labeled with Ki-67. Expression of GABAergic genes was generally higher in the dorsal pallium than in the ganglionic eminences, with lower expression in the intervening ventral pallium. It is widely accepted that the cortical proliferative zones may generate CALB2-positive interneurons from mid-gestation; we now show that the anterior neocortical proliferative layers especially may be a rich source of interneurons in the early neocortex.

  11. [Early morphogenesis of ciliated cells in human oral cavity].

    PubMed

    Kurtova, A I; Chernikov, V P; Savel'ev, S V

    2013-01-01

    Ciliated cells were found in the epithelium of the oral cavity of human embryos and fetuses starting from the seventh week of prenatal development. At the early stages of prenatal development (until the 13th week), cells with cilia cover most of the dorsal surface of the tongue and the soft palate, whereas they are found only near the gland ducts in the circumvallate and foliate lingual papillae after 17 weeks of development. The ultrastructure of the axoneme of cilia corresponds to the structure of motile cilia and is represented by nine microtubule doublets that surround the central pair of microtubule singlets. An immunohistochemical study performed on weeks 10-12 of development identified nerve endings associated with the ciliated cells. Until the 14th week of development, the cytoplasm of ciliated cells is immunopositive for NSE. The spatial distribution of ciliated cells in the tongue epithelium until the 13th week of development is not related to the morphogenesis of lingual papillae, and their role in the human oral cavity during the first trimester of pregnancy is unclear and requires further study.

  12. Immunological characterization of the early human fracture hematoma.

    PubMed

    Hoff, Paula; Gaber, T; Strehl, C; Schmidt-Bleek, K; Lang, A; Huscher, D; Burmester, G R; Schmidmaier, G; Perka, C; Duda, G N; Buttgereit, F

    2016-12-01

    The initial inflammatory phase of fracture healing is of great importance for the clinical outcome. We aimed to develop a detailed time-dependent analysis of the initial fracture hematoma. We analyzed the composition of immune cell subpopulations by flow cytometry and the concentration of cytokines and chemokines by bioplex in 42 samples from human fractures of long bones <72 h post-trauma. The early human fracture hematoma is characterized by maturation of granulocytes and migration of monocytes/macrophages and hematopoietic stem cells. Both T helper cells and cytotoxic T cells proliferate within the fracture hematoma and/or migrate to the fracture site. Humoral immunity characteristics comprise high concentration of pro-inflammatory cytokines such as IL-6, IL-8, IFNγ and TNFα, but also elevated concentration of anti-inflammatory cytokines, e.g., IL-1 receptor antagonist and IL-10. Furthermore, we found that cells of the fracture hematoma represent a source for key chemokines. Even under the bioenergetically restricted conditions that exist in the initial fracture hematoma, immune cells are not only present, but also survive, mature, function and migrate. They secrete a cytokine/chemokine cocktail that contributes to the onset of regeneration. We hypothesize that this specific microenvironment of the initial fracture hematoma is among the crucial factors that determine fracture healing.

  13. Telmisartan inhibits human urological cancer cell growth through early apoptosis

    PubMed Central

    MATSUYAMA, MASAHIDE; FUNAO, KIYOAKI; KURATSUKURI, KATSUYUKI; TANAKA, TOMOAKI; KAWAHITO, YUTAKA; SANO, HAJIME; CHARGUI, JAMEL; TOURAINE, JEAN-LOUIS; YOSHIMURA, NORIO; YOSHIMURA, RIKIO

    2010-01-01

    Angiotensin II receptor blockers (ARBs) are widely used as hypertensive therapeutic agents. In addition, studies have provided evidence that ARBs have the potential to inhibit the growth of several types of cancer cells. It was reported that telmisartan (a type of ARB) has peroxisome proliferator-activated receptor (PPAR)-γ activation activity. We previously reported that the PPAR-γ ligand induces growth arrest in human urological cancer cells through apoptosis. In this study, we evaluated the effects of telmisartan and other ARBs on cell proliferation in renal cell carcinoma (RCC), bladder cancer (BC), prostate cancer (PC) and testicular cancer (TC) cell lines. The inhibitory effects of telmisartan and other ARBs (candesartan, valsartan, irbesartan and losartan) on the growth of the RCC, BC, PC and TC cell lines was investigated using an MTT assay. Flow cytometry and Hoechst staining were used to determine whether the ARBs induced apoptosis. Telmisartan caused marked growth inhibition in the urological cancer cells in a dose- and time-dependent manner. Urological cancer cells treated with 100 μM telmisartan underwent early apoptosis and DNA fragmentation. However, the other ARBs had no effect on cell proliferation in any of the urological cancer cell lines. Telmisartan may mediate potent anti-proliferative effects in urological cancer cells through PPAR-γ. Thus, telmisartan is a potent target for the prevention and treatment of human urological cancer. PMID:22993542

  14. Brain anatomical networks in early human brain development.

    PubMed

    Fan, Yong; Shi, Feng; Smith, Jeffrey Keith; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2011-02-01

    Recent neuroimaging studies have demonstrated that human brain networks have economic small-world topology and modular organization, enabling efficient information transfer among brain regions. However, it remains largely unknown how the small-world topology and modular organization of human brain networks emerge and develop. Using longitudinal MRI data of 28 healthy pediatric subjects, collected at their ages of 1 month, 1 year, and 2 years, we analyzed development patterns of brain anatomical networks derived from morphological correlations of brain regional volumes. The results show that the brain network of 1-month-olds has the characteristically economic small-world topology and nonrandom modular organization. The network's cost efficiency increases with the brain development to 1 year and 2 years, so does the modularity, providing supportive evidence for the hypothesis that the small-world topology and the modular organization of brain networks are established during early brain development to support rapid synchronization and information transfer with minimal rewiring cost, as well as to balance between local processing and global integration of information. Copyright © 2010. Published by Elsevier Inc.

  15. Do Basque- and Caucasian-speaking populations share non-Indo-European ancestors?

    PubMed

    Bertorelle, G; Bertranpetit, J; Calafell, F; Nasidze, I S; Barbujani, G

    1995-01-01

    Genetic evidence is consistent with the view that the Indo-European languages were propagated in Europe by the diffusion of early farmers. The existence of phylogenetic relationships between European populations speaking other languages has been proposed on linguistic and archaeological grounds, and is here tested by analyzing allele frequencies at ten polymorphic protein and blood group loci. Genetic distances between speakers of Basque and Caucasian languages are compared with those between controls, i.e. contiguous populations speaking Indo-European and Altaic. Although some statistical tests show an excess of genetic similarity between Basque and South Caucasian speakers, most results do not support their common origin. If the Basques and the Caucasian-speaking populations share common ancestors, recent evolutionary phenomena must have caused divergence between them, so that their gene frequencies do not appear more similar now than those of random pairs of populations separated by the same geographic distance.

  16. Origin and Evolution of Water Oxidation before the Last Common Ancestor of the Cyanobacteria

    PubMed Central

    Cardona, Tanai; Murray, James W.; Rutherford, A. William

    2015-01-01

    Photosystem II, the water oxidizing enzyme, altered the course of evolution by filling the atmosphere with oxygen. Here, we reconstruct the origin and evolution of water oxidation at an unprecedented level of detail by studying the phylogeny of all D1 subunits, the main protein coordinating the water oxidizing cluster (Mn4CaO5) of Photosystem II. We show that D1 exists in several forms making well-defined clades, some of which could have evolved before the origin of water oxidation and presenting many atypical characteristics. The most ancient form is found in the genome of Gloeobacter kilaueensis JS-1 and this has a C-terminus with a higher sequence identity to D2 than to any other D1. Two other groups of early evolving D1 correspond to those expressed under prolonged far-red illumination and in darkness. These atypical D1 forms are characterized by a dramatically different Mn4CaO5 binding site and a Photosystem II containing such a site may assemble an unconventional metal cluster. The first D1 forms with a full set of ligands to the Mn4CaO5 cluster are grouped with D1 proteins expressed only under low oxygen concentrations and the latest evolving form is the dominant type of D1 found in all cyanobacteria and plastids. In addition, we show that the plastid ancestor had a D1 more similar to those in early branching Synechococcus. We suggest each one of these forms of D1 originated from transitional forms at different stages toward the innovation and optimization of water oxidation before the last common ancestor of all known cyanobacteria. PMID:25657330

  17. Origin and Evolution of Water Oxidation before the Last Common Ancestor of the Cyanobacteria.

    PubMed

    Cardona, Tanai; Murray, James W; Rutherford, A William

    2015-05-01

    Photosystem II, the water oxidizing enzyme, altered the course of evolution by filling the atmosphere with oxygen. Here, we reconstruct the origin and evolution of water oxidation at an unprecedented level of detail by studying the phylogeny of all D1 subunits, the main protein coordinating the water oxidizing cluster (Mn4CaO5) of Photosystem II. We show that D1 exists in several forms making well-defined clades, some of which could have evolved before the origin of water oxidation and presenting many atypical characteristics. The most ancient form is found in the genome of Gloeobacter kilaueensis JS-1 and this has a C-terminus with a higher sequence identity to D2 than to any other D1. Two other groups of early evolving D1 correspond to those expressed under prolonged far-red illumination and in darkness. These atypical D1 forms are characterized by a dramatically different Mn4CaO5 binding site and a Photosystem II containing such a site may assemble an unconventional metal cluster. The first D1 forms with a full set of ligands to the Mn4CaO5 cluster are grouped with D1 proteins expressed only under low oxygen concentrations and the latest evolving form is the dominant type of D1 found in all cyanobacteria and plastids. In addition, we show that the plastid ancestor had a D1 more similar to those in early branching Synechococcus. We suggest each one of these forms of D1 originated from transitional forms at different stages toward the innovation and optimization of water oxidation before the last common ancestor of all known cyanobacteria. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  18. A rock-inhabiting ancestor for mutualistic and pathogen-rich fungal lineages.

    PubMed

    Gueidan, C; Villaseñor, C R; de Hoog, G S; Gorbushina, A A; Untereiner, W A; Lutzoni, F

    2008-01-01

    Rock surfaces are unique terrestrial habitats in which rapid changes in the intensity of radiation, temperature, water supply and nutrient availability challenge the survival of microbes. A specialised, but diverse group of free-living, melanised fungi are amongst the persistent settlers of bare rocks. Multigene phylogenetic analyses were used to study relationships of ascomycetes from a variety of substrates, with a dataset including a broad sampling of rock dwellers from different geographical locations. Rock-inhabiting fungi appear particularly diverse in the early diverging lineages of the orders Chaetothyriales and Verrucariales. Although these orders share a most recent common ancestor, their lifestyles are strikingly different. Verrucariales are mostly lichen-forming fungi, while Chaetothyriales, by contrast, are best known as opportunistic pathogens of vertebrates (e.g. Cladophialophora bantiana and Exophiala dermatitidis, both agents of fatal brain infections) and saprophytes. The rock-dwelling habit is shown here to be key to the evolution of these two ecologically disparate orders. The most recent common ancestor of Verrucariales and Chaetothyriales is reconstructed as a non-lichenised rock-inhabitant. Ancestral state reconstructions suggest Verrucariales as one of the independent ascomycetes group where lichenisation has evolved on a hostile rock surface that might have favored this shift to a symbiotic lifestyle. Rock-inhabiting fungi are also ancestral to opportunistic pathogens, as they are found in the early diverging lineages of Chaetothyriales. In Chaetothyriales and Verrucariales, specific morphological and physiological traits (here referred to as extremotolerance) evolved in response to stresses in extreme conditions prevailing on rock surfaces. These factors facilitated colonisation of various substrates including the brains of vertebrates by opportunistic fungal pathogens, as well as helped establishment of a stable lichen symbiosis.

  19. A rock-inhabiting ancestor for mutualistic and pathogen-rich fungal lineages

    PubMed Central

    Gueidan, C.; Villaseñor, C. R.; de Hoog, G. S.; Gorbushina, A. A.; Untereiner, W. A.; Lutzoni, F.

    2008-01-01

    Rock surfaces are unique terrestrial habitats in which rapid changes in the intensity of radiation, temperature, water supply and nutrient availability challenge the survival of microbes. A specialised, but diverse group of free-living, melanised fungi are amongst the persistent settlers of bare rocks. Multigene phylogenetic analyses were used to study relationships of ascomycetes from a variety of substrates, with a dataset including a broad sampling of rock dwellers from different geographical locations. Rock-inhabiting fungi appear particularly diverse in the early diverging lineages of the orders Chaetothyriales and Verrucariales. Although these orders share a most recent common ancestor, their lifestyles are strikingly different. Verrucariales are mostly lichen-forming fungi, while Chaetothyriales, by contrast, are best known as opportunistic pathogens of vertebrates (e.g. Cladophialophora bantiana and Exophiala dermatitidis, both agents of fatal brain infections) and saprophytes. The rock-dwelling habit is shown here to be key to the evolution of these two ecologically disparate orders. The most recent common ancestor of Verrucariales and Chaetothyriales is reconstructed as a non-lichenised rock-inhabitant. Ancestral state reconstructions suggest Verrucariales as one of the independent ascomycetes group where lichenisation has evolved on a hostile rock surface that might have favored this shift to a symbiotic lifestyle. Rock-inhabiting fungi are also ancestral to opportunistic pathogens, as they are found in the early diverging lineages of Chaetothyriales. In Chaetothyriales and Verrucariales, specific morphological and physiological traits (here referred to as extremotolerance) evolved in response to stresses in extreme conditions prevailing on rock surfaces. These factors facilitated colonisation of various substrates including the brains of vertebrates by opportunistic fungal pathogens, as well as helped establishment of a stable lichen symbiosis. PMID

  20. Looking for the Last Universal Common Ancestor (LUCA).

    PubMed

    Koskela, Minna; Annila, Arto

    2012-01-09

    Genomic sequences across diverse species seem to align towards a common ancestry, eventually implying that eons ago some universal antecedent organism would have lived on the face of Earth. However, when evolution is understood not only as a biological process but as a general thermodynamic process, it becomes apparent that the quest for the last universal common ancestor is unattainable. Ambiguities in alignments are unavoidable because the driving forces and paths of evolution cannot be separated from each other. Thus tracking down life's origin is by its nature a non-computable task. The thermodynamic tenet clarifies that evolution is a path-dependent process of least-time consumption of free energy. The natural process is without a demarcation line between animate and inanimate.

  1. The universal ancestor was a thermophile or a hyperthermophile.

    PubMed

    Di Giulio, M

    2001-12-27

    By exploiting the correlation between the optimal growth temperature of organisms and a thermophily index based on the propensity of amino acids to enter thermophile/hyperthermophile proteins, an analysis is conducted in order to establish whether the last universal common ancestor (LUCA) was a mesophile or a (hyper)thermophile. This objective is reached by using maximum parsimony and maximum likelihood to reconstruct the ancestral sequences of the LUCA for two pairs of sets of paralogous protein sequences by means of the phylogenetic tree topology derived from the small subunit ribosomal RNA, even if this is rooted in all three possible ways. The thermophily index of all the reconstructed ancestral sequences of the LUCA belongs to the set of the thermophile/hyperthermophile sequences, thus supporting the hypotheses that see the LUCA as a thermophile or a hyperthermophile.

  2. node.dating: dating ancestors in phylogenetic trees in R.

    PubMed

    Jones, Bradley R; Poon, Art F Y

    2017-03-15

    Phylogenetic trees encode the evolutionary distances between species or populations. With sufficient information, these evolutionary distances can be rescaled over time to provide estimates of the dates of the most recent ancestors of the species. Here we present the R program node.dating, divergence-time analysis software, which uses a maximum-likelihood method to estimate the dates of the internal nodes of a phylogenetic tree. node.dating is available as a part of the R v3.30 package ape v4.0 (cran.r-project.org). node.dating is also available in the GitHub repository: https://github.com/brj1/node.dating , along with supplementary software and tests. brj1@sfu.ca. Supplementary data are available at Bioinformatics online.

  3. Palaeogenomics of plants: synteny-based modelling of extinct ancestors.

    PubMed

    Abrouk, Michael; Murat, Florent; Pont, Caroline; Messing, Joachim; Jackson, Scott; Faraut, Thomas; Tannier, Eric; Plomion, Christophe; Cooke, Richard; Feuillet, Catherine; Salse, Jérôme

    2010-09-01

    In the past ten years, international initiatives have led to the development of large sets of genomic resources that allow comparative genomic studies between plant genomes at a high level of resolution. Comparison of map-based genomic sequences revealed shared intra-genomic duplications, providing new insights into the evolution of flowering plant genomes from common ancestors. Plant genomes can be presented as concentric circles, providing a new reference for plant chromosome evolutionary relationships and an efficient tool for gene annotation and cross-genome markers development. Recent palaeogenomic data demonstrate that whole-genome duplications have provided a motor for the evolutionary success of flowering plants over the last 50-70 million years. 2010 Elsevier Ltd. All rights reserved.

  4. Palaeogenomics in cereals: modeling of ancestors for modern species improvement.

    PubMed

    Salse, Jérôme; Feuillet, Catherine

    2011-03-01

    During the last decade, technological improvements led to the development of large sets of plant genomic resources permitting the emergence of high-resolution comparative genomic studies. Synteny-based identification of seven shared duplications in cereals led to the modeling of a common ancestral genome structure of 33.6 Mb structured in five protochromosomes containing 9138 protogenes and provided new insights into the evolution of cereal genomes from their extinct ancestors. Recent palaeogenomic data indicate that whole genome duplications were a driving force in the evolutionary success of cereals over the last 50 to 70 millions years. Finally, detailed synteny and duplication relationships led to an improved representation of cereal genomes in concentric circles, thus providing a new reference tool for improved gene annotation and cross-genome markers development. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  5. Astronomical Theory of Early Human Migration (Milutin Milankovic Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Timmermann, Axel; Friedrich, Tobias

    2017-04-01

    Our climate system varies on a wide range of timescales, from seasons to several millions of years. A large part of this variability is internally generated as a result of instabilities of the coupled atmosphere-ocean-ice-carbon cycle system. Other modes of variability, such as glacial cycles, are caused by astronomical forcings with periods of 20, 40, 100 thousand years. These so-called Milankovitch Cycles are associated with earth's axis wobble, axis obliquity and shifts in the eccentricity of earth's orbit around the sun, respectively. When these cycles conspire, they can cause the climate system to plunge into an ice-age. This happened last time 110,000 years ago, when Northern Hemisphere summer radiation decreased substantially and ice-sheets started to form as a result. Around 100,000 years ago northern Hemisphere summer moved again closer to the sun and Homo sapiens started to leave Africa across vegetated corridors in Northeastern Africa and the Arabian Peninsula. This first migration wave must have been relatively weak, but it left unequivocal traces in the fossil and archaeological record. Why Homo sapiens embarked on its grand journey across our planet during glacial climate conditions has been subject of an intense debate in various scientific communities. Moreover, the archaeological records of an early exodus around 100 thousand years ago seem to be at odds with paleo-genetic evidences, that place the first dispersal out of Africa around 70-60 thousand years ago. To elucidate what role climate and environmental conditions played in the dispersal of Anatomically Modern Humans out of Africa, we have developed and applied one of the first integrated climate/human migration computer models. The model simulates ice-ages, abrupt climate change, the "peopling" of our planet and captures the arrival time of Homo sapiens in the Levant, Arabian Peninsula, Southern China and Australia in close agreement with paleo climate reconstructions, fossil and

  6. A Detailed History of Intron-rich Eukaryotic Ancestors Inferred from a Global Survey of 100 Complete Genomes

    PubMed Central

    Csuros, Miklos; Rogozin, Igor B.; Koonin, Eugene V.

    2011-01-01

    Protein-coding genes in eukaryotes are interrupted by introns, but intron densities widely differ between eukaryotic lineages. Vertebrates, some invertebrates and green plants have intron-rich genes, with 6–7 introns per kilobase of coding sequence, whereas most of the other eukaryotes have intron-poor genes. We reconstructed the history of intron gain and loss using a probabilistic Markov model (Markov Chain Monte Carlo, MCMC) on 245 orthologous genes from 99 genomes representing the three of the five supergroups of eukaryotes for which multiple genome sequences are available. Intron-rich ancestors are confidently reconstructed for each major group, with 53 to 74% of the human intron density inferred with 95% confidence for the Last Eukaryotic Common Ancestor (LECA). The results of the MCMC reconstruction are compared with the reconstructions obtained using Maximum Likelihood (ML) and Dollo parsimony methods. An excellent agreement between the MCMC and ML inferences is demonstrated whereas Dollo parsimony introduces a noticeable bias in the estimations, typically yielding lower ancestral intron densities than MCMC and ML. Evolution of eukaryotic genes was dominated by intron loss, with substantial gain only at the bases of several major branches including plants and animals. The highest intron density, 120 to 130% of the human value, is inferred for the last common ancestor of animals. The reconstruction shows that the entire line of descent from LECA to mammals was intron-rich, a state conducive to the evolution of alternative splicing. PMID:21935348

  7. A detailed history of intron-rich eukaryotic ancestors inferred from a global survey of 100 complete genomes.

    PubMed

    Csuros, Miklos; Rogozin, Igor B; Koonin, Eugene V

    2011-09-01

    Protein-coding genes in eukaryotes are interrupted by introns, but intron densities widely differ between eukaryotic lineages. Vertebrates, some invertebrates and green plants have intron-rich genes, with 6-7 introns per kilobase of coding sequence, whereas most of the other eukaryotes have intron-poor genes. We reconstructed the history of intron gain and loss using a probabilistic Markov model (Markov Chain Monte Carlo, MCMC) on 245 orthologous genes from 99 genomes representing the three of the five supergroups of eukaryotes for which multiple genome sequences are available. Intron-rich ancestors are confidently reconstructed for each major group, with 53 to 74% of the human intron density inferred with 95% confidence for the Last Eukaryotic Common Ancestor (LECA). The results of the MCMC reconstruction are compared with the reconstructions obtained using Maximum Likelihood (ML) and Dollo parsimony methods. An excellent agreement between the MCMC and ML inferences is demonstrated whereas Dollo parsimony introduces a noticeable bias in the estimations, typically yielding lower ancestral intron densities than MCMC and ML. Evolution of eukaryotic genes was dominated by intron loss, with substantial gain only at the bases of several major branches including plants and animals. The highest intron density, 120 to 130% of the human value, is inferred for the last common ancestor of animals. The reconstruction shows that the entire line of descent from LECA to mammals was intron-rich, a state conducive to the evolution of alternative splicing.

  8. Early Release of soluble RAGE After Severe Trauma in Humans

    PubMed Central

    Cohen, Mitchell J.; Carles, Michel; Brohi, Karim; Calfee, Carolyn S.; Rahn, Pamela; Call, Mariah S; Chesebro, Brian B.; West, Michael A.; Pittet, Jean-François

    2012-01-01

    Objective The receptor for advanced glycation endproducts (RAGE) recognizes a variety of ligands that play an important role in the posttraumatic inflammatory response. However, whether soluble RAGE (sRAGE) is released early after trauma-hemorrhage in humans and whether such a release is associated with the development of an inflammatory response and coagulopathy is not known and therefore constitutes the aim of the present study. Methods One hundred sixty eight patients were studied as part of a prospective cohort study of severe trauma patients admitted to a single Level 1 Trauma center. Blood was drawn within 10 minutes of arrival to the Emergency Department (ED) before the administration of any fluid resuscitation. sRAGE, TNF-a, IL-6, von Willebrand Factor (vWF), Angiopoietin-2 (Ang-2), Prothrombin time, (PT), prothrombin fragments 1+2 (PF1+2), soluble thrombomodulin (sTM), protein C (PC), plasminogen activator inhibitor-1 (PAI-1), and D-Dimers (fibrin degradation products) were measured using standard techniques. Base deficit was used as a measure of tissue hypoperfusion. Measurements were compared to outcome measures obtained from the electronic medical record and trauma registry. Results Plasma levels of sRAGE were increased within 30 minutes after severe trauma in humans and correlated with the severity of injury, early posttraumatic coagulopathy and hyperfibrinolysis as well as with endothelial cell activation (angiopoietin-1 and complement). Furthermore, we found that there was a significant relationship between plasma levels of sRAGE and the development of acute renal failure. This relationship was not quite significant for patients who developed acute lung injury (p=.11), although patients with less than 26 ventilator-free days had significantly higher plasma levels of sRAGE than those with more than 26 ventilator-free days. Finally, there was no relationship between plasma levels of sRAGE and mortality rate in trauma patients. Conclusions The results

  9. Outgroup, alignment and modelling improvements indicate that two TNFSF13-like genes existed in the vertebrate ancestor.

    PubMed

    Redmond, Anthony K; Pettinello, Rita; Dooley, Helen

    2017-03-01

    The molecular machinery required for lymphocyte development and differentiation appears to have emerged concomitantly with distinct B- and T-like lymphocyte subsets in the ancestor of all vertebrates. The TNFSF superfamily (TNFSF) members BAFF (TNFSF13/Blys) and APRIL (TNFSF13) are key regulators of B cell development survival, and activation in mammals, but the temporal emergence of these molecules, and their precise relationship to the newly identified TNFSF gene BALM (BAFF and APRIL-like molecule), have not yet been elucidated. Here, to resolve the early evolutionary history of this family, we improved outgroup sampling and alignment quality, and applied better fitting substitution models compared to past studies. Our analyses reveal that BALM is a definitive TNFSF13 family member, which split from BAFF in the gnathostome (jawed vertebrate) ancestor. Most importantly, however, we show that both the APRIL and BAFF lineages existed in the ancestors of all extant vertebrates. This implies that APRIL has been lost, or is yet to be found, in cyclostomes (jawless vertebrates). Our results suggest that lineage-specific gene duplication and loss events have caused lymphocyte regulation, despite shared origins, to become secondarily distinct between gnathostomes and cyclostomes. Finally, the structure of lamprey BAFF-like, and its phylogenetic placement as sister to BAFF and BALM, but not the more slowly evolving APRIL, indicates that the primordial lymphocyte regulator was more APRIL-like than BAFF-like.

  10. Renal Vasoconstriction Occurs Early During Shockwave Lithotripsy in Humans.

    PubMed

    Lee, Franklin C; Hsi, Ryan S; Sorensen, Mathew D; Paun, Marla; Dunmire, Barbrina; Liu, Ziyue; Bailey, Michael; Harper, Jonathan D

    2015-12-01

    In animal models, pretreatment with low-energy shock waves and a pause decreased renal injury from shockwave lithotripsy (SWL). This is associated with an increase in perioperative renal resistive index (RI). A perioperative rise is not seen without the protective protocol, which suggests that renal vasoconstriction during SWL plays a role in protecting the kidney from injury. The purpose of our study was to investigate whether there is an increase in renal RI during SWL in humans. Subjects were prospectively recruited from two hospitals. All subjects received an initial 250 shocks at low setting, followed by a 2-minute pause. Treatment power was then increased. Measurements of the renal RI were taken before start of procedure, at 250, after 750, after 1500 shocks, and at the end of the procedure. A linear mixed-effects model was used to compare RIs at the different time points. Fifteen patients were enrolled. Average treatment time was 46 ± 8 minutes. Average RI at pretreatment, after 250, after 750, after 1500 shocks, and post-treatment was 0.67 ± 0.06, 0.69 ± 0.08, 0.71 ± 0.07, 0.73 ± 0.07, and 0.74 ± 0.06, respectively. In adjusted analyses, RI was significantly increased after 750 shocks compared with pretreatment (p = 0.05). Renal RI increases early during SWL in humans with the protective protocol. Monitoring for a rise in RI during SWL is feasible and may provide real-time feedback as to when the kidney is protected.

  11. Renal Vasoconstriction Occurs Early During Shockwave Lithotripsy in Humans

    PubMed Central

    Hsi, Ryan S.; Sorensen, Mathew D.; Paun, Marla; Dunmire, Barbrina; Liu, Ziyue; Bailey, Michael; Harper, Jonathan D.

    2015-01-01

    Abstract Introduction: In animal models, pretreatment with low-energy shock waves and a pause decreased renal injury from shockwave lithotripsy (SWL). This is associated with an increase in perioperative renal resistive index (RI). A perioperative rise is not seen without the protective protocol, which suggests that renal vasoconstriction during SWL plays a role in protecting the kidney from injury. The purpose of our study was to investigate whether there is an increase in renal RI during SWL in humans. Materials and Methods: Subjects were prospectively recruited from two hospitals. All subjects received an initial 250 shocks at low setting, followed by a 2-minute pause. Treatment power was then increased. Measurements of the renal RI were taken before start of procedure, at 250, after 750, after 1500 shocks, and at the end of the procedure. A linear mixed-effects model was used to compare RIs at the different time points. Results: Fifteen patients were enrolled. Average treatment time was 46 ± 8 minutes. Average RI at pretreatment, after 250, after 750, after 1500 shocks, and post-treatment was 0.67 ± 0.06, 0.69 ± 0.08, 0.71 ± 0.07, 0.73 ± 0.07, and 0.74 ± 0.06, respectively. In adjusted analyses, RI was significantly increased after 750 shocks compared with pretreatment (p = 0.05). Conclusion: Renal RI increases early during SWL in humans with the protective protocol. Monitoring for a rise in RI during SWL is feasible and may provide real-time feedback as to when the kidney is protected. PMID:26239232

  12. Opossum carboxylesterases: sequences, phylogeny and evidence for CES gene duplication events predating the marsupial-eutherian common ancestor

    PubMed Central

    2008-01-01

    residues previously reported for human CES1 involved in catalysis, ligand binding, tertiary structure and organelle localization. Phylogenetic studies indicated the gene duplication events which generated ancestral mammalian CES genes predated the common ancestor for marsupial and eutherian mammals, and appear to coincide with the early diversification of tetrapods. PMID:18289373

  13. Opossum carboxylesterases: sequences, phylogeny and evidence for CES gene duplication events predating the marsupial-eutherian common ancestor.

    PubMed

    Holmes, Roger S; Chan, Jeannie; Cox, Laura A; Murphy, William J; VandeBerg, John L

    2008-02-20

    Carboxylesterases (CES) perform diverse metabolic roles in mammalian organisms in the detoxification of a broad range of drugs and xenobiotics and may also serve in specific roles in lipid, cholesterol, pheromone and lung surfactant metabolism. Five CES families have been reported in mammals with human CES1 and CES2 the most extensively studied. Here we describe the genetics, expression and phylogeny of CES isozymes in the opossum and report on the sequences and locations of CES1, CES2 and CES6 'like' genes within two gene clusters on chromosome one. We also discuss the likely sequence of gene duplication events generating multiple CES genes during vertebrate evolution. We report a cDNA sequence for an opossum CES and present evidence for CES1 and CES2 like genes expressed in opossum liver and intestine and for distinct gene locations of five opossum CES genes,CES1, CES2.1, CES2.2, CES2.3 and CES6, on chromosome 1. Phylogenetic and sequence alignment studies compared the predicted amino acid sequences for opossum CES with those for human, mouse, chicken, frog, salmon and Drosophila CES gene products. Phylogenetic analyses produced congruent phylogenetic trees depicting a rapid early diversification into at least five distinct CES gene family clusters: CES2, CES1, CES7, CES3, and CES6. Molecular divergence estimates based on a Bayesian relaxed clock approach revealed an origin for the five mammalian CES gene families between 328-378 MYA. The deduced amino acid sequence for an opossum cDNA was consistent with its identity as a mammalian CES2 gene product (designated CES2.1). Distinct gene locations for opossum CES1 (1: 446,222,550-446,274,850), three CES2 genes (1: 677,773,395-677,927,030) and a CES6 gene (1: 677,585,520-677,730,419) were observed on chromosome 1. Opossum CES1 and multiple CES2 genes were expressed in liver and intestine. Amino acid sequences for opossum CES1 and three CES2 gene products revealed conserved residues previously reported for human CES1

  14. Early Intracellular Trafficking of Granulibacter bethesdensis in Human Macrophages.

    PubMed

    Chu, Jessica; Smelkinson, Margery G; Dorward, David W; Zarember, Kol A; Gallin, John I

    2017-06-01

    Granulibacter bethesdensis is a Gram-negative bacterium that infects patients with chronic granulomatous disease (CGD), a primary immunodeficiency marked by a defect in NOX2, the phagocyte NADPH oxidase. Previous studies have shown that NOX2 is essential for killing of G. bethesdensis by neutrophils and monocytes and that the bacteriostatic activity of monocyte-derived macrophages (MDM) requires NOX2 and gamma interferon (IFN-γ) pretreatment. To determine whether G. bethesdensis evades phagolysosomal killing, a host defense pathway intact in both normal and CGD MDM, or whether it occupies a distinct intracellular niche in CGD MDM, we assessed the trafficking patterns of this organism. We observed colocalization of G. bethesdensis with an early endosome antigen 1 (EEA1)-positive compartment, followed by colocalization with lysosome-associated membrane protein 1 (LAMP1)-positive and LysoTracker-positive late phagosomes; these characteristics were similar in both normal and CGD MDM. Despite localization to acidified late phagosomes, viable G. bethesdensis cells were recovered from viable MDM in numbers greater than in the initial input up to 6 days after infection. G. bethesdensis remains, and in some cases appears to divide, within a membrane-bound compartment for the entire 6-day time course. These findings indicate that this organism resists both oxygen-dependent and oxygen-independent phagolysosomal antimicrobial systems of human macrophages. Copyright © 2017 American Society for Microbiology.

  15. Aberrant Time to Most Recent Common Ancestor as a Signature of Natural Selection.

    PubMed

    Hunter-Zinck, Haley; Clark, Andrew G

    2015-10-01

    Natural selection inference methods often target one mode of selection of a particular age and strength. However, detecting multiple modes simultaneously, or with atypical representations, would be advantageous for understanding a population's evolutionary history. We have developed an anomaly detection algorithm using distributions of pairwise time to most recent common ancestor (TMRCA) to simultaneously detect multiple modes of natural selection in whole-genome sequences. As natural selection distorts local genealogies in distinct ways, the method uses pairwise TMRCA distributions, which approximate genealogies at a nonrecombining locus, to detect distortions without targeting a specific mode of selection. We evaluate the performance of our method, TSel, for both positive and balancing selection over different time-scales and selection strengths and compare TSel's performance with that of other methods. We then apply TSel to the Complete Genomics diversity panel, a set of human whole-genome sequences, and recover loci previously inferred to be under positive or balancing selection.

  16. An early modern human from the Peştera cu Oase, Romania.

    PubMed

    Trinkaus, Erik; Moldovan, Oana; Milota, Stefan; Bîlgăr, Adrian; Sarcina, Laurenţiu; Athreya, Sheela; Bailey, Shara E; Rodrigo, Ricardo; Mircea, Gherase; Higham, Thomas; Ramsey, Christopher Bronk; van der Plicht, Johannes

    2003-09-30

    The 2002 discovery of a robust modern human mandible in the Peştera cu Oase, southwestern Romania, provides evidence of early modern humans in the lower Danubian Corridor. Directly accelerator mass spectrometry radiocarbon (14C)-dated to 34,000-36,000 14C years B.P., the Oase 1 mandible is the oldest definite early modern human specimen in Europe and provides perspectives on the emergence and evolution of early modern humans in the northwestern Old World. The moderately long Oase 1 mandible exhibits a prominent tuber symphyseos and overall proportions that place it close to earlier Upper Paleolithic European specimens. Its symmetrical mandibular incisure, medially placed condyle, small superior medial pterygoid tubercle, mesial mental foramen, and narrow corpus place it closer to early modern humans among Late Pleistocene humans. However, its cross-sectional symphyseal orientation is intermediate between late archaic and early modern humans, the ramus is exceptionally wide, and the molars become progressively larger distally with exceptionally large third molars. The molar crowns lack derived Neandertal features but are otherwise morphologically undiagnostic. However, it has unilateral mandibular foramen lingular bridging, an apparently derived Neandertal feature. It therefore presents a mosaic of archaic, early modern human and possibly Neandertal morphological features, emphasizing both the complex population dynamics of modern human dispersal into Europe and the subsequent morphological evolution of European early modern humans.

  17. Early Human Occupation on the Northeast Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Rhode, D.; Madsen, D.; Brantingham, P.; Perrault, C.

    2010-12-01

    The Tibetan Plateau presents great challenges for human occupation: low oxygen, high ultraviolet radiation, harsh seasonal climate, low overall biological productivity. How and when early humans were able to cope physiologically, genetically, and behaviorally with these extremes is important for understanding the history of human adaptive flexibility. Our investigations of prehistoric human settlement on the northeast Tibetan Plateau focus on (a) establishing well-dated evidence for occupation of altitudes >3000 m, (b) the environmental context of high altitude adaptation, and (c) relations of hunting and pastoralism to lower-altitude agrarian systems. We observe two major prehistoric settlement patterns in the Qinghai Lake area. The earliest, ~15,000-7500 yr old, consists of small isolated firehearths with sparse associated stone tools and wild mammal remains (1). Numerous hearths often occur in the same localities, indicating repeated short-duration occupations by small hunting parties. A second pattern, ~9000-4000 yr old, was established during the Holocene climatic optimum. These sites represent prolonged seasonal residential occupation, containing dark anthropogenic midden, hearth and pit constructions, abundant stone tools, occasional ceramics, and abundant diverse faunal remains (including medium-large mammals but lacking domestic sheep/yak)(2). These Plateau-margin base camps allowed greater intensity of use of the high Plateau. Residential occupation was strongly influenced by nearby lower-altitude farming communities; development of the socioeconomic landscape along the Yellow River likely played at least as great a role in Plateau occupation patterns as did Holocene environmental changes. Holocene vegetation changes in the NE Tibetan Plateau have been attributed to climate (3) or anthropogenic modification (4). Our results document changes in shrub/tree presence from ~12,000-4000 BP, similar to pollen records, that likely reflect climate rather than

  18. Early experience in human hybrid transgastric and transvaginal endoscopic cholecystectomy.

    PubMed

    Salinas, Gustavo; Saavedra, Lil; Agurto, Hellen; Quispe, Rosa; Ramírez, Edwin; Grande, José; Tamayo, Juan; Sánchez, Victoria; Málaga, Daniel; Marks, Jeffrey M

    2010-05-01

    Abdominal procedures have been performed for a long time through the anterior abdominal wall. Since the first reports in the 1980s, laparoscopy has become the standard for cholecystectomy, with many advantages over open procedures. Now a natural-orifice approach to the peritoneal cavity may further reduce the invasiveness of surgery by either diminishing or avoiding abdominal incisions. Several orifice routes to the abdominal cavity have been described: transgastric, transvaginal, transvesical, and transcolonic. Although most experiences with the porcine model showed the possibility of these approaches, few surgeons reported experiences with humans. The authors present their complete early experience with transgastric (TG) and transvaginal (TV) cholecystectomies in human beings. Thirty-nine patients (4 males and 35 females) underwent hybrid NOTES procedures from January 2007 to January 2009. The mean age was 46 years (range = 19-83). The body mass index ranged from 20 to 41 and ASA was I-II. Transgastric (TG) cholecystectomy was performed in 27 patients and 12 patients had a transvaginal (TV) cholecystectomy. The mean operative time was 140 min. Although operative times were slightly shorter in the TG group 005B137 +/- 34.6 min (range = 75-195)] compared to the TV route [147 +/- 31.5 min (range = 95-220)], there were no significant differences between the two groups (p = 0.5, Mann-Whitney U test). Patients were started on liquids within 1 h and discharged 2 h later, except the last 11 TG patients, who went home 24 h later because of enrollment in a separate protocol. An overall 20% morbidity rate and no mortality were found. The complication rates for the TG and TV groups were 18% (5/27) and 25% (3/12), respectively, which was not statistically significant (p = 0.6, chi(2) test). Seventy-five percent of complications (6/8) occurred the first year and 25% (2/8) during the second year of our experience. Transgastric and transvaginal cholecystectomies are feasible

  19. Human cranial diversity and evidence for an ancient lineage of modern humans.

    PubMed

    Schillaci, Michael A

    2008-06-01

    This study examines the genetic affinities of various modern human groupings using a multivariate analysis of morphometric data. Phylogenetic relationships among these groupings are also explored using neighbor-joining analysis of the metric data. Results indicate that the terminal Pleistocene/early Holocene fossils from Australasia exhibit a close genetic affinity with early modern humans from the Levant. Furthermore, recent human populations and Upper Paleolithic Europeans share a most recent common ancestor not shared with either the early Australasians or the early Levantine humans. This pattern of genetic and phylogenetic relationships suggests that the early modern humans from the Levant either contributed directly to the ancestry of an early lineage of Australasians, or that they share a recent common ancestor with them. The principal findings of the study, therefore, lend support to the notion of an early dispersal from Africa by a more ancient lineage of modern human prior to 50 ka, perhaps as early as OIS 5 times (76-100 ka).

  20. The Meckel's cartilage in human embryonic and early fetal periods.

    PubMed

    Wyganowska-Świątkowska, Marzena; Przystańska, Agnieszka

    2011-06-01

    The Meckel's cartilage itself and the mandible are derived from the first branchial arch, and their development depends upon the contribution of the cranial neural crest cells. The prenatal development of the Meckel's cartilage, along with its relationship to the developing mandible and the related structures, were studied histologically in human embryos and fetuses. The material was obtained from a collection of the Department of Anatomy, and laboratory procedures were used to prepare sections, which were stained according to standard light-microscopy methods. The formation of the Meckel's cartilage and its related structures was observed and documented. Some critical moments in the development of the Meckel's cartilage are suggested. The sequential development of the Meckel's cartilage started as early as stage 13 (32 days) with the appearance of condensation of mesenchymal cells within the mandibular prominence. During stage 17 (41 days), the primary ossification center of the mandible appeared on the inferior margin of the Meckel's cartilage. The muscular attachments to the Meckel's cartilage in embryos were observed at stage 18 (44 days). Their subsequent movement into the developing mandible during the 10th week seemed to diminish the role of the Meckel's cartilage as the supportive core; simultaneously, the process of regression within the cartilage was induced. During the embryonic period, the bilateral Meckel's cartilages were in closest contact at the posterior surface of their superior margins, preceding formation of the symphyseal cartilage at this site. The event sequence in the development of the Meckel's cartilage is finally discussed.

  1. Exposure to inorganic arsenic metabolites during early human development.

    PubMed

    Concha, G; Vogler, G; Lezcano, D; Nermell, B; Vahter, M

    1998-08-01

    Because of the lack of data on the exposure to and toxic effects of inorganic arsenic during early human development, the transfer of arsenic to the fetus and suckling infant was studied in a native Andean population, living in the village San Antonio de los Cobres in the North west of Argentina, where the drinking water contains about 200 micrograms/liter. The concentration of arsenic in cord blood (median, 9 micrograms/liter) was almost as high as in maternal blood (median, 11 micrograms/liter), and there was a significant correlation between the two. Thus, at least in late gestation, arsenic is easily transferred to the fetus. The median concentration of arsenic in the placenta was 34 micrograms/kg, compared with 7 micrograms/kg previously reported for nonexposed women. Interestingly, essentially all arsenic in the blood plasma of both the newborns and their mothers was in the form of dimethylarsinic acid (DMA), the end product of inorganic arsenic metabolism. Similarly, about 90% of the arsenic in the urine of both the newborns and mothers in late gestation was present as DMA, compared with about 70% in nonpregnant women (p < 0.001). This may indicate that methylation of arsenic is increased during pregnancy and that DMA is the major form of arsenic transferred to the fetus. The increased methylation in late gestation was associated with lower arsenic concentrations in blood and higher concentrations in urine, compared with a few months postpartum. The arsenic concentrations in the urine of the infants decreased from about 80 micrograms/liter during the first 2 days of life to less than 30 micrograms/liter at 4.4 months (p = 0.025). This could be explained by the low concentrations of arsenic in the breast milk, about 3 micrograms/kg.

  2. The universal ancestor lived in a thermophilic or hyperthermophilic environment.

    PubMed

    Di Giulio, M

    2000-04-07

    Galtier et al. (Science 1999, 283, 220-221) exploit the correlation between the optimal growth temperature in prokaryotes and the G+C content of rRNAs and establish that the last universal common ancestor (LUCA) lived in a mesophilic environment. This result was achieved by estimating the G+C content of the ancestral sequences of the rRNAs of the LUCA through use of a complex Markov model. I have re-analysed their alignments of the rDNAs with maximum parsimony and I have found that their result is not robust and is, in all likelihood, incorrect. In particular, the rRNA ancestral sequences reconstructed with maximum parsimony from these rDNA alignments as well as those reconstructed after eliminating all the sites that turn out to be ambiguous to the parsimony algorithm and to a site-by-site inspection of these alignments, are such as to suggest that the LUCA lived in a thermophilic or hyperthermophilic environment. This finding is also supported by some tRNA ancestral sequences. The main conclusion of this analysis is that if the LUCA was a progenote then the origin of life might have taken place at a high temperature. Copyright 2000 Academic Press.

  3. Protein superfamily evolution and the last universal common ancestor (LUCA).

    PubMed

    Ranea, Juan A G; Sillero, Antonio; Thornton, Janet M; Orengo, Christine A

    2006-10-01

    By exploiting three-dimensional structure comparison, which is more sensitive than conventional sequence-based methods for detecting remote homology, we have identified a set of 140 ancestral protein domains using very restrictive criteria to minimize the potential error introduced by horizontal gene transfer. These domains are highly likely to have been present in the Last Universal Common Ancestor (LUCA) based on their universality in almost all of 114 completed prokaryotic (Bacteria and Archaea) and eukaryotic genomes. Functional analysis of these ancestral domains reveals a genetically complex LUCA with practically all the essential functional systems present in extant organisms, supporting the theory that life achieved its modern cellular status much before the main kingdom separation (Doolittle 2000). In addition, we have calculated different estimations of the genetic and functional versatility of all the superfamilies and functional groups in the prokaryote subsample. These estimations reveal that some ancestral superfamilies have been more versatile than others during evolution allowing more genetic and functional variation. Furthermore, the differences in genetic versatility between protein families are more attributable to their functional nature rather than the time that they have been evolving. These differences in tolerance to mutation suggest that some protein families have eroded their phylogenetic signal faster than others, hiding in many cases, their ancestral origin and suggesting that the calculation of 140 ancestral domains is probably an underestimate.

  4. Cassava genome from a wild ancestor to cultivated varieties

    PubMed Central

    Wang, Wenquan; Feng, Binxiao; Xiao, Jingfa; Xia, Zhiqiang; Zhou, Xincheng; Li, Pinghua; Zhang, Weixiong; Wang, Ying; Møller, Birger Lindberg; Zhang, Peng; Luo, Ming-Cheng; Xiao, Gong; Liu, Jingxing; Yang, Jun; Chen, Songbi; Rabinowicz, Pablo D.; Chen, Xin; Zhang, Hong-Bin; Ceballos, Henan; Lou, Qunfeng; Zou, Meiling; Carvalho, Luiz J.C.B.; Zeng, Changying; Xia, Jing; Sun, Shixiang; Fu, Yuhua; Wang, Haiyan; Lu, Cheng; Ruan, Mengbin; Zhou, Shuigeng; Wu, Zhicheng; Liu, Hui; Kannangara, Rubini Maya; Jørgensen, Kirsten; Neale, Rebecca Louise; Bonde, Maya; Heinz, Nanna; Zhu, Wenli; Wang, Shujuan; Zhang, Yang; Pan, Kun; Wen, Mingfu; Ma, Ping-An; Li, Zhengxu; Hu, Meizhen; Liao, Wenbin; Hu, Wenbin; Zhang, Shengkui; Pei, Jinli; Guo, Anping; Guo, Jianchun; Zhang, Jiaming; Zhang, Zhengwen; Ye, Jianqiu; Ou, Wenjun; Ma, Yaqin; Liu, Xinyue; Tallon, Luke J.; Galens, Kevin; Ott, Sandra; Huang, Jie; Xue, Jingjing; An, Feifei; Yao, Qingqun; Lu, Xiaojing; Fregene, Martin; López-Lavalle, L. Augusto Becerra; Wu, Jiajie; You, Frank M.; Chen, Meili; Hu, Songnian; Wu, Guojiang; Zhong, Silin; Ling, Peng; Chen, Yeyuan; Wang, Qinghuang; Liu, Guodao; Liu, Bin; Li, Kaimian; Peng, Ming

    2014-01-01

    Cassava is a major tropical food crop in the Euphorbiaceae family that has high carbohydrate production potential and adaptability to diverse environments. Here we present the draft genome sequences of a wild ancestor and a domesticated variety of cassava and comparative analyses with a partial inbred line. We identify 1,584 and 1,678 gene models specific to the wild and domesticated varieties, respectively, and discover high heterozygosity and millions of single-nucleotide variations. Our analyses reveal that genes involved in photosynthesis, starch accumulation and abiotic stresses have been positively selected, whereas those involved in cell wall biosynthesis and secondary metabolism, including cyanogenic glucoside formation, have been negatively selected in the cultivated varieties, reflecting the result of natural selection and domestication. Differences in microRNA genes and retrotransposon regulation could partly explain an increased carbon flux towards starch accumulation and reduced cyanogenic glucoside accumulation in domesticated cassava. These results may contribute to genetic improvement of cassava through better understanding of its biology. PMID:25300236

  5. Single origin of Malagasy Carnivora from an African ancestor.

    PubMed

    Yoder, Anne D; Burns, Melissa M; Zehr, Sarah; Delefosse, Thomas; Veron, Geraldine; Goodman, Steven M; Flynn, John J

    2003-02-13

    The Carnivora are one of only four orders of terrestrial mammals living in Madagascar today. All four (carnivorans, primates, rodents and lipotyphlan insectivores) are placental mammals with limited means for dispersal, yet they occur on a large island that has been surrounded by a formidable oceanic barrier for at least 88 million years, predating the age of origin for any of these groups. Even so, as many as four colonizations of Madagascar have been proposed for the Carnivora alone. The mystery of the island's mammalian origins is confounded by its poor Tertiary fossil record, which leaves us with no direct means for estimating dates of initial diversification. Here we use a multi-gene phylogenetic analysis to show that Malagasy carnivorans are monophyletic and thus the product of a single colonization of Madagascar by an African ancestor. Furthermore, a bayesian analysis of divergence ages for Malagasy carnivorans and lemuriforms indicates that their respective colonizations were temporally separated by tens of millions of years. We therefore conclude that a single event, such as vicariance or common dispersal, cannot explain the presence of both groups in Madagascar.

  6. Genome-wide nucleotide-level mammalian ancestor reconstruction.

    PubMed

    Paten, Benedict; Herrero, Javier; Fitzgerald, Stephen; Beal, Kathryn; Flicek, Paul; Holmes, Ian; Birney, Ewan

    2008-11-01

    Recently attention has been turned to the problem of reconstructing complete ancestral sequences from large multiple alignments. Successful generation of these genome-wide reconstructions will facilitate a greater knowledge of the events that have driven evolution. We present a new evolutionary alignment modeler, called "Ortheus," for inferring the evolutionary history of a multiple alignment, in terms of both substitutions and, importantly, insertions and deletions. Based on a multiple sequence probabilistic transducer model of the type proposed by Holmes, Ortheus uses efficient stochastic graph-based dynamic programming methods. Unlike other methods, Ortheus does not rely on a single fixed alignment from which to work. Ortheus is also more scaleable than previous methods while being fast, stable, and open source. Large-scale simulations show that Ortheus performs close to optimally on a deep mammalian phylogeny. Simulations also indicate that significant proportions of errors due to insertions and deletions can be avoided by not assuming a fixed alignment. We additionally use a challenging hold-out cross-validation procedure to test the method; using the reconstructions to predict extant sequence bases, we demonstrate significant improvements over using closest extant neighbor sequences. Accompanying this paper, a new, public, and genome-wide set of Ortheus ancestor alignments provide an intriguing new resource for evolutionary studies in mammals. As a first piece of analysis, we attempt to recover "fossilized" ancestral pseudogenes. We confidently find 31 cases in which the ancestral sequence had a more complete sequence than any of the extant sequences.

  7. Cassava genome from a wild ancestor to cultivated varieties.

    PubMed

    Wang, Wenquan; Feng, Binxiao; Xiao, Jingfa; Xia, Zhiqiang; Zhou, Xincheng; Li, Pinghua; Zhang, Weixiong; Wang, Ying; Møller, Birger Lindberg; Zhang, Peng; Luo, Ming-Cheng; Xiao, Gong; Liu, Jingxing; Yang, Jun; Chen, Songbi; Rabinowicz, Pablo D; Chen, Xin; Zhang, Hong-Bin; Ceballos, Henan; Lou, Qunfeng; Zou, Meiling; Carvalho, Luiz J C B; Zeng, Changying; Xia, Jing; Sun, Shixiang; Fu, Yuhua; Wang, Haiyan; Lu, Cheng; Ruan, Mengbin; Zhou, Shuigeng; Wu, Zhicheng; Liu, Hui; Kannangara, Rubini Maya; Jørgensen, Kirsten; Neale, Rebecca Louise; Bonde, Maya; Heinz, Nanna; Zhu, Wenli; Wang, Shujuan; Zhang, Yang; Pan, Kun; Wen, Mingfu; Ma, Ping-An; Li, Zhengxu; Hu, Meizhen; Liao, Wenbin; Hu, Wenbin; Zhang, Shengkui; Pei, Jinli; Guo, Anping; Guo, Jianchun; Zhang, Jiaming; Zhang, Zhengwen; Ye, Jianqiu; Ou, Wenjun; Ma, Yaqin; Liu, Xinyue; Tallon, Luke J; Galens, Kevin; Ott, Sandra; Huang, Jie; Xue, Jingjing; An, Feifei; Yao, Qingqun; Lu, Xiaojing; Fregene, Martin; López-Lavalle, L Augusto Becerra; Wu, Jiajie; You, Frank M; Chen, Meili; Hu, Songnian; Wu, Guojiang; Zhong, Silin; Ling, Peng; Chen, Yeyuan; Wang, Qinghuang; Liu, Guodao; Liu, Bin; Li, Kaimian; Peng, Ming

    2014-10-10

    Cassava is a major tropical food crop in the Euphorbiaceae family that has high carbohydrate production potential and adaptability to diverse environments. Here we present the draft genome sequences of a wild ancestor and a domesticated variety of cassava and comparative analyses with a partial inbred line. We identify 1,584 and 1,678 gene models specific to the wild and domesticated varieties, respectively, and discover high heterozygosity and millions of single-nucleotide variations. Our analyses reveal that genes involved in photosynthesis, starch accumulation and abiotic stresses have been positively selected, whereas those involved in cell wall biosynthesis and secondary metabolism, including cyanogenic glucoside formation, have been negatively selected in the cultivated varieties, reflecting the result of natural selection and domestication. Differences in microRNA genes and retrotransposon regulation could partly explain an increased carbon flux towards starch accumulation and reduced cyanogenic glucoside accumulation in domesticated cassava. These results may contribute to genetic improvement of cassava through better understanding of its biology.

  8. Multiple origins of viral capsid proteins from cellular ancestors

    PubMed Central

    Koonin, Eugene V.

    2017-01-01

    Viruses are the most abundant biological entities on earth and show remarkable diversity of genome sequences, replication and expression strategies, and virion structures. Evolutionary genomics of viruses revealed many unexpected connections but the general scenario(s) for the evolution of the virosphere remains a matter of intense debate among proponents of the cellular regression, escaped genes, and primordial virus world hypotheses. A comprehensive sequence and structure analysis of major virion proteins indicates that they evolved on about 20 independent occasions, and in some of these cases likely ancestors are identifiable among the proteins of cellular organisms. Virus genomes typically consist of distinct structural and replication modules that recombine frequently and can have different evolutionary trajectories. The present analysis suggests that, although the replication modules of at least some classes of viruses might descend from primordial selfish genetic elements, bona fide viruses evolved on multiple, independent occasions throughout the course of evolution by the recruitment of diverse host proteins that became major virion components. PMID:28265094

  9. Will man wish to prevail? Some fundamental choices facing humanity early in the Third Millennium

    SciTech Connect

    Wood, L.L.

    1994-10-01

    With the subtle but occasionally vital exception of vaccination-induced immunity to many of the major infectious diseases, no human today is other than virtually identical biologically to those who greeted the dawn of the Second Millennium, nearly 1000 years ago. Culturally, however, we of the West are quite highly evolved from our ancestors of a millennium ago, primarily due to the advent of means for communicating with ever smaller latencies and ever higher bandwidths over ever greater distances in space and time: printed documents have been supplemented in succession by telephony, radio, video and, just now, the first personal communications sets. Also, within a fraction of a human lifetime from the present moment, the first prosthesis for the human brain has appeared and just very recently has become quite ubiquitous: digital computing systems. We are hardly members of the same species, culturally speaking; people of 1000 years ago would be truly and utterly lost in our communications-intensive civilization, and even a highly educated person from those times would swear that a personal computer equipped with a wireless communications module was as at least a familiar, if not a golem. Conversely, a computer-using person from our own times somehow translated back to 1000 A.D. would likely find the profound isolation and the ``informational slowness`` of life then to be acutely intolerable, certainly to a far greater extent than would a citizen of the High Middle Ages translated back to Augustus Caesar`s Rome.

  10. Structure–Function Relationships of Glycoprotein Hormones and Their Subunits’ Ancestors

    PubMed Central

    Cahoreau, Claire; Klett, Danièle; Combarnous, Yves

    2015-01-01

    Glycoprotein hormones (GPHs) are the most complex molecules with hormonal activity. They exist only in vertebrates but the genes encoding their subunits’ ancestors are found in most vertebrate and invertebrate species although their roles are still unknown. In the present report, we review the available structural and functional data concerning GPHs and their subunits’ ancestors. PMID:25767463

  11. Early Holocene human remains from the Argentinean Pampas: additional evidence for distinctive cranial morphology of early South Americans.

    PubMed

    Pucciarelli, Héctor M; Perez, S Ivan; Politis, Gustavo G

    2010-10-01

    The cranial morphology of Early Holocene American human samples is characterized by a long and narrow cranial vault, whereas more recent samples exhibit a shorter and wider cranial vault. Two hypotheses have been proposed to account for the morphological differences between early and late-American samples: (a) the migratory hypothesis that suggests that the morphological variation between early and late American samples was the result of a variable number of migratory waves; and (b) the local diversification hypothesis, that is, the morphological differences between early and late American samples were mainly generated by local, random (genetic drift), and nonrandom factors (selection and phenotypic plasticity). We present the first craniometric study of three early skulls from the Argentinean Pampas, dated ∼8,000 cal. years BP (Arroyo Seco 2, Chocorí, and La Tigra), and one associated with mega-faunal remains (Fontezuelas skull). In addition, we studied several Late Holocene samples. We show that the skulls from the Argentinean Pampas are morphologically similar to other Early Holocene American skulls (i.e., Lagoa Santa from Brazil, Tequendama, Checua, and Aguazuque from Colombia, Lauricocha from Peru, and early Mexicans) that exhibit long and narrow cranial vaults. These samples differ from the Late Holocene American samples that exhibit a shorter and wider cranial vault. Our results underscore the important differences in cranial morphology between early and late-American samples. However, we emphasize the need for further studies to discuss alternative hypotheses regarding such differences.

  12. Genomic evidence for large, long-lived ancestors to placental mammals.

    PubMed

    Romiguier, J; Ranwez, V; Douzery, E J P; Galtier, N

    2013-01-01

    It is widely assumed that our mammalian ancestors, which lived in the Cretaceous era, were tiny animals that survived massive asteroid impacts in shelters and evolved into modern forms after dinosaurs went extinct, 65 Ma. The small size of most Mesozoic mammalian fossils essentially supports this view. Paleontology, however, is not conclusive regarding the ancestry of extant mammals, because Cretaceous and Paleocene fossils are not easily linked to modern lineages. Here, we use full-genome data to estimate the longevity and body mass of early placental mammals. Analyzing 36 fully sequenced mammalian genomes, we reconstruct two aspects of the ancestral genome dynamics, namely GC-content evolution and nonsynonymous over synonymous rate ratio. Linking these molecular evolutionary processes to life-history traits in modern species, we estimate that early placental mammals had a life span above 25 years and a body mass above 1 kg. This is similar to current primates, cetartiodactyls, or carnivores, but markedly different from mice or shrews, challenging the dominant view about mammalian origin and evolution. Our results imply that long-lived mammals existed in the Cretaceous era and were the most successful in evolution, opening new perspectives about the conditions for survival to the Cretaceous-Tertiary crisis.

  13. The Malthusian parameter of ascents: What prevents the exponential increase of one’s ancestors?

    PubMed Central

    Ohno, Susumu

    1996-01-01

    The reason that the indefinite exponential increase in the number of one’s ancestors does not take place is found in the law of sibling interference, which can be expressed by the following simple equation:\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\begin{matrix}{\\mathit{N}}_{{\\mathit{n}}} \\enskip & \\\\ {\\mathit{{\\blacksquare}}} \\enskip & \\\\ {\\mathit{ASZ}} \\enskip & \\end{matrix} {\\mathrm{\\hspace{.167em}{\\times}\\hspace{.167em}2\\hspace{.167em}=\\hspace{.167em}}}{\\mathit{N_{n+1},}}\\end{equation*}\\end{document} where Nn is the number of ancestors in the nth generation, ASZ is the average sibling size of these ancestors, and Nn+1 is the number of ancestors in the next older generation (n + 1). Accordingly, the exponential increase in the number of one’s ancestors is an initial anomaly that occurs while ASZ remains at 1. Once ASZ begins to exceed 1, the rate of increase in the number of ancestors is progressively curtailed, falling further and further behind the exponential increase rate. Eventually, ASZ reaches 2, and at that point, the number of ancestors stops increasing for two generations. These two generations, named AN SA and AN SA + 1, are the most critical in the ancestry, for one’s ancestors at that point come to represent all the progeny-produced adults of the entire ancestral population. Thereafter, the fate of one’s ancestors becomes the fate of the entire population. If the population to which one belongs is a successful, slowly expanding one, the number of ancestors would slowly decline as you move toward the remote past. This is because ABZ would exceed 2. Only when ABZ is less than 2 would the number of ancestors increase beyond the AN SA and AN SA + 1 generations. Since the above is an indication of a failing population on the way to

  14. Some problems in proving the existence of the universal common ancestor of life on Earth.

    PubMed

    Yonezawa, Takahiro; Hasegawa, Masami

    2012-01-01

    Although overwhelming circumstantial evidence supports the existence of the universal common ancestor of all extant life on Earth, it is still an open question whether the universal common ancestor existed or not. Theobald (Nature 465, 219-222 (2010)) recently challenged this problem with a formal statistical test applied to aligned sequences of conservative proteins sampled from all domains of life and concluded that the universal common ancestor hypothesis holds. However, we point out that there is a fundamental flaw in Theobald's method which used aligned sequences. We show that the alignment gives a strong bias for the common ancestor hypothesis, and we provide an example that Theobald's method supports a common ancestor hypothesis for two apparently unrelated families of protein-encoding sequences (cytb and nd2 of mitochondria). This arouses suspicion about the effectiveness of the "formal" test.

  15. Cell proliferation during the early stages of human eye development.

    PubMed

    Bozanić, Darka; Saraga-Babić, Mirna

    2004-08-01

    The distribution as well as the ultrastructural and biochemical characteristics of proliferating cells in the human eye were investigated in five conceptuses of 5-9 postovulatory weeks, using morphological techniques and Ki-67 immunostaining. The Ki-67 nuclear protein was used as a proliferation marker because of its expression in all phases of the cell cycle except the resting phase (G0). The labelling indices of Ki-67-positive cells were analysed by means of the Kruskal-Wallis ANOVA test and the Wilcoxon matched-pairs test. In the 5th week, mitotic cells were the most numerous between the two layers of the optic cup, the optic cup and stalk, and between the lens pit and the surface ectoderm. During the 6th week, cells were observed in the lens epithelium covering the whole cavity of the lens vesicle as well as in the neuroblast zone and the pigmented epithelium of the retina. At later stages (7th-9th weeks), Ki-67-positive cells were restricted to the anterior lens epithelium, the outer neuroblast zone, and the pigmented retina. Throughout all stages examined, mitotic figures were found lying exclusively adjacent to the intraretinal space. Early in the lens pit, they were confined to the free epithelial surface, and later were facing the cavity of the lens vesicle. The proliferative activity was the most intensive in the 6th week, whereas it decreased significantly in the later stages. Additionally, when proliferative activities were compared, the peripheral retina appeared to be less mature than the central before the 9th week. In the earliest analysed stage, cell proliferation might be associated with the sculpturing of the optic cup and stalk, the cornea, and the lens. In the 6th week, the most intensive proliferation seems to be involved not only in the further morphogenesis of the optic cup and the lens vesicle but also in the retinal neurogenesis. At later stages, the decreased proliferation might participate in the neurogenesis of the outer neuroblast zone

  16. East African climate pulses and early human evolution

    NASA Astrophysics Data System (ADS)

    Maslin, Mark A.; Brierley, Chris M.; Milner, Alice M.; Shultz, Susanne; Trauth, Martin H.; Wilson, Katy E.

    2014-10-01

    Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at ˜1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis, which was then the basis for the pulsed climate variability hypothesis. The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African

  17. Population genetics of foxtail millet and its wild ancestor.

    PubMed

    Wang, Chunfang; Chen, Jinfeng; Zhi, Hui; Yang, Lu; Li, Wei; Wang, Yongfang; Li, Haiquan; Zhao, Baohua; Chen, Mingsheng; Diao, Xianmin

    2010-10-11

    Foxtail millet (Setaria italica (L.) P. Beauv.), one of the most ancient domesticated crops, is becoming a model system for studying biofuel crops and comparative genomics in the grasses. However, knowledge on the level of genetic diversity and linkage disequilibrium (LD) is very limited in this crop and its wild ancestor, green foxtail (Setaria viridis (L.) P. Beauv.). Such information would help us to understand the domestication process of cultivated species and will allow further research in these species, including association mapping and identification of agricultural significant genes involved in domestication. In this study, we surveyed DNA sequence for nine loci across 50 accessions of cultivated foxtail millet and 34 of its wild progenitor. We found a low level of genetic diversity in wild green foxtail (θ = 0.0059), θ means Watterson's estimator of θ. Despite of a 55% loss of its wild diversity, foxtail millet still harbored a considerable level of diversity (θ = 0.0027) when compared to rice and sorghum (θ = 0.0024 and 0.0034, respectively). The level of LD in the domesticated foxtail millet extends to 1 kb, while it decayed rapidly to a negligible level within 150 bp in wild green foxtail. Using coalescent simulation, we estimated the bottleneck severity at k = 0.6095 when ρ/θ = 1. These results indicated that the domestication bottleneck of foxtail millet was more severe than that of maize but slightly less pronounced than that of rice. The results in this study establish a general framework for the domestication history of foxtail millet. The low level of genetic diversity and the increased level of LD in foxtail millet are mainly caused by a population bottleneck, although gene flow from foxtail millet to green foxtail is another factor that may have shaped the pattern of genetic diversity of these two related gene pools. The knowledge provided in this study will benefit future population based studies in foxtail millet.

  18. Experimental Evolution of a Facultative Thermophile from a Mesophilic Ancestor

    PubMed Central

    Blaby, Ian K.; Lyons, Benjamin J.; Wroclawska-Hughes, Ewa; Phillips, Grier C. F.; Pyle, Tyler P.; Chamberlin, Stephen G.; Benner, Steven A.; Lyons, Thomas J.

    2012-01-01

    Experimental evolution via continuous culture is a powerful approach to the alteration of complex phenotypes, such as optimal/maximal growth temperatures. The benefit of this approach is that phenotypic selection is tied to growth rate, allowing the production of optimized strains. Herein, we demonstrate the use of a recently described long-term culture apparatus called the Evolugator for the generation of a thermophilic descendant from a mesophilic ancestor (Escherichia coli MG1655). In addition, we used whole-genome sequencing of sequentially isolated strains throughout the thermal adaptation process to characterize the evolutionary history of the resultant genotype, identifying 31 genetic alterations that may contribute to thermotolerance, although some of these mutations may be adaptive for off-target environmental parameters, such as rich medium. We undertook preliminary phenotypic analysis of mutations identified in the glpF and fabA genes. Deletion of glpF in a mesophilic wild-type background conferred significantly improved growth rates in the 43-to-48°C temperature range and altered optimal growth temperature from 37°C to 43°C. In addition, transforming our evolved thermotolerant strain (EVG1064) with a wild-type allele of glpF reduced fitness at high temperatures. On the other hand, the mutation in fabA predictably increased the degree of saturation in membrane lipids, which is a known adaptation to elevated temperature. However, transforming EVG1064 with a wild-type fabA allele had only modest effects on fitness at intermediate temperatures. The Evolugator is fully automated and demonstrates the potential to accelerate the selection for complex traits by experimental evolution and significantly decrease development time for new industrial strains. PMID:22020511

  19. Early asymmetry of gene transcription between embryonic human left and right cerebral cortex

    PubMed Central

    Sun, Tao; Patoine, Christina; Abu-Khalil, Amir; Visvader, Jane; Sum, Eleanor; Cherry, Timothy J.; Orkin, Stuart H.; Geschwind, Daniel H.; Walsh, Christopher A.

    2009-01-01

    The human left and right cerebral hemispheres are anatomically and functionally asymmetric. To test whether human cortical asymmetry has a molecular basis, we studied gene expression levels between the left and right embryonic hemispheres using Serial Analysis of Gene Expression (SAGE), and identified and verified 27 differentially expressed genes, suggesting that human cortical asymmetry is accompanied by early, striking transcriptional asymmetries. LMO4 is consistently more highly expressed in the right perisylvian human cerebral cortex than in the left, and is essential for cortical development in mice, suggesting that human left-right specialization reflects asymmetric cortical development at early stages. PMID:15894532

  20. Human Keratinocyte Cultures in the Investigation of Early Steps of Human Papillomavirus Infection

    PubMed Central

    Griffin, Laura M.; Cicchini, Louis; Xu, Tao; Pyeon, Dohun

    2014-01-01

    Summary Human papillomaviruses (HPVs) are non-enveloped DNA viruses that are highly tropic for mucosal and cutaneous epithelia. The HPV life cycle is tightly linked to epithelial cell differentiation, where HPVs only infect the basal proliferating keratinocytes, and progeny virus assembly and release only occurs in differentiated upper-layer keratinocytes. Therefore, human keratinocyte monolayer cultures provide a useful model to study the early stages of HPV infection. However, previous reports have shown some conflicting results of virus-host interactions during HPV entry, which may be partly attributable to the different cell culture models used to examine these steps of HPV infection. Thus, there is a need to have a standardized in vitro model system to study virus-host interactions during HPV entry. Here, we describe the 3 most widely accepted keratinocyte models for studying HPV infection: primary human foreskin keratinocytes (HFK), normal immortalized keratinocytes (NIKS), and transformed HaCaT keratinocytes. We also describe methods to genetically manipulate these cells, enabling the study of candidate host genes that may be important during HPV infection. Lastly, we will outline simple and robust methods to assay HPV infectivity, which can be used to determine whether knockdown or overexpression of a particular gene affects HPV entry. PMID:24281871

  1. Investing in Early Human Development: Timing and Economic Efficiency

    PubMed Central

    Doyle, Orla; Harmon, Colm P.; Heckman, James J.; Tremblay, Richard E.

    2010-01-01

    Policy discussions to ameliorate socioeconomic (SES) inequalities are increasingly focused on investments in early childhood. Yet such interventions are costly to implement, and clear evidence on the optimal time to intervene to yield a high economic and social return in the future is meagre. The majority of successful early childhood interventions start in the preschool years. However socioeconomic gradients in cognitive skills, socio-emotional functioning and health can be observed by age three, suggesting that preventative programmes starting earlier in childhood may be even more effective. We discuss the optimal timing of early childhood intervention with reference to recent research in developmental neuroscience. We motivate the need for early intervention by providing an overview of the impact of adverse risk factors during the antenatal and early childhood periods on outcomes later in life. We provide a brief review of the economic rationale for investing early in life and propose the “antenatal investment hypothesis”. We conclude by discussing a suite of new European interventions that will inform this optimal timing debate. PMID:19213617

  2. The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia.

    PubMed

    Duarte, C; Maurício, J; Pettitt, P B; Souto, P; Trinkaus, E; van der Plicht, H; Zilhão, J

    1999-06-22

    The discovery of an early Upper Paleolithic human burial at the Abrigo do Lagar Velho, Portugal, has provided evidence of early modern humans from southern Iberia. The remains, the largely complete skeleton of a approximately 4-year-old child buried with pierced shell and red ochre, is dated to ca. 24,500 years B.P. The cranium, mandible, dentition, and postcrania present a mosaic of European early modern human and Neandertal features. The temporal bone has an intermediate-sized juxtamastoid eminence. The mandibular mentum osseum and the dental size and proportions, supported by mandibular ramal features, radial tuberosity orientation, and diaphyseal curvature, as well as the pubic proportions align the skeleton with early modern humans. Body proportions, reflected in femorotibial lengths and diaphyseal robusticity plus tibial condylar displacement, as well as mandibular symphyseal retreat and thoracohumeral muscle insertions, align the skeleton with the Neandertals. This morphological mosaic indicates admixture between regional Neandertals and early modern humans dispersing into southern Iberia. It establishes the complexities of the Late Pleistocene emergence of modern humans and refutes strict replacement models of modern human origins.

  3. The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia

    PubMed Central

    Duarte, Cidália; Maurício, João; Pettitt, Paul B.; Souto, Pedro; Trinkaus, Erik; van der Plicht, Hans; Zilhão, João

    1999-01-01

    The discovery of an early Upper Paleolithic human burial at the Abrigo do Lagar Velho, Portugal, has provided evidence of early modern humans from southern Iberia. The remains, the largely complete skeleton of a ≈4-year-old child buried with pierced shell and red ochre, is dated to ca. 24,500 years B.P. The cranium, mandible, dentition, and postcrania present a mosaic of European early modern human and Neandertal features. The temporal bone has an intermediate-sized juxtamastoid eminence. The mandibular mentum osseum and the dental size and proportions, supported by mandibular ramal features, radial tuberosity orientation, and diaphyseal curvature, as well as the pubic proportions align the skeleton with early modern humans. Body proportions, reflected in femorotibial lengths and diaphyseal robusticity plus tibial condylar displacement, as well as mandibular symphyseal retreat and thoracohumeral muscle insertions, align the skeleton with the Neandertals. This morphological mosaic indicates admixture between regional Neandertals and early modern humans dispersing into southern Iberia. It establishes the complexities of the Late Pleistocene emergence of modern humans and refutes strict replacement models of modern human origins. PMID:10377462

  4. Whence genes in pieces: reconstruction of the exon-intron gene structures of the last eukaryotic common ancestor and other ancestral eukaryotes.

    PubMed

    Koonin, Eugene V; Csuros, Miklos; Rogozin, Igor B

    2013-01-01

    In eukaryotes, protein-coding sequences are interrupted by non-coding sequences known as introns. During mRNA maturation, introns are excised by the spliceosome and the coding regions, exons, are spliced to form the mature coding region. The intron densities widely differ between eukaryotic lineages, from 6 to 7 introns per kb of coding sequence in vertebrates, some invertebrates and green plants, to only a few introns across the entire genome in many unicellular eukaryotes. Evolutionary reconstructions using maximum likelihood methods suggest intron-rich ancestors for each major group of eukaryotes. For the last common ancestor of animals, the highest intron density of all extant and extinct eukaryotes was inferred, at 120-130% of the human intron density. Furthermore, an intron density within 53-74% of the human values was inferred for the last eukaryotic common ancestor. Accordingly, evolution of eukaryotic genes in all lines of descent involved primarily intron loss, with substantial gain only at the bases of several branches including plants and animals. These conclusions have substantial biological implications indicating that the common ancestor of all modern eukaryotes was a complex organism with a gene architecture resembling those in multicellular organisms. Alternative splicing most likely initially appeared as an inevitable result of splicing errors and only later was employed to generate structural and functional diversification of proteins.

  5. Somatic mutations reveal asymmetric cellular dynamics in the early human embryo

    DOE PAGES

    Ju, Young Seok; Martincorena, Inigo; Gerstung, Moritz; ...

    2017-03-22

    Somatic cells acquire mutations throughout the course of an individual’s life. Mutations occurring early in embryogenesis are often present in a substantial proportion of, but not all, cells in postnatal humans and thus have particular characteristics and effects. Depending on their location in the genome and the proportion of cells they are present in, these mosaic mutations can cause a wide range of genetic disease syndromes and predispose carriers to cancer. They have a high chance of being transmitted to offspring as de novo germline mutations and, in principle, can provide insights into early human embryonic cell lineages and theirmore » contributions to adult tissues. Although it is known that gross chromosomal abnormalities are remarkably common in early human embryos, our understanding of early embryonic somatic mutations is very limited. Here we use whole-genome sequences of normal blood from 241 adults to identify 163 early embryonic mutations. We estimate that approximately three base substitution mutations occur per cell per cell-doubling event in early human embryogenesis and these are mainly attributable to two known mutational signatures. We used the mutations to reconstruct developmental lineages of adult cells and demonstrate that the two daughter cells of many early embryonic cell-doubling events contribute asymmetrically to adult blood at an approximately 2:1 ratio. As a result, this study therefore provides insights into the mutation rates, mutational processes and developmental outcomes of cell dynamics that operate during early human embryogenesis.« less

  6. Somatic mutations reveal asymmetric cellular dynamics in the early human embryo.

    PubMed

    Ju, Young Seok; Martincorena, Inigo; Gerstung, Moritz; Petljak, Mia; Alexandrov, Ludmil B; Rahbari, Raheleh; Wedge, David C; Davies, Helen R; Ramakrishna, Manasa; Fullam, Anthony; Martin, Sancha; Alder, Christopher; Patel, Nikita; Gamble, Steve; O'Meara, Sarah; Giri, Dilip D; Sauer, Torril; Pinder, Sarah E; Purdie, Colin A; Borg, Åke; Stunnenberg, Henk; van de Vijver, Marc; Tan, Benita K T; Caldas, Carlos; Tutt, Andrew; Ueno, Naoto T; van 't Veer, Laura J; Martens, John W M; Sotiriou, Christos; Knappskog, Stian; Span, Paul N; Lakhani, Sunil R; Eyfjörd, Jórunn Erla; Børresen-Dale, Anne-Lise; Richardson, Andrea; Thompson, Alastair M; Viari, Alain; Hurles, Matthew E; Nik-Zainal, Serena; Campbell, Peter J; Stratton, Michael R

    2017-03-30

    Somatic cells acquire mutations throughout the course of an individual's life. Mutations occurring early in embryogenesis are often present in a substantial proportion of, but not all, cells in postnatal humans and thus have particular characteristics and effects. Depending on their location in the genome and the proportion of cells they are present in, these mosaic mutations can cause a wide range of genetic disease syndromes and predispose carriers to cancer. They have a high chance of being transmitted to offspring as de novo germline mutations and, in principle, can provide insights into early human embryonic cell lineages and their contributions to adult tissues. Although it is known that gross chromosomal abnormalities are remarkably common in early human embryos, our understanding of early embryonic somatic mutations is very limited. Here we use whole-genome sequences of normal blood from 241 adults to identify 163 early embryonic mutations. We estimate that approximately three base substitution mutations occur per cell per cell-doubling event in early human embryogenesis and these are mainly attributable to two known mutational signatures. We used the mutations to reconstruct developmental lineages of adult cells and demonstrate that the two daughter cells of many early embryonic cell-doubling events contribute asymmetrically to adult blood at an approximately 2:1 ratio. This study therefore provides insights into the mutation rates, mutational processes and developmental outcomes of cell dynamics that operate during early human embryogenesis.

  7. Stable isotope dietary analysis of the Tianyuan 1 early modern human

    PubMed Central

    Hu, Yaowu; Shang, Hong; Tong, Haowen; Nehlich, Olaf; Liu, Wu; Zhao, Chaohong; Yu, Jincheng; Wang, Changsui; Trinkaus, Erik; Richards, Michael P.

    2009-01-01

    We report here on the isotopic analysis of the diet of one of the oldest modern humans found in Eurasia, the Tianyuan 1 early modern human dating to ≈40,000 calendar years ago from Tianyuan Cave (Tianyuandong) in the Zhoukoudian region of China. Carbon and nitrogen isotope analysis of the human and associated faunal remains indicate a diet high in animal protein, and the high nitrogen isotope values suggest the consumption of freshwater fish. To confirm this inference, we measured the sulfur isotope values of terrestrial and freshwater animals around the Zhoukoudian area and of the Tianyuan 1 human, which also support the interpretation of a substantial portion of the diet from freshwater fish. This analysis provides the direct evidence for the consumption of aquatic resources by early modern humans in China and has implications for early modern human subsistence and demography. PMID:19581579

  8. ETV6 mutations in early immature human T cell leukemias

    PubMed Central

    Van Vlierberghe, Pieter; Ambesi-Impiombato, Alberto; Perez-Garcia, Arianne; Haydu, J. Erika; Rigo, Isaura; Hadler, Michael; Tosello, Valeria; Della Gatta, Giusy; Paietta, Elisabeth; Racevskis, Janis; Wiernik, Peter H.; Luger, Selina M.; Rowe, Jacob M.; Rue, Montserrat

    2011-01-01

    Early immature T cell acute lymphoblastic leukemias (T-ALLs) account for ∼5–10% of pediatric T-ALLs and are associated with poor prognosis. However, the genetic defects that drive the biology of these tumors remain largely unknown. In this study, analysis of microarray gene expression signatures in adult T-ALL demonstrated a high prevalence of early immature leukemias and revealed a close relationship between these tumors and myeloid leukemias. Many adult immature T-ALLs harbored mutations in myeloid-specific oncogenes and tumor suppressors including IDH1, IDH2, DNMT3A, FLT3, and NRAS. Moreover, we identified ETV6 mutations as a novel genetic lesion uniquely present in immature adult T-ALL. Our results demonstrate that early immature adult T-ALL represents a heterogeneous category of leukemias characterized by the presence of overlapping myeloid and T-ALL characteristics, and highlight the potential role of ETV6 mutations in these tumors. PMID:22162831

  9. Early Differentiation within the Animate Domain: Are Humans Something Special?

    ERIC Educational Resources Information Center

    Pauen, Sabina

    2000-01-01

    Two experiments investigated whether preverbal infants distinguish between humans and mammals. Study 1 found that 7-, 9-, and 11-month-olds distinguished humans from mammals in an object-examination task. Study 2 found that 7-month-olds but not 5-month-olds showed evidence for category discrimination with the 2-dimensional color photos of toy…

  10. Early Differentiation within the Animate Domain: Are Humans Something Special?

    ERIC Educational Resources Information Center

    Pauen, Sabina

    2000-01-01

    Two experiments investigated whether preverbal infants distinguish between humans and mammals. Study 1 found that 7-, 9-, and 11-month-olds distinguished humans from mammals in an object-examination task. Study 2 found that 7-month-olds but not 5-month-olds showed evidence for category discrimination with the 2-dimensional color photos of toy…

  11. Dynamics of thymus organogenesis and colonization in early human development

    PubMed Central

    Farley, Alison M.; Morris, Lucy X.; Vroegindeweij, Eric; Depreter, Marianne L. G.; Vaidya, Harsh; Stenhouse, Frances H.; Tomlinson, Simon R.; Anderson, Richard A.; Cupedo, Tom; Cornelissen, Jan J.; Blackburn, C. Clare

    2013-01-01

    The thymus is the central site of T-cell development and thus is of fundamental importance to the immune system, but little information exists regarding molecular regulation of thymus development in humans. Here we demonstrate, via spatial and temporal expression analyses, that the genetic mechanisms known to regulate mouse thymus organogenesis are conserved in humans. In addition, we provide molecular evidence that the human thymic epithelium derives solely from the third pharyngeal pouch, as in the mouse, in contrast to previous suggestions. Finally, we define the timing of onset of hematopoietic cell colonization and epithelial cell differentiation in the human thymic primordium, showing, unexpectedly, that the first colonizing hematopoietic cells are CD45+CD34int/-. Collectively, our data provide essential information for translation of principles established in the mouse to the human, and are of particular relevance to development of improved strategies for enhancing immune reconstitution in patients. PMID:23571219

  12. Dynamics of thymus organogenesis and colonization in early human development.

    PubMed

    Farley, Alison M; Morris, Lucy X; Vroegindeweij, Eric; Depreter, Marianne L G; Vaidya, Harsh; Stenhouse, Frances H; Tomlinson, Simon R; Anderson, Richard A; Cupedo, Tom; Cornelissen, Jan J; Blackburn, C Clare

    2013-05-01

    The thymus is the central site of T-cell development and thus is of fundamental importance to the immune system, but little information exists regarding molecular regulation of thymus development in humans. Here we demonstrate, via spatial and temporal expression analyses, that the genetic mechanisms known to regulate mouse thymus organogenesis are conserved in humans. In addition, we provide molecular evidence that the human thymic epithelium derives solely from the third pharyngeal pouch, as in the mouse, in contrast to previous suggestions. Finally, we define the timing of onset of hematopoietic cell colonization and epithelial cell differentiation in the human thymic primordium, showing, unexpectedly, that the first colonizing hematopoietic cells are CD45(+)CD34(int/-). Collectively, our data provide essential information for translation of principles established in the mouse to the human, and are of particular relevance to development of improved strategies for enhancing immune reconstitution in patients.

  13. The environmental contexts of early human occupation of Georgia (Transcaucasia).

    PubMed

    Gabunia, L; Vekua, A; Lordkipanidze, D

    2000-06-01

    The hominid mandible and a third metatarsal found in Dmanisi (Republic of Georgia) are accompanied by a rich faunal assemblage and a core-chopper stone tool industry. The mandible represents a somewhat isolated morphological type of Homo erectus that appears, given the combination of its primitive and advanced traits and specific dental morphology, to be a forerunner of both late H. erectus and early archaic H. sapiens. The faunal assemblage mostly consists of Villafranchian mammals, with the majority of the species assigned to an early phase of the Upper Villafranchian (Late Villanian and Early Biharian). Faunal and paleobotanical evidence as well as the depositional nature of the site indicate that hominid occupation took place in a mosaic environment of open steppe and gallery forests. Both the concentration of resources and the warm climatic conditions in the Dmanisi region at the beginning of the early Pleistocene were favorable for hominid occupation. It is possible that hominids reached the Caucasus through the Levantine corridor, and that the environment of this region allowed them to establish a stronghold and later colonize adjacent areas.

  14. Early environmental effects on epigenetic regulation in humans

    USDA-ARS?s Scientific Manuscript database

    We all know our environment affects our risk of disease. But importantly, the health consequences of environmental exposures depend not only on their severity, but also on their timing relative to developmental milestones. The developmental origins hypothesis is based on the fact that certain early ...

  15. In search of the last common ancestor: new findings on wild chimpanzees.

    PubMed

    McGrew, W C

    2010-10-27

    Modelling the behaviour of extinct hominins is essential in order to devise useful hypotheses of our species' evolutionary origins for testing in the palaeontological and archaeological records. One approach is to model the last common ancestor (LCA) of living apes and humans, based on current ethological and ecological knowledge of our closest living relations. Such referential modelling is based on rigorous, ongoing field studies of the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). This paper reviews recent findings from nature, focusing on those with direct implications for hominin evolution, e.g. apes, using elementary technology to access basic resources such as food and water, or sheltering in caves or bathing as thermoregulatory adaptations. I give preference to studies that directly address key issues, such as whether stone artefacts are detectible before the Oldowan, based on the percussive technology of hammer and anvil use by living apes. Detailed comparative studies of chimpanzees living in varied habitats, from rainforest to savannah, reveal that some behavioural patterns are universal (e.g. shelter construction), while others show marked (e.g. extractive foraging) or nuanced (e.g. courtship) cross-populational variation. These findings allow us to distinguish between retained, primitive traits of the LCA versus derived ones in the human lineage.

  16. In search of the last common ancestor: new findings on wild chimpanzees

    PubMed Central

    McGrew, W. C.

    2010-01-01

    Modelling the behaviour of extinct hominins is essential in order to devise useful hypotheses of our species' evolutionary origins for testing in the palaeontological and archaeological records. One approach is to model the last common ancestor (LCA) of living apes and humans, based on current ethological and ecological knowledge of our closest living relations. Such referential modelling is based on rigorous, ongoing field studies of the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). This paper reviews recent findings from nature, focusing on those with direct implications for hominin evolution, e.g. apes, using elementary technology to access basic resources such as food and water, or sheltering in caves or bathing as thermoregulatory adaptations. I give preference to studies that directly address key issues, such as whether stone artefacts are detectible before the Oldowan, based on the percussive technology of hammer and anvil use by living apes. Detailed comparative studies of chimpanzees living in varied habitats, from rainforest to savannah, reveal that some behavioural patterns are universal (e.g. shelter construction), while others show marked (e.g. extractive foraging) or nuanced (e.g. courtship) cross-populational variation. These findings allow us to distinguish between retained, primitive traits of the LCA versus derived ones in the human lineage. PMID:20855301

  17. Friend or Foe? Early Social Evaluation of Human Interactions

    PubMed Central

    Buon, Marine; Jacob, Pierre; Margules, Sylvie; Brunet, Isabelle; Dutat, Michel; Cabrol, Dominique; Dupoux, Emmanuel

    2014-01-01

    We report evidence that 29-month-old toddlers and 10-month-old preverbal infants discriminate between two agents: a pro-social agent, who performs a positive (comforting) action on a human patient and a negative (harmful) action on an inanimate object, and an anti-social agent, who does the converse. The evidence shows that they prefer the former to the latter even though the agents perform the same bodily movements. Given that humans can cause physical harm to their conspecifics, we discuss this finding in light of the likely adaptive value of the ability to detect harmful human agents. PMID:24586355

  18. DNA Microarray Analysis of Human Monocytes Early Response Genes upon Infection with Rickettsia rickettsii

    DTIC Science & Technology

    2004-11-15

    DNA Microarray Analysis of Human Monocytes Early Response Genes upon Infection with Rickettsia rickettsii Chien-Chung Chao Rickettsiae Diseases...TITLE AND SUBTITLE DNA Microarray Analysis of Human Monocytes Early Response Genes upon Infection with Rickettsia rickettsii 5a. CONTRACT NUMBER 5b...ANSI Std Z39-18 Rickettsiae • Gram negative coccobacillary bacteria • Obligate intracellular organisms • Arthropod-borne • Cause febrile diseases (mild

  19. The Early Aurignacian human remains from La Quina-Aval (France).

    PubMed

    Verna, Christine; Dujardin, Véronique; Trinkaus, Erik

    2012-05-01

    There is a dearth of diagnostic human remains securely associated with the Early Aurignacian of western Europe, despite the presence of similarly aged early modern human remains from further east. One small and fragmentary sample of such remains consists of the two partial immature mandibles plus teeth from the Early Aurignacian of La Quina-Aval, Charente, France. The La Quina-Aval 4 mandible exhibits a prominent anterior symphyseal tuber symphyseos on a vertical symphysis and a narrow anterior dental arcade, both features of early modern humans. The dental remains from La Quina-Aval 1 to 4 (a dm(1), 2 dm(2), a P(4) and a P(4)) are unexceptional in size and present occlusal configurations that combine early modern human features with a few retained ancestral ones. Securely dated to ~33 ka (14)C BP (~38 ka cal BP), these remains serve to confirm the association of early modern humans with the Early Aurignacian in western Europe. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Early Childhood Education Curricula: Human Rights and Citizenship in Early Childhood Education

    ERIC Educational Resources Information Center

    Sounoglou, Marina; Michalopoulou, Aikaterini

    2017-01-01

    This study examines the human rights and the notion of citizenship under the prism of pedagogical science. The methodology that was followed was the experimental method. In a sample of 100 children-experimental group and control group held an intervention program with deepening axes of human rights and the concept of citizenship. The analysis of…

  1. On the origin and evolution of thermophily: reconstruction of functional precambrian enzymes from ancestors of Bacillus.

    PubMed

    Hobbs, Joanne K; Shepherd, Charis; Saul, David J; Demetras, Nicholas J; Haaning, Svend; Monk, Colin R; Daniel, Roy M; Arcus, Vickery L

    2012-02-01

    Thermophily is thought to be a primitive trait, characteristic of early forms of life on Earth, that has been gradually lost over evolutionary time. The genus Bacillus provides an ideal model for studying the evolution of thermophily as it is an ancient taxon and its contemporary species inhabit a range of thermal environments. The thermostability of reconstructed ancestral proteins has been used as a proxy for ancient thermal adaptation. The reconstruction of ancestral "enzymes" has the added advantages of demonstrable activity, which acts as an internal control for accurate inference, and providing insights into the evolution of enzymatic catalysis. Here, we report the reconstruction of the structurally complex core metabolic enzyme LeuB (3-isopropylmalate dehydrogenase, E. C. 1.1.1.85) from the last common ancestor (LCA) of Bacillus using both maximum likelihood (ML) and Bayesian inference. ML LeuB from the LCA of Bacillus shares only 76% sequence identity with its closest contemporary homolog, yet it is fully functional, thermophilic, and exhibits high values for k(cat), k(cat)/K(M), and ΔG(‡) for unfolding. The Bayesian version of this enzyme is also thermophilic but exhibits anomalous catalytic kinetics. We have determined the 3D structure of the ML enzyme and found that it is more closely aligned with LeuB from deeply branching bacteria, such as Thermotoga maritima, than contemporary Bacillus species. To investigate the evolution of thermophily, three descendents of LeuB from the LCA of Bacillus were also reconstructed. They reveal a fluctuating trend in thermal evolution, with a temporal adaptation toward mesophily followed by a more recent return to thermophily. Structural analysis suggests that the determinants of thermophily in LeuB from the LCA of Bacillus and the most recent ancestor are distinct and that thermophily has arisen in this genus at least twice via independent evolutionary paths. Our results add significant fluctuations to the broad

  2. 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.

  3. Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario.

    PubMed

    Gunz, Philipp; Bookstein, Fred L; Mitteroecker, Philipp; Stadlmayr, Andrea; Seidler, Horst; Weber, Gerhard W

    2009-04-14

    The interpretation of genetic evidence regarding modern human origins depends, among other things, on assessments of the structure and the variation of ancient populations. Because we lack genetic data from the time when the first anatomically modern humans appeared, between 200,000 and 60,000 years ago, instead we exploit the phenotype of neurocranial geometry to compare the variation in early modern human fossils with that in other groups of fossil Homo and recent modern humans. Variation is assessed as the mean-squared Procrustes distance from the group average shape in a representation based on several hundred neurocranial landmarks and semilandmarks. We find that the early modern group has more shape variation than any other group in our sample, which covers 1.8 million years, and that they are morphologically similar to recent modern humans of diverse geographically dispersed populations but not to archaic groups. Of the currently competing models of modern human origins, some are inconsistent with these findings. Rather than a single out-of-Africa dispersal scenario, we suggest that early modern humans were already divided into different populations in Pleistocene Africa, after which there followed a complex migration pattern. Our conclusions bear implications for the inference of ancient human demography from genetic models and emphasize the importance of focusing research on those early modern humans, in particular, in Africa.

  4. Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario

    PubMed Central

    Gunz, Philipp; Bookstein, Fred L.; Mitteroecker, Philipp; Stadlmayr, Andrea; Seidler, Horst; Weber, Gerhard W.

    2009-01-01

    The interpretation of genetic evidence regarding modern human origins depends, among other things, on assessments of the structure and the variation of ancient populations. Because we lack genetic data from the time when the first anatomically modern humans appeared, between 200,000 and 60,000 years ago, instead we exploit the phenotype of neurocranial geometry to compare the variation in early modern human fossils with that in other groups of fossil Homo and recent modern humans. Variation is assessed as the mean-squared Procrustes distance from the group average shape in a representation based on several hundred neurocranial landmarks and semilandmarks. We find that the early modern group has more shape variation than any other group in our sample, which covers 1.8 million years, and that they are morphologically similar to recent modern humans of diverse geographically dispersed populations but not to archaic groups. Of the currently competing models of modern human origins, some are inconsistent with these findings. Rather than a single out-of-Africa dispersal scenario, we suggest that early modern humans were already divided into different populations in Pleistocene Africa, after which there followed a complex migration pattern. Our conclusions bear implications for the inference of ancient human demography from genetic models and emphasize the importance of focusing research on those early modern humans, in particular, in Africa. PMID:19307568

  5. Early T helper cell programming of gene expression in human.

    PubMed

    Tuomela, Soile; Lahesmaa, Riitta

    2013-11-15

    Molecular mechanisms guiding naïve T helper cell differentiation into functionally specified effector cells are intensively studied. The rapidly growing knowledge is mainly achieved by using mouse cells or disease models. Comparatively exiguous data is gathered from human primary cells although they provide the "ultimate model" for immunology in man, have been exploited in many original studies paving the way for the field, and can be analyzed more easily than ever with the help of modern technology and methods. As usage of mouse models is unavoidable in translational research, parallel human and mouse studies should be performed to assure the relevancy of the hypothesis created during the basic research. In this review, we give an overview on the status of the studies conducted with human primary cells aiming at elucidating the mechanisms instructing the priming of T helper cell subtypes. The special emphasis is given to the recent high-throughput studies. In addition, by comparing the human and mouse studies we intend to point out the regulatory mechanisms and questions which are lacking examination with human primary cells.

  6. Apparatus Named After Our Academic Ancestors — II

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2011-01-01

    In my previous article on apparatus named after physicists and physics teachers, I discussed five relatively common pieces of apparatus from the 1875-1910 era. Now I will go back to the 18th and early-19th centuries to discuss eponymous2 apparatus that we are still using in lecture demonstrations.

  7. Apparatus Named after Our Academic Ancestors--II

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2011-01-01

    In my previous article on apparatus named after physicists and physics teachers, I discussed five relatively common pieces of apparatus from the 1875-1910 era. Now I will go back to the 18th and early-19th centuries to discuss eponymous apparatus that we are still using in lecture demonstrations. [For Part I, see EJ912907.

  8. Intestinal microbiology in early life: specific prebiotics can have similar functionalities as human-milk oligosaccharides.

    PubMed

    Oozeer, Raish; van Limpt, Kees; Ludwig, Thomas; Ben Amor, Kaouther; Martin, Rocio; Wind, Richèle D; Boehm, Günther; Knol, Jan

    2013-08-01

    Human milk is generally accepted as the best nutrition for newborns and has been shown to support the optimal growth and development of infants. On the basis of scientific insights from human-milk research, a specific mixture of nondigestible oligosaccharides has been developed, with the aim to improve the intestinal microbiota in early life. The mixture has been extensively studied and has been shown to be safe and to have potential health benefits that are similar to those of human milk. The specific mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides has been found to affect the development of early microbiota and to increase the Bifidobacterium amounts as observed in human-milk-fed infants. The resulting gut ecophysiology is characterized by high concentrations of lactate, a slightly acidic pH, and specific short-chain fatty acid profiles, which are high in acetate and low in butyrate and propionate. Here, we have summarized the main findings of dietary interventions with these specific oligosaccharides on the gut microbiota in early life. The gut ecophysiology in early life may have consequences for the metabolic, immunologic, and even neurologic development of the child because reports increasingly substantiate the important function of gut microbes in human health. This review highlights major findings in the field of early gut colonization and the potential impact of early nutrition in healthy growth and development.

  9. Early warning signals of regime shifts in coupled human-environment systems.

    PubMed

    Bauch, Chris T; Sigdel, Ram; Pharaon, Joe; Anand, Madhur

    2016-12-20

    In complex systems, a critical transition is a shift in a system's dynamical regime from its current state to a strongly contrasting state as external conditions move beyond a tipping point. These transitions are often preceded by characteristic early warning signals such as increased system variability. However, early warning signals in complex, coupled human-environment systems (HESs) remain little studied. Here, we compare critical transitions and their early warning signals in a coupled HES model to an equivalent environment model uncoupled from the human system. We parameterize the HES model, using social and ecological data from old-growth forests in Oregon. We find that the coupled HES exhibits a richer variety of dynamics and regime shifts than the uncoupled environment system. Moreover, the early warning signals in the coupled HES can be ambiguous, heralding either an era of ecosystem conservationism or collapse of both forest ecosystems and conservationism. The presence of human feedback in the coupled HES can also mitigate the early warning signal, making it more difficult to detect the oncoming regime shift. We furthermore show how the coupled HES can be "doomed to criticality": Strategic human interactions cause the system to remain perpetually in the vicinity of a collapse threshold, as humans become complacent when the resource seems protected but respond rapidly when it is under immediate threat. We conclude that the opportunities, benefits, and challenges of modeling regime shifts and early warning signals in coupled HESs merit further research.

  10. Major genomic mitochondrial lineages delineate early human expansions

    PubMed Central

    Maca-Meyer, Nicole; González, Ana M; Larruga, José M; Flores, Carlos; Cabrera, Vicente M

    2001-01-01

    Background The phylogeographic distribution of human mitochondrial DNA variations allows a genetic approach to the study of modern Homo sapiens dispersals throughout the world from a female perspective. As a new contribution to this study we have phylogenetically analysed complete mitochondrial DNA(mtDNA) sequences from 42 human lineages, representing major clades with known geographic assignation. Results We show the relative relationships among the 42 lineages and present more accurate temporal calibrations than have been previously possible to give new perspectives as how modern humans spread in the Old World. Conclusions The first detectable expansion occurred around 59,000–69,000 years ago from Africa, independently colonizing western Asia and India and, following this southern route, swiftly reaching east Asia. Within Africa, this expansion did not replace but mixed with older lineages detectable today only in Africa. Around 39,000–52,000 years ago, the western Asian branch spread radially, bringing Caucasians to North Africa and Europe, also reaching India, and expanding to north and east Asia. More recent migrations have entangled but not completely erased these primitive footprints of modern human expansions. PMID:11553319

  11. Discontinuity of human presence at Atapuerca during the early Middle Pleistocene: a matter of ecological competition?

    PubMed

    Rodríguez-Gómez, Guillermo; Mateos, Ana; Martín-González, Jesús Angel; Blasco, Ruth; Rosell, Jordi; Rodríguez, Jesús

    2014-01-01

    Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7-0.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7-0.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene.

  12. Discontinuity of Human Presence at Atapuerca during the Early Middle Pleistocene: A Matter of Ecological Competition?

    PubMed Central

    Rodríguez-Gómez, Guillermo; Mateos, Ana; Martín-González, Jesús Angel; Blasco, Ruth; Rosell, Jordi; Rodríguez, Jesús

    2014-01-01

    Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7−0.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7−0.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene. PMID:25054305

  13. Evolutionary origins of Hsp90 chaperones and a deep paralogy in their bacterial ancestors.

    PubMed

    Stechmann, Alexandra; Cavalier-Smith, Thomas

    2004-01-01

    The 82-90 kD family of molecular chaperone proteins has homologs in eukaryotes (Hsp90) and many eubacteria (HtpG) but not in Archaebacteria. We used representatives of all four different eukaryotic paralogs (cytosolic, endoplasmic reticulum (ER), chloroplast, mitochondrial) together with numerous eubacterial HtpG proteins for phylogenetic analyses to investigate their evolutionary origins. Our trees confirm that none of the organellar Hsp90s derives from the endosymbionts of early eukaryotes. Contrary to previous suggestions of distant origins through lateral gene transfer (LGT) all eukaryote Hsp90s are related to Gram-positive eubacterial HtpG proteins. The nucleocytosolic, ER and chloroplast Hsp90 paralogs are clearly mutually related. The origin of mitochondrial Hsp90 is more obscure, as these sequences are deeply nested within eubacteria. Our trees also reveal a deep split within eubacteria into a group of mainly long-branching sequences (including the eukaryote mitochondrial Hsp90s) and another group comprising exclusively short-branching HtpG proteins, from which the cytosolic/ER versions probably arose. Both versions are present in several eubacterial phyla, suggesting gene duplication very early in eubacterial evolution and multiple independent losses thereafter. We identified one probable case of LGT within eubacteria. However, multiple losses can simply explain the evolutionary pattern of the eubacterial HtpG paralogs and predominate over LGT. We suggest that the actinobacterial ancestor of eukaryotes harbored genes for both eubacterial HtpG paralogs, as the actinobacterium Streptomyces coelicolor still does; one could have given rise to the mitochondrial Hsp90 and the other, following another duplication event in the ancestral eukaryote, to the cytosolic and ER Hsp90 homologs.

  14. The dispersed archaeal eukaryome and the complex archaeal ancestor of eukaryotes.

    PubMed

    Koonin, Eugene V; Yutin, Natalya

    2014-04-01

    The ancestral set of eukaryotic genes is a chimera composed of genes of archaeal and bacterial origins thanks to the endosymbiosis event that gave rise to the mitochondria and apparently antedated the last common ancestor of the extant eukaryotes. The proto-mitochondrial endosymbiont is confidently identified as an α-proteobacterium. In contrast, the archaeal ancestor of eukaryotes remains elusive, although evidence is accumulating that it could have belonged to a deep lineage within the TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, Korarchaeota) superphylum of the Archaea. Recent surveys of archaeal genomes show that the apparent ancestors of several key functional systems of eukaryotes, the components of the archaeal "eukaryome," such as ubiquitin signaling, RNA interference, and actin-based and tubulin-based cytoskeleton structures, are identifiable in different archaeal groups. We suggest that the archaeal ancestor of eukaryotes was a complex form, rooted deeply within the TACK superphylum, that already possessed some quintessential eukaryotic features, in particular, a cytoskeleton, and perhaps was capable of a primitive form of phagocytosis that would facilitate the engulfment of potential symbionts. This putative group of Archaea could have existed for a relatively short time before going extinct or undergoing genome streamlining, resulting in the dispersion of the eukaryome. This scenario might explain the difficulty with the identification of the archaeal ancestor of eukaryotes despite the straightforward detection of apparent ancestors to many signature eukaryotic functional systems.

  15. The Dispersed Archaeal Eukaryome and the Complex Archaeal Ancestor of Eukaryotes

    PubMed Central

    Koonin, Eugene V.; Yutin, Natalya

    2014-01-01

    The ancestral set of eukaryotic genes is a chimera composed of genes of archaeal and bacterial origins thanks to the endosymbiosis event that gave rise to the mitochondria and apparently antedated the last common ancestor of the extant eukaryotes. The proto-mitochondrial endosymbiont is confidently identified as an α-proteobacterium. In contrast, the archaeal ancestor of eukaryotes remains elusive, although evidence is accumulating that it could have belonged to a deep lineage within the TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, Korarchaeota) superphylum of the Archaea. Recent surveys of archaeal genomes show that the apparent ancestors of several key functional systems of eukaryotes, the components of the archaeal “eukaryome,” such as ubiquitin signaling, RNA interference, and actin-based and tubulin-based cytoskeleton structures, are identifiable in different archaeal groups. We suggest that the archaeal ancestor of eukaryotes was a complex form, rooted deeply within the TACK superphylum, that already possessed some quintessential eukaryotic features, in particular, a cytoskeleton, and perhaps was capable of a primitive form of phagocytosis that would facilitate the engulfment of potential symbionts. This putative group of Archaea could have existed for a relatively short time before going extinct or undergoing genome streamlining, resulting in the dispersion of the eukaryome. This scenario might explain the difficulty with the identification of the archaeal ancestor of eukaryotes despite the straightforward detection of apparent ancestors to many signature eukaryotic functional systems. PMID:24691961

  16. Spatial and temporal arrival patterns of Madagascar's vertebrate fauna explained by distance, ocean currents, and ancestor type.

    PubMed

    Samonds, Karen E; Godfrey, Laurie R; Ali, Jason R; Goodman, Steven M; Vences, Miguel; Sutherland, Michael R; Irwin, Mitchell T; Krause, David W

    2012-04-03

    How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal from the Paleocene onward, reaching the lowest levels after the mid-Miocene. This finding is consistent with a paleoceanographic model [Ali JR, Huber M (2010) Nature 463:653-656] that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming from Africa, followed by a reconfiguration to present-day flow 15-20 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland.

  17. Evidence that CRABS CLAW and TOUSLED have conserved their roles in carpel development since the ancestor of the extant angiosperms

    PubMed Central

    Fourquin, Chloé; Vinauger-Douard, Marion; Fogliani, Bruno; Dumas, Christian; Scutt, Charles P.

    2005-01-01

    The carpel is the female reproductive organ specific to flowering plants. We aim to define the genes that controlled carpel development in the common ancestor of this group as a step toward determining the molecular events that were responsible for the evolution of the carpel. CRABS CLAW (CRC) and TOUSLED (TSL) control important aspects of carpel development in the model plant, Arabidopsis thaliana. The basal angiosperm species Amborella trichopoda and Cabomba aquatica very likely represent the two most early diverging groups of flowering plants. We have identified putative orthologues of CRC and TSL from A. trichopoda and C. aquatica, respectively. We demonstrate the expression patterns of these genes in carpels to be very highly conserved, both spatially and temporally, with those of their Arabidopsis orthologues. We argue that CRC and TSL in Arabidopsis are likely to have conserved their respective roles in carpel development since the common ancestor of the living flowering plants. We conclude that a divergent role shown for the CRC orthologue in rice, DROOPING LEAF, most probably arose specifically in the monocot lineage. We show that, in addition to its expression in carpels, the TSL orthologue of C. aquatica is expressed in tissues that contribute to buoyancy and argue that its role in these tissues may have arisen later than its role in carpel development. PMID:15767586

  18. Spatial and temporal arrival patterns of Madagascar's vertebrate fauna explained by distance, ocean currents, and ancestor type

    PubMed Central

    Samonds, Karen E.; Godfrey, Laurie R.; Ali, Jason R.; Goodman, Steven M.; Vences, Miguel; Sutherland, Michael R.; Irwin, Mitchell T.; Krause, David W.

    2012-01-01

    How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal from the Paleocene onward, reaching the lowest levels after the mid-Miocene. This finding is consistent with a paleoceanographic model [Ali JR, Huber M (2010) Nature 463:653–656] that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming from Africa, followed by a reconfiguration to present-day flow 15–20 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland. PMID:22431643

  19. Early detection of intentional harm in the human amygdala.

    PubMed

    Hesse, Eugenia; Mikulan, Ezequiel; Decety, Jean; Sigman, Mariano; Garcia, María del Carmen; Silva, Walter; Ciraolo, Carlos; Vaucheret, Esteban; Baglivo, Fabricio; Huepe, David; Lopez, Vladimir; Manes, Facundo; Bekinschtein, Tristan A; Ibanez, Agustin

    2016-01-01

    A decisive element of moral cognition is the detection of harm and its assessment as intentional or unintentional. Moral cognition engages brain networks supporting mentalizing, intentionality, empathic concern and evaluation. These networks rely on the amygdala as a critical hub, likely through frontotemporal connections indexing stimulus salience. We assessed inferences about perceived harm using a paradigm validated through functional magnetic resonance imaging, eye-tracking and electroencephalogram recordings. During the task, we measured local field potentials in three patients with depth electrodes (n = 115) placed in the amygdala and in several frontal, temporal, and parietal locations. Direct electrophysiological recordings demonstrate that intentional harm induces early activity in the amygdala (<200 ms), which--in turn--predicts intention attribution. The amygdala was the only site that systematically discriminated between critical conditions and predicted their classification of events as intentional. Moreover, connectivity analysis showed that intentional harm induced stronger frontotemporal information sharing at early stages. Results support the 'many roads' view of the amygdala and highlight its role in the rapid encoding of intention and salience--critical components of mentalizing and moral evaluation. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Technology, conflict early warning systems, public health, and human rights.

    PubMed

    Pham, Phuong N; Vinck, Patrick

    2012-12-15

    Public health and conflict early warning are evolving rapidly in response to technology changes for the gathering, management, analysis and communication of data. It is expected that these changes will provide an unprecedented ability to monitor, detect, and respond to crises. One of the potentially most profound and lasting expected change affects the roles of the various actors in providing and sharing information and in responding to early warning. Communities and civil society actors have the opportunity to be empowered as a source of information, analysis, and response, while the role of traditional actors shifts toward supporting those communities and building resilience. However, by creating new roles, relationships, and responsibilities, technology changes raise major concerns and ethical challenges for practitioners, pressing the need for practical guidelines and actionable recommendations in line with existing ethical principles. Copyright © 2012 Pham and Vinck. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

  1. 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

  2. Genome-wide analysis of DNA methylation dynamics during early human development.

    PubMed

    Okae, Hiroaki; Chiba, Hatsune; Hiura, Hitoshi; Hamada, Hirotaka; Sato, Akiko; Utsunomiya, Takafumi; Kikuchi, Hiroyuki; Yoshida, Hiroaki; Tanaka, Atsushi; Suyama, Mikita; Arima, Takahiro

    2014-12-01

    DNA methylation is globally reprogrammed during mammalian preimplantation development, which is critical for normal development. Recent reduced representation bisulfite sequencing (RRBS) studies suggest that the methylome dynamics are essentially conserved between human and mouse early embryos. RRBS is known to cover 5-10% of all genomic CpGs, favoring those contained within CpG-rich regions. To obtain an unbiased and more complete representation of the methylome during early human development, we performed whole genome bisulfite sequencing of human gametes and blastocysts that covered>70% of all genomic CpGs. We found that the maternal genome was demethylated to a much lesser extent in human blastocysts than in mouse blastocysts, which could contribute to an increased number of imprinted differentially methylated regions in the human genome. Global demethylation of the paternal genome was confirmed, but SINE-VNTR-Alu elements and some other tandem repeat-containing regions were found to be specifically protected from this global demethylation. Furthermore, centromeric satellite repeats were hypermethylated in human oocytes but not in mouse oocytes, which might be explained by differential expression of de novo DNA methyltransferases. These data highlight both conserved and species-specific regulation of DNA methylation during early mammalian development. Our work provides further information critical for understanding the epigenetic processes underlying differentiation and pluripotency during early human development.

  3. A theoretical framework for early human studies: uncertainty, intervention ensembles, and boundaries

    PubMed Central

    2012-01-01

    Clinical development of novel therapeutics begins with a coordinated sequence of early phase clinical trials. Such early human studies confront a series of methodological and ethical challenges. In what follows, I propose a theoretical framework for early human studies aimed at informing the negotiation of these challenges. At the outset of clinical development, researchers confront a virtually undifferentiated landscape of uncertainty with respect to three variables: outcomes, their probability of occurrence, and operation dimensions needed to effectuate favorable outcomes. Early human trials transform this uncertain landscape into one where there are grounds for belief about risk and benefit for various combined operation dimensions. To accomplish this, studies set out with two aims. First, they identify a set of operation dimensions that, when combined as a package (intervention ensemble), elicits a reasonable probability of a target outcome. Second, they define the boundaries of dimension values within an intervention ensemble. This latter aim entails exposing at least some volunteers in early studies to treatments that are inactive or excessive. I provide examples that illustrate the way early human studies discover and delimit intervention ensembles, and close by offering some implications of this framework for ethics, methodology, and efficiency in clinical development of new interventions. PMID:22999017

  4. Early human communication helps in understanding language evolution.

    PubMed

    Lenti Boero, Daniela

    2014-12-01

    Building a theory on extant species, as Ackermann et al. do, is a useful contribution to the field of language evolution. Here, I add another living model that might be of interest: human language ontogeny in the first year of life. A better knowledge of this phase might help in understanding two more topics among the "several building blocks of a comprehensive theory of the evolution of spoken language" indicated in their conclusion by Ackermann et al., that is, the foundation of the co-evolution of linguistic motor skills with the auditory skills underlying speech perception, and the possible phylogenetic interactions of protospeech production with referential capabilities.

  5. Edwin Grant Dexter: an early researcher in human behavioral biometeorology

    NASA Astrophysics Data System (ADS)

    Stewart, Alan E.

    2014-09-01

    Edwin Grant Dexter (1868-1938) was one of the first researchers to study empirically the effects of specific weather conditions on human behavior. Dexter (1904) published his findings in a book, Weather influences. The author's purposes in this article were to (1) describe briefly Dexter's professional life and examine the historical contexts and motivations that led Dexter to conduct some of the first empirical behavioral biometeorological studies of the time, (2) describe the methods Dexter used to examine weather-behavior relationships and briefly characterize the results that he reported in Weather influences, and (3) provide a historical analysis of Dexter's work and assess its significance for human behavioral biometeorology. Dexter's Weather influences, while demonstrating an exemplary approach to weather, health, and behavior relationships, came at the end of a long era of such studies, as health, social, and meteorological sciences were turning to different paradigms to advance their fields. For these reasons, Dexter's approach and contributions may not have been fully recognized at the time and are, consequently, worthy of consideration by contemporary biometeorologists.

  6. Edwin Grant Dexter: an early researcher in human behavioral biometeorology.

    PubMed

    Stewart, Alan E

    2015-06-01

    Edwin Grant Dexter (1868-1938) was one of the first researchers to study empirically the effects of specific weather conditions on human behavior. Dexter (1904) published his findings in a book, Weather influences. The author's purposes in this article were to (1) describe briefly Dexter's professional life and examine the historical contexts and motivations that led Dexter to conduct some of the first empirical behavioral biometeorological studies of the time, (2) describe the methods Dexter used to examine weather-behavior relationships and briefly characterize the results that he reported in Weather influences, and (3) provide a historical analysis of Dexter's work and assess its significance for human behavioral biometeorology. Dexter's Weather influences, while demonstrating an exemplary approach to weather, health, and behavior relationships, came at the end of a long era of such studies, as health, social, and meteorological sciences were turning to different paradigms to advance their fields. For these reasons, Dexter's approach and contributions may not have been fully recognized at the time and are, consequently, worthy of consideration by contemporary biometeorologists.

  7. Early bone healing events in the human extraction socket.

    PubMed

    Devlin, H; Sloan, P

    2002-12-01

    The tooth extraction socket is unique in terms of a bone-healing defect in that it contains the remnants of periodontal ligament fibroblasts attached to the socket wall. Although these cells have an osteogenic potential in vitro, the origin of cells populating the human extraction socket is unknown and may include bone marrow, periosteum and pericytic cells. Recently, monoclonal antibodies (AML-3, SB-10 and SB-20) have become available which can identify cells undergoing osteogenic differentiation. The aim of this work was to investigate the pattern of osteoblast differentiation in the human extraction socket using these markers. Immunolocalization was used to identify the osteoprogenitor cell population in the extraction sockets of three patients. Runx2 was most strongly expressed by the osteoblasts at the socket margin and in the surrounding marrow spaces. Osteoprogenitor, pre-osteoblast and osteoblast cells surrounded the newly formed trabeculae, and expressed on their cell surface antigens which reacted with the SB-10 and SB-20 antibodies. In a specimen with the tooth and periodontium present, both osteo-blasts and periodontal ligament fibroblasts were immunoreactive with SB-10, and SB-20 and also expressed Runx2. There was heterogeneity of expression of these osteogenic markers e.g. not all osteoblasts expressed Runx2. We have shown that osteoprogenitor cells in the residual periodontal ligament and bone marrow may contribute to bone regeneration following tooth extraction.

  8. Edwin Grant Dexter: an early researcher in human behavioral biometeorology

    NASA Astrophysics Data System (ADS)

    Stewart, Alan E.

    2015-06-01

    Edwin Grant Dexter (1868-1938) was one of the first researchers to study empirically the effects of specific weather conditions on human behavior. Dexter (1904) published his findings in a book, Weather influences. The author's purposes in this article were to (1) describe briefly Dexter's professional life and examine the historical contexts and motivations that led Dexter to conduct some of the first empirical behavioral biometeorological studies of the time, (2) describe the methods Dexter used to examine weather-behavior relationships and briefly characterize the results that he reported in Weather influences, and (3) provide a historical analysis of Dexter's work and assess its significance for human behavioral biometeorology. Dexter's Weather influences, while demonstrating an exemplary approach to weather, health, and behavior relationships, came at the end of a long era of such studies, as health, social, and meteorological sciences were turning to different paradigms to advance their fields. For these reasons, Dexter's approach and contributions may not have been fully recognized at the time and are, consequently, worthy of consideration by contemporary biometeorologists.

  9. Early determination of somatosensory cortex in the human brain.

    PubMed

    Juenger, Hendrik; de Haan, Bianca; Krägeloh-Mann, Ingeborg; Staudt, Martin; Karnath, Hans-Otto

    2011-08-01

    The developing brain possesses a high potential for neuroplasticity. Yet, this remarkable potential of (re-)organization is not a general principle. It seems to vary among different functional systems. Here, we show that distinct brain structures involved in somatosensory processing are already prenatally determined so that a pre- or perinatally acquired (congenital) brain damage of such structures results in a persistent somatosensory deficit. Eleven patients with hemiparesis due to congenital cortico-subcortical unilateral stroke who showed versus not showed a somatosensory deficit were contrasted with magnetic resonance imaging lesion-behavior mapping. The brain areas which were typically damaged in patients with a somatosensory deficit but typically spared in patients without a somatosensory deficit were located in the primary and secondary somatosensory cortex (S1, S2) as well as the inferior parietal cortex directly neighboring S1 and S2. The results argue for an early functional determination of primary and secondary somatosensory cortex, without substantial capacities for (re-)organization. They demonstrate that cortical damage of these areas cannot be compensated by shifting the functional representation to undamaged parts of the cortex.

  10. Immunochemical studies of early alpha chain crosslinking in human fibrin

    SciTech Connect

    Sobel, J.H.

    1987-01-01

    Immunochemical studies were conducted to characterize the earliest covalent ..cap alpha.. chain associations catalyzed by Factor XIII/sub a/ during in vitro fibrin formation. Preparations of purified fibrinogen and Factor XIII were incubated under crosslinking conditions for increasing periods of time and the resulting fibrins subjected to immunoblotting using the characterized monoclonal antibodies, F-103 (anti-A..cap alpha.. number259-276) and F-102 /anti-A..cap alpha.. number540-554). Data obtained for the incorporation of monomeric ..cap alpha.. chains into higher molecular weight immunoreactive species indicate that ..cap alpha.. chain crosslinking begins within the first ten minutes of clotting. Early crosslinked ..cap alpha.. chain species that formed within thirty minutes of in vitro crosslinking were isolated from preparations of reduced, /sup 3/H-S-carboxymethylated fibrin by Sepharose CL-4B gel filtration. Cyanogen bromide treatment of this material resulted in the release of crosslinked and non-crosslinked fragments which could be separated from one another by Sephadex G-150 gel filtration. Derivatives of interest were identified in the column effluent by immunoblotting with F-103 and F-102 and by radioimmunoassays in which polyclonal antisera that detect the known (A) ..cap alpha.. chain crosslinking regions, number241-476 (CNRr VIII) and number518-584 (CNBr X), were employed.

  11. Early Modern Humans and Morphological Variation in Southeast Asia: Fossil Evidence from Tam Pa Ling, Laos

    PubMed Central

    Demeter, Fabrice; Shackelford, Laura; Westaway, Kira; Duringer, Philippe; Bacon, Anne-Marie; Ponche, Jean-Luc; Wu, Xiujie; Sayavongkhamdy, Thongsa; Zhao, Jian-Xin; Barnes, Lani; Boyon, Marc; Sichanthongtip, Phonephanh; Sénégas, Frank; Karpoff, Anne-Marie; Patole-Edoumba, Elise; Coppens, Yves; Braga, José

    2015-01-01

    Little is known about the timing of modern human emergence and occupation in Eastern Eurasia. However a rapid migration out of Africa into Southeast Asia by at least 60 ka is supported by archaeological, paleogenetic and paleoanthropological data. Recent discoveries in Laos, a modern human cranium (TPL1) from Tam Pa Ling‘s cave, provided the first evidence for the presence of early modern humans in mainland Southeast Asia by 63-46 ka. In the current study, a complete human mandible representing a second individual, TPL 2, is described using discrete traits and geometric morphometrics with an emphasis on determining its population affinity. The TPL2 mandible has a chin and other discrete traits consistent with early modern humans, but it retains a robust lateral corpus and internal corporal morphology typical of archaic humans across the Old World. The mosaic morphology of TPL2 and the fully modern human morphology of TPL1 suggest that a large range of morphological variation was present in early modern human populations residing in the eastern Eurasia by MIS 3. PMID:25849125

  12. Early modern humans and morphological variation in Southeast Asia: fossil evidence from Tam Pa Ling, Laos.

    PubMed

    Demeter, Fabrice; Shackelford, Laura; Westaway, Kira; Duringer, Philippe; Bacon, Anne-Marie; Ponche, Jean-Luc; Wu, Xiujie; Sayavongkhamdy, Thongsa; Zhao, Jian-Xin; Barnes, Lani; Boyon, Marc; Sichanthongtip, Phonephanh; Sénégas, Frank; Karpoff, Anne-Marie; Patole-Edoumba, Elise; Coppens, Yves; Braga, José

    2015-01-01

    Little is known about the timing of modern human emergence and occupation in Eastern Eurasia. However a rapid migration out of Africa into Southeast Asia by at least 60 ka is supported by archaeological, paleogenetic and paleoanthropological data. Recent discoveries in Laos, a modern human cranium (TPL1) from Tam Pa Ling's cave, provided the first evidence for the presence of early modern humans in mainland Southeast Asia by 63-46 ka. In the current study, a complete human mandible representing a second individual, TPL 2, is described using discrete traits and geometric morphometrics with an emphasis on determining its population affinity. The TPL2 mandible has a chin and other discrete traits consistent with early modern humans, but it retains a robust lateral corpus and internal corporal morphology typical of archaic humans across the Old World. The mosaic morphology of TPL2 and the fully modern human morphology of TPL1 suggest that a large range of morphological variation was present in early modern human populations residing in the eastern Eurasia by MIS 3.

  13. Ancestral Reconstruction of a Pre-LUCA Aminoacyl-tRNA Synthetase Ancestor Supports the Late Addition of Trp to the Genetic Code.

    PubMed

    Fournier, G P; Alm, E J

    2015-04-01

    The genetic code was likely complete in its current form by the time of the last universal common ancestor (LUCA). Several scenarios have been proposed for explaining the code's pre-LUCA emergence and expansion, and the relative order of the appearance of amino acids used in translation. One co-evolutionary model of genetic code expansion proposes that at least some amino acids were added to the code by the ancient divergence of aminoacyl-tRNA synthetase (aaRS) families. Of all the amino acids used within the genetic code, Trp is most frequently claimed as a relatively recent addition. We observe that, since TrpRS and TyrRS are paralogous protein families retaining significant sequence similarity, the inferred sequence composition of their ancestor can be used to evaluate this co-evolutionary model of genetic code expansion. We show that ancestral sequence reconstructions of the pre-LUCA paralog ancestor of TyrRS and TrpRS have several sites containing Tyr, yet a complete absence of sites containing Trp. This is consistent with the paralog ancestor being specific for the utilization of Tyr, with Trp being a subsequent addition to the genetic code facilitated by a process of aaRS divergence and neofunctionalization. Only after this divergence could Trp be specifically encoded and incorporated into proteins, including the TyrRS and TrpRS descendant lineages themselves. This early absence of Trp is observed under both homogeneous and non-homogeneous models of ancestral sequence reconstruction. Simulations support that this observed absence of Trp is unlikely to be due to chance or model bias. These results support that the final stages of genetic code evolution occurred well within the "protein world," and that the presence-absence of Trp within conserved sites of ancient protein domains is a likely measure of their relative antiquity, permitting the relative timing of extremely early events within protein evolution before LUCA.

  14. Early processing of pitch in the human auditory system.

    PubMed

    Alho, Kimmo; Grimm, Sabine; Mateo-León, Sabina; Costa-Faidella, Jordi; Escera, Carles

    2012-10-01

    Middle-latency auditory evoked potentials, indicating early cortical processing, elicited by pitch changes and repetitions in pure tones and by complex tones with a missing-fundamental pitch were recorded in healthy adults ignoring the sounds while watching a silenced movie. Both for the pure and for the missing-fundamental tones, the Nb middle-latency response was larger for pitch changes (tones preceded by tones of different pitch) than for pitch repetitions (tones preceded by tones of the same pitch). This Nb enhancement was observed even for missing-fundamental tones preceded by repeated tones that had a different missing-fundamental pitch but included all harmonics of the subsequent tone with another missing-fundamental pitch. This finding rules out the possibility that the Nb enhancement in response to a change in missing-fundamental pitch was simply attributable to the activity of auditory cortex neurons responding specifically to the harmonics of missing-fundamental tones. The Nb effect presumably indicates pitch processing at or near the primary auditory cortex, and it was followed by a change-related enhancement of the N1 response, presumably generated in the secondary auditory cortex. This N1 enhancement might have been caused by a mismatch negativity response overlapping with the N1 response. Processing of missing-fundamental pitch was also reflected by the distribution of Nb responses. Tones with a higher missing-fundamental pitch elicited more frontally dominant Nb responses than tones with a lower missing-fundamental pitch. This effect of pitch, not seen for the pure tones, might indicate that the exact location of the Nb generator source in the auditory cortex depends on the missing-fundamental pitch of the eliciting tone.

  15. Early Preferential Responses to Fear Stimuli in Human Right Dorsal Visual Stream - A Meg Study

    PubMed Central

    Meeren, Hanneke K. M.; Hadjikhani, Nouchine; Ahlfors, Seppo P.; Hämäläinen, Matti S.; de Gelder, Beatrice

    2016-01-01

    Emotional expressions of others are salient biological stimuli that automatically capture attention and prepare us for action. We investigated the early cortical dynamics of automatic visual discrimination of fearful body expressions by monitoring cortical activity using magnetoencephalography. We show that right parietal cortex distinguishes between fearful and neutral bodies as early as 80-ms after stimulus onset, providing the first evidence for a fast emotion-attention-action link through human dorsal visual stream. PMID:27095660

  16. The early development and evolution of the human brain.

    PubMed

    Crawford, M A

    1990-01-01

    signal transduction also use high proportions of n-3 fatty acids. However, the n-6 fatty acids also find a place, in the inositol phosphoglyceride (IPG) which appears to be involved with calcium ion transport and hence signal activation and reception. Even in the photoreceptor, the IPG is an arachidonic acid rich phosphoglyceride. THE EVOLUTION OF MAMMALS AND THE LARGE BRAIN: The dominance of n-3 fatty acids in the food chain, persisted until the end of the Cretaceous period when the flowering plants followed on the disappearance of the giant cycads and ferns. A new set of species, the mammals, then evolved with a requirement for n-6 fatty acids for reproduction. This dependance was coincident with the flowering plants which for the first time produced protected seeds: these introduced a rich source of n-6 fatty acids. The brain size of the mammals tended to be relatively larger (that is in relation to body size) by comparison with the previous reptilian or egg laying systems. This process led to the large human brain. A crucial difference between man and other animals, is undoubtedly the extent to which the brain and its peripheral attributes have been developed. This paper will address the possibility that the potential for the evolution of the large human brain may have been released by the evolving human primate occupying an ecological niche which offered a rich source of those nutrients specifically required for the brain. That niche is at the land/water interface.

  17. A molecular palaeobiological hypothesis for the origin of aplacophoran molluscs and their derivation from chiton-like ancestors

    PubMed Central

    Vinther, Jakob; Sperling, Erik A.; Briggs, Derek E. G.; Peterson, Kevin J.

    2012-01-01

    Aplacophorans have long been argued to be basal molluscs. We present a molecular phylogeny, including the aplacophorans Neomeniomorpha (Solenogastres) and Chaetodermomorpha (Caudofoveata), which recovered instead the clade Aculifera (Aplacophora + Polyplacophora). Our relaxed Bayesian molecular clock estimates an Early Ordovician appearance of the aculiferan crown group consistent with the presence of chiton-like molluscs with seven or eight dorsal shell plates by the Late Cambrian (approx. 501–490 Ma). Molecular, embryological and palaeontological data indicate that aplacophorans, as well as chitons, evolved from a paraphyletic assemblage of chiton-like ancestors. The recovery of cephalopods as a sister group to aculiferans suggests that the plesiomorphic condition in molluscs might be a morphology similar to that found in monoplacophorans. PMID:21976685

  18. A molecular palaeobiological hypothesis for the origin of aplacophoran molluscs and their derivation from chiton-like ancestors.

    PubMed

    Vinther, Jakob; Sperling, Erik A; Briggs, Derek E G; Peterson, Kevin J

    2012-04-07

    Aplacophorans have long been argued to be basal molluscs. We present a molecular phylogeny, including the aplacophorans Neomeniomorpha (Solenogastres) and Chaetodermomorpha (Caudofoveata), which recovered instead the clade Aculifera (Aplacophora + Polyplacophora). Our relaxed Bayesian molecular clock estimates an Early Ordovician appearance of the aculiferan crown group consistent with the presence of chiton-like molluscs with seven or eight dorsal shell plates by the Late Cambrian (approx. 501-490 Ma). Molecular, embryological and palaeontological data indicate that aplacophorans, as well as chitons, evolved from a paraphyletic assemblage of chiton-like ancestors. The recovery of cephalopods as a sister group to aculiferans suggests that the plesiomorphic condition in molluscs might be a morphology similar to that found in monoplacophorans.

  19. Apparatus Named After Our Academic Ancestors — I

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2010-12-01

    Let us now praise famous physicists, and the apparatus named after them, with apologies to the writer of Ecclesiastes. I once compiled a list of about 300 pieces of apparatus known to us as X's Apparatus. Some of the values of X are familiar, like Wheatstone and Kelvin and Faraday, but have you heard of Pickering or Rhumkorff or Barlow? In an earlier article about Packard's apparatus,1 I paid homage to an early-20th-century high school teacher, and other articles have mentioned apparatus by a number of other physicists and physics teachers.2 In many cases the apparatus came directly out of research being done by the physicist, or from the need to show the phenomena of physics in the classroom and lecture hall. Here are more stories about apparatus and their makers, starting with three pieces of apparatus that are related to the development of electron physics in the latter half of the 19th century.

  20. Ultrastructure of human Leydig cells at early gonadal embryogenesis.

    PubMed

    Makabe, S; Naguro, T; Heyn, R; Motta, P M

    1995-01-01

    The ultrastructure of human Leydig cells at different stages of the testicular prenatal development is described by means of transmission and scanning electron microscopy. Between 5 and 7 weeks of gestation (w.g.) the interstitial tissue of the gonad is filled with small undifferentiated mesenchymal cells, migrating primordial germ cells and blood vessels. When the embryo is 7 to 8 weeks-old Leydig cells (LC) appear in basically two morphological patterns, light and dark cells. Their most significative feature is the development of the smooth endoplasmic reticulum (SER) as a dense tubulo-vesicular network and the presence of numerous pleomorphic mitochondria with mainly lamellar cristae. At 14 and 16 w.g. the testicular interstitium reaches the maximum development; the cytoplasm of the LC shows a widespread network of anastomosing tubules of the SER and mitochondria with tubular cristae. Fetal LC show a partial cell coat, lack the crystals of Reinke, have few lipid droplets and show no signs of massive cell degeneration, at least until 16 w.g. These ultrastructural modifications in fetal LC are in accordance with the changes in both steroidogenic activity and hCG levels reported by the literature to occur at this stage of development. Junctional complexes were often observed among LC from 7 to 8 w.g. onwards.

  1. The differential role of androgens in early human sex development

    PubMed Central

    2013-01-01

    Sexual development in humans is only partly understood at the molecular level. It is dependent on genetic control primarily induced by the sex chromosomal differences between males and females. This leads to the development of the gonads, whereby afterwards the differentiation of the apparent phenotype is controlled by hormone action. Sex steroids may exert permanent and temporary effects. Their organizational features of inducing permanent changes in phenotype occur through genetic control of downstream genes. In this, androgens are the key elements for the differentiation of male internal and external genitalia as well as other sexual organs and general body composition, acting through a single androgen receptor. The androgen receptor is a nuclear transcription factor modulating DNA transcription of respective target genes and thereby driving development and growth in a stringent manner. The specificity of androgen action seems to be a strictly time-controlled process with the androgen receptor acting in concert with different metabolites and an array of cofactors modulating the cellular response and thereby permanently altering the phenotype of any given individual. For every cell programmed by androgens, a specific ‘androgen response index’ must be proposed. PMID:23800242

  2. Human brain mechanisms for the early analysis of voices.

    PubMed

    Warren, J D; Scott, S K; Price, C J; Griffiths, T D

    2006-07-01

    In this functional magnetic resonance imaging study, we investigated human brain mechanisms that are involved in the analysis of voices as sound sources and in the pre-semantic analysis of voice information. The source of the voice was altered by changing the speaker, and the salience of the voice was altered by changing the amount of spectrotemporal detail. We identified a mechanism for detecting a change in the source of the voice in the posterior superior temporal lobe and anatomically distinct mechanisms for the detailed analysis of voice information in a bilateral network extending from the posterior to the anterior superior temporal lobe surrounding the superior temporal sulcus. The findings are consistent with a processing hierarchy in which general source attributes are analyzed in the posterior superior temporal lobe, abstraction of voice identity features occurs in posterior superior temporal sulcus, and further analysis of voice information occurs in anterior superior temporal sulcus and higher order cortices in the middle and anterior temporal lobe.

  3. Buds of the tree: the highway to the last universal common ancestor

    NASA Astrophysics Data System (ADS)

    de Farias, Savio Torres; Prosdocimi, Francisco

    2017-04-01

    The last universal common ancestor (LUCA) has been considered as the branching point on which Bacteria, Archaea and Eukaryotes have diverged. However, the increased information relating to viruses' genomes and the perception that many virus genes do not have homologs in other organisms opened a new discussion. Based on these facts, there has emerged the idea of an early LUCA that should be moved further into the past to include viruses, implicating that life should have originated before the appearance of cellular life forms. Another point of view from advocates of the RNA-world suggests that the origin of life happened a long time before organisms were capable of organizing themselves into cellular entities. Relevant data about the origin of ribosomes indicate that the catalytic unit of the large ribosomal subunit is what should actually be considered as the turning point that separated chemistry from biology. Other researchers seem to think that a tRNA was probably some sort of a strange attractor on which life has originated. Here we propose a theoretical synthesis that tries to provide a crosstalk among the theories and define important points on which the origin of life could have been originated and made more complex, taking into account gradualist assumptions. Thus, discussions involving the origin of biological activities in the RNA-world might lead into a world of progenotes on which viruses have been taken part until the appearance of the very first cells. Along this route of complexification, we identified some key points on which researchers may consider life as an emerging principle.

  4. The eukaryotic ancestor had a complex ubiquitin signaling system of archaeal origin.

    PubMed

    Grau-Bové, Xavier; Sebé-Pedrós, Arnau; Ruiz-Trillo, Iñaki

    2015-03-01

    The origin of the eukaryotic cell is one of the most important transitions in the history of life. However, the emergence and early evolution of eukaryotes remains poorly understood. Recent data have shown that the last eukaryotic common ancestor (LECA) was much more complex than previously thought. The LECA already had the genetic machinery encoding the endomembrane apparatus, spliceosome, nuclear pore, and myosin and kinesin cytoskeletal motors. It is unclear, however, when the functional regulation of these cellular components evolved. Here, we address this question by analyzing the origin and evolution of the ubiquitin (Ub) signaling system, one of the most important regulatory layers in eukaryotes. We delineated the evolution of the whole Ub, Small-Ub-related MOdifier (SUMO), and Ub-fold modifier 1 (Ufm1) signaling networks by analyzing representatives from all major eukaryotic, bacterial, and archaeal lineages. We found that the Ub toolkit had a pre-eukaryotic origin and is present in three extant archaeal groups. The pre-eukaryotic Ub toolkit greatly expanded during eukaryogenesis, through massive gene innovation and diversification of protein domain architectures. This resulted in a LECA with essentially all of the Ub-related genes, including the SUMO and Ufm1 Ub-like systems. Ub and SUMO signaling further expanded during eukaryotic evolution, especially labeling and delabeling enzymes responsible for substrate selection. Additionally, we analyzed protein domain architecture evolution and found that multicellular lineages have the most complex Ub systems in terms of domain architectures. Together, we demonstrate that the Ub system predates the origin of eukaryotes and that a burst of innovation during eukaryogenesis led to a LECA with complex posttranslational regulation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  5. Specimen-level phylogenetics in paleontology using the Fossilized Birth-Death model with sampled ancestors.

    PubMed

    Cau, Andrea

    2017-01-01

    Bayesian phylogenetic methods integrating simultaneously morphological and stratigraphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa. Among recently introduced Bayesian methodologies, the Fossilized Birth-Death (FBD) model allows incorporation of hypotheses on ancestor-descendant relationships in phylogenetic analyses including fossil taxa. Here, the FBD model is used to infer the relationships among an ingroup formed exclusively by fossil individuals, i.e., dipnoan tooth plates from four localities in the Ain el Guettar Formation of Tunisia. Previous analyses of this sample compared the results of phylogenetic analysis using parsimony with stratigraphic methods, inferred a high diversity (five or more genera) in the Ain el Guettar Formation, and interpreted it as an artifact inflated by depositional factors. In the analysis performed here, the uncertainty on the chronostratigraphic relationships among the specimens was included among the prior settings. The results of the analysis confirm the referral of most of the specimens to the taxa Asiatoceratodus, Equinoxiodus, Lavocatodus and Neoceratodus, but reject those to Ceratodus and Ferganoceratodus. The resulting phylogeny constrained the evolution of the Tunisian sample exclusively in the Early Cretaceous, contrasting with the previous scenario inferred by the stratigraphically-calibrated topology resulting from parsimony analysis. The phylogenetic framework also suggests that (1) the sampled localities are laterally equivalent, (2) but three localities are restricted to the youngest part of the section; both results are in agreement with previous stratigraphic analyses of these localities. The FBD model of specimen-level units provides a novel tool for phylogenetic inference among fossils but also

  6. The Eukaryotic Ancestor Had a Complex Ubiquitin Signaling System of Archaeal Origin

    PubMed Central

    Grau-Bové, Xavier; Sebé-Pedrós, Arnau; Ruiz-Trillo, Iñaki

    2015-01-01

    The origin of the eukaryotic cell is one of the most important transitions in the history of life. However, the emergence and early evolution of eukaryotes remains poorly understood. Recent data have shown that the last eukaryotic common ancestor (LECA) was much more complex than previously thought. The LECA already had the genetic machinery encoding the endomembrane apparatus, spliceosome, nuclear pore, and myosin and kinesin cytoskeletal motors. It is unclear, however, when the functional regulation of these cellular components evolved. Here, we address this question by analyzing the origin and evolution of the ubiquitin (Ub) signaling system, one of the most important regulatory layers in eukaryotes. We delineated the evolution of the whole Ub, Small-Ub-related MOdifier (SUMO), and Ub-fold modifier 1 (Ufm1) signaling networks by analyzing representatives from all major eukaryotic, bacterial, and archaeal lineages. We found that the Ub toolkit had a pre-eukaryotic origin and is present in three extant archaeal groups. The pre-eukaryotic Ub toolkit greatly expanded during eukaryogenesis, through massive gene innovation and diversification of protein domain architectures. This resulted in a LECA with essentially all of the Ub-related genes, including the SUMO and Ufm1 Ub-like systems. Ub and SUMO signaling further expanded during eukaryotic evolution, especially labeling and delabeling enzymes responsible for substrate selection. Additionally, we analyzed protein domain architecture evolution and found that multicellular lineages have the most complex Ub systems in terms of domain architectures. Together, we demonstrate that the Ub system predates the origin of eukaryotes and that a burst of innovation during eukaryogenesis led to a LECA with complex posttranslational regulation. PMID:25525215

  7. Specimen-level phylogenetics in paleontology using the Fossilized Birth-Death model with sampled ancestors

    PubMed Central

    2017-01-01

    Bayesian phylogenetic methods integrating simultaneously morphological and stratigraphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa. Among recently introduced Bayesian methodologies, the Fossilized Birth-Death (FBD) model allows incorporation of hypotheses on ancestor-descendant relationships in phylogenetic analyses including fossil taxa. Here, the FBD model is used to infer the relationships among an ingroup formed exclusively by fossil individuals, i.e., dipnoan tooth plates from four localities in the Ain el Guettar Formation of Tunisia. Previous analyses of this sample compared the results of phylogenetic analysis using parsimony with stratigraphic methods, inferred a high diversity (five or more genera) in the Ain el Guettar Formation, and interpreted it as an artifact inflated by depositional factors. In the analysis performed here, the uncertainty on the chronostratigraphic relationships among the specimens was included among the prior settings. The results of the analysis confirm the referral of most of the specimens to the taxa Asiatoceratodus, Equinoxiodus, Lavocatodus and Neoceratodus, but reject those to Ceratodus and Ferganoceratodus. The resulting phylogeny constrained the evolution of the Tunisian sample exclusively in the Early Cretaceous, contrasting with the previous scenario inferred by the stratigraphically-calibrated topology resulting from parsimony analysis. The phylogenetic framework also suggests that (1) the sampled localities are laterally equivalent, (2) but three localities are restricted to the youngest part of the section; both results are in agreement with previous stratigraphic analyses of these localities. The FBD model of specimen-level units provides a novel tool for phylogenetic inference among fossils but also

  8. Manipulation of human early T lymphopoiesis by coculture on human bone marrow stromal cells: potential utility for adoptive immunotherapy.

    PubMed

    Liu, Bing; Ohishi, Kohshi; Orito, Yuki; Nakamori, Yoshiki; Nishikawa, Hiroyoshi; Ino, Kazuko; Suzuki, Kei; Matsumoto, Takeshi; Masuya, Masahiro; Hamada, Hirofumi; Mineno, Junichi; Ono, Ryoichi; Nosaka, Tetsuya; Shiku, Hiroshi; Katayama, Naoyuki

    2013-04-01

    T cell precursors are an attractive target for adoptive immunotherapy. We examined the regulation of human early T lymphopoiesis by human bone marrow stromal cells to explore in vitro manipulation of human T cell precursors in a human-only coculture system. The generation of CD7(+)CD56(-)cyCD3(-) proT cells from human hematopoietic progenitors on telomerized human bone marrow stromal cells was enhanced by stem cell factor, flt3 ligand, and thrombopoietin, but these stimulatory effects were suppressed by interleukin 3. Expression of Notch ligands Delta-1 and -4 on stromal cells additively promoted T cell differentiation into the CD7(+)cyCD3(+) pre-T cell stage, while cell growth was strongly inhibited. By combining these coculture systems, we found that initial coculture with telomerized stromal cells in the presence of stem cell factor, flt3 ligand, and thrombopoietin, followed by coculture on Delta-1- and -4-coexpressing stromal cells led to a higher percentage and number of pre-T cells. Adoptive immunotherapy using peripheral blood T cells transduced with a tumor antigen-specific T cell receptor (TCR) is a promising strategy but has several limitations, such as the risk of forming a chimeric TCR with the endogenous TCR. We demonstrated that incubation of TCR-transduced hematopoietic progenitors with the combination of coculture systems gave rise to CD7(+)TCR(+)CD3(+)CD1a(-) T cell precursors that rapidly proliferated and differentiated under the culture condition to induce mature T cell differentiation. These data show the regulatory mechanism of early T lymphopoiesis on human stromal cells and the potential utility of engineered human stromal cells to manipulate early T cell development for clinical application.

  9. A late Pleistocene human presence at Huaca Prieta, Peru, and early Pacific Coastal adaptations

    NASA Astrophysics Data System (ADS)

    Dillehay, Tom D.; Bonavia, Duccio; Goodbred, Steve L.; Pino, Mario; Vásquez, Victor; Tham, Teresa Rosales

    2012-05-01

    Archaeological excavations in deep pre-mound levels at Huaca Prieta in northern Peru have yielded new evidence of late Pleistocene cultural deposits that shed insights into the early human occupation of the Pacific coast of South America. Radiocarbon dates place this occupation between ~ 14,200 and 13,300 cal yr BP. The cultural evidence shares certain basic technological and subsistence traits, including maritime resources and simple flake tools, with previously discovered late Pleistocene sites along the Pacific coast of Peru and Chile. The results help to expand our knowledge of early maritime societies and human adaption to changing coastal environments.

  10. High early life mortality in free-ranging dogs is largely influenced by humans

    PubMed Central

    Paul, Manabi; Sen Majumder, Sreejani; Sau, Shubhra; Nandi, Anjan K.; Bhadra, Anindita

    2016-01-01

    Free-ranging dogs are a ubiquitous part of human habitations in many developing countries, leading a life of scavengers dependent on human wastes for survival. The effective management of free-ranging dogs calls for understanding of their population dynamics. Life expectancy at birth and early life mortality are important factors that shape life-histories of mammals. We carried out a five year-long census based study in seven locations of West Bengal, India, to understand the pattern of population growth and factors affecting early life mortality in free-ranging dogs. We observed high rates of mortality, with only ~19% of the 364 pups from 95 observed litters surviving till the reproductive age; 63% of total mortality being human influenced. While living near people increases resource availability for dogs, it also has deep adverse impacts on their population growth, making the dog-human relationship on streets highly complex. PMID:26804633

  11. High early life mortality in free-ranging dogs is largely influenced by humans.

    PubMed

    Paul, Manabi; Sen Majumder, Sreejani; Sau, Shubhra; Nandi, Anjan K; Bhadra, Anindita

    2016-01-25

    Free-ranging dogs are a ubiquitous part of human habitations in many developing countries, leading a life of scavengers dependent on human wastes for survival. The effective management of free-ranging dogs calls for understanding of their population dynamics. Life expectancy at birth and early life mortality are important factors that shape life-histories of mammals. We carried out a five year-long census based study in seven locations of West Bengal, India, to understand the pattern of population growth and factors affecting early life mortality in free-ranging dogs. We observed high rates of mortality, with only ~19% of the 364 pups from 95 observed litters surviving till the reproductive age; 63% of total mortality being human influenced. While living near people increases resource availability for dogs, it also has deep adverse impacts on their population growth, making the dog-human relationship on streets highly complex.

  12. Waves of early transcriptional activation and pluripotency program initiation during human preimplantation development

    PubMed Central

    Vassena, Rita; Boué, Stéphanie; González-Roca, Eva; Aran, Begoña; Auer, Herbert; Veiga, Anna; Belmonte, Juan Carlos Izpisua

    2011-01-01

    The events regulating human preimplantation development are still largely unknown owing to a scarcity of material, ethical and legal limitations and a lack of reliable techniques to faithfully amplify the transcriptome of a single cell. Nonetheless, human embryology is gathering renewed interest due to its close relationship with both stem cell biology and epigenetic reprogramming to pluripotency and their importance in regenerative medicine. Carefully timed genome-wide transcript analyses of single oocytes and embryos uncovered a series of successive waves of embryonic transcriptional initiation that start as early as the 2-cell stage. In addition, we identified the hierarchical activation of genes involved in the regulation of pluripotency. Finally, we developed HumER, a database of human preimplantation gene expression, to serve the scientific community. Importantly, our work links early transcription in the human embryo with the correct execution of the pluripotency program later in development and paves the way for the identification of factors to improve epigenetic reprogramming. PMID:21775417

  13. Molecular paleontology and complexity in the last eukaryotic common ancestor.

    PubMed

    Koumandou, V Lila; Wickstead, Bill; Ginger, Michael L; van der Giezen, Mark; Dacks, Joel B; Field, Mark C

    2013-01-01

    Eukaryogenesis, the origin of the eukaryotic cell, represents one of the fundamental evolutionary transitions in the history of life on earth. This event, which is estimated to have occurred over one billion years ago, remains rather poorly understood. While some well-validated examples of fossil microbial eukaryotes for this time frame have been described, these can provide only basic morphology and the molecular machinery present in these organisms has remained unknown. Complete and partial genomic information has begun to fill this gap, and is being used to trace proteins and cellular traits to their roots and to provide unprecedented levels of resolution of structures, metabolic pathways and capabilities of organisms at these earliest points within the eukaryotic lineage. This is essentially allowing a molecular paleontology. What has emerged from these studies is spectacular cellular complexity prior to expansion of the eukaryotic lineages. Multiple reconstructed cellular systems indicate a very sophisticated biology, which by implication arose following the initial eukaryogenesis event but prior to eukaryotic radiation and provides a challenge in terms of explaining how these early eukaryotes arose and in understanding how they lived. Here, we provide brief overviews of several cellular systems and the major emerging conclusions, together with predictions for subsequent directions in evolution leading to extant taxa. We also consider what these reconstructions suggest about the life styles and capabilities of these earliest eukaryotes and the period of evolution between the radiation of eukaryotes and the eukaryogenesis event itself.

  14. Molecular paleontology and complexity in the last eukaryotic common ancestor

    PubMed Central

    Koumandou, V. Lila; Wickstead, Bill; Ginger, Michael L.; van der Giezen, Mark; Dacks, Joel B.

    2013-01-01

    Eukaryogenesis, the origin of the eukaryotic cell, represents one of the fundamental evolutionary transitions in the history of life on earth. This event, which is estimated to have occurred over one billion years ago, remains rather poorly understood. While some well-validated examples of fossil microbial eukaryotes for this time frame have been described, these can provide only basic morphology and the molecular machinery present in these organisms has remained unknown. Complete and partial genomic information has begun to fill this gap, and is being used to trace proteins and cellular traits to their roots and to provide unprecedented levels of resolution of structures, metabolic pathways and capabilities of organisms at these earliest points within the eukaryotic lineage. This is essentially allowing a molecular paleontology. What has emerged from these studies is spectacular cellular complexity prior to expansion of the eukaryotic lineages. Multiple reconstructed cellular systems indicate a very sophisticated biology, which by implication arose following the initial eukaryogenesis event but prior to eukaryotic radiation and provides a challenge in terms of explaining how these early eukaryotes arose and in understanding how they lived. Here, we provide brief overviews of several cellular systems and the major emerging conclusions, together with predictions for subsequent directions in evolution leading to extant taxa. We also consider what these reconstructions suggest about the life styles and capabilities of these earliest eukaryotes and the period of evolution between the radiation of eukaryotes and the eukaryogenesis event itself. PMID:23895660

  15. Constitutively Expressed IFITM3 Protein in Human Endothelial Cells Poses an Early Infection Block to Human Influenza Viruses

    PubMed Central

    Sun, Xiangjie; Zeng, Hui; Kumar, Amrita; Belser, Jessica A.; Maines, Taronna R.

    2016-01-01

    ABSTRACT A role for pulmonary endothelial cells in the orchestration of cytokine production and leukocyte recruitment during influenza virus infection, leading to severe lung damage, has been recently identified. As the mechanistic pathway for this ability is not fully known, we extended previous studies on influenza virus tropism in cultured human pulmonary endothelial cells. We found that a subset of avian influenza viruses, including potentially pandemic H5N1, H7N9, and H9N2 viruses, could infect human pulmonary endothelial cells (HULEC) with high efficiency compared to human H1N1 or H3N2 viruses. In HULEC, human influenza viruses were capable of binding to host cellular receptors, becoming internalized and initiating hemifusion but failing to uncoat the viral nucleocapsid and to replicate in host nuclei. Unlike numerous cell types, including epithelial cells, we found that pulmonary endothelial cells constitutively express a high level of the restriction protein IFITM3 in endosomal compartments. IFITM3 knockdown by small interfering RNA (siRNA) could partially rescue H1N1 virus infection in HULEC, suggesting IFITM3 proteins were involved in blocking human influenza virus infection in endothelial cells. In contrast, selected avian influenza viruses were able to escape IFITM3 restriction in endothelial cells, possibly by fusing in early endosomes at higher pH or by other, unknown mechanisms. Collectively, our study demonstrates that the human pulmonary endothelium possesses intrinsic immunity to human influenza viruses, in part due to the constitutive expression of IFITM3 proteins. Notably, certain avian influenza viruses have evolved to escape this restriction, possibly contributing to virus-induced pneumonia and severe lung disease in humans. IMPORTANCE Avian influenza viruses, including H5N1 and H7N9, have been associated with severe respiratory disease and fatal outcomes in humans. Although acute respiratory distress syndrome (ARDS) and progressive pulmonary

  16. Global gene expression profiling of individual human oocytes and embryos demonstrates heterogeneity in early development.

    PubMed

    Shaw, Lisa; Sneddon, Sharon F; Zeef, Leo; Kimber, Susan J; Brison, Daniel R

    2013-01-01

    Early development in humans is characterised by low and variable embryonic viability, reflected in low fecundity and high rates of miscarriage, relative to other mammals. Data from assisted reproduction programmes provides additional evidence that this is largely mediated at the level of embryonic competence and is highly heterogeneous among embryos. Understanding the basis of this heterogeneity has important implications in a number of areas including: the regulation of early human development, disorders of pregnancy, assisted reproduction programmes, the long term health of children which may be programmed in early development, and the molecular basis of pluripotency in human stem cell populations. We have therefore investigated global gene expression profiles using polyAPCR amplification and microarray technology applied to individual human oocytes and 4-cell and blastocyst stage embryos. In order to explore the basis of any variability in detail, each developmental stage is replicated in triplicate. Our data show that although transcript profiles are highly stage-specific, within each stage they are relatively variable. We describe expression of a number of gene families and pathways including apoptosis, cell cycle and amino acid metabolism, which are variably expressed and may be reflective of embryonic developmental competence. Overall, our data suggest that heterogeneity in human embryo developmental competence is reflected in global transcript profiles, and that the vast majority of existing human embryo gene expression data based on pooled oocytes and embryos need to be reinterpreted.

  17. Early modern humans from the Peştera Muierii, Baia de Fier, Romania

    PubMed Central

    Soficaru, Andrei; Doboş, Adrian; Trinkaus, Erik

    2006-01-01

    The early modern human remains from the Peştera Muierii, Romania have been directly dated to ≈30,000 radiocarbon years before present (≈30 ka 14C BP) (≈35 ka cal BP) (“calendrical” age; based on CalPal 2005) and augment a small sample of securely dated, European, pre-28 ka 14C BP (≈32.5 ka cal BP) modern human remains. The Muierii fossils exhibit a suite of derived modern human features, including reduced maxillae with pronounced canine fossae, a narrow nasal aperture, small superciliary arches, an arched parietal curve, zygomatic arch above the auditory porous, laterally bulbous mastoid processes, narrow mandibular corpus, reduced anterior dentition, ventral-to-bisulcate scapular axillary border, and planoconcave tibial and fibular diaphyseal surfaces. However, these traits co-occur with contextually archaic and/or Neandertal features, including a moderately low frontal arc, a large occipital bun, a high coronoid process and asymmetrical mandibular notch, a more medial mandibular notch crest to condylar position, and a narrow scapular glenoid fossa. As with other European early modern humans, the mosaic of modern human and archaic/Neandertal features, relative to their potential Middle Paleolithic ancestral populations, indicates considerable Neandertal/modern human admixture. Moreover, the narrow scapular glenoid fossa suggests habitual movements at variance with the associated projectile technology. The reproductive and scapulohumeral functional inferences emphasize the subtle natures of behavioral contrasts between Neandertals and these early modern Europeans. PMID:17085588

  18. Early human occupation of the Red Sea coast of Eritrea during the last interglacial.

    PubMed

    Walter, R C; Buffler, R T; Bruggemann, J H; Guillaume, M M; Berhe, S M; Negassi, B; Libsekal, Y; Cheng, H; Edwards, R L; von Cosel, R; Néraudeau, D; Gagnon, M

    2000-05-04

    The geographical origin of modern humans is the subject of ongoing scientific debate. The 'multiregional evolution' hypothesis argues that modern humans evolved semi-independently in Europe, Asia and Africa between 100,000 and 40,000 years ago, whereas the 'out of Africa' hypothesis contends that modern humans evolved in Africa between 200 and 100 kyr ago, migrating to Eurasia at some later time. Direct palaeontological, archaeological and biological evidence is necessary to resolve this debate. Here we report the discovery of early Middle Stone Age artefacts in an emerged reef terrace on the Red Sea coast of Eritrea, which we date to the last interglacial (about 125 kyr ago) using U-Th mass spectrometry techniques on fossil corals. The geological setting of these artefacts shows that early humans occupied coastal areas and exploited near-shore marine food resources in East Africa by this time. Together with similar, tentatively dated discoveries from South Africa this is the earliest well-dated evidence for human adaptation to a coastal marine environment, heralding an expansion in the range and complexity of human behaviour from one end of Africa to the other. This new, wide-spread adaptive strategy may, in part, signal the onset of modern human behaviour, which supports an African origin for modern humans by 125 kyr ago.

  19. Early and early disseminated phases of Lyme disease in the rhesus monkey: a model for infection in humans.

    PubMed Central

    Philipp, M T; Aydintug, M K; Bohm, R P; Cogswell, F B; Dennis, V A; Lanners, H N; Lowrie, R C; Roberts, E D; Conway, M D; Karaçorlu, M

    1993-01-01

    We demonstrate that Borrelia burgdorferi infection in the rhesus monkey mimics the early and early disseminated phases of human Lyme disease. Clinical, bacteriological, immunological, and pathological signs of infection were investigated during 13 weeks after inoculation of the spirochete. Three animals were given B. burgdorferi (strain JD1) by needle inoculations, six animals were exposed to the bite of B. burgdorferi-infected Ixodes dammini ticks, and three animals were uninfected controls. B. burgdorferi could be recovered from all animals that were given the spirochete. Bacteria were detectable until week 6 postinoculation (p.i.) in blood, until week 8 p.i. in skin biopsies, and at 10 weeks p.i. in the conjunctiva of one of two animals which developed conjunctivitis. Erythema migrans (EM) appeared in one of the three animals infected by needle inoculation and in five of the six animals infected by ticks. Deep dermal perivascular lymphocytic infiltrations (characteristic of human EM) were observed in all animals showing EM clinically. Both EM and conjunctivitis were documented concomitantly with the presence of the spirochete. Lethargy, splenomegaly, and cerebrospinal fluid pleocytosis were also noted in some animals, but the direct connection of these signs with the infection was not shown. The appearance rate of immunoglobulin M and immunoglobulin G antibodies to B. burgdorferi, as well as the antigen spectra recognized, were remarkably similar to those seen in humans. Serum antibodies from infected animals were able to kill B. burgdorferi in vitro in the presence of rhesus complement. The rhesus monkey model appears to be useful for the investigation of the immunology and pathogenesis of Lyme disease and for the development of immunoprophylactic, diagnostic, and chemotherapeutic protocols. Images PMID:8514412

  20. Tracking the complex flow of chromosome rearrangements from the Hominoidea Ancestor to extant Hylobates and Nomascus Gibbons by high-resolution synteny mapping.

    PubMed

    Misceo, Doriana; Capozzi, Oronzo; Roberto, Roberta; Dell'oglio, Maria P; Rocchi, Mariano; Stanyon, Roscoe; Archidiacono, Nicoletta

    2008-09-01

    In this study we characterized the extension, reciprocal arrangement, and orientation of syntenic chromosomal segments in the lar gibbon (Hylobates lar, HLA) by hybridization of a panel of approximately 1000 human BAC clones. Each lar gibbon rearrangement was defined by a splitting BAC clone or by two overlapping clones flanking the breakpoint. A reconstruction of the synteny arrangement of the last common ancestor of all living lesser apes was made by combining these data with previous results in Nomascus leucogenys, Hoolock hoolock, and Symphalangus syndactylus. The definition of the ancestral synteny organization facilitated tracking the cascade of chromosomal changes from the Hominoidea ancestor to the present day karyotype of Hylobates and Nomascus. Each chromosomal rearrangement could be placed within an approximate phylogenetic and temporal framework. We identified 12 lar-specific rearrangements and five previously undescribed rearrangements that occurred in the Hylobatidae ancestor. The majority of the chromosomal differences between lar gibbons and humans are due to rearrangements that occurred in the Hylobatidae ancestor (38 events), consistent with the hypothesis that the genus Hylobates is the most recently evolved lesser ape genus. The rates of rearrangements in gibbons are 10 to 20 times higher than the mammalian default rate. Segmental duplication may be a driving force in gibbon chromosome evolution, because a consistent number of rearrangements involves pericentromeric regions (10 events) and centromere inactivation (seven events). Both phenomena can be reasonably supposed to have strongly contributed to the euchromatic dispersal of segmental duplications typical of pericentromeric regions. This hypothesis can be more fully tested when the sequence of this gibbon species becomes available. The detailed synteny map provided here will, in turn, substantially facilitate sequence assembly efforts.

  1. Tracking the complex flow of chromosome rearrangements from the Hominoidea Ancestor to extant Hylobates and Nomascus Gibbons by high-resolution synteny mapping

    PubMed Central

    Misceo, Doriana; Capozzi, Oronzo; Roberto, Roberta; Dell’Oglio, Maria P.; Rocchi, Mariano; Stanyon, Roscoe; Archidiacono, Nicoletta

    2008-01-01

    In this study we characterized the extension, reciprocal arrangement, and orientation of syntenic chromosomal segments in the lar gibbon (Hylobates lar, HLA) by hybridization of a panel of ∼1000 human BAC clones. Each lar gibbon rearrangement was defined by a splitting BAC clone or by two overlapping clones flanking the breakpoint. A reconstruction of the synteny arrangement of the last common ancestor of all living lesser apes was made by combining these data with previous results in Nomascus leucogenys, Hoolock hoolock, and Symphalangus syndactylus. The definition of the ancestral synteny organization facilitated tracking the cascade of chromosomal changes from the Hominoidea ancestor to the present day karyotype of Hylobates and Nomascus. Each chromosomal rearrangement could be placed within an approximate phylogenetic and temporal framework. We identified 12 lar-specific rearrangements and five previously undescribed rearrangements that occurred in the Hylobatidae ancestor. The majority of the chromosomal differences between lar gibbons and humans are due to rearrangements that occurred in the Hylobatidae ancestor (38 events), consistent with the hypothesis that the genus Hylobates is the most recently evolved lesser ape genus. The rates of rearrangements in gibbons are 10 to 20 times higher than the mammalian default rate. Segmental duplication may be a driving force in gibbon chromosome evolution, because a consistent number of rearrangements involves pericentromeric regions (10 events) and centromere inactivation (seven events). Both phenomena can be reasonably supposed to have strongly contributed to the euchromatic dispersal of segmental duplications typical of pericentromeric regions. This hypothesis can be more fully tested when the sequence of this gibbon species becomes available. The detailed synteny map provided here will, in turn, substantially facilitate sequence assembly efforts. PMID:18552313

  2. Globin-coupled sensors, protoglobins, and the last universal common ancestor.

    PubMed

    Freitas, Tracey Allen K; Saito, Jennifer A; Hou, Shaobin; Alam, Maqsudul

    2005-01-01

    The strategy for detecting oxygen, carbon monoxide, nitric oxide, and sulfides is predominantly through heme-based sensors utilizing either a globin domain or a PAS domain. Whereas PAS domains bind various cofactors, globins bind only heme. Globin-coupled sensors (GCSs) were first described as regulators of the aerotactic responses in Bacillus subtilis and Halobacterium salinarum. GCSs were also identified in diverse microorganisms that appear to have roles in regulating gene expression. Functional and evolutionary analyses of the GCSs, their protoglobin ancestor, and their relationship to the last universal common ancestor (LUCA) are discussed in the context of globin-based signal transduction.

  3. Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages.

    PubMed

    Cruciani, Fulvio; Trombetta, Beniamino; Sellitto, Daniele; Massaia, Andrea; Destro-Bisol, Giovanni; Watson, Elizabeth; Beraud Colomb, Eliane; Dugoujon, Jean-Michel; Moral, Pedro; Scozzari, Rosaria

    2010-07-01

    Although human Y chromosomes belonging to haplogroup R1b are quite rare in Africa, being found mainly in Asia and Europe, a group of chromosomes within the paragroup R-P25(*) are found concentrated in the central-western part of the African continent, where they can be detected at frequencies as high as 95%. Phylogenetic evidence and coalescence time estimates suggest that R-P25(*) chromosomes (or their phylogenetic ancestor) may have been carried to Africa by an Asia-to-Africa back migration in prehistoric times. Here, we describe six new mutations that define the relationships among the African R-P25(*) Y chromosomes and between these African chromosomes and earlier reported R-P25 Eurasian sub-lineages. The incorporation of these new mutations into a phylogeny of the R1b haplogroup led to the identification of a new clade (R1b1a or R-V88) encompassing all the African R-P25(*) and about half of the few European/west Asian R-P25(*) chromosomes. A worldwide phylogeographic analysis of the R1b haplogroup provided strong support to the Asia-to-Africa back-migration hypothesis. The analysis of the distribution of the R-V88 haplogroup in >1800 males from 69 African populations revealed a striking genetic contiguity between the Chadic-speaking peoples from the central Sahel and several other Afroasiatic-speaking groups from North Africa. The R-V88 coalescence time was estimated at 9.2-5.6 [corrected] kya, in the early mid Holocene. We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view.

  4. Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages

    PubMed Central

    Cruciani, Fulvio; Trombetta, Beniamino; Sellitto, Daniele; Massaia, Andrea; Destro-Bisol, Giovanni; Watson, Elizabeth; Beraud Colomb, Eliane; Dugoujon, Jean-Michel; Moral, Pedro; Scozzari, Rosaria

    2010-01-01

    Although human Y chromosomes belonging to haplogroup R1b are quite rare in Africa, being found mainly in Asia and Europe, a group of chromosomes within the paragroup R-P25* are found concentrated in the central-western part of the African continent, where they can be detected at frequencies as high as 95%. Phylogenetic evidence and coalescence time estimates suggest that R-P25* chromosomes (or their phylogenetic ancestor) may have been carried to Africa by an Asia-to-Africa back migration in prehistoric times. Here, we describe six new mutations that define the relationships among the African R-P25* Y chromosomes and between these African chromosomes and earlier reported R-P25 Eurasian sub-lineages. The incorporation of these new mutations into a phylogeny of the R1b haplogroup led to the identification of a new clade (R1b1a or R-V88) encompassing all the African R-P25* and about half of the few European/west Asian R-P25* chromosomes. A worldwide phylogeographic analysis of the R1b haplogroup provided strong support to the Asia-to-Africa back-migration hypothesis. The analysis of the distribution of the R-V88 haplogroup in >1800 males from 69 African populations revealed a striking genetic contiguity between the Chadic-speaking peoples from the central Sahel and several other Afroasiatic-speaking groups from North Africa. The R-V88 coalescence time was estimated at 9200–5600 kya, in the early mid Holocene. We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin, and geomorphological evidence is consistent with this view. PMID:20051990

  5. NaChBac: The Long Lost Sodium Channel Ancestor

    PubMed Central

    2011-01-01

    In excitable cells, the main mediators of sodium conductance across membranes are voltage-gated sodium channels (NaVs). Eukaryotic NaVs are essential elements in neuronal signaling and muscular contraction and in humans have been causally related to a variety of neurological and cardiovascular channelopathies. They are complex heavily glycosylated intrinsic membrane proteins present in only trace quantities that have proven to be challenging objects of study. However, in recent years, a number of simpler prokaryotic sodium channels have been identified, with NaChBac from Bacillus halodurans being the most well-characterized to date. The availability of a bacterial NaV that is amenable to heterologous expression and functional characterization in both bacterial and mammalian systems has provided new opportunities for structure–function studies. This review describes features of NaChBac as an exemplar of this class of bacterial channels, compares prokaryotic and eukaryotic NaVs with respect to their structural organization, pharmacological profiling, and functional kinetics, and discusses how voltage-gated ion channels may have evolved to deal with the complex functional demands of higher organisms. PMID:21770445

  6. Early Motherhood and Harsh Parenting: The Role of Human, Social, and Cultural Capital

    ERIC Educational Resources Information Center

    Lee, Yookyong

    2009-01-01

    Objective: This study examined the role of maternal human, social, and cultural capital in the relationship between early motherhood and harsh parenting behavior. Methods: This study used data from the Fragile Families and Child Wellbeing (FFCW) Study. Harsh parenting behaviors by mothers who were 19 years or younger at birth of the focal child (n…

  7. Early Pleistocene human occupation at the edge of the boreal zone in northwest Europe.

    PubMed

    Parfitt, Simon A; Ashton, Nick M; Lewis, Simon G; Abel, Richard L; Coope, G Russell; Field, Mike H; Gale, Rowena; Hoare, Peter G; Larkin, Nigel R; Lewis, Mark D; Karloukovski, Vassil; Maher, Barbara A; Peglar, Sylvia M; Preece, Richard C; Whittaker, John E; Stringer, Chris B

    2010-07-08

    The dispersal of early humans from Africa by 1.75 Myr ago led to a marked expansion of their range, from the island of Flores in the east to the Iberian peninsula in the west. This range encompassed tropical forest, savannah and Mediterranean habitats, but has hitherto not been demonstrated beyond 45 degrees N. Until recently, early colonization in Europe was thought to be confined to the area south of the Pyrenees and Alps. However, evidence from Pakefield (Suffolk, UK) at approximately 0.7 Myr indicated that humans occupied northern European latitudes when a Mediterranean-type climate prevailed. This provided the basis for an 'ebb and flow' model, where human populations were thought to survive in southern refugia during cold stages, only expanding northwards during fully temperate climates. Here we present new evidence from Happisburgh (Norfolk, UK) demonstrating that Early Pleistocene hominins were present in northern Europe >0.78 Myr ago when they were able to survive at the southern edge of the boreal zone. This has significant implications for our understanding of early human behaviour, adaptation and survival, as well as the tempo and mode of colonization after their first dispersal out of Africa.

  8. Early Motherhood and Harsh Parenting: The Role of Human, Social, and Cultural Capital

    ERIC Educational Resources Information Center

    Lee, Yookyong

    2009-01-01

    Objective: This study examined the role of maternal human, social, and cultural capital in the relationship between early motherhood and harsh parenting behavior. Methods: This study used data from the Fragile Families and Child Wellbeing (FFCW) Study. Harsh parenting behaviors by mothers who were 19 years or younger at birth of the focal child (n…

  9. Early Identification of Seronegative Human Immunodeficiency Virus Type 1 Infection with Severe Presentation▿

    PubMed Central

    Chin, Bum Sik; Lee, Sun Hee; Kim, Gab Jung; Kee, Mee Kyung; Suh, Soon Deok; Kim, Sung Soon

    2007-01-01

    Specific antibodies against human immunodeficiency virus (HIV), usually used for diagnosis, almost invariably become detectable within 3 months of exposure. We report on a patient whose HIV infection was identified early by a combined antigen/antibody test, but seroconversion did not occur for 7 months, until the implementation of antiretroviral therapy. PMID:17344360

  10. Human Development, Early Childhood Care and Education and Family Welfare. Compendium of Researches, Volume III.

    ERIC Educational Resources Information Center

    Saraswathi, T. S., Ed.; And Others

    This volume encompasses 44 research studies that were conducted mainly by graduate students in the Department of Human Development and Family Studies, M.S. University of Baroda, India. The studies are organized in six broad categories: (1) child care in tribal, rural and urban poor, and institutional settings; (2) early childhood care and…

  11. Biomonitoring of human fetal exposure to environmental chemicals in early pregnancy.

    PubMed

    Cooke, Gerard M

    2014-01-01

    The first trimester of human fetal life, a period of extremely rapid development of physiological systems, represents the most rapid growth phase in human life. Interference in the establishment of organ systems may result in abnormal development that may be manifest immediately or programmed for later abnormal function. Exposure to environmental chemicals may be affecting development at these early stages, and yet there is limited knowledge of the quantities and identities of the chemicals to which the fetus is exposed during early pregnancy. Clearly, opportunities for assessing fetal chemical exposure directly are extremely limited. Hence, this review describes indirect means of assessing fetal exposure in early pregnancy to chemicals that are considered disrupters of development. Consideration is given to such matrices as maternal hair, fingernails, urine, saliva, sweat, breast milk, amniotic fluid and blood, and fetal matrices such as cord blood, cord tissue, meconium, placenta, and fetal liver. More than 150 articles that presented data from chemical analysis of human maternal and fetal tissues and fluids were reviewed. Priority was given to articles where chemical analysis was conducted in more than one matrix. Where correlations between maternal and fetal matrices were determined, these articles were included and are highlighted, as these may provide the basis for future investigations of early fetal exposure. The determination of fetal chemical exposure, at the time of rapid human growth and development, will greatly assist regulatory agencies in risk assessments and establishment of advisories for risk management concerning environmental chemicals.

  12. Primary Cortical Folding in the Human Newborn: An Early Marker of Later Functional Development

    ERIC Educational Resources Information Center

    Dubois, J.; Benders, M.; Borradori-Tolsa, C.; Cachia, A.; Lazeyras, F.; Leuchter, R. Ha-Vinh; Sizonenko, S. V.; Warfield, S. K.; Mangin, J. F.; Huppi, P. S.

    2008-01-01

    In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain developmental and neuropsychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormalities might be…

  13. Primary Cortical Folding in the Human Newborn: An Early Marker of Later Functional Development

    ERIC Educational Resources Information Center

    Dubois, J.; Benders, M.; Borradori-Tolsa, C.; Cachia, A.; Lazeyras, F.; Leuchter, R. Ha-Vinh; Sizonenko, S. V.; Warfield, S. K.; Mangin, J. F.; Huppi, P. S.

    2008-01-01

    In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain developmental and neuropsychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormalities might be…

  14. Early In-Situ Resource Utilization (ISRU) Leading to Robust Sample Return and Human Exploration Missions

    NASA Astrophysics Data System (ADS)

    Sanders, G. B.; Larson, W. E.; Interbartolo, M. A.; Mueller, R. P.; Muscatello, A. C.

    2012-06-01

    ISRU to make propellants from Mars resources should be pursued early due to the benefits to Mars sample return and human exploration and synergism with lunar and Mars science objectives. Existing hardware can be used for a low cost/low risk demo 2018.

  15. The early spread and epidemic ignition of HIV-1 in human populations

    PubMed Central

    Faria, Nuno R.; Rambaut, Andrew; Suchard, Marc A.; Baele, Guy; Bedford, Trevor; Ward, Melissa J.; Tatem, Andrew J.; Sousa, João D.; Arinaminpathy, Nimalan; Pépin, Jacques; Posada, David; Peeters, Martine; Pybus, Oliver G.; Lemey, Philippe

    2014-01-01

    Thirty years after the discovery of HIV-1, the early transmission, dissemination, and establishment of the virus in human populations remain unclear. Using statistical approaches applied to HIV-1 sequence data from central Africa, we show that from the 1920s Kinshasa (in what is now the Democratic Republic of Congo) was the focus of early transmission and the source of pre-1960 pandemic viruses elsewhere. Location and dating estimates were validated using the earliest HIV-1 archival sample, also from Kinshasa. The epidemic histories of HIV-1 group M and nonpandemic group O were similar until ~1960, after which group M underwent an epidemiological transition and outpaced regional population growth. Our results reconstruct the early dynamics of HIV-1 and emphasize the role of social changes and transport networks in the establishment of this virus in human populations. PMID:25278604

  16. Controlled fire use in early humans might have triggered the evolutionary emergence of tuberculosis

    PubMed Central

    Chisholm, Rebecca H.; Trauer, James M.; Curnoe, Darren; Tanaka, Mark M.

    2016-01-01

    Tuberculosis (TB) is caused by the Mycobacterium tuberculosis complex (MTBC), a wildly successful group of organisms and the leading cause of death resulting from a single bacterial pathogen worldwide. It is generally accepted that MTBC established itself in human populations in Africa and that animal-infecting strains diverged from human strains. However, the precise causal factors of TB emergence remain unknown. Here, we propose that the advent of controlled fire use in early humans created the ideal conditions for the emergence of TB as a transmissible disease. This hypothesis is supported by mathematical modeling together with a synthesis of evidence from epidemiology, evolutionary genetics, and paleoanthropology. PMID:27457933

  17. Estimating the Age of the Common Ancestor of a DNA Sample Using the Number of Segregating Sites

    PubMed Central

    Fu, Y. X.

    1996-01-01

    The number of segregating sites in a sample of DNA sequences and the age of the most recent common ancestor (MRCA) of the sequences in the sample are positively correlated. The value of the former can be used to estimate the value of the latter. Using the coalescent approach, we derive in this paper the joint probability distribution of the number of segregating sites and the age of the MRCA of a sample under the neutral Wright-Fisher model. From this distribution, we are able to compute the likelihood function of the number of segregating sites and the posterior probability of the age of the MRCA of a sample. Three point estimators and one interval estimator of the age of the MRCA are developed; their relationships and properties are investigated. The estimation of the age of the MRCA of human Y chromosomes from a sample of no variation is discussed. PMID:8889543

  18. Immediate-early gene region of human cytomegalovirus trans-activates the promoter of human immunodeficiency virus

    SciTech Connect

    Davis, M.G.; Kenney, S.C.; Kamine, J.; Pagano, J.S.; Huang, E.S.

    1987-12-01

    Almost all homosexual patients with acquired immunodeficiency syndrome are also actively infected with human cytomegalovirus (HCMV). The authors have hypothesized that an interaction between HCMV and human immunodeficiency virus (HIV), the agent that causes acquired immunodeficiency syndrome, may exist at a molecular level and contribute to the manifestations of HIV infection. In this report, they demonstrate that the immediate-early gene region of HCMV, in particular immediate-early region 2, trans-activates the expression of the bacterial gene chloramphenicol acetyltransferase that is fused to the HIV long terminal repeat and carried by plasmid pHIV-CAT. The HCMV immediate-early trans-activator increases the level of mRNA from the plamid pHIV-CAT. The sequences of HIV that are responsive to trans-activation by the HDMV immediate-early region are distinct from HIV sequences that are required for response to the HIV tat. The stimulation of HIV gene expression by HDMV gene functions could enhance the consequences of HIV infection in persons with previous or concurrent HCMV infection.

  19. Early Pleistocene third metacarpal from Kenya and the evolution of modern human-like hand morphology.

    PubMed

    Ward, Carol V; Tocheri, Matthew W; Plavcan, J Michael; Brown, Francis H; Manthi, Fredrick Kyalo

    2014-01-07

    Despite discoveries of relatively complete hands from two early hominin species (Ardipithecus ramidus and Australopithecus sediba) and partial hands from another (Australopithecus afarensis), fundamental questions remain about the evolution of human-like hand anatomy and function. These questions are driven by the paucity of hand fossils in the hominin fossil record between 800,000 and 1.8 My old, a time interval well documented for the emergence and subsequent proliferation of Acheulian technology (shaped bifacial stone tools). Modern and Middle to Late Pleistocene humans share a suite of derived features in the thumb, wrist, and radial carpometacarpal joints that is noticeably absent in early hominins. Here we show that one of the most distinctive features of this suite in the Middle Pleistocene to recent human hand, the third metacarpal styloid process, was present ∼1.42 Mya in an East African hominin from Kaitio, West Turkana, Kenya. This fossil thus provides the earliest unambiguous evidence for the evolution of a key shared derived characteristic of modern human and Neandertal hand morphology and suggests that the distinctive complex of radial carpometacarpal joint features in the human hand arose early in the evolution of the genus Homo and probably in Homo erectus sensu lato.

  20. Early Pleistocene third metacarpal from Kenya and the evolution of modern human-like hand morphology

    PubMed Central

    Ward, Carol V.; Tocheri, Matthew W.; Plavcan, J. Michael; Brown, Francis H.; Manthi, Fredrick Kyalo

    2014-01-01

    Despite discoveries of relatively complete hands from two early hominin species (Ardipithecus ramidus and Australopithecus sediba) and partial hands from another (Australopithecus afarensis), fundamental questions remain about the evolution of human-like hand anatomy and function. These questions are driven by the paucity of hand fossils in the hominin fossil record between 800,000 and 1.8 My old, a time interval well documented for the emergence and subsequent proliferation of Acheulian technology (shaped bifacial stone tools). Modern and Middle to Late Pleistocene humans share a suite of derived features in the thumb, wrist, and radial carpometacarpal joints that is noticeably absent in early hominins. Here we show that one of the most distinctive features of this suite in the Middle Pleistocene to recent human hand, the third metacarpal styloid process, was present ∼1.42 Mya in an East African hominin from Kaitio, West Turkana, Kenya. This fossil thus provides the earliest unambiguous evidence for the evolution of a key shared derived characteristic of modern human and Neandertal hand morphology and suggests that the distinctive complex of radial carpometacarpal joint features in the human hand arose early in the evolution of the genus Homo and probably in Homo erectus sensu lato. PMID:24344276

  1. Vertebral numbers and human evolution.

    PubMed

    Williams, Scott A; Middleton, Emily R; Villamil, Catalina I; Shattuck, Milena R

    2016-01-01

    Ever since Tyson (1699), anatomists have noted and compared differences in the regional numbers of vertebrae among humans and other hominoids. Subsequent workers interpreted these differences in phylogenetic, functional, and behavioral frameworks and speculated on the history of vertebral numbers during human evolution. Even in a modern phylogenetic framework and with greatly expanded sample sizes of hominoid species, researchers' conclusions vary drastically, positing that hominins evolved from either a "long-backed" (numerically long lumbar column) or a "short-backed" (numerically short lumbar column) ancestor. We show that these disparate interpretations are due in part to the use of different criteria for what defines a lumbar vertebra, but argue that, regardless of which lumbar definition is used, hominins are similar to their great ape relatives in possessing a short trunk, a rare occurrence in mammals and one that defines the clade Hominoidea. Furthermore, we address the recent claim that the early hominin thoracolumbar configuration is not distinct from that of modern humans and conclude that early hominins show evidence of "cranial shifting," which might explain the anomalous morphology of several early hominin fossils. Finally, we evaluate the competing hypotheses on numbers of vertebrae and argue that the current data support a hominin ancestor with an African ape-like short trunk and lower back. © 2016 Wiley Periodicals, Inc.

  2. 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.

  3. Size and power required for motion with implication for the evolution of early hominids.

    PubMed

    Wang, W J; Crompton, R H

    2003-09-01

    The fossil record of early hominids (early human ancestors) suggests that their stature and weight had a tendency to increase, but their robusticity (the proportion of radius to length) to decrease. Using a simple musculo-skeletal model, this paper explores possible relationships between size, power required for motion (PRM) and cycle-time, deriving relationships which indicate that PRM per unit of mass and velocity is proportional to robusticity, but inversely proportional to stature. The results derived appear to be in general agreement with published data from physiological experiments. If the material properties of early hominids were similar to those of modern humans and the achievement of minimum PRM was the selective criterion, human stature might tend to increase slightly in human evolution (and, if selective pressures are not removed, might do so in the future but at lower rate). If mobility and stability under loading are the selective criteria, however, human size should not substantially increase in the future.

  4. Early childhood development in Rwanda: a policy analysis of the human rights legal framework.

    PubMed

    Binagwaho, Agnes; Scott, Kirstin W; Harward, Sardis H

    2016-01-12

    Early childhood development (ECD) is a critical period that continues to impact human health and productivity throughout the lifetime. Failing to provide policies and programs that support optimal developmental attainment when such services are financially and logistically feasible can result in negative population health, education and economic consequences that might otherwise be avoided. Rwanda, with its commitment to rights-based policy and program planning, serves as a case study for examination of the national, regional, and global human rights legal frameworks that inform ECD service delivery. In this essay, we summarize key causes and consequences of the loss of early developmental potential and how this relates to the human rights legal framework in Rwanda. We contend that sub-optimal early developmental attainment constitutes a violation of individuals' rights to health, education, and economic prosperity. These rights are widely recognized in global, regional and national human rights instruments, and are guaranteed by Rwanda's constitution. Recent policy implementation by several Rwandan ministries has increased access to health and social services that promote achievement of full developmental potential. These ECD-centric activities are characterized by an integrated approach to strengthening the services provided by several public sectors. Combining population level activities with those at the local level, led by local community health workers and women's councils, can bolster community education and ensure uptake of ECD services. Realization of the human rights to health, education, and economic prosperity requires and benefits from attention to the period of ECD, as early childhood has the potential to be an opportunity for expedient intervention or the first case of human rights neglect in a lifetime of rights violations. Efforts to improve ECD services and outcomes at the population level require multisector collaboration at the highest echelons

  5. Digital Literacy Practices and Pedagogical Moments: Human and Non-Human Intertwining in Early Childhood Education

    ERIC Educational Resources Information Center

    Lafton, Tove

    2015-01-01

    Various forms of digital devices have established themselves as resources within constructions of professional practices in early childhood education. This article is centred on the question of how we might rethink an example of digital practice based on a Foucauldian understanding of discourse and a rhizomatic understanding of digital practice…

  6. Digital Literacy Practices and Pedagogical Moments: Human and Non-Human Intertwining in Early Childhood Education

    ERIC Educational Resources Information Center

    Lafton, Tove

    2015-01-01

    Various forms of digital devices have established themselves as resources within constructions of professional practices in early childhood education. This article is centred on the question of how we might rethink an example of digital practice based on a Foucauldian understanding of discourse and a rhizomatic understanding of digital practice…

  7. Early childhood development: impact of national human development, family poverty, parenting practices and access to early childhood education.

    PubMed

    Tran, T D; Luchters, S; Fisher, J

    2017-05-01

    This study was to describe and quantify the relationships among family poverty, parents' caregiving practices, access to education and the development of children living in low- and middle-income countries (LAMIC). We conducted a secondary analysis of data collected in UNICEF's Multiple Indicator Cluster Surveys (MICS). Early childhood development was assessed in four domains: language-cognitive, physical, socio-emotional and approaches to learning. Countries were classified into three groups on the basis of the Human Development Index (HDI). Overall, data from 97 731 children aged 36 to 59 months from 35 LAMIC were included in the after analyses. The mean child development scale score was 4.93 out of a maximum score of 10 (95%CI 4.90 to 4.97) in low-HDI countries and 7.08 (95%CI 7.05 to 7.12) in high-HDI countries. Family poverty was associated with lower child development scores in all countries. The total indirect effect of family poverty on child development score via attending early childhood education, care for the child at home and use of harsh punishments at home was -0.13 SD (77.8% of the total effect) in low-HDI countries, -0.09 SD (23.8% of the total effect) in medium-HDI countries and -0.02 SD (6.9% of the total effect) in high-HDI countries. Children in the most disadvantaged position in their societies and children living in low-HDI countries are at the greatest risk of failing to reach their developmental potential. Optimizing care for child development at home is essential to reduce the adverse effects of poverty on children's early development and subsequent life. © 2016 John Wiley & Sons Ltd.

  8. IL-17A mediates inflammatory and tissue remodelling events in early human tendinopathy

    PubMed Central

    Millar, Neal L.; Akbar, Moeed; Campbell, Abigail L.; Reilly, James H.; Kerr, Shauna C.; McLean, Michael; Frleta-Gilchrist, Marina; Fazzi, Umberto G.; Leach, William J.; Rooney, Brian P.; Crowe, Lindsay A. N.; Murrell, George A. C.; McInnes, Iain B.

    2016-01-01

    Increasingly, inflammatory mediators are considered crucial to the onset and perpetuation of tendinopathy. We sought evidence of interleukin 17A (IL-17A) expression in early human tendinopathy and thereafter, explored mechanisms whereby IL-17A mediated inflammation and tissue remodeling in human tenocytes. Torn supraspinatus tendon (established pathology) and matched intact subscapularis tendon (representing ‘early pathology’) along with control biopsies were collected from patients undergoing shoulder surgery. Markers of inflammation and IL-17A were quantified by RT-PCR and immunohistochemistry. Human tendon cells were derived from hamstring tendon obtained during ACL reconstruction. In vitro effects of IL-17A upon tenocytes were measured using RT-PCR, multiplex cytokine assays, apoptotic proteomic profiling, immunohistochemistry and annexin V FACS staining. Increased expression of IL-17A was detected in ‘early tendinopathy’ compared to both matched samples and non-matched control samples (p < 0.01) by RT-PCR and immunostaining. Double immunofluoresence staining revealed IL-17A expression in leukocyte subsets including mast cells, macrophages and T cells. IL-17A treated tenocytes exhibited increased production of proinflammatory cytokines (p < 0.001), altered matrix regulation (p < 0.01) with increased Collagen type III and increased expression of several apoptosis related factors. We propose IL-17A as an inflammatory mediator within the early tendinopathy processes thus providing novel therapeutic approaches in the management of tendon disorders. PMID:27263531

  9. Therapeutic angiogenesis of human early endothelial progenitor cells is enhanced by thrombomodulin.

    PubMed

    Li, Jiun-Yi; Su, Cheng-Huang; Wu, Yih-Jer; Tien, Ting-Yi; Hsieh, Chin-Ling; Chen, Chih-Hao; Tseng, Ya-Ming; Shi, Guey-Yueh; Wu, Hua-Lin; Tsai, Cheng-Ho; Lin, Fang-Yue; Yeh, Hung-I

    2011-11-01

    We examined the effect of thrombomodulin (TM) domains 2 and 3 (TMD23) on human early endothelial progenitor cells (EPCs). TM was expressed and released by human EPCs cultured from peripheral blood mononuclear cells (PBMCs). Addition of TMD23 (100 ng/mL) to the cultured PBMCs increased the colony-forming units, chemotactic motility, matrix metalloproteinase activity, and interleukin-8 secretion but decreased tumor necrosis factor-α (TNF-α) release. Analysis of the signal pathway showed that TMD23 activated Akt. Inhibition of phosphatidylinositol-3 kinase-Akt blocked the effects of TMD23 on chemotactic motility, matrix metalloproteinase-9, interleukin-8, and TNF-α. In hindlimb ischemia mice, laser Doppler perfusion imaging of the ischemic limb during the 21 days after arterial ligation showed that the perfusion recovered best with intraperitoneal infusion of TMD23 plus local injection of early EPCs, followed by either infusion of TMD23 or injection of the cells. Animals without either treatment had the worst results. Animals treated with TMD23 also had lower circulating and tissue levels of TNF-α. TM is expressed and released by human circulating EPCs. Exogenous TMD23 enhances the angiogenic potential of early EPCs in vitro through activation of phosphatidylinositol-3 kinase-Akt pathway. Coadministration of TMD23 plus early EPCs augments therapeutic angiogenesis of the EPCs in ischemic tissues.

  10. Starch grains on human teeth reveal early broad crop diet in northern Peru

    PubMed Central

    Piperno, Dolores R.; Dillehay, Tom D.

    2008-01-01

    Previous research indicates that the Ñanchoc Valley in northern Peru was an important locus of early and middle Holocene human settlement, and that between 9200 and 5500 14C yr B.P. the valley inhabitants adopted major crop plants such as squash (Cucurbita moschata), peanuts (Arachis sp.), and cotton (Gossypium barbadense). We report here an examination of starch grains preserved in the calculus of human teeth from these sites that provides direct evidence for the early consumption of cultivated squash and peanuts along with two other major food plants not previously detected. Starch from the seeds of Phaseolus and Inga feuillei, the flesh of Cucurbita moschata fruits, and the nuts of Arachis was routinely present on numerous teeth that date to between 8210 and 6970 14C yr B.P. Early plant diets appear to have been diverse and stable through time and were rich in cultivated foods typical of later Andean agriculture. Our data provide early archaeological evidence for Phaseolus beans and I. feuillei, an important tree crop, and indicate that effective food production systems that contributed significant dietary inputs were present in the Ñanchoc region by 8000 14C yr B.P. Starch grain studies of dental remains document plants and edible parts of them not normally preserved in archaeological records and can assume primary roles as direct indicators of ancient human diets and agriculture. PMID:19066222

  11. The genome sequences of Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanut

    USDA-ARS?s Scientific Manuscript database

    Cultivated peanut (Arachis hypogaea) is an allotetraploid with closely related subgenomes of total size ~2.7 Gb. This makes assembly of chromosomal pseudomolecules very challenging. Here we report genome sequences of cultivated peanut’s diploid ancestors (A. duranensis and A. ipaënsis). We show they...

  12. Evolution of the most recent common ancestor of a population with no selection

    NASA Astrophysics Data System (ADS)

    Simon, Damien; Derrida, Bernard

    2006-05-01

    We consider the evolution of a population of fixed size with no selection. The number of generations G to reach the first common ancestor evolves in time. This evolution can be described by a simple Markov process, which allows one to calculate several characteristics of the time dependence of G. We also study how G is correlated to the genetic diversity.

  13. Analyzing the Rate at Which Languages Lose the Influence of a Common Ancestor

    ERIC Educational Resources Information Center

    Rafferty, Anna N.; Griffiths, Thomas L.; Klein, Dan

    2014-01-01

    Analyzing the rate at which languages change can clarify whether similarities across languages are solely the result of cognitive biases or might be partially due to descent from a common ancestor. To demonstrate this approach, we use a simple model of language evolution to mathematically determine how long it should take for the distribution over…

  14. Genome sequence and annotation of Trichoderma parareesei, the ancestor of the cellulase producer Trichoderma reesei

    DOE PAGES

    Yang, Dongqing; Pomraning, Kyle; Kopchinskiy, Alexey; ...

    2015-08-13

    The filamentous fungus Trichoderma parareesei is the asexually reproducing ancestor of Trichoderma reesei, the holomorphic industrial producer of cellulase and hemicellulase. Here, we present the genome sequence of the T. parareesei type strain CBS 125925, which contains genes for 9,318 proteins.

  15. Markov-chain approach to the distribution of ancestors in species of biparental reproduction

    NASA Astrophysics Data System (ADS)

    Caruso, M.; Jarne, C.

    2014-08-01

    We studied how to obtain a distribution for the number of ancestors in species of sexual reproduction. Present models concentrate on the estimation of distributions repetitions of ancestors in genealogical trees. It has been shown that it is not possible to reconstruct the genealogical history of each species along all its generations by means of a geometric progression. This analysis demonstrates that it is possible to rebuild the tree of progenitors by modeling the problem with a Markov chain. For each generation, the maximum number of possible ancestors is different. This presents huge problems for the resolution. We found a solution through a dilation of the sample space, although the distribution defined there takes smaller values with respect to the initial problem. In order to correct the distribution for each generation, we introduced the invariance under a gauge (local) group of dilations. These ideas can be used to study the interaction of several processes and provide a new approach on the problem of the common ancestor. In the same direction, this model also provides some elements that can be used to improve models of animal reproduction.

  16. Analyzing the Rate at Which Languages Lose the Influence of a Common Ancestor

    ERIC Educational Resources Information Center

    Rafferty, Anna N.; Griffiths, Thomas L.; Klein, Dan

    2014-01-01

    Analyzing the rate at which languages change can clarify whether similarities across languages are solely the result of cognitive biases or might be partially due to descent from a common ancestor. To demonstrate this approach, we use a simple model of language evolution to mathematically determine how long it should take for the distribution over…

  17. Combining information from ancestors and personal experiences to predict individual differences in developmental trajectories.

    PubMed

    Stamps, Judy A; Krishnan, V V

    2014-11-01

    A persistent question in biology is how information from ancestors combines with personal experiences over the lifetime to affect the developmental trajectories of phenotypic traits. We address this question by modeling individual differences in behavioral developmental trajectories on the basis of two assumptions: (1) differences among individuals in the behavior expressed at birth or hatching are based on information from their ancestors (via genes, epigenes, and prenatal maternal effects), and (2) information from ancestors is combined with information from personal experiences over ontogeny via Bayesian updating. The model predicts relationships between the means and the variability of the behavior expressed by neonates and the subsequent developmental trajectories of their behavior when every individual is reared under the same environmental conditions. Several predictions of the model are supported by data from previous studies of behavioral development, for example, that the temporal stability of personality will increase with age and that the intercepts and slopes of developmental trajectories for boldness will be negatively correlated across individuals or genotypes when subjects are raised in safe environments. We describe how other specific predictions of the model can be used to test the hypothesis that information from ancestors and information from personal experiences are combined via nonadditive, Bayesian-like processes.

  18. The universal ancestor was a thermophile or a hyperthermophile: tests and further evidence.

    PubMed

    Di Giulio, Massimo

    2003-04-07

    The existence of a correlation between the optimal growth temperature of various organisms and a thermophily index (based on the propensity of amino acids to enter more frequently into the proteins of thermophiles/hyperthermophiles) allows inferences to be made on the mesophilic or thermophilic nature of the last universal common ancestor (LUCA). By reconstructing the ancestral sequences of the various ancestors using methods based on maximum likelihood and maximum parsimony, these sequences can be attributed to the mesophiles or (hyper)thermophiles and the following conclusions can be drawn. (1) There is no evidence that the LUCA might have been a mesophile and observations seem to imply that the LUCA was a thermophile or a hyperthermophile; (2) The ancestors of the Archaea and Bacteria domains seem to be (hyper)thermophiles while that of the Eukarya domain turns out to be a mesophile. These conclusions are independent of both (i) where the root is located on the topology of the universal tree (based on that of the small subunit ribosomal RNA) and (ii) the presence of hyperthermophile bacteria near the node of the Bacteria domain ancestor. These conclusions are easier to interpret in the light of the hypotheses that see the origin of life taking place at a high temperature. Copyright 2003 Elsevier Science Ltd.

  19. Effect of reference population size and available ancestor genotypes on imputation of Mexican Holstein genotypes

    USDA-ARS?s Scientific Manuscript database

    The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNPs) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local popula...

  20. The compact Brachypodium genome conserves centromeric regions of a common ancestor with wheat and rice

    USDA-ARS?s Scientific Manuscript database

    The evolution of five chromosomes of Brachypodium distachyon from a 12-chromosome ancestor of all grasses by dysploidy raises an interesting question about the fate of redundant centromeres. Three independent but complementary approaches were pursued to study centromeric region homologies among the ...

  1. Integration of Morphological Data into Molecular Phylogenetic Analysis: Toward the Identikit of the Stylasterid Ancestor

    PubMed Central

    Puce, Stefania; Pica, Daniela; Schiaparelli, Stefano; Negrisolo, Enrico

    2016-01-01

    Stylasteridae is a hydroid family including 29 worldwide-distributed genera, all provided with a calcareous skeleton. They are abundant in shallow and deep waters and represent an important component of marine communities. In the present paper, we studied the evolution of ten morphological characters, currently used in stylasterid taxonomy, using a phylogenetic approach. Our results indicate that stylasterid morphology is highly plastic and that many events of independent evolution and reversion have occurred. Our analysis also allows sketching a possible identikit of the stylasterid ancestor. It had calcareous skeleton, reticulate-granular coenosteal texture, polyps randomly arranged, gastrostyle, and dactylopore spines, while lacking a gastropore lip and dactylostyles. If the ancestor had single or double/multiple chambered gastropore tube is uncertain. These data suggest that the ancestor was similar to the extant genera Cyclohelia and Stellapora. Our investigation is the first attempt to integrate molecular and morphological information to clarify the stylasterid evolutionary scenario and represents the first step to infer the stylasterid ancestor morphology. PMID:27537333

  2. The Lin28/Let-7 system in early human embryonic tissue and ectopic pregnancy.

    PubMed

    Lozoya, Teresa; Domínguez, Francisco; Romero-Ruiz, Antonio; Steffani, Liliana; Martínez, Sebastián; Monterde, Mercedes; Ferri, Blanca; Núñez, Maria Jose; AinhoaRomero-Espinós; Zamora, Omar; Gurrea, Marta; Sangiao-Alvarellos, Susana; Vega, Olivia; Simón, Carlos; Pellicer, Antonio; Tena-Sempere, Manuel

    2014-01-01

    Our objective was to determine the expression of the elements of the Lin28/Let-7 system, and related microRNAs (miRNAs), in early stages of human placentation and ectopic pregnancy, as a means to assess the potential role of this molecular hub in the pathogenesis of ectopic gestation. Seventeen patients suffering from tubal ectopic pregnancy (cases) and forty-three women with normal on-going gestation that desired voluntary termination of pregnancy (VTOP; controls) were recruited for the study. Embryonic tissues were subjected to RNA extraction and quantitative PCR analyses for LIN28B, Let-7a, miR-132, miR-145 and mir-323-3p were performed. Our results demonstrate that the expression of LIN28B mRNA was barely detectable in embryonic tissue from early stages of gestation and sharply increased thereafter to plateau between gestational weeks 7-9. In contrast, expression levels of Let-7, mir-132 and mir-145 were high in embryonic tissue from early gestations (≤ 6-weeks) and abruptly declined thereafter, especially for Let-7. Opposite trends were detected for mir-323-3p. Embryonic expression of LIN28B mRNA was higher in early stages (≤ 6-weeks) of ectopic pregnancy than in normal gestation. In contrast, Let-7a expression was significantly lower in early ectopic pregnancies, while miR-132 and miR-145 levels were not altered. Expression of mir-323-3p was also suppressed in ectopic embryonic tissue. We are the first to document reciprocal changes in the expression profiles of the gene encoding the RNA-binding protein, LIN28B, and the related miRNAs, Let-7a, mir-132 and mir-145, in early stages of human placentation. This finding suggests the potential involvement of LIN28B/Let-7 (de)regulated pathways in the pathophysiology of ectopic pregnancy in humans.

  3. Early and Late Damages in Chromosome 3 of Human Lymphocytes After Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Sunagawa, Mayumi; Mangala, Lingegowda; Zhang, Ye; Kahdim, Munira; Wilson, Bobby; Cucinotta, Francis A.; Wu, Honglu

    2011-01-01

    Tumor formation in humans or animals is a multi-step process. An early stage of cancer development is believed to be genomic instability (GI) which accelerates the mutation rate in the descendants of the cells surviving radiation exposure. GI is defined as elevated or persistent genetic damages occurring many generations after the cells are exposed. While early studies have demonstrated radiation-induced GI in several cell types as detected in endpoints such as mutation, apoptosis and damages in chromosomes, the dependence of GI on the quality of radiation remains uncertain. To investigate GI in human lymphocytes induced by both low- and high-LET radiation, we initially exposed white blood cells collected from healthy subjects to gamma rays in vitro, and cultured the cells for multiple generations. Chromosome aberrations were analyzed in cells collected at first mitosis post irradiation and at several intervals during the culture period. Among a number of biological endpoints planned for the project, the multi-color banding fluorescent in situ hybridization (mBAND) allows identification of inversions that were expected to be stable. We present here early and late chromosome aberrations detected with mBAND in chromosome 3 after gamma exposure. Comparison of chromosome damages in between human lymphocytes and human epithelial cells is also discussed

  4. A Re-Appraisal of the Early Andean Human Remains from Lauricocha in Peru

    PubMed Central

    Kuzminsky, Susan; Rohland, Nadin; Santos, Fabrício R.; Kaulicke, Peter; Valverde, Guido; Richards, Stephen M.; Nordenfelt, Susanne; Seidenberg, Verena; Mallick, Swapan; Cooper, Alan; Reich, David; Haak, Wolfgang

    2015-01-01

    The discovery of human remains from the Lauricocha cave in the Central Andean highlands in the 1960’s provided the first direct evidence for human presence in the high altitude Andes. The skeletons found at this site were ascribed to the Early to Middle Holocene and represented the oldest known population of Western South America, and thus were used in several studies addressing the early population history of the continent. However, later excavations at Lauricocha led to doubts regarding the antiquity of the site. Here, we provide new dating, craniometric, and genetic evidence for this iconic site. We obtained new radiocarbon dates, generated complete mitochondrial genomes and nuclear SNP data from five individuals, and re-analyzed the human remains of Lauricocha to revise the initial morphological and craniometric analysis conducted in the 1960’s. We show that Lauricocha was indeed occupied in the Early to Middle Holocene but the temporal spread of dates we obtained from the human remains show that they do not qualify as a single contemporaneous population. However, the genetic results from five of the individuals fall within the spectrum of genetic diversity observed in pre-Columbian and modern Native Central American populations. PMID:26061688

  5. Human amniotic fluid contaminants alter thyroid hormone signalling and early brain development in Xenopus embryos

    NASA Astrophysics Data System (ADS)

    Fini, Jean-Baptiste; Mughal, Bilal B.; Le Mével, Sébastien; Leemans, Michelle; Lettmann, Mélodie; Spirhanzlova, Petra; Affaticati, Pierre; Jenett, Arnim; Demeneix, Barbara A.

    2017-03-01

    Thyroid hormones are essential for normal brain development in vertebrates. In humans, abnormal maternal thyroid hormone levels during early pregnancy are associated with decreased offspring IQ and modified brain structure. As numerous environmental chemicals disrupt thyroid hormone signalling, we questioned whether exposure to ubiquitous chemicals affects thyroid hormone responses during early neurogenesis. We established a mixture of 15 common chemicals at concentrations reported in human amniotic fluid. An in vivo larval reporter (GFP) assay served to determine integrated thyroid hormone transcriptional responses. Dose-dependent effects of short-term (72 h) exposure to single chemicals and the mixture were found. qPCR on dissected brains showed significant changes in thyroid hormone-related genes including receptors, deiodinases and neural differentiation markers. Further, exposure to mixture also modified neural proliferation as well as neuron and oligodendrocyte size. Finally, exposed tadpoles showed behavioural responses with dose-dependent reductions in mobility. In conclusion, exposure to a mixture of ubiquitous chemicals at concentrations found in human amniotic fluid affect thyroid hormone-dependent transcription, gene expression, brain development and behaviour in early embryogenesis. As thyroid hormone signalling is strongly conserved across vertebrates the results suggest that ubiquitous chemical mixtures could be exerting adverse effects on foetal human brain development.

  6. Human amniotic fluid contaminants alter thyroid hormone signalling and early brain development in Xenopus embryos.

    PubMed

    Fini, Jean-Baptiste; Mughal, Bilal B; Le Mével, Sébastien; Leemans, Michelle; Lettmann, Mélodie; Spirhanzlova, Petra; Affaticati, Pierre; Jenett, Arnim; Demeneix, Barbara A

    2017-03-07

    Thyroid hormones are essential for normal brain development in vertebrates. In humans, abnormal maternal thyroid hormone levels during early pregnancy are associated with decreased offspring IQ and modified brain structure. As numerous environmental chemicals disrupt thyroid hormone signalling, we questioned whether exposure to ubiquitous chemicals affects thyroid hormone responses during early neurogenesis. We established a mixture of 15 common chemicals at concentrations reported in human amniotic fluid. An in vivo larval reporter (GFP) assay served to determine integrated thyroid hormone transcriptional responses. Dose-dependent effects of short-term (72 h) exposure to single chemicals and the mixture were found. qPCR on dissected brains showed significant changes in thyroid hormone-related genes including receptors, deiodinases and neural differentiation markers. Further, exposure to mixture also modified neural proliferation as well as neuron and oligodendrocyte size. Finally, exposed tadpoles showed behavioural responses with dose-dependent reductions in mobility. In conclusion, exposure to a mixture of ubiquitous chemicals at concentrations found in human amniotic fluid affect thyroid hormone-dependent transcription, gene expression, brain development and behaviour in early embryogenesis. As thyroid hormone signalling is strongly conserved across vertebrates the results suggest that ubiquitous chemical mixtures could be exerting adverse effects on foetal human brain development.

  7. Dynamic changes in gene expression during human early embryo development: from fundamental aspects to clinical applications.

    PubMed

    Assou, Said; Boumela, Imène; Haouzi, Delphine; Anahory, Tal; Dechaud, Hervé; De Vos, John; Hamamah, Samir

    2011-01-01

    The first week of human embryonic development comprises a series of events that change highly specialized germ cells into undifferentiated human embryonic stem cells (hESCs) that display an extraordinarily broad developmental potential. The understanding of these events is crucial to the improvement of the success rate of in vitro fertilization. With the emergence of new technologies such as Omics, the gene expression profiling of human oocytes, embryos and hESCs has been performed and generated a flood of data related to the molecular signature of early embryo development. In order to understand the complex genetic network that controls the first week of embryo development, we performed a systematic review and study of this issue. We performed a literature search using PubMed and EMBASE to identify all relevant studies published as original articles in English up to March 2010 (n = 165). We also analyzed the transcriptome of human oocytes, embryos and hESCs. Distinct sets of genes were revealed by comparing the expression profiles of oocytes, embryos on Day 3 and hESCs, which are associated with totipotency, pluripotency and reprogramming properties, respectively. Known components of two signaling pathways (WNT and transforming growth factor-β) were linked to oocyte maturation and early embryonic development. Omics analysis provides tools for understanding the molecular mechanisms and signaling pathways controlling early embryonic development. Furthermore, we discuss the clinical relevance of using a non-invasive molecular approach to embryo selection for the single-embryo transfer program.

  8. Human amniotic fluid contaminants alter thyroid hormone signalling and early brain development in Xenopus embryos

    PubMed Central

    Fini, Jean-Baptiste; Mughal, Bilal B.; Le Mével, Sébastien; Leemans, Michelle; Lettmann, Mélodie; Spirhanzlova, Petra; Affaticati, Pierre; Jenett, Arnim; Demeneix, Barbara A.

    2017-01-01

    Thyroid hormones are essential for normal brain development in vertebrates. In humans, abnormal maternal thyroid hormone levels during early pregnancy are associated with decreased offspring IQ and modified brain structure. As numerous environmental chemicals disrupt thyroid hormone signalling, we questioned whether exposure to ubiquitous chemicals affects thyroid hormone responses during early neurogenesis. We established a mixture of 15 common chemicals at concentrations reported in human amniotic fluid. An in vivo larval reporter (GFP) assay served to determine integrated thyroid hormone transcriptional responses. Dose-dependent effects of short-term (72 h) exposure to single chemicals and the mixture were found. qPCR on dissected brains showed significant changes in thyroid hormone-related genes including receptors, deiodinases and neural differentiation markers. Further, exposure to mixture also modified neural proliferation as well as neuron and oligodendrocyte size. Finally, exposed tadpoles showed behavioural responses with dose-dependent reductions in mobility. In conclusion, exposure to a mixture of ubiquitous chemicals at concentrations found in human amniotic fluid affect thyroid hormone-dependent transcription, gene expression, brain development and behaviour in early embryogenesis. As thyroid hormone signalling is strongly conserved across vertebrates the results suggest that ubiquitous chemical mixtures could be exerting adverse effects on foetal human brain development. PMID:28266608

  9. Welcome to the Twilight Zone: a forgotten early phase of human evolutionary studies.

    PubMed

    Delisle, Richard G

    2012-06-01

    The field of paleoanthropology arose out of a strange and unacknowledged early phase of development prior to about the 1930s. It is often assumed that a key pillar of the discipline, the unity of humankind--the notion that humans are clearly separated phylogenetically (genealogically) from other non-human primates--was widely accepted from the inception of paleoanthropology around 1860. However, a final consensus on this fundamental question only appeared later on in the 20th century. This paper will focus on two key areas of disagreement, which reveal the unsettled state of this question during this early period: the question of uncertainty with respect to the number, identity and boundary of primate species (including humans) which prevailed in the 18th, 19th and early 20th centuries; and the matter of uncertainty with respect to the nature of the phylogenetic relationships among the various human populations and the other primate species which prevailed between 1864 and 1931. Consideration of these matters reveals that the modern research structure that paleoanthropologists take for granted today is much more recent than believed.

  10. A Re-Appraisal of the Early Andean Human Remains from Lauricocha in Peru.

    PubMed

    Fehren-Schmitz, Lars; Llamas, Bastien; Lindauer, Susanne; Tomasto-Cagigao, Elsa; Kuzminsky, Susan; Rohland, Nadin; Santos, Fabrício R; Kaulicke, Peter; Valverde, Guido; Richards, Stephen M; Nordenfelt, Susanne; Seidenberg, Verena; Mallick, Swapan; Cooper, Alan; Reich, David; Haak, Wolfgang

    2015-01-01

    The discovery of human remains from the Lauricocha cave in the Central Andean highlands in the 1960's provided the first direct evidence for human presence in the high altitude Andes. The skeletons found at this site were ascribed to the Early to Middle Holocene and represented the oldest known population of Western South America, and thus were used in several studies addressing the early population history of the continent. However, later excavations at Lauricocha led to doubts regarding the antiquity of the site. Here, we provide new dating, craniometric, and genetic evidence for this iconic site. We obtained new radiocarbon dates, generated complete mitochondrial genomes and nuclear SNP data from five individuals, and re-analyzed the human remains of Lauricocha to revise the initial morphological and craniometric analysis conducted in the 1960's. We show that Lauricocha was indeed occupied in the Early to Middle Holocene but the temporal spread of dates we obtained from the human remains show that they do not qualify as a single contemporaneous population. However, the genetic results from five of the individuals fall within the spectrum of genetic diversity observed in pre-Columbian and modern Native Central American populations.

  11. Digit ratios predict polygyny in early apes, Ardipithecus, Neanderthals and early modern humans but not in Australopithecus.

    PubMed

    Nelson, Emma; Rolian, Campbell; Cashmore, Lisa; Shultz, Susanne

    2011-05-22

    Social behaviour of fossil hominoid species is notoriously difficult to predict owing to difficulties in estimating body size dimorphism from fragmentary remains and, in hominins, low canine size dimorphism. Recent studies have shown that the second-to-fourth digit ratio (2D : 4D), a putative biomarker for prenatal androgen effects (PAEs), covaries with intra-sexual competition and social systems across haplorrhines; non-pair-bonded polygynous taxa have significantly lower 2D : 4D ratios (high PAE) than pair-bonded monogamous species. Here, we use proximal phalanx ratios of extant and fossil specimens to reconstruct the social systems of extinct hominoids. Pierolapithecus catalaunicus, Hispanopithecus laietanus and Ardipithecus ramidus have ratios consistent with polygynous extant species, whereas the ratio of Australopithecus afarensis is consistent with monogamous extant species. The early anatomically modern human Qafzeh 9 and Neanderthals have lower digit ratios than most contemporary human populations, indicating increased androgenization and possibly higher incidence of polygyny. Although speculative owing to small sample sizes, these results suggest that digit ratios represent a supplementary approach for elucidating the social systems of fossil hominins.

  12. Digit ratios predict polygyny in early apes, Ardipithecus, Neanderthals and early modern humans but not in Australopithecus

    PubMed Central

    Nelson, Emma; Rolian, Campbell; Cashmore, Lisa; Shultz, Susanne

    2011-01-01

    Social behaviour of fossil hominoid species is notoriously difficult to predict owing to difficulties in estimating body size dimorphism from fragmentary remains and, in hominins, low canine size dimorphism. Recent studies have shown that the second-to-fourth digit ratio (2D : 4D), a putative biomarker for prenatal androgen effects (PAEs), covaries with intra-sexual competition and social systems across haplorrhines; non-pair-bonded polygynous taxa have significantly lower 2D : 4D ratios (high PAE) than pair-bonded monogamous species. Here, we use proximal phalanx ratios of extant and fossil specimens to reconstruct the social systems of extinct hominoids. Pierolapithecus catalaunicus, Hispanopithecus laietanus and Ardipithecus ramidus have ratios consistent with polygynous extant species, whereas the ratio of Australopithecus afarensis is consistent with monogamous extant species. The early anatomically modern human Qafzeh 9 and Neanderthals have lower digit ratios than most contemporary human populations, indicating increased androgenization and possibly higher incidence of polygyny. Although speculative owing to small sample sizes, these results suggest that digit ratios represent a supplementary approach for elucidating the social systems of fossil hominins. PMID:21047863

  13. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

    PubMed

    Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P; Rohling, Eelco J; Satow, Chris; Smith, Victoria C; Stringer, Chris B; Tomlinson, Emma L; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Boric, Dusan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C

    2012-08-21

    Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

  14. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards

    PubMed Central

    Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L.; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S.; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P.; Rohling, Eelco J.; Satow, Chris; Smith, Victoria C.; Stringer, Chris B.; Tomlinson, Emma L.; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Borić, Dušan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C.; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C.

    2012-01-01

    Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters. PMID:22826222

  15. Differences in Gene Expression between Mouse and Human for Dynamically Regulated Genes in Early Embryo

    PubMed Central

    Madissoon, Elo; Töhönen, Virpi; Vesterlund, Liselotte; Katayama, Shintaro; Unneberg, Per; Inzunza, Jose; Hovatta, Outi; Kere, Juha

    2014-01-01

    Infertility is a worldwide concern that can be treated with in vitro fertilization (IVF). Improvements in IVF and infertility treatment depend largely on better understanding of the molecular mechanisms for human preimplantation development. Several large-scale studies have been conducted to identify gene expression patterns for the first five days of human development, and many functional studies utilize mouse as a model system. We have identified genes of possible importance for this time period by analyzing human microarray data and available data from online databases. We selected 70 candidate genes for human preimplantation development and investigated their expression in the early mouse development from oocyte to the 8-cell stage. Maternally loaded genes expectedly decreased in expression during development both in human and mouse. We discovered that 25 significantly upregulated genes after fertilization in human included 13 genes whose orthologs in mouse behaved differently and mimicked the expression profile of maternally expressed genes. Our findings highlight many significant differences in gene expression patterns during mouse and human preimplantation development. We also describe four cancer-testis antigen families that are also highly expressed in human embryos: PRAME, SSX, GAGE and MAGEA. PMID:25089626

  16. Differences in gene expression between mouse and human for dynamically regulated genes in early embryo.

    PubMed

    Madissoon, Elo; Töhönen, Virpi; Vesterlund, Liselotte; Katayama, Shintaro; Unneberg, Per; Inzunza, Jose; Hovatta, Outi; Kere, Juha

    2014-01-01

    Infertility is a worldwide concern that can be treated with in vitro fertilization (IVF). Improvements in IVF and infertility treatment depend largely on better understanding of the molecular mechanisms for human preimplantation development. Several large-scale studies have been conducted to identify gene expression patterns for the first five days of human development, and many functional studies utilize mouse as a model system. We have identified genes of possible importance for this time period by analyzing human microarray data and available data from online databases. We selected 70 candidate genes for human preimplantation development and investigated their expression in the early mouse development from oocyte to the 8-cell stage. Maternally loaded genes expectedly decreased in expression during development both in human and mouse. We discovered that 25 significantly upregulated genes after fertilization in human included 13 genes whose orthologs in mouse behaved differently and mimicked the expression profile of maternally expressed genes. Our findings highlight many significant differences in gene expression patterns during mouse and human preimplantation development. We also describe four cancer-testis antigen families that are also highly expressed in human embryos: PRAME, SSX, GAGE and MAGEA.

  17. Evidence for declines in human population densities during the early Upper Paleolithic in western Europe

    PubMed Central

    Morin, Eugène

    2008-01-01

    In western Europe, the Middle to Upper Paleolithic (M/UP) transition, dated between ≈35,000 and ≈40,000 radiocarbon years, corresponded to a period of major human biological and cultural changes. However, information on human population densities is scarce for that period. New faunal data from the high-resolution record of Saint-Césaire, France, indicate an episode of significant climatic deterioration during the early Upper Paleolithic (EUP), which also was associated with a reduction in mammalian species diversity. High correlations between ethnographic data and mammalian species diversity suggest that this shift decreased human population densities. Reliance on reindeer (Rangifer tarandus), a highly fluctuating resource, would also have promoted declines in human population densities. These data suggest that the EUP represented for humans a period of significant niche contraction in western Europe. In this context, the possibility that a modern human expansion occurred in this region seems low. Instead, it is suggested that population bottlenecks, genetic drift, and gene flow prevailed over human population replacement as mechanisms of evolution in humans during the EUP. PMID:18172204

  18. [Early life stressful experiences and neuropsychiatric vulnerability: evidences from human and animal models].

    PubMed

    Rincel, Marion; Lépinay, Amandine; Gabory, Anne; Théodorou, Vassilia; Koehl, Muriel; Daugé, Valérie; Maccari, Stefania; Darnaudéry, Muriel

    2016-01-01

    The human newborn is highly dependent on parental care for its survival but also for the healthy development of its brain. A large body of literature demonstrates the impact of early life adversity, even during the prenatal period, on the adult's health. The susceptibility to neuropsychiatric diseases is often potentiated by early stress. If there is an agreement that a critical developmental period exists, the mechanisms underlying the long term effects of early life adversity are still poorly understood. Recent studies in animals highlight the involvement of epigenetic processes in the transmission of such vulnerabilities, notably via modifications in germ cells, which can be transmitted in the next generations. © 2016 médecine/sciences – Inserm.

  19. Auditory triggered mental imagery of shape involves visual association areas in early blind humans.

    PubMed

    De Volder, A G; Toyama, H; Kimura, Y; Kiyosawa, M; Nakano, H; Vanlierde, A; Wanet-Defalque, M C; Mishina, M; Oda, K; Ishiwata, K; Senda, M

    2001-07-01

    Previous neuroimaging studies identified a large network of cortical areas involved in visual imagery in the human brain, which includes occipitotemporal and visual associative areas. Here we test whether the same processes can be elicited by tactile and auditory experiences in subjects who became blind early in life. Using positron emission tomography, regional cerebral blood flow was assessed in six right-handed early blind and six age-matched control volunteers during three conditions: resting state, passive listening to noise sounds, and mental imagery task (imagery of object shape) triggered by the sound of familiar objects. Activation foci were found in occipitotemporal and visual association areas, particularly in the left fusiform gyrus (Brodmann areas 19-37), during mental imagery of shape by both groups. Since shape imagery by early blind subjects does involve similar visual structures as controls at an adult age, it indicates their developmental crossmodal reorganization to allow perceptual representation in the absence of vision.

  20. [On the road to a new humanity: the reception of psychoanalysis in the early Kinderladen movement].

    PubMed

    Kauders, Anthony D

    2014-01-01

    In the late 1960s a group of students in West Germany founded the so-called Kinderläden (day care centers) in order to experiment with new forms of early childhood education. Members of the early Kinderladen movement in particular pursued a radically utopian approach that, they hoped, would engender new human beings. With the aid of psychoanalytic writings, especially those of Wilhelm Reich, they sought to create subjects that would overcome repressive bourgeois norms and live out their sexuality freely. This reliance on Reich entailed a new interpretation of the "base", as psychoanalytic drive theory supplanted Marxist theory. As such, the early Kinderladen ac- tivists regarded the "basis" of society in biological, psychological, and pedagogic rather than economic terms.

  1. Early humans' egalitarian politics: runaway synergistic competition under an adapted veil of ignorance.

    PubMed

    Harvey, Marc

    2014-09-01

    This paper proposes a model of human uniqueness based on an unusual distinction between two contrasted kinds of political competition and political status: (1) antagonistic competition, in quest of dominance (antagonistic status), a zero-sum, self-limiting game whose stake--who takes what, when, how--summarizes a classical definition of politics (Lasswell 1936), and (2) synergistic competition, in quest of merit (synergistic status), a positive-sum, self-reinforcing game whose stake becomes "who brings what to a team's common good." In this view, Rawls's (1971) famous virtual "veil of ignorance" mainly conceals politics' antagonistic stakes so as to devise the principles of a just, egalitarian society, yet without providing any means to enforce these ideals (Sen 2009). Instead, this paper proposes that human uniqueness flourished under a real "adapted veil of ignorance" concealing the steady inflation of synergistic politics which resulted from early humans' sturdy egalitarianism. This proposition divides into four parts: (1) early humans first stumbled on a purely cultural means to enforce a unique kind of within-team antagonistic equality--dyadic balanced deterrence thanks to handheld weapons (Chapais 2008); (2) this cultural innovation is thus closely tied to humans' darkest side, but it also launched the cumulative evolution of humans' brightest qualities--egalitarian team synergy and solidarity, together with the associated synergistic intelligence, culture, and communications; (3) runaway synergistic competition for differential merit among antagonistically equal obligate teammates is the single politically selective mechanism behind the cumulative evolution of all these brighter qualities, but numerous factors to be clarified here conceal this mighty evolutionary driver; (4) this veil of ignorance persists today, which explains why humans' unique prosocial capacities are still not clearly understood by science. The purpose of this paper is to start lifting

  2. 3D quantitative analysis of early decomposition changes of the human face.

    PubMed

    Caplova, Zuzana; Gibelli, Daniele Maria; Poppa, Pasquale; Cummaudo, Marco; Obertova, Zuzana; Sforza, Chiarella; Cattaneo, Cristina

    2017-07-13

    Decomposition of the human body and human face is influenced, among other things, by environmental conditions. The early decomposition changes that modify the appearance of the face may hamper the recognition and identification of the deceased. Quantitative assessment of those changes may provide important information for forensic identification. This report presents a pilot 3D quantitative approach of tracking early decomposition changes of a single cadaver in controlled environmental conditions by summarizing the change with weekly morphological descriptions. The root mean square (RMS) value was used to evaluate the changes of the face after death. The results showed a high correlation (r = 0.863) between the measured RMS and the time since death. RMS values of each scan are presented, as well as the average weekly RMS values. The quantification of decomposition changes could improve the accuracy of antemortem facial approximation and potentially could allow the direct comparisons of antemortem and postmortem 3D scans.

  3. Modeling Mycobacterium tuberculosis early granuloma formation in experimental human lung tissue.

    PubMed

    Parasa, Venkata Ramanarao; Rahman, Muhammad Jubayer; Ngyuen Hoang, Anh Thu; Svensson, Mattias; Brighenti, Susanna; Lerm, Maria

    2014-02-01

    The widely used animal models for tuberculosis (TB) display fundamental differences from human TB. Therefore, a validated model that recapitulates human lung TB is attractive for TB research. Here, we describe a unique method for establishment of TB infection in an experimental human lung tissue model. The model is based on cell lines derived from human lungs and primary macrophages from peripheral blood, and displays characteristics of human lung tissue, including evenly integrated macrophages throughout the epithelium, production of extracellular matrix, stratified epithelia and mucus secretion. Establishment of experimental infection in the model tissue with Mycobacterium tuberculosis, the bacterium that causes TB, resulted in clustering of macrophages at the site of infection, reminiscent of early TB granuloma formation. We quantitated the extent of granuloma formation induced by different strains of mycobacteria and validated our model against findings in other TB models. We found that early granuloma formation is dependent on ESAT-6, which is secreted via the type VII secretion machinery of virulent mycobacteria. Our model, which can facilitate the discovery of the interactions between mycobacteria and host cells in a physiological environment, is the first lung tissue model described for TB.

  4. Sustained live poultry market surveillance contributes to early warnings for human infection with avian influenza viruses

    PubMed Central

    Fang, Shisong; Bai, Tian; Yang, Lei; Wang, Xin; Peng, Bo; Liu, Hui; Geng, Yijie; Zhang, Renli; Ma, Hanwu; Zhu, Wenfei; Wang, Dayan; Cheng, Jinquan; Shu, Yuelong

    2016-01-01

    Sporadic human infections with the highly pathogenic avian influenza (HPAI) A (H5N6) virus have been reported in different provinces in China since April 2014. From June 2015 to January 2016, routine live poultry market (LPM) surveillance was conducted in Shenzhen, Guangdong Province. H5N6 viruses were not detected until November 2015. The H5N6 virus-positive rate increased markedly beginning in December 2015, and viruses were detected in LPMs in all districts of the city. Coincidently, two human cases with histories of poultry exposure developed symptoms and were diagnosed as H5N6-positive in Shenzhen during late December 2015 and early January 2016. Similar viruses were identified in environmental samples collected in the LPMs and the patients. In contrast to previously reported H5N6 viruses, viruses with six internal genes derived from the H9N2 or H7N9 viruses were detected in the present study. The increased H5N6 virus-positive rate in the LPMs and the subsequent human infections demonstrated that sustained LPM surveillance for avian influenza viruses provides an early warning for human infections. Interventions, such as LPM closures, should be immediately implemented to reduce the risk of human infection with the H5N6 virus when the virus is widely detected during LPM surveillance. PMID:27485495

  5. Isotopic evidence for the diets of European Neanderthals and early modern humans

    PubMed Central

    Richards, Michael P.; Trinkaus, Erik

    2009-01-01

    We report here on the direct isotopic evidence for Neanderthal and early modern human diets in Europe. Isotopic methods indicate the sources of dietary protein over many years of life, and show that Neanderthals had a similar diet through time (≈120,000 to ≈37,000 cal BP) and in different regions of Europe. The isotopic evidence indicates that in all cases Neanderthals were top-level carnivores and obtained all, or most, of their dietary protein from large herbivores. In contrast, early modern humans (≈40,000 to ≈27,000 cal BP) exhibited a wider range of isotopic values, and a number of individuals had evidence for the consumption of aquatic (marine and freshwater) resources. This pattern includes Oase 1, the oldest directly dated modern human in Europe (≈40,000 cal BP) with the highest nitrogen isotope value of all of the humans studied, likely because of freshwater fish consumption. As Oase 1 was close in time to the last Neanderthals, these data may indicate a significant dietary shift associated with the changing population dynamics of modern human emergence in Europe. PMID:19706482

  6. Sustained live poultry market surveillance contributes to early warnings for human infection with avian influenza viruses.

    PubMed

    Fang, Shisong; Bai, Tian; Yang, Lei; Wang, Xin; Peng, Bo; Liu, Hui; Geng, Yijie; Zhang, Renli; Ma, Hanwu; Zhu, Wenfei; Wang, Dayan; Cheng, Jinquan; Shu, Yuelong

    2016-08-03

    Sporadic human infections with the highly pathogenic avian influenza (HPAI) A (H5N6) virus have been reported in different provinces in China since April 2014. From June 2015 to January 2016, routine live poultry market (LPM) surveillance was conducted in Shenzhen, Guangdong Province. H5N6 viruses were not detected until November 2015. The H5N6 virus-positive rate increased markedly beginning in December 2015, and viruses were detected in LPMs in all districts of the city. Coincidently, two human cases with histories of poultry exposure developed symptoms and were diagnosed as H5N6-positive in Shenzhen during late December 2015 and early January 2016. Similar viruses were identified in environmental samples collected in the LPMs and the patients. In contrast to previously reported H5N6 viruses, viruses with six internal genes derived from the H9N2 or H7N9 viruses were detected in the present study. The increased H5N6 virus-positive rate in the LPMs and the subsequent human infections demonstrated that sustained LPM surveillance for avian influenza viruses provides an early warning for human infections. Interventions, such as LPM closures, should be immediately implemented to reduce the risk of human infection with the H5N6 virus when the virus is widely detected during LPM surveillance.

  7. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex

    PubMed Central

    Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C.; Roelfsema, Pieter R.

    2016-01-01

    Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons’ receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex. PMID:27015604

  8. Constitutively Expressed IFITM3 Protein in Human Endothelial Cells Poses an Early Infection Block to Human Influenza Viruses.

    PubMed

    Sun, Xiangjie; Zeng, Hui; Kumar, Amrita; Belser, Jessica A; Maines, Taronna R; Tumpey, Terrence M

    2016-12-15

    A role for pulmonary endothelial cells in the orchestration of cytokine production and leukocyte recruitment during influenza virus infection, leading to severe lung damage, has been recently identified. As the mechanistic pathway for this ability is not fully known, we extended previous studies on influenza virus tropism in cultured human pulmonary endothelial cells. We found that a subset of avian influenza viruses, including potentially pandemic H5N1, H7N9, and H9N2 viruses, could infect human pulmonary endothelial cells (HULEC) with high efficiency compared to human H1N1 or H3N2 viruses. In HULEC, human influenza viruses were capable of binding to host cellular receptors, becoming internalized and initiating hemifusion but failing to uncoat the viral nucleocapsid and to replicate in host nuclei. Unlike numerous cell types, including epithelial cells, we found that pulmonary endothelial cells constitutively express a high level of the restriction protein IFITM3 in endosomal compartments. IFITM3 knockdown by small interfering RNA (siRNA) could partially rescue H1N1 virus infection in HULEC, suggesting IFITM3 proteins were involved in blocking human influenza virus infection in endothelial cells. In contrast, selected avian influenza viruses were able to escape IFITM3 restriction in endothelial cells, possibly by fusing in early endosomes at higher pH or by other, unknown mechanisms. Collectively, our study demonstrates that the human pulmonary endothelium possesses intrinsic immunity to human influenza viruses, in part due to the constitutive expression of IFITM3 proteins. Notably, certain avian influenza viruses have evolved to escape this restriction, possibly contributing to virus-induced pneumonia and severe lung disease in humans.

  9. Early Upper Paleolithic in Eastern Europe and implications for the dispersal of modern humans.

    PubMed

    Anikovich, M V; Sinitsyn, A A; Hoffecker, John F; Holliday, Vance T; Popov, V V; Lisitsyn, S N; Forman, Steven L; Levkovskaya, G M; Pospelova, G A; Kuz'mina, I E; Burova, N D; Goldberg, Paul; Macphail, Richard I; Giaccio, Biagio; Praslov, N D

    2007-01-12

    Radiocarbon and optically stimulated luminescence dating and magnetic stratigraphy indicate Upper Paleolithic occupation-probably representing modern humans-at archaeological sites on the Don River in Russia 45,000 to 42,000 years ago. The oldest levels at Kostenki underlie a volcanic ash horizon identified as the Campanian Ignimbrite Y5 tephra that is dated elsewhere to about 40,000 years ago. The occupation layers contain bone and ivory artifacts, including possible figurative art, and fossil shells imported more than 500 kilometers. Thus, modern humans appeared on the central plain of Eastern Europe as early as anywhere else in northern Eurasia.

  10. Open access publication in the fields of human fertility, infertility and early pregnancy.

    PubMed

    Schust, Danny J; Ginsburg, Elizabeth S

    2015-01-01

    The study of human fertility has expanded dramatically since the birth of IVF and with it, the body of literature. That said, the availability of open access publication in the field remains somewhat limited. Fertility Research and Practice offers a new open access, peer-reviewed venue for quality clinical, basic science and translational studies and scholarly reviews in human fertility, infertility and early pregnancy. The journal specifically encourages works from international contributors and from investigators in less-resourced environments and has gathered an editorial board with a breadth of geographic representation to support this mission.

  11. Feasibility of terahertz reflectometry for discrimination of human early gastric cancers

    PubMed Central

    Ji, Young Bin; Park, Chan Hyuk; Kim, Hyunki; Kim, Sang-Hoon; Lee, Gyu Min; Noh, Sam Kyu; Jeon, Tae-In; Son, Joo-Hiuk; Huh, Yong-Min; Haam, Seungjoo; Oh, Seung Jae; Lee, Sang Kil; Suh, Jin-Suck

    2015-01-01

    We have investigated the feasibility of THz time-domain reflectometry for the discrimination of human early gastric cancer (EGC) from the normal gastric region. Eight fresh EGC tissues, which were resected by endoscopic submucosal dissection, were studied. Of them, six lesions were well discriminated on THz images and the regions well correlated with tumor regions on pathologically mapped images. Four THz parameters could be suggested for quantitative discrimination of EGCs. PMID:25909023

  12. Conserved epigenetic sensitivity to early life experience in the rat and human hippocampus.

    PubMed

    Suderman, Matthew; McGowan, Patrick O; Sasaki, Aya; Huang, Tony C T; Hallett, Michael T; Meaney, Michael J; Turecki, Gustavo; Szyf, Moshe

    2012-10-16

    Early life experience is associated with long-term effects on behavior and epigenetic programming of the NR3C1 (GLUCOCORTICOID RECEPTOR) gene in the hippocampus of both rats and humans. However, it is unlikely that such effects completely capture the evolutionarily conserved epigenetic mechanisms of early adaptation to environment. Here we present DNA methylation profiles spanning 6.5 million base pairs centered at the NR3C1 gene in the hippocampus of humans who experienced abuse as children and nonabused controls. We compare these profiles to corresponding DNA methylation profiles in rats that received differential levels of maternal care. The profiles of both species reveal hundreds of DNA methylation differences associated with early life experience distributed across the entire region in nonrandom patterns. For instance, methylation differences tend to cluster by genomic location, forming clusters covering as many as 1 million bases. Even more surprisingly, these differences seem to specifically target regulatory regions such as gene promoters, particularly those of the protocadherin α, β, and γ gene families. Beyond these high-level similarities, more detailed analyses reveal methylation differences likely stemming from the significant biological and environmental differences between species. These results provide support for an analogous cross-species epigenetic regulatory response at the level of the genomic region to early life experience.

  13. Conserved epigenetic sensitivity to early life experience in the rat and human hippocampus

    PubMed Central

    Suderman, Matthew; McGowan, Patrick O.; Sasaki, Aya; Huang, Tony C. T.; Hallett, Michael T.; Meaney, Michael J.; Turecki, Gustavo; Szyf, Moshe

    2012-01-01

    Early life experience is associated with long-term effects on behavior and epigenetic programming of the NR3C1 (GLUCOCORTICOID RECEPTOR) gene in the hippocampus of both rats and humans. However, it is unlikely that such effects completely capture the evolutionarily conserved epigenetic mechanisms of early adaptation to environment. Here we present DNA methylation profiles spanning 6.5 million base pairs centered at the NR3C1 gene in the hippocampus of humans who experienced abuse as children and nonabused controls. We compare these profiles to corresponding DNA methylation profiles in rats that received differential levels of maternal care. The profiles of both species reveal hundreds of DNA methylation differences associated with early life experience distributed across the entire region in nonrandom patterns. For instance, methylation differences tend to cluster by genomic location, forming clusters covering as many as 1 million bases. Even more surprisingly, these differences seem to specifically target regulatory regions such as gene promoters, particularly those of the protocadherin α, β, and γ gene families. Beyond these high-level similarities, more detailed analyses reveal methylation differences likely stemming from the significant biological and environmental differences between species. These results provide support for an analogous cross-species epigenetic regulatory response at the level of the genomic region to early life experience. PMID:23045659

  14. Age estimation in fossil hominins: comparing dental development in early Homo with modern humans.

    PubMed

    Dean, M Christopher; Liversidge, Helen M

    2015-01-01

    Previous studies have used molar tooth eruption as a comparative marker of maturation in early fossil hominins. However, tooth eruption and tooth formation are independent maturational processes. To determine whether estimates of age for entering a stage of dental development in three early hominin fossils fell within the distribution of a modern human sample. This study used a comparative model of dental development to identify the stages of dental development most likely to provide information about length of the growth period in early fossil hominins. Age estimates for stages of dental development in fossils were superimposed onto a normal distribution of the same radiographically defined stages derived from a sample of 6540 children of diverse geographical origin. Both within the dentition of S7-37, from Sangiran, Java, but also for stages of two other specimens (KNM-WT 15000 from Kenya and StW 151 from South Africa), all age estimates for later stages of tooth formation fell within the modern sample range. A pattern appears to exist in early Homo where, both within and between developing dentitions, age estimates for stages of P4, M2 and M3 tooth formation fell consistently among the more advanced individuals of the modern human sample.

  15. Consequences of early adverse rearing experience (EARE) on development: insights from non-human primate studies

    PubMed Central

    Zhang, Bo

    2017-01-01

    Early rearing experiences are important in one's whole life, whereas early adverse rearing experience (EARE) is usually related to various physical and mental disorders in later life. Although there were many studies on human and animals, regarding the effect of EARE on brain development, neuroendocrine systems, as well as the consequential mental disorders and behavioral abnormalities, the underlying mechanisms remain unclear. Due to the close genetic relationship and similarity in social organizations with humans, non-human primate (NHP) studies were performed for over 60 years. Various EARE models were developed to disrupt the early normal interactions between infants and mothers or peers. Those studies provided important insights of EARE induced effects on the physiological and behavioral systems of NHPs across life span, such as social behaviors (including disturbance behavior, social deficiency, sexual behavior, etc), learning and memory ability, brain structural and functional developments (including influences on neurons and glia cells, neuroendocrine systems, e.g., hypothalamic-pituitary-adrenal (HPA) axis, etc). In this review, the effects of EARE and the underlying epigenetic mechanisms were comprehensively summarized and the possibility of rehabilitation was discussed. PMID:28271667

  16. Visualization of early influenza A virus trafficking in human dendritic cells using STED microscopy

    PubMed Central

    Baharom, Faezzah; Thomas, Oliver S.; Lepzien, Rico; Mellman, Ira; Chalouni, Cécile

    2017-01-01

    Influenza A viruses (IAV) primarily target respiratory epithelial cells, but can also replicate in immune cells, including human dendritic cells (DCs). Super-resolution microscopy provides a novel method of visualizing viral trafficking by overcoming the resolution limit imposed by conventional light microscopy, without the laborious sample preparation of electron microscopy. Using three-color Stimulated Emission Depletion (STED) microscopy, we visualized input IAV nucleoprotein (NP), early and late endosomal compartments (EEA1 and LAMP1 respectively), and HLA-DR (DC membrane/cytosol) by immunofluorescence in human DCs. Surface bound IAV were internalized within 5 min of infection. The association of virus particles with early endosomes peaked at 5 min when 50% of NP+ signals were also EEA1+. Peak association with late endosomes occurred at 15 min when 60% of NP+ signals were LAMP1+. At 30 min of infection, the majority of NP signals were in the nucleus. Our findings illustrate that early IAV trafficking in human DCs proceeds via the classical endocytic pathway. PMID:28591131

  17. Molecular analysis of LEFTY-expressing cells in early human embryoid bodies.

    PubMed

    Dvash, Tamar; Sharon, Nadav; Yanuka, Ofra; Benvenisty, Nissim

    2007-02-01

    Human ESCs (HESCs) are self-renewing pluripotent cell lines that are derived from the inner cell mass of blastocyst-stage embryos. These cells can produce terminally differentiated cells representing the three embryonic germ layers. We thus hypothesized that during the course of in vitro differentiation of HESCs, progenitor-like cells are transiently formed. We demonstrated that LEFTY proteins, which are known to play a major role during mouse gastrulation, are transiently expressed during HESC differentiation. Moreover, LEFTY proteins seemed to be exclusively expressed by a certain population of cells in the early human embryoid bodies that does not overlap with the population expressing the ESC marker OCT4. We also showed that LEFTY expression is regulated at the cellular transcription level by molecular labeling of LEFTY-positive cells. A DNA microarray analysis of LEFTY-overexpressing cells revealed a signature of cell surface markers such as CADHERIN 2 and 11. Expression of LEFTY controlled by NODAL appears to have a substantial role in mesodermal origin cell population establishment, since inhibition of NODAL activity downregulated expression not only of LEFTY A and LEFTY B but also of BRACHYURY, an early mesodermal marker. In addition, other mesodermal lineage-related genes were downregulated, and this was accompanied by an upregulation in ectoderm-related genes. We propose that during the initial step of HESC differentiation, mesoderm progenitor-like cells appear via activation of the NODAL pathway. Our analysis suggests that in vitro differentiation of HESCs can model early events in human development.

  18. Visualization of early influenza A virus trafficking in human dendritic cells using STED microscopy.

    PubMed

    Baharom, Faezzah; Thomas, Oliver S; Lepzien, Rico; Mellman, Ira; Chalouni, Cécile; Smed-Sörensen, Anna

    2017-01-01

    Influenza A viruses (IAV) primarily target respiratory epithelial cells, but can also replicate in immune cells, including human dendritic cells (DCs). Super-resolution microscopy provides a novel method of visualizing viral trafficking by overcoming the resolution limit imposed by conventional light microscopy, without the laborious sample preparation of electron microscopy. Using three-color Stimulated Emission Depletion (STED) microscopy, we visualized input IAV nucleoprotein (NP), early and late endosomal compartments (EEA1 and LAMP1 respectively), and HLA-DR (DC membrane/cytosol) by immunofluorescence in human DCs. Surface bound IAV were internalized within 5 min of infection. The association of virus particles with early endosomes peaked at 5 min when 50% of NP+ signals were also EEA1+. Peak association with late endosomes occurred at 15 min when 60% of NP+ signals were LAMP1+. At 30 min of infection, the majority of NP signals were in the nucleus. Our findings illustrate that early IAV trafficking in human DCs proceeds via the classical endocytic pathway.

  19. The First Modern Human Dispersals across Africa

    PubMed Central

    Rito, Teresa; Richards, Martin B.; Fernandes, Verónica; Alshamali, Farida; Cerny, Viktor

    2013-01-01

    The emergence of more refined chronologies for climate change and archaeology in prehistoric Africa, and for the evolution of human mitochondrial DNA (mtDNA), now make it feasible to test more sophisticated models of early modern human dispersals suggested by mtDNA distributions. Here we have generated 42 novel whole-mtDNA genomes belonging to haplogroup L0, the most divergent clade in the maternal line of descent, and analysed them alongside the growing database of African lineages belonging to L0’s sister clade, L1’6. We propose that the last common ancestor of modern human mtDNAs (carried by “mitochondrial Eve”) possibly arose in central Africa ~180 ka, at a time of low population size. By ~130 ka two distinct groups of anatomically modern humans co-existed in Africa: broadly, the ancestors of many modern-day Khoe and San populations in the south and a second central/eastern African group that includes the ancestors of most extant worldwide populations. Early modern human dispersals correlate with climate changes, particularly the tropical African “megadroughts” of MIS 5 (marine isotope stage 5, 135–75 ka) which paradoxically may have facilitated expansions in central and eastern Africa, ultimately triggering the dispersal out of Africa of people carrying haplogroup L3 ~60 ka. Two south to east migrations are discernible within haplogroup LO. One, between 120 and 75 ka, represents the first unambiguous long-range modern human dispersal detected by mtDNA and might have allowed the dispersal of several markers of modernity. A second one, within the last 20 ka signalled by L0d, may have been responsible for the spread of southern click-consonant languages to eastern Africa, contrary to the view that these eastern examples constitute relicts of an ancient, much wider distribution. PMID:24236171

  20. The first modern human dispersals across Africa.

    PubMed

    Rito, Teresa; Richards, Martin B; Fernandes, Verónica; Alshamali, Farida; Cerny, Viktor; Pereira, Luísa; Soares, Pedro

    2013-01-01

    The emergence of more refined chronologies for climate change and archaeology in prehistoric Africa, and for the evolution of human mitochondrial DNA (mtDNA), now make it feasible to test more sophisticated models of early modern human dispersals suggested by mtDNA distributions. Here we have generated 42 novel whole-mtDNA genomes belonging to haplogroup L0, the most divergent clade in the maternal line of descent, and analysed them alongside the growing database of African lineages belonging to L0's sister clade, L1'6. We propose that the last common ancestor of modern human mtDNAs (carried by "mitochondrial Eve") possibly arose in central Africa ~180 ka, at a time of low population size. By ~130 ka two distinct groups of anatomically modern humans co-existed in Africa: broadly, the ancestors of many modern-day Khoe and San populations in the south and a second central/eastern African group that includes the ancestors of most extant worldwide populations. Early modern human dispersals correlate with climate changes, particularly the tropical African "megadroughts" of MIS 5 (marine isotope stage 5, 135-75 ka) which paradoxically may have facilitated expansions in central and eastern Africa, ultimately triggering the dispersal out of Africa of people carrying haplogroup L3 ~60 ka. Two south to east migrations are discernible within haplogroup LO. One, between 120 and 75 ka, represents the first unambiguous long-range modern human dispersal detected by mtDNA and might have allowed the dispersal of several markers of modernity. A second one, within the last 20 ka signalled by L0d, may have been responsible for the spread of southern click-consonant languages to eastern Africa, contrary to the view that these eastern examples constitute relicts of an ancient, much wider distribution.

  1. Early myeloid cell-specific expression of the human cathepsin G gene in transgenic mice.

    PubMed

    Grisolano, J L; Sclar, G M; Ley, T J

    1994-09-13

    The human cathepsin G (CG) gene is expressed only in promyelocytes and encodes a neutral serine protease that is packaged in the azurophil (primary) granules of myeloid cells. To define the cis-acting DNA elements that are responsible for promyelocyte-specific "targeting," we injected a 6-kb transgene containing the entire human CG gene, including coding sequences contained in a 2.7-kb region, approximately 2.5 kb of 5' flanking sequence, and approximately 0.8 kb of 3' flanking sequence. Seven of seven "transient transgenic" murine embryos revealed human CG expression in the fetal livers at embryonic day 15. Stable transgenic founder lines were created with the same 6-kb fragment; four of five founder lines expressed human CG in the bone marrow. The level of human CG expression was relatively low per gene copy when compared with the endogenous murine CG gene, and expression was integration-site dependent; however, the level of gene expression correlated roughly with gene copy number. The human CG transgene and the endogenous murine CG gene were coordinately expressed in the bone marrow and the spleen. Immunohistochemical analysis of transgenic bone marrow revealed that the human CG protein was expressed exclusively in myeloid cells. Expression of human CG protein was highest in myeloid precursors and declined in mature myeloid cells. These data suggest that the human CG gene was appropriately targeted and developmentally regulated, demonstrating that the cis-acting DNA sequences required for the early myeloid cell-specific expression of human CG are present in this small genomic fragment.

  2. The one ancestor per generation rule and three other rules of mitochondrial inheritance.

    PubMed

    Ohno, S

    1997-07-22

    In mammals, at least, a species-specific mechanism exists that eliminates sperm-derived mitochondrial DNA from a fertilized egg. The result is the "one female ancestor per generation" rule and three other rules of mitochondrial inheritance. The second, third, and fourth rules are as follows. (ii) Sublineages of a given mitochondrial line can be generated only during the parallel descents from ancestral sisters. (iii) In a static population in which the production of one female progeny per mated pair per generation has been a rule, several ancient mitochondrial lineages harking back to the female founders of the speciation may persist side by side. (iv) Two or more individuals not related to each other in the recent past may share the identical or nearly identical mitochondrial genome derived from the common female ancestor or ancestral sisters of many generations ago.

  3. Deciphering voltage-gated Na(+) and Ca(2+) channels by studying prokaryotic ancestors.

    PubMed

    Catterall, William A; Zheng, Ning

    2015-09-01

    Voltage-gated sodium channels (NaVs) and calcium channels (CaVs) are involved in electrical signaling, contraction, secretion, synaptic transmission, and other physiological processes activated in response to depolarization. Despite their physiological importance, the structures of these closely related proteins have remained elusive because of their size and complexity. Bacterial NaVs have structures analogous to a single domain of eukaryotic NaVs and CaVs and are their likely evolutionary ancestor. Here we review recent work that has led to new understanding of NaVs and CaVs through high-resolution structural studies of their prokaryotic ancestors. New insights into their voltage-dependent activation and inactivation, ion conductance, and ion selectivity provide realistic structural models for the function of these complex membrane proteins at the atomic level. Published by Elsevier Ltd.

  4. Evidence for the existence of a common ancestor of scorpion toxins affecting ion channels.

    PubMed

    Zhijian, Cao; Yingliang, Wu; Jiqun, Sheng; Wanhong, Liu; Fan, Xiao; Xin, Mao; Hui, Liu; Dahe, Jiang; Wenxin, Li

    2003-01-01

    All scorpion toxins from different 30 species are simply reviewed. A new classification system of scorpion toxins is first proposed: scorpion toxins are classified into three families (long-chain scorpion toxins with 4 disulfide bridges, short-chain scorpion toxins with 3 disulfide bridges, and intermediate-type scorpion toxins with 3 or 4 disulfide bridges). Intermediate-type scorpion toxins provide a strong proof for the conclusion that channel toxins from scorpion venoms evolve from a common ancestor. Common organization of precursor nucleotides and genomic sequence, similar 3-dimensional structure, and the existence of intermediate type scorpion toxins and functionally intercrossing scorpion toxins show that all scorpion toxins affecting ion channels evolve from the common ancestor, which produce millions of scorpion toxins with function-diversity. Copyright 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:235-238, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10083

  5. Effects of early human handling on the pain sensitivity of young lambs.

    PubMed

    Guesgen, Mirjam J; Beausoleil, Ngaio J; Stewart, Mairi

    2013-01-01

    Pain sensitivity of lambs changes over the first weeks of life. However, the effects of early treatments such as human handling on pain sensitivity are unknown for this species. This study investigated the effects of regular early gentle human handling on the pain sensitivity of lambs, indicated by their behavioural responses to tail docking. Prospective part-blinded experimental study. Twenty-nine singleton Coopworth lambs (females n=14, males n=15). Starting at one day of age, lambs were either handled twice daily for 2 weeks (Handled), were kept in the presence of lambs who were being handled but were not handled themselves (Presence), or were exposed to a human only during routine feeding and care (Control). At 3 weeks of age, all lambs were tail docked using rubber rings. Changes in behaviour due to docking were calculated and change data were analyzed using two-way anova with treatment and test pen as main factors. All lambs showed significant increases in the frequency and duration of behaviours indicative of pain, including 'abnormal' behaviours, and decreases in the frequency and duration of 'normal' behaviours after docking. Handled lambs showed a smaller increase in the time spent lying abnormally after docking than did Control lambs (mean transformed change in proportion of 30 minutes spent±SE: Control 0.55±0.04; Handled 0.38±0.03; Presence 0.48±0.03; C versus H t=3.45, p=0.007). These results provide some evidence that handling early in life may reduce subsequent pain sensitivity in lambs. While the behavioural effects of handling on pain behaviour were subtle, the results suggest, at the very least, that early handling does not increase pain sensitivity in lambs and suggests there is still flexibility postnatally in the pain processing system of a precocial species. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

  6. Monitoring of human populations for early markers of cadmium toxicity: A review

    SciTech Connect

    Fowler, Bruce A.

    2009-08-01

    Exposure of human populations to cadmium (Cd) from air, food and water may produce effects in organs such as the kidneys, liver, lungs, cardiovascular, immune and reproductive systems. Since Cd has been identified as a human carcinogen, biomarkers for early detection of susceptibility to cancer are of an importance to public health. The ability to document Cd exposure and uptake of this element through biological monitoring is a first step towards understanding its health effects. Interpretation and application of biological monitoring data for predicting human health outcomes require correlation with biological measures of organ system responses to the documented exposure. Essential to this understanding is the detection and linkage of early biological responses toxic effects in target cell populations. Fortunately, advances in cell biology have resulted in the development of pre-clinical biological markers (biomarkers) that demonstrate measurable and characteristic molecular changes in organ systems following chemical exposures that occur prior to the onset of overt clinical disease or development of cancer. Technical advances have rendered a number of these biomarkers practical for monitoring Cd-exposed human populations. Biomarkers will be increasingly important in relation to monitoring effects from the exposure to new Cd-based high technology materials. For example, cadmium-selenium (CdSe), nano-materials made from combinations of these elements have greatly altered cellular uptake characteristics due to particle size. These differences may greatly alter effects at the target cell level and hence risks for organ toxicities from such exposures. The value of validated biomarkers for early detection of systemic Cd-induced effects in humans cannot be underestimated due to the rapid expansion of nano-material technologies. This review will attempt to briefly summarize the applications, to date, of biomarker endpoints for assessing target organ system effects in

  7. Tools to Support Human Factors and Systems Engineering Interactions During Early Analysis

    NASA Technical Reports Server (NTRS)

    Thronesbery, Carroll; Malin, Jane T.; Holden, Kritina; Smith, Danielle Paige

    2006-01-01

    We describe an approach and existing software tool support for effective interactions between human factors engineers and systems engineers in early analysis activities during system acquisition. We examine the tasks performed during this stage, emphasizing those tasks where system engineers and human engineers interact. The Concept of Operations (ConOps) document is an important product during this phase, and particular attention is paid to its influences on subsequent acquisition activities. Understanding this influence helps ConOps authors describe a complete system concept that guides subsequent acquisition activities. We identify commonly used system engineering and human engineering tools and examine how they can support the specific tasks associated with system definition. We identify possible gaps in the support of these tasks, the largest of which appears to be creating the ConOps document itself. Finally, we outline the goals of our future empirical investigations of tools to support system concept definition.

  8. Tools to Support Human Factors and Systems Engineering Interactions During Early Analysis

    NASA Technical Reports Server (NTRS)

    Thronesbery, Carroll; Malin, Jane T.; Holden, Kritina; Smith, Danielle Paige

    2005-01-01

    We describe an approach and existing software tool support for effective interactions between human factors engineers and systems engineers in early analysis activities during system acquisition. We examine the tasks performed during this stage, emphasizing those tasks where system engineers and human engineers interact. The Concept of Operations (ConOps) document is an important product during this phase, and particular attention is paid to its influences on subsequent acquisition activities. Understanding this influence helps ConOps authors describe a complete system concept that guides subsequent acquisition activities. We identify commonly used system engineering and human engineering tools and examine how they can support the specific tasks associated with system definition. We identify possible gaps in the support of these tasks, the largest of which appears to be creating the ConOps document itself. Finally, we outline the goals of our future empirical investigations of tools to support system concept definition.

  9. Effect of reference population size and available ancestor genotypes on imputation of Mexican Holstein genotypes.

    PubMed

    García-Ruiz, A; Ruiz-Lopez, F J; Wiggans, G R; Van Tassell, C P; Montaldo, H H

    2015-05-01

    The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNP) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local population of 2,011 genotyped Mexican Holsteins, (2) animals in scenario 1 plus 866 Holsteins in the US genotype database (GDB) with genotyped Mexican daughters, and (3) animals in scenario 1 and all US GDB Holsteins (338,073). Genotypes from 4 chip densities (2 low density, 1 mid density, and 1 high density) were imputed using findhap (version 3) to the 45,195 markers on the mid-density chip. Imputation success was determined by comparing the numbers of SNP with 1 or 2 alleles missing and the numbers of differently predicted SNP (conflicts) among the 3 scenarios. Imputation accuracy improved as chip density and numbers of genotyped ancestors increased, and the percentage of SNP with 1 missing allele was greater than that for 2 missing alleles for all scenarios. The largest numbers of conflicts were found between scenarios 1 and 3. The inclusion of information from direct ancestors (dam or sire) with US GDB genotypes in the imputation of Mexican Holstein genotypes increased imputation accuracy by 1 percentage point for low-density genotypes and by 0.5 percentage points for high-density genotypes, which was about half the gain found with information from all US GDB Holsteins. A larger reference population and the availability of genotyped ancestors improved imputation; animals with genotyped parents in a large reference population had higher imputation accuracy than those with no or few genotyped relatives in a small reference population. For small local populations, including genotypes from other related populations can aid in improving imputation accuracy.

  10. The European Society of Human Genetics: beginnings, early history and development over its first 25 years.

    PubMed

    Harper, Peter S

    2017-05-10

    The European Society of Human Genetics (ESHG) was founded on 15 March 1967, after preliminary discussions at the International Human Genetics Congress in Chicago the previous year and in Copenhagen in early 1967. Its initial meeting was held on 18-19 November 1967, also in Copenhagen, and annual meetings have been held from that time until the present, apart from years in which the International Congress of Human Genetics was also being held. The character of the Society during its early years was strongly influenced by its founding and permanent Secretary, Jan Mohr, head of the Copenhagen Institute of Medical Genetics, whose records are archived in the Tage Kemp/Jan Mohr Archive, now part of the Danish National Archives. These records show Jan Mohr's determination to keep the activities of the Society limited to the holding of an annual meeting to enhance contacts between European human geneticists, and to resist expansion to other activities. Pressures for a wider role of ESHG became irresistible in the late 1980s and a revised constitution, adopted in 1991, reshaped the Society into a more conventional and less restrictive structure. This has allowed it to play a wider and increasingly influential role in the development of human and medical genetics across Europe, with its own Journal, a range of committees covering different aspects of the field and a series of valuable reports on specific important topics, to be described in a forthcoming article on the Society's more recent history.European Journal of Human Genetics advance online publication, 10 May 2017; doi:10.1038/ejhg.2017.34.

  11. Metacarpal torsion in apes, humans, and early Australopithecus: implications for manipulatory abilities.

    PubMed

    Drapeau, Michelle S M

    2015-01-01

    Human hands, when compared to that of apes, have a series of adaptations to facilitate manipulation. Numerous studies have shown that Australopithecus afarensis and Au. africanus display some of these adaptations, such as a longer thumb relative to the other fingers, asymmetric heads on the second and fifth metacarpals, and orientation of the second metacarpal joints with the trapezium and capitate away from the sagittal plane, while lacking others such as a very mobile fifth metacarpal, a styloid process on the third, and a flatter metacarpo-trapezium articulation, suggesting some adaptation to manipulation but more limited than in humans. This paper explores variation in metacarpal torsion, a trait said to enhance manipulation, in humans, apes, early australopithecines and specimens from Swartkrans. This study shows that humans are different from large apes in torsion of the third and fourth metacarpals. Humans are also characterized by wedge-shaped bases of the third and fourth metacarpals, making the metacarpal-base row very arched mediolaterally and placing the ulnar-most metacarpals in a position that facilitate opposition to the thumb in power or cradle grips. The third and fourth metacarpals of Au. afarensis are very human-like, suggesting that the medial palm was already well adapted for these kinds of grips in that taxon. Au. africanus present a less clear human-like morphology, suggesting, perhaps, that the medial palm was less suited to human-like manipulation in that taxa than in Au. afarensis. Overall, this study supports previous studies on Au. afarensis and Au. africanus that these taxa had derived hand morphology with some adaptation to human-like power and precision grips and support the hypothesis that dexterous hands largely predated Homo.

  12. Immune thrombocytopenic purpura might be an early hematologic manifestation of undiagnosed human immunodeficiency virus infection.

    PubMed

    Lai, Shih-Wei; Lin, Hsien-Feng; Lin, Cheng-Li; Liao, Kuan-Fu

    2017-03-01

    Little research focuses on the association between immune thrombocytopenic purpura and human immunodeficiency virus infection in Taiwan. This study investigated whether immune thrombocytopenic purpura might be an early hematologic manifestation of undiagnosed human immunodeficiency virus infection in Taiwan. We conducted a retrospective population-based cohort study using data of individuals enrolled in Taiwan National Health Insurance Program. There were 5472 subjects aged 1-84 years with a new diagnosis of immune thrombocytopenic purpura as the purpura group since 1998-2010 and 21,887 sex-matched and age-matched, randomly selected subjects without immune thrombocytopenic purpura as the non-purpura group. The incidence of human immunodeficiency virus infection at the end of 2011 was measured in both groups. We used the multivariable Cox proportional hazards regression model to measure the hazard ratio and 95 % confidence interval (CI) for the association between immune thrombocytopenic purpura and human immunodeficiency virus infection. The overall incidence of human immunodeficiency virus infection was 6.47-fold higher in the purpura group than that in the non-purpura group (3.78 vs. 0.58 per 10,000 person-years, 95 % CI 5.83-7.18). After controlling for potential confounding factors, the adjusted HR of human immunodeficiency virus infection was 6.3 (95 % CI 2.58-15.4) for the purpura group, as compared with the non-purpura group. We conclude that individuals with immune thrombocytopenic purpura are 6.47-fold more likely to have human immunodeficiency virus infection than those without immune thrombocytopenic purpura. We suggest not all patients, but only those who have risk factors for human immunodeficiency virus infection should receive testing for undiagnosed human immunodeficiency virus infection when they develop immune thrombocytopenic purpura.

  13. Metacarpal torsion in apes, humans, and early Australopithecus: implications for manipulatory abilities

    PubMed Central

    2015-01-01

    Human hands, when compared to that of apes, have a series of adaptations to facilitate manipulation. Numerous studies have shown that Australopithecus afarensis and Au. africanus display some of these adaptations, such as a longer thumb relative to the other fingers, asymmetric heads on the second and fifth metacarpals, and orientation of the second metacarpal joints with the trapezium and capitate away from the sagittal plane, while lacking others such as a very mobile fifth metacarpal, a styloid process on the third, and a flatter metacarpo-trapezium articulation, suggesting some adaptation to manipulation but more limited than in humans. This paper explores variation in metacarpal torsion, a trait said to enhance manipulation, in humans, apes, early australopithecines and specimens from Swartkrans. This study shows that humans are different from large apes in torsion of the third and fourth metacarpals. Humans are also characterized by wedge-shaped bases of the third and fourth metacarpals, making the metacarpal-base row very arched mediolaterally and placing the ulnar-most metacarpals in a position that facilitate opposition to the thumb in power or cradle grips. The third and fourth metacarpals of Au. afarensis are very human-like, suggesting that the medial palm was already well adapted for these kinds of grips in that taxon. Au. africanus present a less clear human-like morphology, suggesting, perhaps, that the medial palm was less suited to human-like manipulation in that taxa than in Au. afarensis. Overall, this study supports previous studies on Au. afarensis and Au. africanus that these taxa had derived hand morphology with some adaptation to human-like power and precision grips and support the hypothesis that dexterous hands largely predated Homo. PMID:26500820

  14. Application of Carnegie stages of development to unify human and baboon ultrasound findings early in pregnancy.

    PubMed

    Santolaya-Forgas, Joaquin; De Leon-Luis, Juan; Friel, Lara A; Wolf, Roman

    2007-09-01

    The objective of this study was to determine if very early ultrasonographic measurements obtained from human and baboon are comparable. For this purpose, the gestational, amniotic and yolk sacs, embryonic crown rump length (CRL) and heart rate were measured ultrasonographically between 35 and 47 days from the mean day of a three-day mating period in baboons (n=18) and between 42 to 58 days from fertilization as calculated from the CRL measurements in human pregnancies (n=82). Ultrasonographic measurements from both species were then plotted in the same graph using Carnegie stages of embryonic development as the independent variable to allow for visual comparisons. Mean gestational age at ultrasonographic studies was significantly different for humans and baboons (50.4 vs. 41 days, respectively; p>0.01). Significant correlations (p>0.01) were noted between ultrasonographic measurements and Carnegie stages of development in both humans and baboons. Only the gestational and the yolk sacs were significantly smaller in baboons than in humans (p>0.05). The findings that embryonic CRL, extra-embryonic space and heart rate are very similar between the 17th and 23rd Carnegie developmental stages make the baboon a promising surrogate of human pregnancy for investigations using celocentesis.

  15. Electrical Excitability of Early Neurons in the Human Cerebral Cortex during the Second Trimester of Gestation

    PubMed Central

    Moore, Anna R.; Filipovic, Radmila; Mo, Zhicheng; Rasband, Matthew N.; Zecevic, Nada

    2009-01-01

    Information about development of the human cerebral cortex (proliferation, migration, and differentiation of neurons) is largely based on postmortem histology. Physiological properties of developing human cortical neurons are difficult to access experimentally and therefore remain largely unexplored. Animal studies have shown that information about the arousal of electrical activity in individual cells within fundamental cortical zones (subventricular zone [SVZ], intermediate zone, subplate [SP], and cortical plate [CP]) is necessary for understanding normal brain development. Here we ask where, in what cortical zone, and when, in what gestational week (gw), human neurons acquire the ability to generate nerve impulses (action potentials [APs]). We performed electrical recordings from individual cells in acute brain slices harvested postmortem from the human fetal cerebral cortex (16–22 gw). Tetrodotoxin-sensitive Na+ current occurs more frequently among CP cells and with significantly greater peak amplitudes than in SVZ. As early as 16 gw, a relatively small population of CP neurons (27%) was able to generate sodium APs upon direct current injection. Neurons located in the SP exhibited the highest level of cellular differentiation, as judged by their ability to fire repetitive APs. At 19 gw, a fraction of human CP and SP neurons possess βIV spectrin–positive axon initial segments populated with voltage-gated sodium channels (PanNav). These results yield the first physiological characterization of developing human fetal cortical neurons with preserved morphologies in intact surrounding brain tissue. PMID:19015375

  16. The common ancestor of archaea and eukarya was not an archaeon.

    PubMed

    Forterre, Patrick

    2013-01-01

    It is often assumed that eukarya originated from archaea. This view has been recently supported by phylogenetic analyses in which eukarya are nested within archaea. Here, I argue that these analyses are not reliable, and I critically discuss archaeal ancestor scenarios, as well as fusion scenarios for the origin of eukaryotes. Based on recognized evolutionary trends toward reduction in archaea and toward complexity in eukarya, I suggest that their last common ancestor was more complex than modern archaea but simpler than modern eukaryotes (the bug in-between scenario). I propose that the ancestors of archaea (and bacteria) escaped protoeukaryotic predators by invading high temperature biotopes, triggering their reductive evolution toward the "prokaryotic" phenotype (the thermoreduction hypothesis). Intriguingly, whereas archaea and eukarya share many basic features at the molecular level, the archaeal mobilome resembles more the bacterial than the eukaryotic one. I suggest that selection of different parts of the ancestral virosphere at the onset of the three domains played a critical role in shaping their respective biology. Eukarya probably evolved toward complexity with the help of retroviruses and large DNA viruses, whereas similar selection pressure (thermoreduction) could explain why the archaeal and bacterial mobilomes somehow resemble each other.

  17. The Common Ancestor of Archaea and Eukarya Was Not an Archaeon

    PubMed Central

    Forterre, Patrick

    2013-01-01

    It is often assumed that eukarya originated from archaea. This view has been recently supported by phylogenetic analyses in which eukarya are nested within archaea. Here, I argue that these analyses are not reliable, and I critically discuss archaeal ancestor scenarios, as well as fusion scenarios for the origin of eukaryotes. Based on recognized evolutionary trends toward reduction in archaea and toward complexity in eukarya, I suggest that their last common ancestor was more complex than modern archaea but simpler than modern eukaryotes (the bug in-between scenario). I propose that the ancestors of archaea (and bacteria) escaped protoeukaryotic predators by invading high temperature biotopes, triggering their reductive evolution toward the “prokaryotic” phenotype (the thermoreduction hypothesis). Intriguingly, whereas archaea and eukarya share many basic features at the molecular level, the archaeal mobilome resembles more the bacterial than the eukaryotic one. I suggest that selection of different parts of the ancestral virosphere at the onset of the three domains played a critical role in shaping their respective biology. Eukarya probably evolved toward complexity with the help of retroviruses and large DNA viruses, whereas similar selection pressure (thermoreduction) could explain why the archaeal and bacterial mobilomes somehow resemble each other. PMID:24348094

  18. Heterokont Predator Develorapax marinus gen. et sp. nov. – A Model of the Ochrophyte Ancestor

    PubMed Central

    Aleoshin, Vladimir V.; Mylnikov, Alexander P.; Mirzaeva, Gulnara S.; Mikhailov, Kirill V.; Karpov, Sergey A.

    2016-01-01

    Heterotrophic lineages of Heterokonta (or stramenopiles), in contrast to a single monophyletic group of autotrophs, Ochrophyta, form several clades that independently branch off the heterokont stem lineage. The nearest neighbors of Ochrophyta in the phylogenetic tree appear to be almost exclusively bacterivorous, whereas the hypothesis of plastid acquisition by the ancestors of the ochrophyte lineage suggests an ability to engulf eukaryotic alga. In line with this hypothesis, the heterotrophic predator at the base of the ochrophyte lineage may be regarded as a model for the ochrophyte ancestor. Here, we present a new genus and species of marine free-living heterotrophic heterokont Develorapax marinus, which falls into an isolated heterokont cluster, along with the marine flagellate Developayella elegans, and is able to engulf eukaryotic cells. Together with environmental sequences D. marinus and D. elegans form a class-level clade Developea nom. nov. represented by species adapted to different environmental conditions and with a wide geographical distribution. The position of Developea among Heterokonta in large-scale phylogenetic tree is discussed. We propose that members of the Developea clade represent a model for transition from bacterivory to a predatory feeding mode by selection for larger prey. Presumably, such transition in the grazing strategy is possible in the presence of bacterial biofilms or aggregates expected in eutrophic environment, and has likely occurred in the ochrophyte ancestor. PMID:27536283

  19. Evidence for the presence of a cellulase gene in the last common ancestor of bilaterian animals.

    PubMed Central

    Lo, Nathan; Watanabe, Hirofumi; Sugimura, Masahiro

    2003-01-01

    Until recently, the textbook view of cellulose hydrolysis in animals was that gut-resident symbiotic organisms such as bacteria or unicellular eukaryotes are responsible for the cellulases produced. This view has been challenged by the characterization and sequencing of endogenous cellulase genes from some invertebrate animals, including plant-parasitic nematodes, arthropods and a mollusc. Most of these genes are completely unrelated in terms of sequence, and their evolutionary origins remain unclear. In the case of plant-parasitic nematodes, it has been suggested that their ancestor obtained a cellulase gene via horizontal gene transfer from a prokaryote, and similar suggestions have been made about a cellulase gene recently discovered in a sea squirt. To improve understanding about the evolution of animal cellulases, we searched for all known types of these enzymes in GenBank, and performed phylogenetic comparisons. Low phylogenetic resolution was found among most of the sequences examined, however, positional identity in the introns of cellulase genes from a termite, a sea squirt and an abalone provided compelling evidence that a similar gene was present in the last common ancestor of protostomes and deuterostomes. In a different enzyme family, cellulases from beetles and plant-parasitic nematodes were found to cluster together. This result questions the idea of lateral gene transfer into the ancestors of the latter, although statistical tests did not allow this possibility to be ruled out. Overall, our results suggest that at least one family of endogenous cellulases may be more widespread in animals than previously thought. PMID:12952640

  20. Dynamic changes in gene expression during human early embryo development: from fundamental aspects to clinical applications

    PubMed Central

    Assou, Said; Boumela, Imène; Haouzi, Delphine; Anahory, Tal; Dechaud, Hervé; De Vos, John; Hamamah, Samir

    2010-01-01

    BACKGROUND The first week of human embryonic development comprises a series of events that change highly specialized germ cells into undifferentiated human embryonic stem cells (hESCs) that display an extraordinarily broad developmental potential. The understanding of these events is crucial to the improvement of the success rate of in vitro fertilization (IVF). With the emergence of new technologies such as Omics, the gene expression profiling of human oocytes, embryos, and hESCs has been performed and generated a flood of data related to the molecular signature of early embryo development. METHODS In order to understand the complex genetic network that controls the first week of embryo development, we performed a systematic review and study of this issue. We performed a literature search using PubMed and EMBASE to identify all relevant studies published as original articles in English up to March 2010 (n=165). We also analyzed the transcriptome of human oocytes, embryos and hESCs. RESULTS Distinct sets of genes were revealed by comparing the expression profiles of oocytes, embryos on day-3 and hESCs, that are associated with totipotency, pluripotency and reprogramming properties, respectively. Known components of two signalling pathways (WNT and transforming growth factor-beta) were linked to oocyte maturation and early embryonic development. CONCLUSION Omics analysis provides tools for understanding the molecular mechanisms and signalling pathways controlling early embryonic development. Furthermore, we discuss the clinical relevance of using a non-invasive molecular approach to embryo selection for the single embryo transfer (SET) program. PMID:20716614

  1. The Human Early-Life Exposome (HELIX): Project Rationale and Design

    PubMed Central

    Slama, Rémy; Robinson, Oliver; Chatzi, Leda; Coen, Muireann; van den Hazel, Peter; Thomsen, Cathrine; Wright, John; Athersuch, Toby J.; Avellana, Narcis; Basagaña, Xavier; Brochot, Celine; Bucchini, Luca; Bustamante, Mariona; Carracedo, Angel; Casas, Maribel; Estivill, Xavier; Fairley, Lesley; van Gent, Diana; Gonzalez, Juan R.; Granum, Berit; Gražulevicˇiene˙, Regina; Gutzkow, Kristine B.; Julvez, Jordi; Keun, Hector C.; Kogevinas, Manolis; McEachan, Rosemary R.C.; Meltzer, Helle Margrete; Sabidó, Eduard; Schwarze, Per E.; Siroux, Valérie; Sunyer, Jordi; Want, Elizabeth J.; Zeman, Florence; Nieuwenhuijsen, Mark J.

    2014-01-01

    Background: Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure–health effect relationships. The “exposome” concept encompasses the totality of exposures from conception onward, complementing the genome. Objectives: The Human Early-Life Exposome (HELIX) project is a new collaborative research project that aims to implement novel exposure assessment and biomarker methods to characterize early-life exposure to multiple environmental factors and associate these with omics biomarkers and child health outcomes, thus characterizing the “early-life exposome.” Here we describe the general design of the project. Methods: In six existing birth cohort studies in Europe, HELIX will estimate prenatal and postnatal exposure to a broad range of chemical and physical exposures. Exposure models will be developed for the full cohorts totaling 32,000 mother–child pairs, and biomarkers will be measured in a subset of 1,200 mother–child pairs. Nested repeat-sampling panel studies (n = 150) will collect data on biomarker variability, use smartphones to assess mobility and physical activity, and perform personal exposure monitoring. Omics techniques will determine molecular profiles (metabolome, proteome, transcriptome, epigenome) associated with exposures. Statistical methods for multiple exposures will provide exposure–response estimates for fetal and child growth, obesity, neurodevelopment, and respiratory outcomes. A health impact assessment exercise will evaluate risks and benefits of combined exposures. Conclusions: HELIX is one of the first attempts to describe the early-life exposome of European populations and unravel its relation to omics markers and health in childhood. As proof of concept, it will form an important first step toward the life-course exposome. Citation: Vrijheid M, Slama R, Robinson O, Chatzi L, Coen M, van den Hazel P

  2. Early influences on human energy regulation: thrifty genotypes and thrifty phenotypes.

    PubMed

    Prentice, Andrew M

    2005-12-15

    Early influences on human ingestive behavior and other aspects of energy homeostasis can be defined according to two very different time scales: the evolutionary time frame responsible for selection of behavioral and metabolic traits embedded within the genome; and the life-course time frame responsible for setting the phenotype. Evolutionary influences: Famine has been a constant threat to human survival leading to the selection of thrifty genes. Thriftiness can take many forms: metabolic (an 'energy-sparing' super-efficient metabolism); adipogenic (a propensity to rapid fat gain); physiologic (an ability to switch off non-essential processes); gluttony (a tendency to gorge when food is available); sloth (a tendency to conserve energy through inactivity); or behavioral (hoarding, meanness, theft, etc). Life-course influences: The nutritional environment of the early embryo can have a major impact on its survival, and its immediate and later physiology. Subsequently, the fetus is sensitive to its nutrient supply that in turn is affected by maternal fuel supply and by the constraints of the utero-placental unit. Adaptive plasticity also continues through infancy. Ingestive behavior in terms of appetite and satiety could theoretically be affected by some of these metabolic adaptations. This paper will describe the key elements of the thrifty genotype and phenotype and review the evidence base relating these early effects to differences in ingestive behavior.

  3. Basic fibroblast growth factor promotes the development of human ovarian early follicles during growth in vitro.

    PubMed

    Wang, Tian-ren; Yan, Li-ying; Yan, Jie; Lu, Cui-ling; Xia, Xi; Yin, Tai-lang; Zhu, Xiao-hui; Gao, Jiang-man; Ding, Ting; Hu, Wei-hong; Guo, Hong-yan; Li, Rong; Qiao, Jie

    2014-03-01

    What is the effect of basic fibroblast growth factor (bFGF) on the growth of individual early human follicles in a three-dimensional (3D) culture system in vitro? The addition of 200 ng bFGF/ml improves human early follicle growth, survival and viability during growth in vitro. It has been demonstrated that bFGF enhances primordial follicle development in human ovarian tissue culture. However, the growth and survival of individual early follicles in encapsulated 3D culture have not been reported. The maturation in vitro of human ovarian follicles was investigated. Ovarian tissue (n= 11) was obtained from 11 women during laparoscopic surgery for gynecological disease, after obtaining written informed consent. One hundred and fifty-four early follicles were isolated by enzymic digestion and mechanical disruption. They were individually encapsulated into alginate (1% w/v) and randomly assigned to be cultured with 0, 100, 200 or 300 ng bFGF/ml for 8 days. Individual follicles were cultured in minimum essential medium α (αMEM) supplemented with bFGF. Follicle survival and growth were assessed by microscopy. Follicle viability was evaluated under confocal laser scanning microscope following Calcein-AM and Ethidium homodimer-I (Ca-AM/EthD-I) staining. After 8 days in culture, all 154 follicles had increased in size. The diameter and survival rate of the follicles and the percentage with good viability were significantly higher in the group cultured with 200 ng bFGF/ml than in the group without bFGF (P < 0.05). The percentage of follicles in the pre-antral stage was significantly higher in the 200 ng bFGF/ml group than in the group without bFGF (P < 0.05), while the percentages of primordial and primary follicles were significantly lower (P < 0.05). The study focuses on the effect of bFGF on the development of individual human early follicles in 3D culture in vitro and has limited ability to reveal the specific effect of bFGF at each different stage. The findings

  4. Differences and similarities between culture-confirmed human granulocytic anaplasmosis and early lyme disease.

    PubMed

    Wormser, Gary P; Aguero-Rosenfeld, Maria E; Cox, Mary E; Nowakowski, John; Nadelman, Robert B; Holmgren, Diane; McKenna, Donna; Bittker, Susan; Zentmaier, Lois; Cooper, Denise; Liveris, Dionysios; Schwartz, Ira; Horowitz, Harold W

    2013-03-01

    Lyme disease is transmitted by the bite of certain Ixodes ticks, which can also transmit Anaplasma phagocytophilum, the cause of human granulocytic anaplasmosis (HGA). Although culture can be used to identify patients infected with A. phagocytophilum and is the microbiologic gold standard, few studies have evaluated culture-confirmed patients with HGA. We conducted a prospective study in which blood culture was used to detect HGA infection in patients with a compatible clinical illness. Early Lyme disease was defined by the presence of erythema migrans. The epidemiologic, clinical, and laboratory features of 44 patients with culture-confirmed HGA were compared with those of a convenience sample of 62 patients with early Lyme disease. Coinfected patients were excluded. Patients with HGA had more symptoms (P = 0.003) and had a higher body temperature on presentation (P < 0.001) than patients with early Lyme disease. HGA patients were also more likely to have a headache, dizziness, myalgias, abdominal pain, anorexia, leukopenia, lymphopenia, thrombocytopenia, or elevated liver enzymes. A direct correlation between the number of symptoms and the duration of illness at time of presentation (rho = 0.389, P = 0.009) was observed for HGA patients but not for patients with Lyme disease. In conclusion, although there are overlapping features, culture-confirmed HGA is a more severe illness than early Lyme disease.

  5. Mitochondria, the Cell Cycle, and the Origin of Sex via a Syncytial Eukaryote Common Ancestor.

    PubMed

    Garg, Sriram G; Martin, William F

    2016-07-02

    Theories for the origin of sex traditionally start with an asexual mitosing cell and add recombination, thereby deriving meiosis from mitosis. Though sex was clearly present in the eukaryote common ancestor, the order of events linking the origin of sex and the origin of mitosis is unknown. Here, we present an evolutionary inference for the origin of sex starting with a bacterial ancestor of mitochondria in the cytosol of its archaeal host. We posit that symbiotic association led to the origin of mitochondria and gene transfer to host's genome, generating a nucleus and a dedicated translational compartment, the eukaryotic cytosol, in which-by virtue of mitochondria-metabolic energy was not limiting. Spontaneous protein aggregation (monomer polymerization) and Adenosine Tri-phosphate (ATP)-dependent macromolecular movement in the cytosol thereby became selectable, giving rise to continuous microtubule-dependent chromosome separation (reduction division). We propose that eukaryotic chromosome division arose in a filamentous, syncytial, multinucleated ancestor, in which nuclei with insufficient chromosome numbers could complement each other through mRNA in the cytosol and generate new chromosome combinations through karyogamy. A syncytial (or coenocytic, a synonym) eukaryote ancestor, or Coeca, would account for the observation that the process of eukaryotic chromosome separation is more conserved than the process of eukaryotic cell division. The first progeny of such a syncytial ancestor were likely equivalent to meiospores, released into the environment by the host's vesicle secretion machinery. The natural ability of archaea (the host) to fuse and recombine brought forth reciprocal recombination among fusing (syngamy and karyogamy) progeny-sex-in an ancestrally meiotic cell cycle, from which the simpler haploid and diploid mitotic cell cycles arose. The origin of eukaryotes was the origin of vertical lineage inheritance, and sex was required to keep vertically

  6. Mitochondria, the Cell Cycle, and the Origin of Sex via a Syncytial Eukaryote Common Ancestor

    PubMed Central

    Garg, Sriram G.; Martin, William F.

    2016-01-01

    Theories for the origin of sex traditionally start with an asexual mitosing cell and add recombination, thereby deriving meiosis from mitosis. Though sex was clearly present in the eukaryote common ancestor, the order of events linking the origin of sex and the origin of mitosis is unknown. Here, we present an evolutionary inference for the origin of sex starting with a bacterial ancestor of mitochondria in the cytosol of its archaeal host. We posit that symbiotic association led to the origin of mitochondria and gene transfer to host’s genome, generating a nucleus and a dedicated translational compartment, the eukaryotic cytosol, in which—by virtue of mitochondria—metabolic energy was not limiting. Spontaneous protein aggregation (monomer polymerization) and Adenosine Tri-phosphate (ATP)-dependent macromolecular movement in the cytosol thereby became selectable, giving rise to continuous microtubule-dependent chromosome separation (reduction division). We propose that eukaryotic chromosome division arose in a filamentous, syncytial, multinucleated ancestor, in which nuclei with insufficient chromosome numbers could complement each other through mRNA in the cytosol and generate new chromosome combinations through karyogamy. A syncytial (or coenocytic, a synonym) eukaryote ancestor, or Coeca, would account for the observation that the process of eukaryotic chromosome separation is more conserved than the process of eukaryotic cell division. The first progeny of such a syncytial ancestor were likely equivalent to meiospores, released into the environment by the host’s vesicle secretion machinery. The natural ability of archaea (the host) to fuse and recombine brought forth reciprocal recombination among fusing (syngamy and karyogamy) progeny—sex—in an ancestrally meiotic cell cycle, from which the simpler haploid and diploid mitotic cell cycles arose. The origin of eukaryotes was the origin of vertical lineage inheritance, and sex was required to keep

  7. Origin of the Genetic Components of the Vomeronasal System in the Common Ancestor of all Extant Vertebrates

    PubMed Central

    Grus, Wendy E.; Zhang, Jianzhi

    2009-01-01

    Comparative genomics provides a valuable tool for inferring the evolutionary history of physiological systems, particularly when this information is difficult to ascertain by morphological traits. One such example is the vomeronasal system (VNS), a vertebrate nasal chemosensory system that is responsible for detecting intraspecific pheromonal cues as well as environmental odorants. The morphological components of the VNS are found only in tetrapods, but the genetic components of the system have been found in teleost fish, in addition to tetrapods. To determine when the genetic components of the VNS originated, we searched for the VNS-specific genes in the genomes of two early diverging vertebrate lineages: the sea lamprey from jawless fishes and the elephant shark from cartilaginous fishes. Genes encoding vomeronasal type 1 receptors (V1Rs) and Trpc2, two components of the vomeronasal signaling pathway, are present in the sea lamprey genome, and both are expressed in the olfactory organ, revealing that the genetic components of the present-day VNS existed in the common ancestor of all extant vertebrates. Additionally, all three VNS genes, Trpc2, V1Rs, and vomeronasal type 2 receptors (V2Rs), are found in the elephant shark genome. Because V1Rs and V2Rs are related to two families of taste receptors, we also searched the early diverging vertebrate genomes for taste system genes and found them in the shark genome but not in the lamprey. Coupled with known distributions of the genetic components of the vertebrate main olfactory system, our results suggest staggered origins of vertebrate sensory systems. These findings are important for understanding the evolution of vertebrate sensory systems and illustrate the utility of the genome sequences of early diverging vertebrates for uncovering the evolution of vertebrate-specific traits. PMID:19008528

  8. From the Cover: Feature Article: Ecosystem variability and early human habitats in eastern Africa

    NASA Astrophysics Data System (ADS)

    Magill, Clayton R.; Ashley, Gail M.; Freeman, Katherine H.

    2013-01-01

    The role of savannas during the course of early human evolution has been debated for nearly a century, in part because of difficulties in characterizing local ecosystems from fossil and sediment records. Here, we present high-resolution lipid biomarker and isotopic signatures for organic matter preserved in lake sediments at Olduvai Gorge during a key juncture in human evolution about 2.0 Ma-the emergence and dispersal of Homo erectus (sensu lato). Using published data for modern plants and soils, we construct a framework for ecological interpretations of stable carbon-isotope compositions (expressed as δ13C values) of lipid biomarkers from ancient plants. Within this framework, δ13C values for sedimentary leaf lipids and total organic carbon from Olduvai Gorge indicate recurrent ecosystem variations, where open C4 grasslands abruptly transitioned to closed C3 forests within several hundreds to thousands of years. Carbon-isotopic signatures correlate most strongly with Earth's orbital geometry (precession), and tropical sea-surface temperatures are significant secondary predictors in partial regression analyses. The scale and pace of repeated ecosystem variations at Olduvai Gorge contrast with long-held views of directional or stepwise aridification and grassland expansion in eastern Africa during the early Pleistocene and provide a local perspective on environmental hypotheses of human evolution.

  9. Early human-plant interactions based on palaeovegetation simulations of Africa over glacial-interglacial cycles

    NASA Astrophysics Data System (ADS)

    Cowling, S. A.; Cox, P. M.; Jones, C. D.; Maslin, M. A.; Spall, S. A.

    2003-04-01

    A greater understanding of African palaeovegetation environments over the Pleistocene (1.6 Mya) is important for evaluating potential catalysts underlying the anatomical, social and demographic changes observed in early human populations. We used a state-of-the-art fully-coupled earth system model (HADLEY-GCM3) to simulate typical glacial and interglacial environments likely encountered by late-Pleistocene humans. Our simulations indicate that tropical broadleaf forests of central Africa were not severely restricted by expanding grasslands during the last glacial maximum, although the carbon content of stem and density of leaf components were substantially reduced. We interpret a natural eastern migration corridor between southern Africa and the Rift Valley based on simulations of a no-analogue vegetation assemblage characterised by a unique combination of grass and low density forest. We postulate that early human populations in southern Africa were isolated from northern groups during warm interglacials, and that trans-African migration was facilitated during glacial cycles via a more openly forested eastern corridor.

  10. Matriptase regulates proliferation and early, but not terminal, differentiation of human keratinocytes.

    PubMed

    Chen, Ya-Wen; Wang, Jehng-Kang; Chou, Fen-Pai; Wu, Bai-Yao; Hsiao, Hui-Chung; Chiu, Han; Xu, Zhonghong; Baksh, Adrienne N H; Shi, Galen; Kaul, Malvika; Barndt, Robert; Shanmugam, Victoria K; Johnson, Michael D; Lin, Chen-Yong

    2014-02-01

    Genetic defects in matriptase are linked to two congenital ichthyoses: autosomal recessive ichthyosis with hypotrichosis (ARIH, OMIM 610765) and ichthyosis, follicular atrophoderma, hypotrichosis, and hypohidrosis (IFAH, OMIM 602400). Mouse models with matriptase deficiency indicate an involvement of matriptase in suprabasal keratinocytes in the maintenance of the epidermal barrier. In contrast to what has been reported for mouse skin, we show that in human skin matriptase is primarily expressed in the basal and spinous keratinocytes, but not in the more differentiated keratinocytes of the granular layer. In addition, matriptase zymogen activation was predominantly detected in the basal cells. Furthermore, by using skin organotypic cultures as a model system to monitor the course of human epidermal differentiation, we found elevated matriptase zymogen activation during early stages of epidermal differentiation, coupled with a loss of matriptase expression in the late stages of this process. We also show here that matriptase deficiency in HaCaT cells modestly reduces cell proliferation and temporally affects calcium-induced expression of differentiation markers. These collective data suggest that, unlike mouse matriptase, human matriptase may be involved in the regulation of keratinocyte growth and early differentiation, rather than terminal differentiation, providing mechanistic insights into the pathology of the two congenital ichthyoses: ARIH and IFAH.

  11. Human transgenerational responses to early-life experience: potential impact on development, health and biomedical research

    PubMed Central

    Pembrey, Marcus; Saffery, Richard; Bygren, Lars Olov

    2014-01-01

    Mammalian experiments provide clear evidence of male line transgenerational effects on health and development from paternal or ancestral early-life exposures such as diet or stress. The few human observational studies to date suggest (male line) transgenerational effects exist that cannot easily be attributed to cultural and/or genetic inheritance. Here we summarise relevant studies, drawing attention to exposure sensitive periods in early life and sex differences in transmission and offspring outcomes. Thus, variation, or changes, in the parental/ancestral environment may influence phenotypic variation for better or worse in the next generation(s), and so contribute to common, non-communicable disease risk including sex differences. We argue that life-course epidemiology should be reframed to include exposures from previous generations, keeping an open mind as to the mechanisms that transmit this information to offspring. Finally, we discuss animal experiments, including the role of epigenetic inheritance and non-coding RNAs, in terms of what lessons can be learnt for designing and interpreting human studies. This review was developed initially as a position paper by the multidisciplinary Network in Epigenetic Epidemiology to encourage transgenerational research in human cohorts. PMID:25062846

  12. Laminin and beta1 integrin distribution in the early stages of human kidney development.

    PubMed

    Bernardini, N; Bianchi, F; Dolfi, A

    1999-01-01

    Laminin, an extracellular matrix molecule (EMM) widely expressed in the basal laminae, interacts with specific membrane receptors among which the integrin molecules are the best known. During embryo development laminin is the first synthesized EMM and plays a significant role in the morphogenesis of organs in which epithelial-mesenchymal interactions and branching take place. The present study describes the distribution of laminin and of beta1 integrin receptors during the very early stages of human kidney development. The observations were carried out on paraffin sections of human embryos ranging between the 4th and the 7th gestational week. Laminin was detected within the basement membranes of mesonephric duct, vesicles, glomerular vessels and celomic epithelium. The metanephric anlage reacted with anti-laminin immunoglobulins in the basement membrane underlying the ampullae and in few blastemic cap cells. Low levels of beta1 integrin reactivity were found in both the mesonephric and metanephric structures. This study provides for the first time data about the distribution of laminin and beta1 integrin in the early stages of human renal organogenesis suggesting a key role for these molecules in the epithelial-mesenchymal interactions necessary for kidney development.

  13. Variability of Gene Expression Identifies Transcriptional Regulators of Early Human Embryonic Development

    PubMed Central

    Hasegawa, Yu; Taylor, Deanne; Ovchinnikov, Dmitry A.; Wolvetang, Ernst J.; de Torrenté, Laurence; Mar, Jessica C.

    2015-01-01

    An analysis of gene expression variability can provide an insightful window into how regulatory control is distributed across the transcriptome. In a single cell analysis, the inter-cellular variability of gene expression measures the consistency of transcript copy numbers observed between cells in the same population. Application of these ideas to the study of early human embryonic development may reveal important insights into the transcriptional programs controlling this process, based on which components are most tightly regulated. Using a published single cell RNA-seq data set of human embryos collected at four-cell, eight-cell, morula and blastocyst stages, we identified genes with the most stable, invariant expression across all four developmental stages. Stably-expressed genes were found to be enriched for those sharing indispensable features, including essentiality, haploinsufficiency, and ubiquitous expression. The stable genes were less likely to be associated with loss-of-function variant genes or human recessive disease genes affected by a DNA copy number variant deletion, suggesting that stable genes have a functional impact on the regulation of some of the basic cellular processes. Genes with low expression variability at early stages of development are involved in regulation of DNA methylation, responses to hypoxia and telomerase activity, whereas by the blastocyst stage, low-variability genes are enriched for metabolic processes as well as telomerase signaling. Based on changes in expression variability, we identified a putative set of gene expression markers of morulae and blastocyst stages. Experimental validation of a blastocyst-expressed variability marker demonstrated that HDDC2 plays a role in the maintenance of pluripotency in human ES and iPS cells. Collectively our analyses identified new regulators involved in human embryonic development that would have otherwise been missed using methods that focus on assessment of the average expression

  14. Saffold virus, a human Theiler's-like cardiovirus, is ubiquitous and causes infection early in life.

    PubMed

    Zoll, Jan; Erkens Hulshof, Sandra; Lanke, Kjerstin; Verduyn Lunel, Frans; Melchers, Willem J G; Schoondermark-van de Ven, Esther; Roivainen, Merja; Galama, Jochem M D; van Kuppeveld, Frank J M

    2009-05-01

    The family Picornaviridae contains well-known human pathogens (e.g., poliovirus, coxsackievirus, rhinovirus, and parechovirus). In addition, this family contains a number of viruses that infect animals, including members of the genus Cardiovirus such as Encephalomyocarditis virus (EMCV) and Theiler's murine encephalomyelits virus (TMEV). The latter are important murine pathogens that cause myocarditis, type 1 diabetes and chronic inflammation in the brains, mimicking multiple sclerosis. Recently, a new picornavirus was isolated from humans, named Saffold virus (SAFV). The virus is genetically related to Theiler's virus and classified as a new species in the genus Cardiovirus, which until the discovery of SAFV did not contain human viruses. By analogy with the rodent cardioviruses, SAFV may be a relevant new human pathogen. Thus far, SAFVs have sporadically been detected by molecular techniques in respiratory and fecal specimens, but the epidemiology and clinical significance remained unclear. Here we describe the first cultivated SAFV type 3 (SAFV-3) isolate, its growth characteristics, full-length sequence, and epidemiology. Unlike the previously isolated SAFV-1 and -2 viruses, SAFV-3 showed efficient growth in several cell lines with a clear cytopathic effect. The latter allowed us to conduct a large-scale serological survey by a virus-neutralization assay. This survey showed that infection by SAFV-3 occurs early in life (>75% positive at 24 months) and that the seroprevalence reaches >90% in older children and adults. Neutralizing antibodies were found in serum samples collected in several countries in Europe, Africa, and Asia. In conclusion, this study describes the first cultivated SAFV-3 isolate, its full-length sequence, and epidemiology. SAFV-3 is a highly common and widespread human virus causing infection in early childhood. This finding has important implications for understanding the impact of these ubiquitous viruses and their possible role in acute

  15. Saffold Virus, a Human Theiler's-Like Cardiovirus, Is Ubiquitous and Causes Infection Early in Life

    PubMed Central

    Lanke, Kjerstin; Verduyn Lunel, Frans; Melchers, Willem J. G.; Schoondermark-van de Ven, Esther; Roivainen, Merja; Galama, Jochem M. D.; van Kuppeveld, Frank J. M.

    2009-01-01

    The family Picornaviridae contains well-known human pathogens (e.g., poliovirus, coxsackievirus, rhinovirus, and parechovirus). In addition, this family contains a number of viruses that infect animals, including members of the genus Cardiovirus such as Encephalomyocarditis virus (EMCV) and Theiler's murine encephalomyelits virus (TMEV). The latter are important murine pathogens that cause myocarditis, type 1 diabetes and chronic inflammation in the brains, mimicking multiple sclerosis. Recently, a new picornavirus was isolated from humans, named Saffold virus (SAFV). The virus is genetically related to Theiler's virus and classified as a new species in the genus Cardiovirus, which until the discovery of SAFV did not contain human viruses. By analogy with the rodent cardioviruses, SAFV may be a relevant new human pathogen. Thus far, SAFVs have sporadically been detected by molecular techniques in respiratory and fecal specimens, but the epidemiology and clinical significance remained unclear. Here we describe the first cultivated SAFV type 3 (SAFV-3) isolate, its growth characteristics, full-length sequence, and epidemiology. Unlike the previously isolated SAFV-1 and -2 viruses, SAFV-3 showed efficient growth in several cell lines with a clear cytopathic effect. The latter allowed us to conduct a large-scale serological survey by a virus-neutralization assay. This survey showed that infection by SAFV-3 occurs early in life (>75% positive at 24 months) and that the seroprevalence reaches >90% in older children and adults. Neutralizing antibodies were found in serum samples collected in several countries in Europe, Africa, and Asia. In conclusion, this study describes the first cultivated SAFV-3 isolate, its full-length sequence, and epidemiology. SAFV-3 is a highly common and widespread human virus causing infection in early childhood. This finding has important implications for understanding the impact of these ubiquitous viruses and their possible role in acute

  16. Human and mouse TPIT gene mutations cause early onset pituitary ACTH deficiency

    PubMed Central

    Pulichino, Anne-Marie; Vallette-Kasic, Sophie; Couture, Catherine; Gauthier, Yves; Brue, Thierry; David, Michel; Malpuech, Georges; Deal, Cheri; Van Vliet, Guy; De Vroede, Monique; Riepe, Felix G.; Partsch, Carl-Joachim; Sippell, Wolfgang G.; Berberoglu, Merih; Atasay, Begüm; Drouin, Jacques

    2003-01-01

    Tpit is a highly cell-restricted transcription factor that is required for expression of the pro-opiomelanocortin (POMC) gene and for terminal differentiation of the pituitary corticotroph lineage. Its exclusive expression in pituitary POMC-expressing cells has suggested that its mutation may cause isolated deficiency of pituitary adrenocorticotropin (ACTH). We now show that Tpit-deficient mice constitute a model of isolated ACTH deficiency (IAD) that is very similar to human IAD patients carrying TPIT gene mutations. Through genetic analysis of a panel of IAD patients, we show that TPIT gene mutations are associated at high frequency with early onset IAD, but not with juvenile forms of this deficiency. We identified seven different TPIT mutations, including nonsense, missense, point deletion, and a genomic deletion. This work defines congenital early onset IAD as a relatively homogeneous clinical entity caused by recessive transmission of loss-of-function mutations in the TPIT gene. PMID:12651888

  17. Nanomaterial interference with early human placenta: Sophisticated matter meets sophisticated tissues.

    PubMed

    Juch, Herbert; Nikitina, Liudmila; Debbage, Paul; Dohr, Gottfried; Gauster, Martin

    2013-11-01

    Next to nothing is known about nanoparticle and nanofiber trafficking at the feto-maternal interface in early human pregnancy. As the first trimester is thought to be crucial for the further placental and fetal development, it will be important to assess the possible risks of nanomaterial exposures during this period. There are some intriguing observations in nanotoxicology, however, indicating certain differences between classical toxicology and nanotoxicology. To understand nanomaterial-biokinetics and placental toxicity in early gestation, the special architecture, the hypoxic condition, the bilayer of villous trophoblast, the plugging of spiral arteries and the contribution of intrauterine glands to nutrition, as well as the delicate immunologic situation at the implantation site, will have to be considered. Unless nano-specific biokinetics are properly understood, it will be difficult to ensure identification of potential "nano-thalidomides" among all the newly engineered nanoparticles and fibers, based on the models available in reproductive toxicology. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Human and mouse TPIT gene mutations cause early onset pituitary ACTH deficiency.

    PubMed

    Pulichino, Anne-Marie; Vallette-Kasic, Sophie; Couture, Catherine; Gauthier, Yves; Brue, Thierry; David, Michel; Malpuech, Georges; Deal, Cheri; Van Vliet, Guy; De Vroede, Monique; Riepe, Felix G; Partsch, Carl-Joachim; Sippell, Wolfgang G; Berberoglu, Merih; Atasay, Begüm; Drouin, Jacques

    2003-03-15

    Tpit is a highly cell-restricted transcription factor that is required for expression of the pro-opiomelanocortin (POMC) gene and for terminal differentiation of the pituitary corticotroph lineage. Its exclusive expression in pituitary POMC-expressing cells has suggested that its mutation may cause isolated deficiency of pituitary adrenocorticotropin (ACTH). We now show that Tpit-deficient mice constitute a model of isolated ACTH deficiency (IAD) that is very similar to human IAD patients carrying TPIT gene mutations. Through genetic analysis of a panel of IAD patients, we show that TPIT gene mutations are associated at high frequency with early onset IAD, but not with juvenile forms of this deficiency. We identified seven different TPIT mutations, including nonsense, missense, point deletion, and a genomic deletion. This work defines congenital early onset IAD as a relatively homogeneous clinical entity caused by recessive transmission of loss-of-function mutations in the TPIT gene.

  19. Early ontogeny of the central benzodiazepine receptor in human embryos and fetuses

    SciTech Connect

    Hebebrand, J.; Hofmann, D.; Reichelt, R.; Schnarr, S.; Knapp, M.; Propping, P.; Foedisch, H.J.

    1988-01-01

    The early ontogeny of the central benzodiazepine receptor (BZR) was investigated in human embryos and fetuses between 7 and 26 weeks of gestation. Brain tissue was gained from terminated pregnancies or spontaneous abortions. Binding studies, which were performed with /sup 3/H-flunitrazepam (FNZ), revealed that specific benzodiazepine binding is already detectable at an embryonal age of 7 weeks post conception. Binding at this early stage can be displaced potently by clonazepam and the inverse agonist ..beta..-CCE. Additionally, /sup 3/H-FNZ binding is enhanced by GABA. Thus, benzodiazepine binding is of the central type. Receptor density increases steeply in whole brain between weeks 8 and 11 of gestation. In frontal cortex receptor density increases gradually between weeks 12 and 26 of gestation. No specific fetal disease entity (including trisomy 21) was consistently associated with exceptionally high or low B/sub max/-values.

  20. The human startle reflex and alcohol cue reactivity: effects of early versus late abstinence.

    PubMed

    Saladin, Michael E; Drobes, David J; Coffey, Scott F; Libet, Julian M

    2002-06-01

    This study investigated the human eyeblink startle reflex as a measure of alcohol cue reactivity. Alcohol-dependent participants early (n = 36) and late (n = 34) in abstinence received presentations of alcohol and water cues. Consistent with previous research, greater salivation and higher ratings of urge to drink occurred in response to the alcohol cues. Differential salivary and urge responding to alcohol versus water cues did not vary as a function of abstinence duration. Of special interest was the finding that startle response magnitudes were relatively elevated to alcohol cues, but only in individuals early in abstinence. Affective ratings of alcohol cues suggested that alcohol cues were perceived as aversive. Methodological and theoretical implications of the findings are discussed.

  1. Heatwave early warning systems and adaptation advice to reduce human health consequences of heatwaves.

    PubMed

    Lowe, Dianne; Ebi, Kristie L; Forsberg, Bertil

    2011-12-01

    With climate change, there has been an increase in the frequency, intensity and duration of heatwave events. In response to the devastating mortality and morbidity of recent heatwave events, many countries have introduced heatwave early warning systems (HEWS). HEWS are designed to reduce the avoidable human health consequences of heatwaves through timely notification of prevention measures to vulnerable populations. To identify the key characteristics of HEWS in European countries to help inform modification of current, and development of, new systems and plans. We searched the internet to identify HEWS policy or government documents for 33 European countries and requested information from relevant organizations. We translated the HEWS documents and extracted details on the trigger indicators, thresholds for action, notification strategies, message intermediaries, communication and dissemination strategies, prevention strategies recommended and specified target audiences. Twelve European countries have HEWS. Although there are many similarities among the HEWS, there also are differences in key characteristics that could inform improvements in heatwave early warning plans.

  2. When right differs from left: human limb directional asymmetry emerges during very early development.

    PubMed

    Van Dongen, Stefan; Galis, Frietson; Ten Broek, Clara; Heikinheimo, Kristiina; Wijnaendts, Liliane C D; Delen, Sofie; Bots, Jessica

    2014-01-01

    The often observed directional asymmetry (DA) in human limb bones may have a genetic/developmental basis and/or could emerge from different mechanical loadings across sides due to handedness. Because behavioural lateralization in itself has a genetic basis, it has been suggested that DA in limbs could develop prenatally as a pre-adaptation to adult life. However, the presence of consistent differences in the size of left and right limb bones in early development is understudied. We study asymmetry in limb bones during early development (10-20 weeks of gestation) in a sample of 178 aborted foetuses. Statistically significant DA was found in several upper and lower limb bones, where the right-hand side was consistently larger than the left. We argue that this pattern is probably the consequence of developmental processes related to internal asymmetric positioning of organs.

  3. New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile.

    PubMed

    Dillehay, Tom D; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M; Pino, Mario; Collins, Michael B; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S; Hartmann, Gelvam A; Mella, Mauricio; González, Andrea; Dix, George

    2015-01-01

    Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.

  4. Defining the Genomic Signature of Totipotency and Pluripotency during Early Human Development

    PubMed Central

    Galan, Amparo; Diaz-Gimeno, Patricia; Poo, Maria Eugenia; Valbuena, Diana; Sanchez, Eva; Ruiz, Veronica; Dopazo, Joaquin; Montaner, David; Conesa, Ana; Simon, Carlos

    2013-01-01

    The genetic mechanisms governing human pre-implantation embryo development and the in vitro counterparts, human embryonic stem cells (hESCs), still remain incomplete. Previous global genome studies demonstrated that totipotent blastomeres from day-3 human embryos and pluripotent inner cell masses (ICMs) from blastocysts, display unique and differing transcriptomes. Nevertheless, comparative gene expression analysis has revealed that no significant differences exist between hESCs derived from blastomeres versus those obtained from ICMs, suggesting that pluripotent hESCs involve a new developmental progression. To understand early human stages evolution, we developed an undifferentiation network signature (UNS) and applied it to a differential gene expression profile between single blastomeres from day-3 embryos, ICMs and hESCs. This allowed us to establish a unique signature composed of highly interconnected genes characteristic of totipotency (61 genes), in vivo pluripotency (20 genes), and in vitro pluripotency (107 genes), and which are also proprietary according to functional analysis. This systems biology approach has led to an improved understanding of the molecular and signaling processes governing human pre-implantation embryo development, as well as enabling us to comprehend how hESCs might adapt to in vitro culture conditions. PMID:23614026

  5. New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

    PubMed Central

    Dillehay, Tom D.; Ocampo, Carlos; Saavedra, José; Sawakuchi, Andre Oliveira; Vega, Rodrigo M.; Pino, Mario; Collins, Michael B.; Scott Cummings, Linda; Arregui, Iván; Villagran, Ximena S.; Hartmann, Gelvam A.; Mella, Mauricio; González, Andrea; Dix, George

    2015-01-01

    Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia. PMID:26580202

  6. Electromechanical probe and automated indentation maps are sensitive techniques in assessing early degenerated human articular cartilage.

    PubMed

    Sim, Sotcheadt; Chevrier, Anik; Garon, Martin; Quenneville, Eric; Lavigne, Patrick; Yaroshinsky, Alex; Hoemann, Caroline D; Buschmann, Michael D

    2016-06-09

    Recent advances in the development of new drugs to halt or even reverse the progression of Osteoarthritis at an early-stage requires new tools to detect early degeneration of articular cartilage. We investigated the ability of an electromechanical probe and an automated indentation technique to characterize entire human articular surfaces for rapid non-destructive discrimination between early degenerated and healthy articular cartilage. Human cadaveric asymptomatic articular surfaces (4 pairs of distal femurs and 4 pairs of tibial plateaus) were used. They were assessed ex vivo: macroscopically, electromechanically (maps of the electromechanical quantitative parameter, QP, reflecting streaming potentials), mechanically (maps of the instantaneous modulus, IM) and through cartilage thickness. Osteochondral cores were also harvested from healthy and degenerated regions for histological assessment, biochemical analyses and unconfined compression tests. The macroscopic visual assessment delimited three distinct regions on each articular surface: region I was macroscopically degenerated, region II was macroscopically normal but adjacent to region I and region III was the remaining normal articular surface. Thus, each extracted core was assigned to one of the three regions. A mixed effect model revealed that only the QP (p < 0.0001) and IM (p < 0.0001) were able to statistically discriminate the three regions. Effect size was higher for QP and IM than other assessments, indicating greater sensitivity to distinguish early degeneration of cartilage. When considering the mapping feature of the QP and IM techniques, it also revealed bilateral symmetry in a moderately similar distribution pattern between bilateral joints. This article is protected by copyright. All rights reserved.

  7. CSF Levels of Hypocretin-1 (Orexin-A) Peak during Early Infancy in Humans

    PubMed Central

    Aran, Adi; Shors, Irina; Lin, Ling; Mignot, Emmanuel; Schimmel, Michael S.

    2012-01-01

    Study Objectives: Hypocretin (orexin) is a unique neuropeptide involved in the consolidation of wakefulness and sleep. Although hypocretin-1 levels in the cerebrospinal fluid (CSF) are stable after infancy, how levels change in preterm and term human infants is unknown. Design, Patients, and Setting: Hypocretin-1 levels were measured in CSF samples, obtained from 284 preterm (25-37 gestational weeks) and full-term infants in the first 4 months of life and 35 older children (ages 0.5-13 years), in a tertiary hospital. Measurements and Results: Detailed clinical and laboratory data were collected for each of the 319 participants. Based on that data, 108 neurologically intact children were selected (95 infants [43 preterm and 52 term] and 13 older children). CSF hypocretin-1 was measured by direct radioimmunoassay. Hypocretin-1 levels at the first weeks of the 3rd embryonic trimester (gestational age [GA] 28-34 weeks) were 314 ± 65 pg/mL (n = 17). The levels linearly increased during the third trimester and early infancy (r = 0.6), peaking in infants of 2-4 months ages (476 ± 72 pg/mL; n = 16) and decreasing thereafter; hypocretin levels in 2- to 4-month-old infants were significantly higher than those in children 0.5-13 years old (353 ± 78 pg/mL, n = 13; P = 0.0001). Conclusions: The present findings indicate that in human infants, CSF hypocretin-1 increases during the third embryonic trimester and is highest at 4 months of life. Thereafter, and consistent with previously published results, hypocretin levels are lower and stable until the geriatric age. This pattern may reflect the role of hypocretin in the dramatic process of sleep and wakefulness consolidation that occurs during early infancy. Citation: Aran A; Shors I; Lin L; Mignot E; Schimmel MS. CSF levels of hypocretin-1 (orexin-A) peak during early infancy in humans. SLEEP 2012;35(2):187-191. PMID:22294808

  8. Plant foods and the dietary ecology of Neanderthals and early modern humans.

    PubMed

    Henry, Amanda G; Brooks, Alison S; Piperno, Dolores R

    2014-04-01

    One of the most important challenges in anthropology is understanding the disappearance of Neanderthals. Previous research suggests that Neanderthals had a narrower diet than early modern humans, in part because they lacked various social and technological advances that lead to greater dietary variety, such as a sexual division of labor and the use of complex projectile weapons. The wider diet of early modern humans would have provided more calories and nutrients, increasing fertility, decreasing mortality and supporting large population sizes, allowing them to out-compete Neanderthals. However, this model for Neanderthal dietary behavior is based on analysis of animal remains, stable isotopes, and other methods that provide evidence only of animal food in the diet. This model does not take into account the potential role of plant food. Here we present results from the first broad comparison of plant foods in the diets of Neanderthals and early modern humans from several populations in Europe, the Near East, and Africa. Our data comes from the analysis of plant microremains (starch grains and phytoliths) in dental calculus and on stone tools. Our results suggest that both species consumed a similarly wide array of plant foods, including foods that are often considered low-ranked, like underground storage organs and grass seeds. Plants were consumed across the entire range of individuals and sites we examined, and none of the expected predictors of variation (species, geographic region, or associated stone tool technology) had a strong influence on the number of plant species consumed. Our data suggest that Neanderthal dietary ecology was more complex than previously thought. This implies that the relationship between Neanderthal technology, social behavior, and food acquisition strategies must be better explored.

  9. The cult of amphioxus in German Darwinism; or, our gelatinous ancestors in Naples' blue and balmy bay.

    PubMed

    Hopwood, Nick

    2015-01-01

    Biologists having rediscovered amphioxus, also known as the lancelet or Branchiostoma, it is time to reassess its place in early Darwinist debates over vertebrate origins. While the advent of the ascidian-amphioxus theory and challenges from various competitors have been, documented, this article offers a richer account of the public appeal of amphioxus as a primitive ancestor. The focus is on how the 'German Darwin' Ernst Haeckel persuaded general magazine and newspaper readers to revere this "flesh of our flesh and blood of our blood", and especially on Das neue Laienbrevier des Haeckelismus (The new lay breviary of Haeckelism) by Moritz Reymond with cartoons by Fritz Steub. From the late 1870s these successful little books of verse introduced the Neapolitan discoveries that made the animal's name and satirized Haeckel's rise as high priest of its cult. One song is reproduced and translated here, with a contemporary "imitation" by the Canadian palaeontologist Edward John Chapman, and extracts from others. Predating the American "It's a long way from amphioxus" by decades, these rhymes dramatize neglected 'species politics' of Darwinism and highlight the roles of humour in negotiating evolution.

  10. A memory already like an elephant's? The advanced brain morphology of the last common ancestor of Afrotheria (Mammalia).

    PubMed

    Benoit, Julien; Crumpton, Nick; Mérigeaud, Samuel; Tabuce, Rodolphe

    2013-01-01

    Virtually reconstructed and natural endocranial casts are used in the study of brain evolution through geological time. We here present work investigating the paleoneurological evolution of afrotherian mammals. Using microCT-generated endocasts we show that, with the exception of the subfamilies Macroscelidinae and Tenrecoidea, most Afroinsectiphilia display a more or less gyrencephalic and ventrally expanded neopallium, two derived features that are unexpected for these insectivore-grade afrotherians. This implies that the endocranial cast morphology at the root of the afrotherian clade may have been more advanced than previously thought. The reconstructed endocranial morphology of the Afrotheria's last common ancestor reaches the level of complexity of some early Cenozoic archaic ungulates. Our result gives support to the hypothesis of an ungulate-like ancestral body plan for Afrotheria. It also implies that the a priori 'primitive' suite of traits evident in the brain of Afroinsectivora, especially in the tenrecs, may have been secondarily acquired. Implications on the overestimation of the divergence age of Afrotheria are discussed. Copyright © 2013 S. Karger AG, Basel.

  11. Modern mRNA proofreading and repair: clues that the last universal common ancestor possessed an RNA genome?

    PubMed

    Poole, Anthony M; Logan, Derek T

    2005-06-01

    RNA repair has now been demonstrated to be a genuine biological process and appears to be present in all three domains of life. In this article, we consider what this might mean for the transition from an early RNA-dominated world to modern cells possessing genetically encoded proteins and DNA. There are significant gaps in our understanding of how the modern protein-DNA world could have evolved from a simpler system, and it is currently uncertain whether DNA genomes evolved once or twice. Against this backdrop, the discovery of RNA repair in modern cells is timely food for thought and brings us conceptually one step closer to understanding how RNA genomes were replaced by DNA genomes. We have examined the available literature on multisubunit RNA polymerase structure and function and conclude that a strong case can be made that the Last Universal Common Ancestor (LUCA) possessed a repair-competent RNA polymerase, which would have been capable of acting on an RNA genome. However, while this lends credibility to the proposal that the LUCA had an RNA genome, the alternative, that LUCA had a DNA genome, cannot be completely ruled out.

  12. 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…

  13. 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…

  14. Catastrophic early Holocene sea level rise, human migration and the Neolithic transition in Europe

    NASA Astrophysics Data System (ADS)

    Turney, Chris S. M.; Brown, Heidi

    2007-09-01

    The collapse of the Laurentide Ice Sheet and release of freshwater 8740-8160 years ago abruptly raised global sea levels by up to 1.4 m. The effect on human populations is largely unknown. Here we constrain the time of the main sea level rise and investigate its effect on the onset of the Neolithic across Europe. An analysis of radiocarbon ages and palaeoshoreline reconstruction supports the hypothesis that flooding of coastal areas led to the sudden loss of land favoured by early farmers and initiated an abrupt expansion of activity across Europe, driven by migrating Neolithic peoples.

  15. Early developmental exposures shape trade-offs between acquired and innate immunity in humans

    PubMed Central

    Georgiev, Alexander V.; Kuzawa, Christopher W.; McDade, Thomas W.

    2016-01-01

    Background and objectives Life history theory predicts resource allocation trade-offs between competing functions and processes. We test the hypothesis that relative investment towards innate versus acquired immunity in humans is subject to such trade-offs and that three types of early developmental exposures are particularly salient in shaping adult immunophenotype: (i) pathogen exposure, (ii) nutritional resources; and (iii) extrinsic mortality cues. Methodology We quantified one aspect each of innate and acquired immune function, via C-reactive protein and Epstein–Barr virus antibodies, respectively, in a sample of 1248 men and women from the Philippines (ca. 21.5 years old). Early developmental exposures were assessed via long-term data collected prospectively since participants’ birth (1983–4). We calculated a standardized ratio to assess relative bias towards acquired versus innate immune function and examined its relationship to a suite of predictors via multiple regression. Results In partial support of our predictions, some of the measures of higher pathogen exposure, greater availability of nutritional resources, and lower extrinsic mortality cues in early life were associated with a bias toward acquired immunity in both men and women. The immune profile of women, in particular, appeared to be more sensitive to early life pathogen exposures than those of men. Finally, contrary to prediction, women exhibited a greater relative investment toward innate, not acquired, immunity. Conclusions and implications Early environments can exert considerable influence on the development of immunity. They affect trade-offs between innate and acquired immunity, which show adaptive plasticity and may differ in their influence in men and women. PMID:27530543

  16. Early influence of auditory stimuli on upper-limb movements in young human infants: an overview.

    PubMed

    Ferronato, Priscilla A M; Domellöf, Erik; Rönnqvist, Louise

    2014-01-01

    Given that the auditory system is rather well developed at the end of the third trimester of pregnancy, it is likely that couplings between acoustics and motor activity can be integrated as early as at the beginning of postnatal life. The aim of the present mini-review was to summarize and discuss studies on early auditory-motor integration, focusing particularly on upper-limb movements (one of the most crucial means to interact with the environment) in association with auditory stimuli, to develop further understanding of their significance with regard to early infant development. Many studies have investigated the relationship between various infant behaviors (e.g., sucking, visual fixation, head turning) and auditory stimuli, and established that human infants can be observed displaying couplings between action and environmental sensory stimulation already from just after birth, clearly indicating a propensity for intentional behavior. Surprisingly few studies, however, have investigated the associations between upper-limb movements and different auditory stimuli in newborns and young infants, infants born at risk for developmental disorders/delays in particular. Findings from studies of early auditory-motor interaction support that the developing integration of sensory and motor systems is a fundamental part of the process guiding the development of goal-directed action in infancy, of great importance for continued motor, perceptual, and cognitive development. At-risk infants (e.g., those born preterm) may display increasing central auditory processing disorders, negatively affecting early sensory-motor integration, and resulting in long-term consequences on gesturing, language development, and social communication. Consequently, there is a need for more studies on such implications.

  17. Preference for language in early infancy: the human language bias is not speech specific.

    PubMed

    Krentz, Ursula C; Corina, David P

    2008-01-01

    Fundamental to infants' acquisition of their native language is an inherent interest in the language spoken around them over non-linguistic environmental sounds. The following studies explored whether the bias for linguistic signals in hearing infants is specific to speech, or reflects a general bias for all human language, spoken and signed. Results indicate that 6-month-old infants prefer an unfamiliar, visual-gestural language (American Sign Language) over non-linguistic pantomime, but 10-month-olds do not. These data provide evidence against a speech-specific bias in early infancy and provide insights into those properties of human languages that may underlie this language-general attentional bias.

  18. Radiocarbon dating of interstratified Neanderthal and early modern human occupations at the Chatelperronian type-site.

    PubMed

    Gravina, Brad; Mellars, Paul; Ramsey, Christopher Bronk

    2005-11-03

    The question of the coexistence and potential interaction between the last Neanderthal and the earliest intrusive populations of anatomically modern humans in Europe has recently emerged as a topic of lively debate in the archaeological and anthropological literature. Here we report the results of radiocarbon accelerator dating for what has been reported as an interstratified sequence of late Neanderthal and early anatomically modern occupations at the French type-site of the Chatelperronian, the Grotte des Fées de Châtelperron, in east-central France. The radiocarbon measurements seem to provide the earliest secure dates for the presence of Aurignacian technology--and from this, we infer the presence of anatomically modern human populations--in France.

  19. Human radiation studies: Remembering the early years. Oral history of Julie Langham Grilly, February 3, 1995

    SciTech Connect

    1995-09-01

    Julie Langham Grilly was interviewed by representatives of the US DOE Office of Human Radiation Experiments (OHRE) being the widow of Dr. Wright Langham, an investigator of principal interest of the committee. Her extensive experience with research at LANL was also of interest to the committee. Following a brief biographical sketch, Ms. Grilly relates her early postwar experience and her knowledge of Wright Langham`s involvement in animal research at Los Alamos, radiolanthanum tests on monkeys, Eniwetok tissue examinations, research on tritium uptake in humans, plutonium injections, tritium injections, EDTA, and etc. In addition to illuminating her former husband as a researcher and as an individual, she also relates her remembrances of Louis Hempelman, Enrico Fermi, Oppenheimer, Edward Teller, and many others.

  20. Early human use of anadromous salmon in North America at 11,500 y ago.

    PubMed

    Halffman, Carrin M; Potter, Ben A; McKinney, Holly J; Finney, Bruce P; Rodrigues, Antonia T; Yang, Dongya Y; Kemp, Brian M

    2015-10-06

    Salmon represented a critical resource for prehistoric foragers along the North Pacific Rim, and continue to be economically and culturally important; however, the origins of salmon exploitation remain unresolved. Here we report 11,500-y-old salmon associated with a cooking hearth and human burials from the Upward Sun River Site, near the modern extreme edge of salmon habitat in central Alaska. This represents the earliest known human use of salmon in North America. Ancient DNA analyses establish the species as Oncorhynchus keta (chum salmon), and stable isotope analyses indicate anadromy, suggesting that salmon runs were established by at least the terminal Pleistocene. The early use of this resource has important implications for Paleoindian land use, economy, and expansions into northwest North America.

  1. Early human use of anadromous salmon in North America at 11,500 y ago

    PubMed Central

    Halffman, Carrin M.; Potter, Ben A.; McKinney, Holly J.; Finney, Bruce P.; Rodrigues, Antonia T.; Yang, Dongya Y.; Kemp, Brian M.

    2015-01-01

    Salmon represented a critical resource for prehistoric foragers along the North Pacific Rim, and continue to be economically and culturally important; however, the origins of salmon exploitation remain unresolved. Here we report 11,500-y-old salmon associated with a cooking hearth and human burials from the Upward Sun River Site, near the modern extreme edge of salmon habitat in central Alaska. This represents the earliest known human use of salmon in North America. Ancient DNA analyses establish the species as Oncorhynchus keta (chum salmon), and stable isotope analyses indicate anadromy, suggesting that salmon runs were established by at least the terminal Pleistocene. The early use of this resource has important implications for Paleoindian land use, economy, and expansions into northwest North America. PMID:26392548

  2. Auditory-driven phase reset in visual cortex: Human electrocorticography reveals mechanisms of early multisensory integration

    PubMed Central

    Mercier, Manuel R.; Foxe, John J.; Fiebelkorn, Ian C.; Butler, John S.; Schwartz, Theodore H.; Molholm, Sophie

    2013-01-01

    Findings in animal models demonstrate that activity within hierarchically early sensory cortical regions can be modulated by cross-sensory inputs through resetting of the phase of ongoing intrinsic neural oscillations. Here, subdural recordings evaluated whether phase resetting by auditory inputs would impact multisensory integration processes in human visual cortex. Results clearly showed auditory-driven phase reset in visual cortices and, in some cases, frank auditory event-related potentials (ERP) were also observed over these regions. Further, when audiovisual bisensory stimuli were presented, this led to robust multisensory integration effects which were observed in both the ERP and in measures of phase concentration. These results extend findings from animal models to human visual cortices, and highlight the impact of cross-sensory phase resetting by a non-primary stimulus on multisensory integration in ostensibly unisensory cortices. PMID:23624493

  3. A transient microenvironment loaded mainly with macrophages in the early developing human pancreas.

    PubMed

    Banaei-Bouchareb, L; Peuchmaur, M; Czernichow, P; Polak, M

    2006-03-01

    We have previously shown that the human developing pancreas, as a tissue under construction and remodeling, is composed of epithelial ducts and differentiated endocrine cells surrounded by mesenchyme. The physiologic importance of resident tissue leukocytes, expected to enter through the mesenchyme in remodeling functions, prompted us to investigate human developing pancreases for the presence of leukocyte lineages and for expression of cytokines and receptors involved in their recruitment and differentiation. Immunohistochemistry studies were performed on 69 human, paraffin-embedded pancreases at 6-12 weeks of development (WD). Cytokines and receptor transcripts were monitored by reverse transcription (RT)-PCR, by immunohistochemistry when antibodies were available or by in situ hybridization (ISH). We show that numerous cells expressing CD45RA, HLADR and CD68 antigens are cellular components of the mesenchyme of all the pancreases at 6-12 WD. So-called constitutive chemokines (SLC (CCL19), stromal-derived factor 1 (SDF1) (CXCL12)) and a macrophage-specific growth/survival factor, colony-stimulating factor 1 (CSF1), were detected in epithelial duct cells. Both epithelial and mesenchymal cells expressed chemokine receptors, suggesting a role in leukocyte recruitment and possibly in early pancreatic development. In conclusion, we demonstrated the presence of CD45RA resident leukocyte-derived lineages, mostly macrophages, in the early human pancreatic mesenchyme. These cells may have migrated in the tissue through the vascular system, attracted by constitutively expressed chemokines, and locally surviving through CSF1 signaling. The role of macrophages in epithelium/mesenchyme interaction-mediated pancreatic development remains to be demonstrated.

  4. Early evolutionary history and genomic features of gene duplicates in the human genome.

    PubMed

    Bu, Lijing; Katju, Vaishali

    2015-08-20

    Human gene duplicates have been the focus of intense research since the development of array-based and targeted next-generation sequencing approaches in the last decade. These studies have primarily concentrated on determining the extant copy-number variation from a population-genomic perspective but lack a robust evolutionary framework to elucidate the early structural and genomic characteristics of gene duplicates at emergence and their subsequent evolution with increasing age. We analyzed 184 gene duplicate pairs comprising small gene families in the draft human genome with 10% or less synonymous sequence divergence. Human gene duplicates primarily originate from DNA-mediated events, taking up genomic residence as intrachromosomal copies in direct or inverse orientation. The distribution of paralogs on autosomes follows random expectations in contrast to their significant enrichment on the sex chromosomes. Furthermore, human gene duplicates exhibit a skewed gradient of distribution along the chromosomal length with significant clustering in pericentromeric regions. Surprisingly, despite the large average length of human genes, the majority of extant duplicates (83%) are complete duplicates, wherein the entire ORF of the ancestral copy was duplicated. The preponderance of complete duplicates is in accord with an extremely large median duplication span of 36 kb, which enhances the probability of capturing ancestral ORFs in their entirety. With increasing evolutionary age, human paralogs exhibit declines in (i) the frequency of intrachromosomal paralogs, and (ii) the proportion of complete duplicates. These changes may reflect lower survival rates of certain classes of duplicates and/or the role of purifying selection. Duplications arising from RNA-mediated events comprise a small fraction (11.4%) of all human paralogs and are more numerous in older evolutionary cohorts of duplicates. The degree of structural resemblance, genomic location and duplication span

  5. Early modern human dispersal from Africa: genomic evidence for multiple waves of migration.

    PubMed

    Tassi, Francesca; Ghirotto, Silvia; Mezzavilla, Massimo; Vilaça, Sibelle Torres; De Santi, Lisa; Barbujani, Guido

    2015-01-01

    Anthropological and genetic data agree in indicating the African continent as the main place of origin for anatomically modern humans. However, it is unclear whether early modern humans left Africa through a single, major process, dispersing simultaneously over Asia and Europe, or in two main waves, first through the Arab Peninsula into southern Asia and Oceania, and later through a northern route crossing the Levant. Here, we show that accurate genomic estimates of the divergence times between European and African populations are more recent than those between Australo-Melanesia and Africa and incompatible with the effects of a single dispersal. This difference cannot possibly be accounted for by the effects of either hybridization with archaic human forms in Australo-Melanesia or back migration from Europe into Africa. Furthermore, in several populations of Asia we found evidence for relatively recent genetic admixture events, which could have obscured the signatures of the earliest processes. We conclude that the hypothesis of a single major human dispersal from Africa appears hardly compatible with the observed historical and geographical patterns of genome diversity and that Australo-Melanesian populations seem still to retain a genomic signature of a more ancient divergence from Africa.

  6. Distinct vestibular effects on early and late somatosensory cortical processing in humans.

    PubMed

    Pfeiffer, Christian; van Elk, Michiel; Bernasconi, Fosco; Blanke, Olaf

    2016-01-15

    In non-human primates several brain areas contain neurons that respond to both vestibular and somatosensory stimulation. In humans, vestibular stimulation activates several somatosensory brain regions and improves tactile perception. However, less is known about the spatio-temporal dynamics of such vestibular-somatosensory interactions in the human brain. To address this issue, we recorded high-density electroencephalography during left median nerve electrical stimulation to obtain Somatosensory Evoked Potentials (SEPs). We analyzed SEPs during vestibular activation following sudden decelerations from constant-velocity (90°/s and 60°/s) earth-vertical axis yaw rotations and SEPs during a non-vestibular control period. SEP analysis revealed two distinct temporal effects of vestibular activation: An early effect (28-32ms post-stimulus) characterized by vestibular suppression of SEP response strength that depended on rotation velocity and a later effect (97-112ms post-stimulus) characterized by vestibular modulation of SEP topographical pattern that was rotation velocity-independent. Source estimation localized these vestibular effects, during both time periods, to activation differences in a distributed cortical network including the right postcentral gyrus, right insula, left precuneus, and bilateral secondary somatosensory cortex. These results suggest that vestibular-somatosensory interactions in humans depend on processing in specific time periods in somatosensory and vestibular cortical regions. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Early Pleistocene human humeri from the Gran Dolina-TD6 site (Sierra de Atapuerca, Spain).

    PubMed

    Bermúdez de Castro, José María; Carretero, José Miguel; García-González, Rebeca; Rodríguez-García, Laura; Martinón-Torres, María; Rosell, Jordi; Blasco, Ruth; Martín-Francés, Laura; Modesto, Mario; Carbonell, Eudald

    2012-04-01

    In this report, we present a morphometric comparative study of two Early Pleistocene humeri recovered from the TD6 level of the Gran Dolina cave site in Sierra de Atapuerca, northern Spain. ATD6-121 belongs to a child between 4 and 6 years old, whereas ATD6-148 corresponds to an adult. ATD6-148 exhibits the typical pattern of the genus Homo, but it also shows a large olecranon fossa and very thin medial and lateral pillars (also present in ATD6-121), sharing these features with European Middle Pleistocene hominins, Neandertals, and the Bodo Middle Pleistocene humerus. The morphology of the distal epiphysis, together with a few dental traits, suggests a phylogenetic relationship between the TD6 hominins and the Neandertal lineage. Given the older geochronological age of these hominins (ca. 900 ka), which is far from the age estimated by palaeogenetic studies for the population divergence of modern humans and Neandertals (ca. 400 ka), we suggest that this suite of derived "Neandertal" features appeared early in the evolution of the genus Homo. Thus, these features are not "Neandertal" apomorphies but traits which appeared in an ancestral and polymorphic population during the Early Pleistocene. Copyright © 2012 Wiley Periodicals, Inc.

  8. Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts

    PubMed Central

    Thaler, Lore; Arnott, Stephen R.; Goodale, Melvyn A.

    2011-01-01

    Background A small number of blind people are adept at echolocating silent objects simply by producing mouth clicks and listening to the returning echoes. Yet the neural architecture underlying this type of aid-free human echolocation has not been investigated. To tackle this question, we recruited echolocation experts, one early- and one late-blind, and measured functional brain activity in each of them while they listened to their own echolocation sounds. Results When we compared brain activity for sounds that contained both clicks and the returning echoes with brain activity for control sounds that did not contain the echoes, but were otherwise acoustically matched, we found activity in calcarine cortex in both individuals. Importantly, for the same comparison, we did not observe a difference in activity in auditory cortex. In the early-blind, but not the late-blind participant, we also found that the calcarine activity was greater for echoes reflected from surfaces located in contralateral space. Finally, in both individuals, we found activation in middle temporal and nearby cortical regions when they listened to echoes reflected from moving targets. Conclusions These findings suggest that processing of click-echoes recruits brain regions typically devoted to vision rather than audition in both early and late blind echolocation experts. PMID:21633496

  9. Gram-positive pathogenic bacteria induce a common early response in human monocytes

    PubMed Central

    2010-01-01

    Background We infected freshly isolated human peripheral monocytes with live bacteria of three clinically important gram-positive bacterial species, Staphylococcus aureus, Streptococcus pneumoniae and Listeria monocytogenes and studied the ensuing early transcriptional response using expression microarrays. Thus the observed response was unbiased by signals originating from other helper and effector cells of the host and was not limited to induction by solitary bacterial constituents. Results Activation of monocytes was demonstrated by the upregulation of chemokine rather than interleukin genes except for the prominent expression of interleukin 23, marking it as the early lead cytokine. This activation was accompanied by cytoskeleton rearrangement signals and a general anti-oxidative stress and anti-apoptotic reaction. Remarkably, the expression profiles also provide evidence that monocytes participate in the regulation of angiogenesis and endothelial function in response to these pathogens. Conclusion Regardless of the invasion properties and survival mechanisms of the pathogens used, we found that the early response comprised of a consistent and common response. The common response was hallmarked by the upregulation of interleukin 23, a rather unexpected finding regarding Listeria infection, as this cytokine has been linked primarily to the control of extracellular bacterial dissemination. PMID:21044323

  10. Changes in Laminin Expression Pattern during Early Differentiation of Human Embryonic Stem Cells.

    PubMed

    Pook, Martin; Teino, Indrek; Kallas, Ade; Maimets, Toivo; Ingerpuu, Sulev; Jaks, Viljar

    2015-01-01

    Laminin isoforms laminin-511 and -521 are expressed by human embryonic stem cells (hESC) and can be used as a growth matrix to culture these cells under pluripotent conditions. However, the expression of these laminins during the induction of hESC differentiation has not been studied in detail. Furthermore, the data regarding the expression pattern of laminin chains in differentiating hESC is scarce. In the current study we aimed to fill this gap and investigated the potential changes in laminin expression during early hESC differentiation induced by retinoic acid (RA). We found that laminin-511 but not -521 accumulates in the committed cells during early steps of hESC differentiation. We also performed a comprehensive analysis of the laminin chain repertoire and found that pluripotent hESC express a more diverse range of laminin chains than shown previously. In particular, we provide the evidence that in addition to α1, α5, β1, β2 and γ1 chains, hESC express α2, α3, β3, γ2 and γ3 chain proteins and mRNA. Additionally, we found that a variant of laminin α3 chain-145 kDa-accumulated in RA-treated hESC showing that these cells produce prevalently specifically modified version of α3 chain in early phase of differentiation.

  11. Critical band 3 multiprotein complex interactions establish early during human erythropoiesis

    PubMed Central

    Satchwell, Timothy J; Bell, Amanda J.; Pellegrin, Stephanie; Kupzig, Sabine; Ridgwell, Kay; Daniels, Geoff; Anstee, David J

    2015-01-01

    Band 3, the major anion transport protein of human erythrocytes forms the core of a multiprotein complex in the erythrocyte membrane. Here we studied the spatio-temporal mechanisms of band 3 multiprotein complex assembly during erythropoiesis. Significant pools of intracellular band 3 and RhAG were found in the basophilic erythroblast. These intracellular pools decreased in the polychromatic erythroblast whilst surface expression increased, and were lowest in the orthochromatic erythroblast and reticulocytes. Protease treatment of intact cells to remove extracellular epitopes recognized by antibodies to band 3 and RhAG was used to study surface delivery kinetics and intracellular complex composition from the proerythroblast stage to the enucleated reticulocyte. Newly synthesized band 3 and protein 4.2 interact initially in the early stages of the secretory pathway and are found associated at the plasma membrane from the basophilic stage of erythropoiesis. Although we could successfully co-immunoprecipitate Rh with RhAG from plasma membrane pools at a similar stage, no intracellular interaction between these proteins was detectable. Knockdown of RhAG during early erythropoiesis was accompanied by a concomitant drop in membrane expression of Rh polypeptides. These data are consistent with assembly of major components of the band 3 macrocomplex at an early stage during erythropoiesis. PMID:21527529

  12. Changes in Laminin Expression Pattern during Early Differentiation of Human Embryonic Stem Cells

    PubMed Central

    Pook, Martin; Teino, Indrek; Kallas, Ade; Maimets, Toivo; Ingerpuu, Sulev; Jaks, Viljar

    2015-01-01

    Laminin isoforms laminin-511 and -521 are expressed by human embryonic stem cells (hESC) and can be used as a growth matrix to culture these cells under pluripotent conditions. However, the expression of these laminins during the induction of hESC differentiation has not been studied in detail. Furthermore, the data regarding the expression pattern of laminin chains in differentiating hESC is scarce. In the current study we aimed to fill this gap and investigated the potential changes in laminin expression during early hESC differentiation induced by retinoic acid (RA). We found that laminin-511 but not -521 accumulates in the committed cells during early steps of hESC differentiation. We also performed a comprehensive analysis of the laminin chain repertoire and found that pluripotent hESC express a more diverse range of laminin chains than shown previously. In particular, we provide the evidence that in addition to α1, α5, β1, β2 and γ1 chains, hESC express α2, α3, β3, γ2 and γ3 chain proteins and mRNA. Additionally, we found that a variant of laminin α3 chain—145 kDa—accumulated in RA-treated hESC showing that these cells produce prevalently specifically modified version of α3 chain in early phase of differentiation. PMID:26378917

  13. Abnormalities in Resting-State Functional Connectivity in Early Human Immunodeficiency Virus Infection

    PubMed Central

    Wang, Xue; Foryt, Paul; Ochs, Renee; Chung, Jae-Hoon; Wu, Ying; Parrish, Todd

    2011-01-01

    Abstract Limited information is available concerning changes that occur in the brain early in human immunodeficiency virus (HIV) infection. This investigation evaluated resting-state functional connectivity, which is based on correlations of spontaneous blood oxygen level-dependent functional magnetic resonance imaging (fMRI) oscillations between brain regions, in 15 subjects within the first year of HIV infection and in 15 age-matched controls. Resting-state fMRI data for each session were concatenated in time across subjects to create a single 4D dataset and decomposed into 36 independent component analysis (ICA) using Multivariate Exploratory Linear Optimized Decomposition into Independent Components. ICA components were back-reconstructed for each subject's 4D data to estimate subject-specific spatial maps using the dual-regression technique. Comparison of spatial maps between HIV and controls revealed significant differences in the lateral occipital cortex (LOC) network. Reduced coactivation in left inferior parietal cortex within the LOC network was identified in the HIV subjects. Connectivity strength within this region correlated with performance on tasks involving visual-motor coordination (Grooved Pegboard and Rey Figure Copy) in the HIV group. The findings indicate prominent changes in resting-state functional connectivity of visual networks early in HIV infection. This network may sustain injury in association with the intense viremia and brain viral invasion before immune defenses can contain viral replication. Resting-state functional connectivity may have utility as a noninvasive neuroimaging biomarker for central nervous system impairment in early HIV infection. PMID:22433049

  14. Primary cortical folding in the human newborn: an early marker of later functional development

    PubMed Central

    Benders, M.; Borradori-Tolsa, C.; Cachia, A.; Lazeyras, F.; Ha-Vinh Leuchter, R.; Sizonenko, S. V.; Warfield, S. K.; Mangin, J. F.; Hüppi, P. S.

    2008-01-01

    In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain developmental and neuropsychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormalities might be present long before the appearance of functional symptoms. So far, the precise mechanisms responsible for such alteration in the convolution pattern during intra-uterine or post-natal development are still poorly understood. Here we compared anatomical and functional brain development in vivo among 45 premature newborns who experienced different intra-uterine environments: 22 normal singletons, 12 twins and 11 newborns with intrauterine growth restriction (IUGR). Using magnetic resonance imaging (MRI) and dedicated post-processing tools, we investigated early disturbances in cortical formation at birth, over the developmental period critical for the emergence of convolutions (26–36 weeks of gestational age), and defined early ‘endophenotypes’ of sulcal development. We demonstrated that twins have a delayed but harmonious maturation, with reduced surface and sulcation index compared to singletons, whereas the gyrification of IUGR newborns is discordant to the normal developmental trajectory, with a more pronounced reduction of surface in relation to the sulcation index compared to normal newborns. Furthermore, we showed that these structural measurements of the brain at birth are predictors of infants’ outcome at term equivalent age, for MRI-based cerebral volumes and neurobehavioural development evaluated with the assessment of preterm infant's behaviour (APIB). PMID:18587151

  15. Measurement of hepatic insulin sensitivity early after the bypass of the proximal small bowel in humans

    PubMed Central

    Herring, R.; Vusirikala, A.; Shojaee‐Moradi, F.; Jackson, N. C.; Chandaria, S.; Jackson, S. N.; Goldstone, A. P.; Hakim, N.; Patel, A. G.; Umpleby, A. M.; Le Roux, C. W.

    2016-01-01

    Summary Objective Unlike gastric banding or sleeve gastrectomy procedures, intestinal bypass procedures, Roux‐en‐Y gastric bypass in particular, lead to rapid improvements in glycaemia early after surgery. The bypass of the proximal small bowel may have weight loss and even caloric restriction‐independent glucose‐lowering properties on hepatic insulin sensitivity. In this first human mechanistic study, we examined this hypothesis by investigating the early effects of the duodeno‐jejunal bypass liner (DJBL; GI Dynamics, USA) on the hepatic insulin sensitivity by using the gold standard euglycaemic hyperinsulinaemic clamp methodology. Method Seven patients with obesity underwent measurement of hepatic insulin sensitivity at baseline, 1 week after a low‐calorie liquid diet and after a further 1 week following insertion of the DJBL whilst on the same diet. Results Duodeno‐jejunal bypass liner did not improve the insulin sensitivity of hepatic glucose production beyond the improvements achieved with caloric restriction. Conclusions Caloric restriction may be the predominant driver of early increases in hepatic insulin sensitivity after the endoscopic bypass of the proximal small bowel. The same mechanism may be at play after Roux‐en‐Y gastric bypass and explain, at least in part, the rapid improvements in glycaemia.

  16. Desert speleothems reveal climatic window for African exodus of early modern humans

    NASA Astrophysics Data System (ADS)

    Vaks, Anton; Bar-Matthews, Miryam; Ayalon, Avner; Matthews, Alan; Halicz, Ludwik; Frumkin, Amos

    2007-09-01

    One of the first movements of early modern humans out of Africa occurred 130-100 thousand years ago (ka), when they migrated northward to the Levant region. The climatic conditions that accompanied this migration are still under debate. Using high-precision multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) U-Th methods, we dated carbonate cave deposits (speleothems) from the central and southern Negev Desert of Israel, located at the northeastern margin of the Saharan-Arabian Desert. Speleothems grow only when rainwater enters the unsaturated zone, and this study reveals that a major cluster of wet episodes (the last recorded in the area) occurred between 140 and 110 ka. This episodic wet period coincided with increased monsoonal precipitation in the southern parts of the Saharan-Arabian Desert. The disappearance at this time of the desert barrier between central Africa and the Levant, and particularly in the Sinai-Negev land bridge between Africa and Asia, would have created a climatic “window” for early modern human dispersion to the Levant.

  17. The habenulo-interpeduncular and mammillothalamic tracts: early developed fiber tracts in the human fetal diencephalon.

    PubMed

    Cho, Kwang Ho; Mori, Shigemi; Jang, Hyung Suk; Kim, Ji Hyun; Abe, Hiroshi; Rodriguez-Vazquez, Jose Francisco; Murakami, Gen

    2014-09-01

    The habenulo-interpeduncular (HI) and mammillothalamic (MT) tracts are phylogenetically ancient. The clinical relevance of these tracts has recently received attention. In this work, we map the anatomy the developing HI and MT. To investigate the topographical anatomy of developing fiber tracts in and around the diencephalon, we examined the horizontal, frontal, and sagittal serial paraffin sections of 28 human fetuses at 8-12 weeks of gestation. In all specimens, eosinophilic early fiber bundles were limited to the bilateral HI and MT tracts in contrast to pale-colored later developing fibers such as the thalamocortical projections and optic tract. The HI and MT tracts ran nearly parallel and sandwiched the thalamus from the dorsal and ventral sides, respectively. The nerve tract course appeared to range from 5-7 mm for the HI tract and 3-5 mm for the MT tract in 15 specimens at 11-12 weeks. The HI tract was embedded in, adjacent to, or distant from the developing parvocellular red nucleus. In early human fetuses, HI and MT tracts might be limited pathways for primitive cholinergic fiber connections between the ventral midbrain and epithalamic limbic system.

  18. Early embryonic failure: Expression and imprinted status of candidate genes on human chromosome 21

    SciTech Connect

    Sherman, L.S.; Bennett, P.R.; Moore, G.E.

    1994-09-01

    Two cases of maternal uniparental (hetero)disomy for human chromosome 21 (mUPD21) have been identified in a systematic search for UPD in 23 cases of early embryonic failure (EEF). Bi-parental origin of the other chromosome pairs was confirmed using specific VNTR probes or dinucleotide repeat analysis. Both maternally and paternally derived isochromosomes 21q have previously been identified in two individuals with normal phenotypes. Full UPD21 has a different mechanism of origin than uniparental isochromosome 21q and its effect on imprinted genes and phenotypic outcome will therefore not necessarily be the same. EEF associated with mUPD21 suggests that developmentally important genes on HSA 21 may be imprinted such that they are only expressed from either the maternally or paternally derived alleles. We have searched for monoallelic expression of candidate genes on HSA 21 in human pregnancy (CBS, IFNAR, COL6A1) using intragenic DNA polymorphisms. These genes were chosen either because their murine homologues lie in imprinted regions or because they are potentially important in embryogenesis. Once imprinted candidate genes have been identified, their methylation status and expression in normal, early embryonic failure and uniparental disomy 21 pregnancies will be studied. At the same time, a larger number of cases of EEF are being examined to further investigate the incidence of UPD21 in this group.

  19. Characterization of early stages of human B cell development by gene expression profiling.

    PubMed

    Hystad, Marit E; Myklebust, June H; Bø, Trond H; Sivertsen, Einar A; Rian, Edith; Forfang, Lise; Munthe, Else; Rosenwald, Andreas; Chiorazzi, Michael; Jonassen, Inge; Staudt, Louis M; Smeland, Erlend B

    2007-09-15

    We have characterized several stages of normal human B cell development in adult bone marrow by gene expression profiling of hemopoietic stem cells, early B (E-B), pro-B, pre-B, and immature B cells, using RNA amplification and Lymphochip cDNA microarrays (n = 6). Hierarchical clustering of 758 differentially expressed genes clearly separated the five populations. We used gene sets to investigate the functional assignment of the differentially expressed genes. Genes involved in VDJ recombination as well as B lineage-associated transcription factors (TCF3 (E2A), EBF, BCL11A, and PAX5) were turned on in E-B cells, before acquisition of CD19. Several transcription factors with unknown roles in B lymphoid cells demonstrated interesting expression patterns, including ZCCHC7 and ZHX2. Compared with hemopoietic stem cells and pro-B cells, E-B cells had increased expression of 18 genes, and these included IGJ, IL1RAP, BCL2, and CD62L. In addition, E-B cells expressed T/NK lineage and myeloid-associated genes including CD2, NOTCH1, CD99, PECAM1, TNFSF13B, and MPO. Expression of key genes was confirmed at the protein level by FACS analysis. Several of these Ags were heterogeneously expressed, providing a basis for further subdivision of E-B cells. Altogether, these results provide new information regarding expression of genes in early stages of human B cell development.

  20. Unpredicted ovulations and conceptions during early pregnancy: an explanatory mechanism of human superfetation.

    PubMed

    Tarín, Juan J; García-Pérez, Miguel A; Hermenegildo, Carlos; Cano, Antonio

    2013-01-01

    In this bioessay, a literature review on human superfetation was performed in order to find epidemiological variables associated with this phenomenon. Thereafter, an explanatory mechanism of superfetation compatible with the endocrinological, histological and physiological changes undergone by women during early pregnancy is proposed. Superfetation can be defined as the ovulation, fertilisation and implantation of a second or additional embryo(s) during pregnancy. The literature review evidences a small discordance in gestational age between dizygotic twins in humans (range: 2-4 weeks; mean ± s.e.m.: 3.3 ± 0.3 weeks). This difference is compatible with a luteal out-of-phase (LOOP; i.e. atypical increase in E2 levels in the mid-luteal phase)-like event occurring between 1 and 3 weeks after the ovulation that allowed the first pregnancy to take place. The LOOP-like event may allow passive sperm transport from the vaginal fornix to the Fallopian tube ipsilateral to the ovulatory ovary and trigger a LH peak and ovulation. Furthermore, during very early pregnancy, the decidual reaction is not yet completed and at least one proximal Fallopian ostium may be opened, allowing the passage of the spermatozoa ascending to the fertilisation site and the extra embryo(s) descending to the implantation site(s).

  1. Early Human Activity (pre-332 BC) in Alexandria, Egypt: New findings in Eastern Harbor Cores

    NASA Astrophysics Data System (ADS)

    Stanley, J.; Landau, E. A.

    2005-12-01

    Historians have long postulated that a settlement called Rhakotis was present on Egypt's Mediterranean coast in the area subsequently occupied by the city of Alexandria. To date, however, the precise position of that site has not been located in the immediate area of the city founded by Alexander the Great. Also undefined are the earliest phases of occupation that pre-date Alexandria on Pharos Island and in the harbour area. A geoarchaeological project emphasizing sediment cores in Alexandria's Eastern Harbour now provides evidence of human occupation adjacent to these settings prior to establishment of Greece's great port in 332 BC. A radiocarbon-dated stratigraphic unit, defined as Middle Sand (III) and older than the 4th century BC, includes locally produced ceramics, along with rock fragments of non-local origin, and increased content of sand-sized heavy mineral and organic matter. Together, these date at least to Egypt's Late Dynastic Period (712-332 BC). Moreover, the geographic positions of core sites containing these markers indicate that early habitation occurred both at Pharos Island and on the mainland where the future Alexandria would be built. New findings in cores recovered in this marine environment are adding to knowledge of both natural processes and effects of human activity in early Alexandria.

  2. Fourier transform infrared microspectroscopy identifies early lineage commitment in differentiating human embryonic stem cells.

    PubMed

    Heraud, Philip; Ng, Elizabeth S; Caine, Sally; Yu, Qing C; Hirst, Claire; Mayberry, Robyn; Bruce, Amanda; Wood, Bayden R; McNaughton, Don; Stanley, Edouard G; Elefanty, Andrew G

    2010-03-01

    Human ESCs (hESCs) are a valuable tool for the study of early human development and represent a source of normal differentiated cells for pharmaceutical and biotechnology applications and ultimately for cell replacement therapies. For all applications, it will be necessary to develop assays to validate the efficacy of hESC differentiation. We explored the capacity for FTIR spectroscopy, a technique that rapidly characterises cellular macromolecular composition, to discriminate mesendoderm or ectoderm committed cells from undifferentiated hESCs. Distinct infrared spectroscopic "signatures" readily distinguished hESCs from these early differentiated progeny, with bioinformatic models able to correctly classify over 97% of spectra. These data identify a role for FTIR spectroscopy as a new modality to complement conventional analyses of hESCs and their derivatives. FTIR spectroscopy has the potential to provide low-cost, automatable measurements for the quality control of stem and differentiated cells to be used in industry and regenerative medicine. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

  3. Early short-term treatment with neutralizing human monoclonal antibodies halts SHIV infection in infant macaques.

    PubMed

    Hessell, Ann J; Jaworski, J Pablo; Epson, Erin; Matsuda, Kenta; Pandey, Shilpi; Kahl, Christoph; Reed, Jason; Sutton, William F; Hammond, Katherine B; Cheever, Tracy A; Barnette, Philip T; Legasse, Alfred W; Planer, Shannon; Stanton, Jeffrey J; Pegu, Amarendra; Chen, Xuejun; Wang, Keyun; Siess, Don; Burke, David; Park, Byung S; Axthelm, Michael K; Lewis, Anne; Hirsch, Vanessa M; Graham, Barney S; Mascola, John R; Sacha, Jonah B; Haigwood, Nancy L

    2016-04-01

    Prevention of mother-to-child transmission (MTCT) of HIV remains a major objective where antenatal care is not readily accessible. We tested HIV-1-specific human neutralizing monoclonal antibodies (NmAbs) as a post-exposure therapy in an infant macaque model for intrapartum MTCT. One-month-old rhesus macaques were inoculated orally with the simian-human immunodeficiency virus SHIVSF162P3. On days 1, 4, 7 and 10 after virus exposure, we injected animals subcutaneously with NmAbs and quantified systemic distribution of NmAbs in multiple tissues within 24 h after antibody administration. Replicating virus was found in multiple tissues by day 1 in animals that were not treated. All NmAb-treated macaques were free of virus in blood and tissues at 6 months after exposure. We detected no anti-SHIV T cell responses in blood or tissues at necropsy, and no virus emerged after CD8(+) T cell depletion. These results suggest that early passive immunotherapy can eliminate early viral foci and thereby prevent the establishment of viral reservoirs.

  4. Odontometric sex estimation in humans using measurements on permanent canines. A comparison of an early Neolithic and an early medieval assemblage from Germany.

    PubMed

    Flohr, Stefan; Kierdorf, Uwe; Kierdorf, Horst

    This study analyzed whether cervical canine dimensions measured at the enamel-cement junction can provide a basis for sex estimation in human skeletal remains and whether discriminant functions developed for one assemblage can be successfully applied also to others. Cervical canine dimensions were recorded for an Early Neolithic (Linear Pottery Culture) and an early medieval skeletal assemblage from Germany. Only individuals in whom sex estimation based on standard diagnostic criteria could be performed with a high degree of certainty were included. Sexual dimorphism in cervical canine dimensions was higher in the early medieval assemblage. Values in females of the Early Neolithic assemblage exceeded those of the early medieval assemblage, while there were no significant differences in males. Discriminant analysis led to a maximum correct classification of sex (cross validation results) of 94.0% in the early medieval and of 79.2% in the Early Neolithic assemblage. Applying the discriminant functions developed on one assemblage to the other led to poor classification results. Cervical canine dimensions are highly correlated with sexually dimorphic skeletal traits and may provide a good basis for sexing archaeological individuals. It is suggested that due to population differences in canine dimensions, either assemblage specific discriminant functions should be developed or the applicability of existing formulae obtained on other assemblages to the assemblage under study should be carefully checked.

  5. Comparing salt tolerance of beet cultivars and their halophytic ancestor: consequences of domestication and breeding programmes

    PubMed Central

    Rozema, Jelte; Cornelisse, Danny; Zhang, Yuancheng; Li, Hongxiu; Bruning, Bas; Katschnig, Diana; Broekman, Rob; Ji, Bin; van Bodegom, Peter

    2015-01-01

    Salt tolerance of higher plants is determined by a complex set of traits, the timing and rate of evolution of which are largely unknown. We compared the salt tolerance of cultivars of sugar beet and their ancestor, sea beet, in hydroponic studies and evaluated whether traditional domestication and more recent breeding have changed salt tolerance of the cultivars relative to their ancestor. Our comparison of salt tolerance of crop cultivars is based on values of the relative growth rate (RGR) of the entire plant at various salinity levels. We found considerable salt tolerance of the sea beet and slightly, but significantly, reduced salt tolerance of the sugar beet cultivars. This indicates that traditional domestication by selection for morphological traits such as leaf size, beet shape and size, enhanced productivity, sugar content and palatability slightly affected salt tolerance of sugar beet cultivars. Salt tolerance among four sugar beet cultivars, three of which have been claimed to be salt tolerant, did not differ. We analysed the components of RGR to understand the mechanism of salt tolerance at the whole-plant level. The growth rate reduction at higher salinity was linked with reduced leaf area at the whole-plant level (leaf area ratio) and at the individual leaf level (specific leaf area). The leaf weight fraction was not affected by increased salinity. On the other hand, succulence and leaf thickness and the net assimilation per unit of leaf area (unit leaf rate) increased in response to salt treatment, thus partially counteracting reduced capture of light by lower leaf area. This compensatory mechanism may form part of the salt tolerance mechanism of sea beet and the four studied sugar beet cultivars. Together, our results indicate that domestication of the halophytic ancestor sea beet slightly reduced salt tolerance and that breeding for improved salt tolerance of sugar beet cultivars has not been effective. PMID:25492122

  6. Human Macrophage Response to L. (Viannia) panamensis: Microarray Evidence for an Early Inflammatory Response

    PubMed Central

    Rojas, Ricardo; Ettinger, Nicholas A.; Tikhonova, Irina; Alexander, Neal D.; Valderrama, Liliana; Hager, Janet; Wilson, Mary E.; Lin, Aiping; Zhao, Hongyu; Saravia, Nancy G.; McMahon-Pratt, Diane

    2012-01-01

    Background Previous findings indicate that susceptibility to Leishmania (Viannia) panamensis infection of monocyte-derived macrophages from patients and asymptomatically infected individuals were associated with the adaptive immune response and clinical outcome. Methodology/Principal Findings To understand the basis for this difference we examined differential gene expression of human monocyte-derived macrophages following exposure to L. (V.) panamensis. Gene activation profiles were determined using macrophages from healthy volunteers cultured with or without stationary phase promastigotes of L. (V.) panamensis. Significant changes in expression (>1.5-fold change; p<0.05; up- or down-regulated) were identified at 0.5, 4 and 24 hours. mRNA abundance profiles varied over time, with the highest level of activation occurring at earlier time points (0.5 and 4 hrs). In contrast to observations for other Leishmania species, most significantly changed mRNAs were up- rather than down-regulated, especially at early time points. Up-regulated transcripts over the first 24 hours belonged to pathways involving eicosanoid metabolism, oxidative stress, activation of PKC through G protein coupled receptors, or mechanism of gene regulation by peroxisome proliferators via PPARα. Additionally, a marked activation of Toll-receptor mediated pathways was observed. Comparison with published microarray data from macrophages infected with L. (Leishmania) chagasi indicate differences in the regulation of genes involved in signaling, motility and the immune response. Conclusions Results show that the early (0.5 to 24 hours) human monocyte-derived macrophage response to L. (Viannia) panamensis is not quiescent, in contrast to published reports examining later response times (48–96 hours). Early macrophage responses are important for the developing cellular response at the site of infection. The kinetics and the mRNA abundance profiles induced by L. (Viannia) panamensis illustrate the

  7. The Early Development of Human Mirror Mechanisms: Evidence from Electromyographic Recordings at 3 and 6 Months

    ERIC Educational Resources Information Center

    Turati, Chiara; Natale, Elena; Bolognini, Nadia; Senna, Irene; Picozzi, Marta; Longhi, Elena; Cassia, Viola Macchi

    2013-01-01

    In primates and adult humans direct understanding of others' action is provided by mirror mechanisms matching action observation and action execution (e.g. Casile, Caggiano & Ferrari, 2011). Despite the growing body of evidence detailing the existence of these mechanisms in the adult human brain, their origins and early development are…

  8. The Early Development of Human Mirror Mechanisms: Evidence from Electromyographic Recordings at 3 and 6 Months

    ERIC Educational Resources Information Center

    Turati, Chiara; Natale, Elena; Bolognini, Nadia; Senna, Irene; Picozzi, Marta; Longhi, Elena; Cassia, Viola Macchi

    2013-01-01

    In primates and adult humans direct understanding of others' action is provided by mirror mechanisms matching action observation and action execution (e.g. Casile, Caggiano & Ferrari, 2011). Despite the growing body of evidence detailing the existence of these mechanisms in the adult human brain, their origins and early development are…

  9. A More-than-Social Movement: The Post-Human Condition of Quality in the Early Years

    ERIC Educational Resources Information Center

    Arndt, Sonja; Tesar, Marek

    2016-01-01

    This article explores quality in early childhood education by de-elevating the importance of the human subject and experience, and heightening instead a focus on and tensions with the post-human. The argument traces the intricate web of "qualities" woven throughout entanglements of subjects, objects and things that constitute what is…

  10. The (Bio)Politicization of Neuroscience in Australian Early Years Policies: Fostering Brain-Resources "as" Human Capital

    ERIC Educational Resources Information Center

    Millei, Zsuzsa; Joronen, Mikko

    2016-01-01

    At the present, human capital theory (HCT) and neuroscience reasoning are dominant frameworks in early childhood education and care (ECEC) worldwide. Popular since the 1960s, HCT has provided an economic understanding of human beings and offered strategies to manage the population with the promise of bringing improvements to nations. Neuroscience…