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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. PMID:26098372

  3. 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. PMID:26852813

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

    PubMed

    Teaford, M F; Ungar, P S

    2000-12-01

    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

  5. 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

  6. 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

  7. The vertebral formula of the last common ancestor of African apes and humans.

    PubMed

    McCollum, Melanie A; Rosenman, Burt A; Suwa, Gen; Meindl, Richard S; Lovejoy, C Owen

    2010-03-15

    The modal number of lumbar vertebrae in modern humans is five. It varies between three and four in extant African apes (mean=3.5). Because both chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) possess the same distributions of thoracic, lumbar, and sacral vertebrae, it has been assumed from parsimony that the last common ancestor (LCA) of African apes and humans possessed a similarly short lower back. This "short-backed LCA" scenario has recently been viewed favorably in an analysis of the intra- and interspecific variation in axial formulas observed among African apes and humans (Pilbeam, 2004. J Exp Zool 302B:241-267). However, the number of bonobo (Pan paniscus) specimens in that study was small (N=17). Here we reconsider vertebral type and number in the LCA in light of an expanded P. paniscus sample as well as evidence provided by the human fossil record. The precaudal (pre-coccygeal) axial column of bonobos differs from those of chimpanzees and gorillas in displaying one additional vertebra as well as significantly different combinations of sacral, lumbar, and thoracic vertebrae. These findings, along with the six-segmented lumbar column of early Australopithecus and early Homo, suggest that the LCA possessed a long axial column and long lumbar spine and that reduction in the lumbar column occurred independently in humans and in each ape clade, and continued after separation of the two species of Pan as well. Such an explanation is strongly congruent with additional details of lumbar column reduction and lower back stabilization in African apes. PMID:19688850

  8. A hominid from the lower Pleistocene of Atapuerca, Spain: possible ancestor to Neandertals and modern humans.

    PubMed

    Bermúdez de Castro, J M; Arsuaga, J L; Carbonell, E; Rosas, A; Martínez, I; Mosquera, M

    1997-05-30

    Human fossil remains recovered from the TD6 level (Aurora stratum) of the lower Pleistocene cave site of Gran Dolina, Sierra de Atapuerca, Spain, exhibit a unique combination of cranial, mandibular, and dental traits and are suggested as a new species of Homo-H. antecessor sp. nov. The fully modern midfacial morphology of the fossils antedates other evidence of this feature by about 650, 000 years. The midfacial and subnasal morphology of modern humans may be a retention of a juvenile pattern that was not yet present in H. ergaster. Homo antecessor may represent the last common ancestor for Neandertals and modern humans. PMID:9162001

  9. 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

  10. 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

  11. 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. PMID:26351685

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence.

    PubMed

    Dutheil, Julien Y; Munch, Kasper; Nam, Kiwoong; Mailund, Thomas; Schierup, Mikkel H

    2015-08-01

    The human and chimpanzee X chromosomes are less divergent than expected based on autosomal divergence. We study incomplete lineage sorting patterns between humans, chimpanzees and gorillas to show that this low divergence can be entirely explained by megabase-sized regions comprising one-third of the X chromosome, where polymorphism in the human-chimpanzee ancestral species was severely reduced. We show that background selection can explain at most 10% of this reduction of diversity in the ancestor. Instead, we show that several strong selective sweeps in the ancestral species can explain it. We also report evidence of population specific sweeps in extant humans that overlap the regions of low diversity in the ancestral species. These regions further correspond to chromosomal sections shown to be devoid of Neanderthal introgression into modern humans. This suggests that the same X-linked regions that undergo selective sweeps are among the first to form reproductive barriers between diverging species. We hypothesize that meiotic drive is the underlying mechanism causing these two observations. PMID:26274919

  1. Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence

    PubMed Central

    Dutheil, Julien Y.; Munch, Kasper; Nam, Kiwoong; Mailund, Thomas; Schierup, Mikkel H.

    2015-01-01

    The human and chimpanzee X chromosomes are less divergent than expected based on autosomal divergence. We study incomplete lineage sorting patterns between humans, chimpanzees and gorillas to show that this low divergence can be entirely explained by megabase-sized regions comprising one-third of the X chromosome, where polymorphism in the human-chimpanzee ancestral species was severely reduced. We show that background selection can explain at most 10% of this reduction of diversity in the ancestor. Instead, we show that several strong selective sweeps in the ancestral species can explain it. We also report evidence of population specific sweeps in extant humans that overlap the regions of low diversity in the ancestral species. These regions further correspond to chromosomal sections shown to be devoid of Neanderthal introgression into modern humans. This suggests that the same X-linked regions that undergo selective sweeps are among the first to form reproductive barriers between diverging species. We hypothesize that meiotic drive is the underlying mechanism causing these two observations. PMID:26274919

  2. 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…

  3. 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

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

    PubMed

    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

  5. 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. PMID:26886800

  6. 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

  7. Duplication of the gamma-globin gene mediated by L1 long interspersed repetitive elements in an early ancestor of simian primates.

    PubMed Central

    Fitch, D H; Bailey, W J; Tagle, D A; Goodman, M; Sieu, L; Slightom, J L

    1991-01-01

    Regions surrounding the single gamma-globin gene of galago and the duplicated gamma 1- and gamma 2-globin genes of gibbon, rhesus monkey, and spider monkey were sequenced and aligned with those from humans. Contrary to previous studies, spider monkey was found to have not one but two gamma-globin genes, only one of which (gamma 2) is functional. The reconstructed evolutionary history of the gamma-globin genes and their flanking sequences traces their origin to a tandem duplication of a DNA segment approximately 5.5 kilobases long that occurred before catarrhine primates (humans, apes, and Old World monkeys) diverged from platyrrhines (New World monkeys), much earlier than previously thought. This reconstructed molecular history also reveals that the duplication resulted from an unequal homologous crossover between two related L1 long interspersed repetitive elements, one upstream and one downstream of the single ancestral gamma-globin gene. Perhaps facilitated by the redundancy resulting from the duplication, the gamma-globin genes escaped the selective constraints of embryonically functioning genes and evolved into fetally functioning genes. This view is supported by the finding that a burst of nonsynonymous substitutions occurred in the gamma-globin genes while they became restructured for fetal expression in the common ancestor of platyrrhines and catarrhines. PMID:1908094

  8. 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

  9. 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

  10. 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

    2015-01-01

    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

  11. 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

  12. 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

  13. What did our ancestors eat?

    PubMed

    Garn, S M; Leonard, W R

    1989-11-01

    Over the millennia various hominoids and hominids have subsisted on very different dietaries, depending on climate, hunting proficiency, food-processing technology, and available foods. The Australopithecines were not browsers and fruit-eaters with very high intakes of vitamin C; rather they were scavengers of kills made by other animals. The hominids who followed did include some cold-climate hunters of large game, but the amount of animal protein decreased with the advent of grain-gathering and decreased further with the introduction of cereal agriculture, with a concomitant decrease in body size. From what we know about food adequacy, preparation, and storage, the notion that the postulated "primitive" diet was generally adequate, safe, and prudent can be rejected. Over evolutionary time, many of our ancestors ate poorly, especially during climate extremes, and they were often at risk for vitamin deficiencies, food-borne diseases, and neurotoxins. Until the advent of modern processing technologies, dirt, grit, and fiber constituted a large part of most early diets. PMID:2689923

  14. 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.

  15. 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

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

    PubMed

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

    2008-04-01

    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

  17. 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. PMID:26985732

  18. 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.

  19. Transcriptome Encyclopedia of Early Human Development.

    PubMed

    Sahakyan, Anna; Plath, Kathrin

    2016-05-01

    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. PMID:27153491

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. Early Defensive Mechanisms against Human Papillomavirus Infection.

    PubMed

    Moerman-Herzog, Andrea; Nakagawa, Mayumi

    2015-08-01

    Cervical cancer is the fourth most common cancer in women and is almost exclusively caused by human papillomavirus (HPV) infection. HPV is also frequently associated with other cancers arising from mucosal epithelium, including anal and oropharyngeal cancers, which are becoming more common in both men and women. Viral persistence and progression through precancerous lesion stages are prerequisites for HPV-associated cancer and reflect the inability of cell-mediated immune mechanisms to clear infections and eliminate abnormal cells in some individuals. Cell-mediated immune responses are initiated by innate pathogen sensing and subsequent secretion of soluble immune mediators and amplified by the recruitment and activation of effector T lymphocytes. This review discusses early defensive mechanisms of innate responders to natural HPV infection, their influence on response polarization, and the underappreciated role of keratinocytes in this process. PMID:26063238

  8. Early Defensive Mechanisms against Human Papillomavirus Infection

    PubMed Central

    Moerman-Herzog, Andrea

    2015-01-01

    Cervical cancer is the fourth most common cancer in women and is almost exclusively caused by human papillomavirus (HPV) infection. HPV is also frequently associated with other cancers arising from mucosal epithelium, including anal and oropharyngeal cancers, which are becoming more common in both men and women. Viral persistence and progression through precancerous lesion stages are prerequisites for HPV-associated cancer and reflect the inability of cell-mediated immune mechanisms to clear infections and eliminate abnormal cells in some individuals. Cell-mediated immune responses are initiated by innate pathogen sensing and subsequent secretion of soluble immune mediators and amplified by the recruitment and activation of effector T lymphocytes. This review discusses early defensive mechanisms of innate responders to natural HPV infection, their influence on response polarization, and the underappreciated role of keratinocytes in this process. PMID:26063238

  9. 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

  10. 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

  11. Technical comment on "The placental mammal ancestor and the post-K-Pg radiation of placentals".

    PubMed

    Springer, Mark S; Meredith, Robert W; Teeling, Emma C; Murphy, William J

    2013-08-01

    O'Leary et al. (Research Article, 8 February 2013, p. 662) examined mammalian relationships and divergence times and concluded that a single placental ancestor crossed the Cretaceous-Paleogene (K-Pg) boundary. This conclusion relies on phylogenetic analyses that fail to discriminate between homology and homoplasy and further implies virus-like rates of nucleotide substitution in early Paleocene placentals. PMID:23929967

  12. 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

  13. 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. PMID:25703300

  14. 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. PMID:16510414

  15. Human Granulocytic Ehrlichiosis Complicating Early Pregnancy

    PubMed Central

    Muffly, Tyler; McCormick, T. Chad; Cook, Christopher; Wall, Jeffrey

    2008-01-01

    Background. The goal of this case is to review the zoonotic infection, human granulocytic ehrlichiosis, presenting with pyrexia. Case. A 22-year-old multigravid female presented to the emergency department with a painful skin rash, high fever, and severe myalgias. The patient underwent a diagnostic evaluation for zoonotic infections due to her geographical and seasonal risk factors. Treatment of human granulocytic ehrlichiosis was successful though the patient spontaneously aborted presumably due to the severity of the acute illness. Conclusion. Treatment of human granulocytic ehrlichiosis in pregnancy presents unique challenges. Management of pyrexia during pregnancy is limited to external cooling in the setting of thrombocytopenia and elevated aminotransferases. Extensive counseling regarding teratogenic potential of medications allows the patient to weigh the pros and cons of treatment. PMID:18509484

  16. The Neurobiological Toll of Early Human Deprivation

    PubMed Central

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

    2013-01-01

    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. PMID:25018565

  17. 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…

  18. 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

    2016-01-01

    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. PMID:27562259

  19. 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. PMID:26438870

  20. 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

  1. Palmitic Acid in Early Human Development.

    PubMed

    Innis, Sheila M

    2016-09-01

    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. PMID:25764297

  2. 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. PMID:17344203

  3. U.S. Human Immunodeficiency Virus Type 1 Epidemic: Date of Origin, Population History, and Characterization of Early Strains

    PubMed Central

    Robbins, Kenneth E.; Lemey, Philippe; Pybus, Oliver G.; Jaffe, Harold W.; Youngpairoj, Ae S.; Brown, Teresa M.; Salemi, Marco; Vandamme, Anne-Mieke; Kalish, Marcia L.

    2003-01-01

    Human immunodeficiency virus (HIV) type 1 subtype B sequences (whole envelope and the p17 region of gag) were obtained from peripheral blood mononuclear cell samples collected in 1981 from seven HIV-infected U.S. individuals and in 1982 from one infected Canadian resident. Phylogenetic and nucleotide distance analyses were performed by using database sequences representing North American strains collected from 1978 to 1995. The estimated phylogeny was starlike, with early strains represented on different lineages. When sequences were grouped by years of collection, nucleotide distance comparisons demonstrated an increase in diversity over time and indicated that contemporary strains are more closely related to early epidemic strains than to each other. Using a recently developed likelihood ratio reduction procedure, the date of origin of the U.S. epidemic was estimated to be 1968 ± 1.4 years. A coalescent approach was also used to estimate the population history of the U.S. subtype B epidemic. Our analyses provide new information that implies an exponential growth rate from the beginning of the U.S. HIV epidemic. The dating results suggest a U.S. introduction date (or date of divergence from the most recent common ancestor) that precedes the date of the earliest known AIDS cases in the late 1970s. Furthermore, the estimated epidemic growth curve shows a period of exponential growth that preceded most of the early documented cases and also indicates a leveling of prevalence rates in the recent past. PMID:12743293

  4. 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.

  5. 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

  6. 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

  7. Direct dating of Early Upper Palaeolithic human remains from Mladec.

    PubMed

    Wild, Eva M; Teschler-Nicola, Maria; Kutschera, Walter; Steier, Peter; Trinkaus, Erik; Wanek, Wolfgang

    2005-05-19

    The human fossil assemblage from the Mladec Caves in Moravia (Czech Republic) has been considered to derive from a middle or later phase of the Central European Aurignacian period on the basis of archaeological remains (a few stone artefacts and organic items such as bone points, awls, perforated teeth), despite questions of association between the human fossils and the archaeological materials and concerning the chronological implications of the limited archaeological remains. The morphological variability in the human assemblage, the presence of apparently archaic features in some specimens, and the assumed early date of the remains have made this fossil assemblage pivotal in assessments of modern human emergence within Europe. We present here the first successful direct accelerator mass spectrometry radiocarbon dating of five representative human fossils from the site. We selected sample materials from teeth and from one bone for 14C dating. The four tooth samples yielded uncalibrated ages of approximately 31,000 14C years before present, and the bone sample (an ulna) provided an uncertain more-recent age. These data are sufficient to confirm that the Mladec human assemblage is the oldest cranial, dental and postcranial assemblage of early modern humans in Europe and is therefore central to discussions of modern human emergence in the northwestern Old World and the fate of the Neanderthals. PMID:15902255

  8. 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…

  9. 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

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

    PubMed

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

    2016-05-13

    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 44weeks, 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

  12. Early diagnosis and testing for human immunodeficiency virus.

    PubMed

    Hesman, Amanda

    2016-06-01

    Human immunodeficiency virus (HIV) is now considered a long-term condition. However, HIV can only become a long-term condition if it is diagnosed early and antiretroviral therapy is commenced immediately. Individuals with HIV who are diagnosed late have an increased risk of death in the year after diagnosis compared to those diagnosed promptly. This article outlines HIV testing policy in the UK, the importance of the early diagnosis of HIV, the barriers to HIV testing, and how to offer testing in a range of settings. PMID:27286626

  13. 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

  14. Telomerase Activity is Downregulated Early During Human Brain Development.

    PubMed

    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

  15. 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

  16. Developmental atlas of the early first trimester human embryo.

    PubMed

    Yamada, Shigehito; Samtani, Rajeev R; Lee, Elaine S; Lockett, Elizabeth; Uwabe, Chigako; Shiota, Kohei; Anderson, Stasia A; Lo, Cecilia W

    2010-06-01

    Rapid advances in medical imaging are facilitating the clinical assessment of first-trimester human embryos at increasingly earlier stages. To obtain data on early human development, we used magnetic resonance (MR) imaging and episcopic fluorescence capture (EFIC) to acquire digital images of human embryos spanning the time of dynamic tissue remodeling and organogenesis (Carnegie stages 13 to 23). These imaging data sets are readily resectioned digitally in arbitrary planes, suitable for rapid high-resolution three-dimensional (3D) observation. Using these imaging datasets, a web-accessible digital Human Embryo Atlas (http://apps.devbio.pitt.edu/humanatlas/) was created containing serial 2D images of human embryos in three standard histological planes: sagittal, frontal, and transverse. In addition, annotations and 3D reconstructions were generated for visualizing different anatomical structures. Overall, this Human Embryo Atlas is a unique resource that provides morphologic data of human developmental anatomy that can accelerate basic research investigations into developmental mechanisms that underlie human congenital anomalies. PMID:20503356

  17. 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. PMID:25544676

  18. 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

  19. 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. PMID:24710771

  20. 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…

  1. 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

  2. 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

  3. 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

  4. 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. PMID:23267092

  5. The human microbiome. Early life determinant of health outcomes.

    PubMed

    Martinez, Fernando D

    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

  6. 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

  7. Early gait development in human infants: Plasticity and clinical applications.

    PubMed

    Teulier, Caroline; Lee, Do Kyeong; Ulrich, Beverly D

    2015-05-01

    In this paper we focus on how a developmental perspective on plasticity in the control of human movement can promote early therapy and improve gait acquisition in infants with developmental disabilities. Current knowledge about stepping development in healthy infants across the first year of life highlights strong plasticity, both in behavioral outcome and in underlying neuro-muscular activation. These data show that stepping, like other motor skills, emerges from the interaction between infant's maturation and the environment. This view is reinforced by showing that infants with different internal resources (like genetic disorder or neural tube defect) show unique developmental trajectories when supported on a treadmill, yet do respond. Moreover, we will show that their behavior can be improved by context manipulations (mostly sensory stimulation) or practice. Overall, plasticity in the neural, skeletal, and muscle tissues create new opportunities for optimizing early intervention by creatively tapping into the same developmental processes experienced by healthy infants. PMID:25782975

  8. 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

  9. 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. PMID:23267102

  10. 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

  11. 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.

  12. 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. PMID:25960070

  13. 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.

  14. Photochemical etiology of promising ancestors of the RNA nucleobases.

    PubMed

    Brister, M M; Pollum, M; Crespo-Hernández, C E

    2016-07-27

    RNA is a product of chemical and biological evolution and the identification of its heterocyclic ancestors is essential for understanding the molecular origins of life. Among a diverse array of selection pressures thought to have shaped the composition of the nucleobases on prebiotic Earth, protection against intense ultraviolet radiation must have been essential. In this contribution, a detailed spectroscopic and photophysical investigation of barbituric acid and 2,4,6-triaminopyrimidine, two promising candidates for the prebiotic ancestors of RNA nucleobases, is presented in aqueous solution. It is shown that although these pyrimidine derivatives absorb ultraviolet radiation strongly, both compounds possess efficient electronic relaxation mechanisms for dissipating most of the absorbed ultraviolet energy to their aqueous environment as heat within hundreds of femtoseconds, thus safeguarding their chemical integrity. In fact, these two heterocyclic compounds rival the photostability observed in the canonical nucleobases in aqueous solution, thus supporting the recent proposal that both barbituric acid and 2,4,6-triaminopyrimidine are promising ancestors of the RNA nucleobases. PMID:26898746

  15. 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. PMID:23158518

  16. Early Human Evolution in the Western Palaearctic: Ecological Scenarios

    NASA Astrophysics Data System (ADS)

    Carrión, José S.; Rose, James; Stringer, Chris

    2011-06-01

    This review presents the themes of a special issue dealing with environmental scenarios of human evolution during the Early Pleistocene (2.6-0.78 Ma; MIS 103-MIS 19) and early Middle Pleistocene (0.78-0.47 Ma; MIS 19-base of MIS 12) within the western Palaearctic. This period is one of dramatic changes in the climates and the distribution of Palaearctic biota. These changes have played their role in generating adaptive and phyletic patterns within the human ancestry, involving several species such as Homo habilis, "Homo georgicus", Homo erectus, Homo antecessor and Homo heidelbergensis. In the archaeological record, these species include the Oldowan (Mode 1) and Acheulian (Mode 2) lithic technologies. Taphonomic considerations of palaeoecological research in hominin-bearing sites are provided and evaluated. Syntheses are provided for north Africa, western Asia, the Mediterranean Basin, Britain, and continental Europe. Palaeoenvironmental reconstructions based on multidisciplinary data are given for Ain Boucherit, Ain Hanech and El-Kherba in Algeria, Dmanisi in Georgia, Atapuerca, Cueva Negra, and the Orce Basin in Spain, Monte Poggiolo and Pirro Nord in Italy, Pont-de-Lavaud in France, and Mauer in Germany. The state of the art with the Out of Africa 1 dispersal model is reviewed. A source-sink dynamics model for Palaeolithic Europe is described to explain the morphological disparity of H. heidelbergensis (we will sometimes use the informal name "Heidelbergs") and early Neanderthals. Other aspects debated here are the selective value of habitat mosaics including reconstructions based on mammal and avian databases, and the role of geological instability combined with topographic complexity. This review is completed by addressing the question of whether the appearance of evolutionary trends within hominins is concentrated in regions of highest worldwide biological diversity (biodiversity hotspots). It is concluded that the keys for the activation of evolutionary

  17. UVA Phototransduction Drives Early Melanin Synthesis in Human Melanocytes

    PubMed Central

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

    2013-01-01

    Summary Exposure of human skin to solar ultraviolet radiation (UVR), a powerful carcinogen [1] comprising ~95% UVA and ~5% 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 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 five-fold after 24 hours. 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. PMID:22055294

  18. Early Human Prostate Adenocarcinomas Harbor Androgen-Independent Cancer Cells

    PubMed Central

    Fiñones, Rita R.; Yeargin, Jo; Lee, Melissa; Kaur, Aman Preet; Cheng, Clari; Sun, Paulina; Wu, Christopher; Nguyen, Catherine; Wang-Rodriguez, Jessica; Meyer, April N.; Baird, Stephen M.; Donoghue, Daniel J.; Haas, Martin

    2013-01-01

    Although blockade of androgen receptor (AR) signaling represents the main treatment for advanced prostate cancer (PrCa), many patients progress to a lethal phenotype of “Castration-Resistant” prostate cancer (CR-PrCa). With the hypothesis that early PrCa may harbor a population of androgen-unresponsive cancer cells as precursors to CR-recurrent disease, we undertook the propagation of androgen-independent cells from PrCa-prostatectomy samples of early, localized (Stage-I) cases. A collection of 120 surgical specimens from prostatectomy cases was established, among which 54 were adenocarcinomas. Hormone-free cell culture conditions were developed allowing routine propagation of cells expressing prostate basal cell markers and stem/progenitor cell markers, and which proliferated as spheres/spheroids in suspension cultures. Colonies of androgen-independent epithelial cells grew out from 30/43 (70%) of the adenocarcinoma cases studied in detail. Fluorescence microscopy and flow cytometry showed that CR-PrCa cells were positive for CD44, CD133, CK5/14, c-kit, integrin α2β1, SSEA4, E-Cadherin and Aldehyde Dehydrogenase (ALDH). All 30 CR-PrCa cell cultures were also TERT-positive, but negative for TMPRSS2-ERG. Additionally, a subset of 22 of these CR-PrCa cell cultures was examined by orthotopic xenografting in intact and castrated SCID mice, generating histologically typical locally-invasive human PrCa or undifferentiated cancers, respectively, in 6–8 weeks. Cultured PrCa cells and orthotopically-induced in vivo cancers lacked PSA expression. We report here the propagation of Cancer Initiating Cells (CIC) directly from Stage I human PrCa tissue without selection or genetic manipulation. The propagation of stem/progenitor-like CR-PrCa cells derived from early human prostate carcinomas suggests the existence of a subpopulation of cells resistant to androgen-deprivation therapy and which may drive the subsequent emergence of disseminated CR-PrCa. PMID:24086346

  19. 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.

  20. Early Trypanosoma cruzi Infection Reprograms Human Epithelial Cells

    PubMed Central

    Chiribao, María Laura; Libisch, Gabriela; Parodi-Talice, Adriana; Robello, Carlos

    2014-01-01

    Trypanosoma cruzi, the causative agent of Chagas disease, has the peculiarity, when compared with other intracellular parasites, that it is able to invade almost any type of cell. This property makes Chagas a complex parasitic disease in terms of prophylaxis and therapeutics. The identification of key host cellular factors that play a role in the T. cruzi invasion is important for the understanding of disease pathogenesis. In Chagas disease, most of the focus is on the response of macrophages and cardiomyocytes, since they are responsible for host defenses and cardiac lesions, respectively. In the present work, we studied the early response to infection of T. cruzi in human epithelial cells, which constitute the first barrier for establishment of infection. These studies identified up to 1700 significantly altered genes regulated by the immediate infection. The global analysis indicates that cells are literally reprogrammed by T. cruzi, which affects cellular stress responses (neutrophil chemotaxis, DNA damage response), a great number of transcription factors (including the majority of NFκB family members), and host metabolism (cholesterol, fatty acids, and phospholipids). These results raise the possibility that early host cell reprogramming is exploited by the parasite to establish the initial infection and posterior systemic dissemination. PMID:24812617

  1. mRNAs from human adenovirus 2 early region 4.

    PubMed Central

    Virtanen, A; Gilardi, P; Näslund, A; LeMoullec, J M; Pettersson, U; Perricaudet, M

    1984-01-01

    The molecular structure of the mRNAs from early region 4 of human adenovirus 2 has been studied by Northern blot analysis, S1 nuclease analysis, and sequence analysis of cDNA clones. The results make it possible to identify four different splice donor sites and six different splice acceptor sites. The structure of 12 different mRNAs can be deduced from the analysis. The mRNAs have identical 5' and 3' ends and are thus likely to be processed from a common mRNA precursor by differential splicing. The different mRNA species are formed by the removal of one to three introns, and they all carry a short 5' leader segment. The introns appear to serve two functions; they either place a 5' leader segment in juxtaposition with an open reading frame or fuse two open translational reading frames. The early region 4 mRNAs can encode at least seven unique polypeptides. Images PMID:6088804

  2. 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

  3. 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. PMID:24047602

  4. Mobile elements reveal small population size in the ancient ancestors of Homo sapiens

    PubMed Central

    Huff, Chad D.; Xing, Jinchuan; Rogers, Alan R.; Witherspoon, David; Jorde, Lynn B.

    2010-01-01

    The genealogies of different genetic loci vary in depth. The deeper the genealogy, the greater the chance that it will include a rare event, such as the insertion of a mobile element. Therefore, the genealogy of a region that contains a mobile element is on average older than that of the rest of the genome. In a simple demographic model, the expected time to most recent common ancestor (TMRCA) is doubled if a rare insertion is present. We test this expectation by examining single nucleotide polymorphisms around polymorphic Alu insertions from two completely sequenced human genomes. The estimated TMRCA for regions containing a polymorphic insertion is two times larger than the genomic average (P < <10−30), as predicted. Because genealogies that contain polymorphic mobile elements are old, they are shaped largely by the forces of ancient population history and are insensitive to recent demographic events, such as bottlenecks and expansions. Remarkably, the information in just two human DNA sequences provides substantial information about ancient human population size. By comparing the likelihood of various demographic models, we estimate that the effective population size of human ancestors living before 1.2 million years ago was 18,500, and we can reject all models where the ancient effective population size was larger than 26,000. This result implies an unusually small population for a species spread across the entire Old World, particularly in light of the effective population sizes of chimpanzees (21,000) and gorillas (25,000), which each inhabit only one part of a single continent. PMID:20133859

  5. Resting state functional connectivity in early blind humans

    PubMed Central

    Burton, Harold; Snyder, Abraham Z.; Raichle, Marcus E.

    2014-01-01

    Task-based neuroimaging studies in early blind humans (EB) have demonstrated heightened visual cortex responses to non-visual paradigms. Several prior functional connectivity studies in EB have shown altered connections consistent with these task-based results. But these studies generally did not consider behavioral adaptations to lifelong blindness typically observed in EB. Enhanced cognitive abilities shown in EB include greater serial recall and attention to memory. Here, we address the question of the extent to which brain intrinsic activity in EB reflects such adaptations. We performed a resting-state functional magnetic resonance imaging study contrasting 14 EB with 14 age/gender matched normally sighted controls (NS). A principal finding was markedly greater functional connectivity in EB between visual cortex and regions typically associated with memory and cognitive control of attention. In contrast, correlations between visual cortex and non-deprived sensory cortices were significantly lower in EB. Thus, the available data, including that obtained in prior task-based and resting state fMRI studies, as well as the present results, indicate that visual cortex in EB becomes more heavily incorporated into functional systems instantiating episodic recall and attention to non-visual events. Moreover, EB appear to show a reduction in interactions between visual and non-deprived sensory cortices, possibly reflecting suppression of inter-sensory distracting activity. PMID:24778608

  6. 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

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

    PubMed Central

    Koskela, Minna; Annila, Arto

    2012-01-01

    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. PMID:24704844

  8. 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

  9. Autophagy in human keratinocytes: an early step of the differentiation?

    PubMed

    Aymard, Elodie; Barruche, Vincent; Naves, Thomas; Bordes, Sylvie; Closs, Brigitte; Verdier, Mireille; Ratinaud, Marie-Hélène

    2011-03-01

    Studies have established that autophagy constitutes an efficient process to recycle cellular components and certain proteins. The phenomenon was demonstrated primarily in response to nutrient starvation, and there are increasing evidences that it is implied in differentiation. Keratinocyte differentiation was going along an activation of lysosomal enzymes and organelle clearance, and terminal steps are sometimes described as a specialized form of cell death leading to corneocytes. We examined whether initiation of the process in human keratinocyte HaCaT involves autophagy. The KSFM™ culture medium was substituted by M199, which contains a low glucose concentration but a high calcium level (known to induce differentiation). Metabolic stress reduced enhanced cell number in G(1) phase, without apoptotic features (ΔΨmt and membrane integrity are unchanged). Morphological changes were associated with a lower integrin ß1 expression and modifications of protein levels involved in keratinocyte differentiation (involucrin, keratin K10 and ΔNp63α). Whereas autophagic signalling was supported by SIRT1 and pAMPK (T172) increase according to time kinetic, which led to the disappearance of mTOR phosphorylated on S2448 residue. The significant Bcl-X(L) level reduction with stress promoted autophagy, by the release of Beclin-1, whereas ATG5-ATG12 and LC3-II that are involved in autophagosome formation were enhanced significantly. Then, the level of lysosomal protein cathepsin B rose to execute autophagy. Kinetic studies established that autophagy would constitute an early signalling process required for keratinocyte commitment in differentiation pathway. PMID:21166723

  10. 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

  11. Upd3--an ancestor of the four-helix bundle cytokines.

    PubMed

    Oldefest, Mirja; Nowinski, Jana; Hung, Chien-Wen; Neelsen, Denis; Trad, Ahmad; Tholey, Andreas; Grötzinger, Joachim; Lorenzen, Inken

    2013-06-21

    The unpaired-like protein 3 (Upd3) is one of the three cytokines of Drosophila melanogaster supposed to activate the JAK/STAT signaling pathway (Janus tyrosine kinases/signal transducer and activator of transcription). This activation occurs via the type-I cytokine receptor domeless, an orthologue of gp130, the common signal transducer of all four-helix bundle interleukin-6 (IL-6) type cytokines. Both receptors are known to exist as preformed dimers in the plasma membrane and initiate the acute-phase response. These facts indicate an evolutionary relation between vertebrate IL-6 and the Drosophila protein Upd3. Here we presented data which strengthen this notion. Upd3 was recombinantly expressed, a renaturation and purification protocol was established which allows to obtain high amounts of biological active protein. This protein is, like human IL-6, a monomeric-α helical cytokine, implicating that Upd3 is an "ancestor" of the four-helix bundle cytokines. PMID:23707937

  12. 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.

  13. 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. PMID:20623674

  14. 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

  15. Investing in early human development: timing and economic efficiency.

    PubMed

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

    2009-03-01

    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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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. PMID:22949523

  1. 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

  2. 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

  3. 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…

  4. Early environmental effects on epigenetic regulation in humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  5. Experimental evolution of a facultative thermophile from a mesophilic ancestor.

    PubMed

    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; Crécy-Lagard, Valérie de; Crécy, Eudes de

    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

  6. 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

  7. Fine specificity of cellular immune responses in humans to human cytomegalovirus immediate-early 1 protein.

    PubMed Central

    Alp, N J; Allport, T D; Van Zanten, J; Rodgers, B; Sissons, J G; Borysiewicz, L K

    1991-01-01

    Cell-mediated immunity is important in maintaining the virus-host equilibrium in persistent human cytomegalovirus (HCMV) infection. The HCMV 72-kDa major immediate early 1 protein (IE1) is a target for CD8+ cytotoxic T cells in humans, as is the equivalent 89-kDa protein in mouse. Less is known about responses against this protein by CD4+ T cells, which may be important as direct effector cells or helper cells for antibody and CD8+ responses. Proliferative-T-cell responses to HCMV IE1 were studied in normal seropositive subjects. Peripheral blood mononuclear cells from 85% of seropositive subjects proliferated in response to HCMV from infected fibroblasts, and of these, 73% responded to recombinant baculovirus IE1. Responding cells were predominantly CD3+ CD4+. IE1 antigen preparations, including baculovirus recombinant protein, transfected rat cell nuclei, and synthetic peptides, induced IE1-specific T-cell lines which cross-reacted between the preparations. The fine specificity of these IE1-specific T-cell lines was studied by using overlapping synthetic peptides encompassing the entire sequence of the IE1 protein. The regions of the IE1 molecule recognized were identified and these varied between individuals, possibly reflecting differences in major histocompatibility complex (MHC) class II haplotype. In one subject, the peptide specificities of proliferative and MHC class I-restricted cytotoxic determinants on IE1 were spatially distinct. Thus, no single immunodominant T-cell determinant within HCMV IE1 was identified, suggesting that multiple peptides or a region of the 72-kDa IE1 protein would be required to induce specific T-cell responses in humans. PMID:1714519

  8. Early-season avian deaths from West Nile virus as warnings of human infection

    USGS Publications Warehouse

    Guptill, S.C.; Julian, K.G.; Campbell, G.L.; Price, S.D.; Marfin, A.A.

    2003-01-01

    An analysis of 2001 and 2002 West Nile virus (WNV) surveillance data shows that counties that report WNV-infected dead birds early in the transmission season are more likely to report subsequent WNV disease cases in humans than are counties that do not report early WNV-infected dead birds.

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

    PubMed

    Pham, Phuong N; Vinck, Patrick

    2012-01-01

    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. PMID:23568944

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

    PubMed

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

    2014-07-01

    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. PMID:24994657

  11. 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

  12. Human Ecology and Television in Early Childhood Education.

    ERIC Educational Resources Information Center

    Schleicher, Klaus

    A human ecological approach to the study of children's television viewing raises questions that researchers have largely neglected. Does television influence the interaction patterns of socializing agents with children and with one another? Are there long-term, psychological consequences of unintegrated and competing influences from television and…

  13. A Life-Span Human Development Model of Learning for Early Education.

    ERIC Educational Resources Information Center

    Languis, Marlin; Wilcox, Jean

    1981-01-01

    A life-span human development model of learning in early childhood is presented. Learning is viewed as a human enterprise which spans the entire lifetime and involves interaction among people. The bounds of interaction are derived from philosophy and from the biological and social behavioral sciences. (JN)

  14. No Evidence of Neandertal mtDNA Contribution to Early Modern Humans

    PubMed Central

    2004-01-01

    The retrieval of mitochondrial DNA (mtDNA) sequences from four Neandertal fossils from Germany, Russia, and Croatia has demonstrated that these individuals carried closely related mtDNAs that are not found among current humans. However, these results do not definitively resolve the question of a possible Neandertal contribution to the gene pool of modern humans since such a contribution might have been erased by genetic drift or by the continuous influx of modern human DNA into the Neandertal gene pool. A further concern is that if some Neandertals carried mtDNA sequences similar to contemporaneous humans, such sequences may be erroneously regarded as modern contaminations when retrieved from fossils. Here we address these issues by the analysis of 24 Neandertal and 40 early modern human remains. The biomolecular preservation of four Neandertals and of five early modern humans was good enough to suggest the preservation of DNA. All four Neandertals yielded mtDNA sequences similar to those previously determined from Neandertal individuals, whereas none of the five early modern humans contained such mtDNA sequences. In combination with current mtDNA data, this excludes any large genetic contribution by Neandertals to early modern humans, but does not rule out the possibility of a smaller contribution. PMID:15024415

  15. 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. PMID:25054305

  16. 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

  17. Estimating time to the most recent common ancestor (TMRCA): comparison and application of eight methods.

    PubMed

    Zhou, Jin; Teo, Yik-Ying

    2016-08-01

    Investigating how an ancestral population diverges to give rise to distinct subpopulations remains a fundamental pursuit in population genetics. There is broad consensus for the 'Out-of-Africa' hypothesis that states that modern humans arose ∼200 000 years ago in Africa and spread throughout the continent ∼100 000 years ago. This was followed by several waves of major population dispersals across the globe, although the exact nature of the population divergence remains debatable. Existing methods to estimate population divergence time differ in their methodological frameworks and demographic assumptions, and require different types of genetic data as input. These fundamental differences often result in the methods producing inconsistent estimates of the population divergence time, further confounding attempts to robustly uncover the history of human migration, especially when most population genetic studies do not employ multiple methods to estimate the time to the most recent common ancestor (TMRCA). Here, we chose eight popular methods for estimating TMRCA and evaluated their robustness and accuracy in correctly identifying the true TMRCA through a series of simulations that mimicked different evolutionary scenarios. We subsequently applied all eight methods to estimate the population divergence time between Southeast Asian Malays and South Asian Indians using deep whole-genome sequencing data. PMID:26669663

  18. 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

  19. Early electrophysiological markers of visual awareness in the human brain.

    PubMed

    Ohla, Kathrin; Busch, Niko A; Herrmann, Christoph S

    2007-10-01

    The present study investigated neuronal correlates of stimulus processing leading to conscious perception of a task irrelevant global structure in a visual display. To study the underlying neuronal processes, participants were presented different types of dot patterns (Glass patterns) either forming a global structure or forming no global structure while EEG was recorded. Participants were naive about the pattern types and performed a demanding colour discrimination task. Following the experiment, the degree to which participants acquired awareness of the global visual structure was assessed. Early gamma-frequency band responses (gamma, 25-100 Hz) over occipital, parietal, and central areas were enhanced to circular Glass patterns as compared to random dot patterns at 90 ms post-stimulus. This effect was observed exclusively in participants who were subjectively aware of the global pattern structure. In this group of observers, the pattern effect built up gradually during the course of the experiment. The significance of enhanced early gamma responses to global patterns for the production of awareness of the pattern might lie in the increased impact of information conveyed by well synchronised neuronal assemblies to upstream cortical areas. PMID:17656113

  20. 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. PMID:26608745

  1. Human memory development and its dysfunction after early hippocampal injury.

    PubMed

    de Haan, Michelle; Mishkin, Mortimer; Baldeweg, Torsten; Vargha-Khadem, Faraneh

    2006-07-01

    Cognitive memory involves long-term memories for facts (semantic memory) and personal experiences (episodic memory) that can be brought to mind. There is consensus that the hippocampus and related medial temporal lobe (MTL) structures are crucial for adult cognitive memory, but much less is known about their contribution to memory during infancy and childhood. We argue that the MTL is involved in memory from early in life, supporting recognition memory within the first postnatal months and recall memory within the first year. We propose that normal development involves a sequence in which a form of semantic-like memory emerges first, whereas the characteristics of episodic memory develop only later with progressive development of the hippocampus. Early bilateral injury to the hippocampus disrupts this normal pattern such that memory skills cannot develop beyond the stage of semantic memories. This review is part of the INMED/TINS special issue "Nature and nurture in brain development and neurological disorders", based on presentations at the annual INMED/TINS symposium (http://inmednet.com/). PMID:16750273

  2. 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

  3. 76 FR 20802 - Culturally Significant Objects Imported for Exhibition Determinations: “Ancestors of the Lake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... Sentani and Humboldt Bay'' SUMMARY: Notice is hereby given of the following determinations: Pursuant to... the exhibition ``Ancestors of the Lake: Art from Lake Sentani and Humboldt Bay,'' imported from...

  4. Brightness–Color Interactions in Human Early Visual Cortex

    PubMed Central

    Ouni, Ahmed; Chen, Stephanie; Sahmoud, Hinde; Gordon, James; Shapley, Robert

    2015-01-01

    The interaction between brightness and color causes there to be different color appearance when one and the same object is viewed against surroundings of different brightness. Brightness contrast causes color to be desaturated, as has been found in perceptual experiments on color induction and color-gamut expansion in human vision. However, it is not clear yet where in the cerebral cortex the brightness–color interaction that causes these major perceptual effects is located. One hypothesis is that brightness and color signals are processed separately and in parallel within the primary visual cortex V1 and only interact in extrastriate cortex. Another hypothesis is that color and brightness contrast interact strongly already within V1. We localized the brightness–color interaction in human V1 by means of recording the chromatic visual-evoked potential. The chromatic visual-evoked potential measurements decisively support the idea that brightness–color interaction arises in a recurrent inhibitory network in V1. Furthermore, our results show that the inhibitory signal for brightness–color interaction is generated by local brightness contrast at the boundary between target and surround, instead of by the luminance difference between the interior of the color target and its large background. PMID:25653377

  5. 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.

  6. 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.

  7. mga genosensor for early detection of human rheumatic heart disease.

    PubMed

    Singh, Swati; Kaushal, Ankur; Khare, Shashi; Kumar, Ashok

    2014-05-01

    The 5' amino-labeled DNA probe complementary to mga gene of Streptococcus pyogenes was immobilized on carboxylated multiwall carbon nanotubes electrode and hybridized with 0.1-100 ng/6 μl single-stranded genomic DNA (ssG-DNA) of S. pyogenes from throat swab of suspected rheumatic heart disease (RHD) patients. Electrochemical response was measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance (EI). The sensitivity of the sensor was 106.03 (μA/cm(2))/ng and limit of detection (LOD) was found 0.014 ng/6 μl with regression coefficient (R(2)) of 0.921 using DPV. The genosensor was characterized by FTIR and SEM, and electrode was found stable for 6 months on storage at 4 °C with 5-6 % loss in initial DPV current. mga genosensor is the first report on RHD sensor which can save life of several suspected patients by early diagnosis in 30 min. PMID:24639090

  8. 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

  9. 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. PMID:25849125

  10. 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

  11. 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.

  12. 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

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

    PubMed

    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

  14. 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

  15. Reconstructing the ancestor of Mycobacterium leprae: The dynamics of gene loss and genome reduction

    PubMed Central

    Gómez-Valero, Laura; Rocha, Eduardo P.C.; Latorre, Amparo; Silva, Francisco J.

    2007-01-01

    We have reconstructed the gene content and order of the last common ancestor of the human pathogens Mycobacterium leprae and Mycobacterium tuberculosis. During the reductive evolution of M. leprae, 1537 of 2977 ancestral genes were lost, among which we found 177 previously unnoticed pseudogenes. We find evidence that a massive gene inactivation took place very recently in the M. leprae lineage, leading to the loss of hundreds of ancestral genes. A large proportion of their nucleotide content (∼89%) still remains in the genome, which allowed us to characterize and date them. The age of the pseudogenes was computed using a new methodology based on the rates and patterns of substitution in the pseudogenes and functional orthologous genes of closely related genomes. The position of the genes that were lost in the ancestor’s genome revealed that the process of function loss and degradation mainly took place through a gene-to-gene inactivation process, followed by the gradual loss of their DNA. This suggests a scenario of massive genome reduction through many nearly simultaneous pseudogenization events, leading to a highly specialized pathogen. PMID:17623808

  16. [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. PMID:26850613

  17. 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

  18. 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

  19. Early loss of oligodendrocytes in human and experimental neuromyelitis optica lesions

    PubMed Central

    Wrzos, Claudia; Winkler, Anne; Metz, Imke; Kayser, Dieter M.; Thal, Dietmar R.; Wegner, Christiane; Brück, Wolfgang; Nessler, Stefan; Bennett, Jeffrey L.

    2014-01-01

    Neuromyelitis optica (NMO) is a chronic, mostly relapsing inflammatory demyelinating disease of the CNS characterized by serum anti-aquaporin 4 (AQP4) antibodies in the majority of patients. Anti-AQP4 antibodies derived from NMO patients target and deplete astrocytes in experimental models when co-injected with complement. However, the time course and mechanisms of oligodendrocyte loss and demyelination and the fate of oligodendrocyte precursor cells (OPC) have not been examined in detail. Also, no studies regarding astrocyte repopulation of experimental NMO lesions have been reported. We utilized two rat models using either systemic transfer or focal intracerebral injection of recombinant human anti-AQP4 antibodies to generate NMO-like lesions. Time-course experiments were performed to examine oligodendroglial and astroglial damage and repair. In addition, oligodendrocyte pathology was studied in early human NMO lesions. Apart from early complement-mediated astrocyte destruction, we observed a prominent, very early loss of oligodendrocytes and oligodendrocyte precursor cells (OPCs) as well as a delayed loss of myelin. Astrocyte repopulation of focal NMO lesions was already substantial after 1 week. Olig2-positive OPCs reappeared before NogoA-positive, mature oligodendrocytes. Thus, using two experimental models that closely mimic the human disease, our study demonstrates that oligodendrocyte and OPC loss is an extremely early feature in the formation of human and experimental NMO lesions and leads to subsequent, delayed demyelination, highlighting an important difference in the pathogenesis of MS and NMO. PMID:24292009

  20. The Influence of Theoretical Conceptions of Human Development on the Practice of Early Childhood Education.

    ERIC Educational Resources Information Center

    Gardner, D. Bruce

    Communication is urged between theorists of human development and practitioners in early childhood education. Major psychological theories on maturation, child development, child behavior, personality formation, and affective and intellectual development are summarized and their effects on nursery school practices from the 1920's to the present…

  1. 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…

  2. 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…

  3. STATIONARY PATTERN ADAPTATION AND THE EARLY COMPONENTS IN HUMAN VISUAL EVOKED POTENTIALS

    EPA Science Inventory

    Pattern-onset visual evoked potentials were elicited from humans by sinusoidal gratings of 0.5., 1, 2 and 4 cpd (cycles/degree) following adaptation to a blank field or one of the gratings. The wave forms recorded after blank field adaptation showed an early positive component, P...

  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. 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

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

    PubMed

    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

    2014-10-01

    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

  7. 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. PMID:25525215

  8. 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.

  9. Early pregnancy factor is an immunosuppressive contaminant of commercial preparations of human chorionic gonadotrophin.

    PubMed Central

    Rolfe, B E; Morton, H; Clarke, F M

    1983-01-01

    Early pregnancy factor (EPF) is a pregnancy associated substance detected in human serum and urine throughout the first and second trimesters of pregnancy. It has also been detected in several commercial preparations of human chorionic gonadotrophin (hCG). The various molecular weight forms of EPF which occur in human pregnancy serum, urine and commercial hCG preparations have been partially characterized and found to be similar to each other but distinct from hCG. Further evidence is presented which suggests that it is EPF rather than hCG which is responsible for the immunosuppressive activity of some crude hCG preparations. PMID:6831771

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

    PubMed

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

    2016-08-01

    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

  11. Synthesis of human adenovirus early RNA species is similar in productive and abortive infections of monkey and human cells.

    PubMed Central

    Anderson, K P; Klessig, D F

    1982-01-01

    Northern (RNA) blot analysis has been used to show that synthesis of early mRNA species is similar in monkey cells productively or abortively infected with human adenovirus. mRNA species from all five major early regions (1A, 1B, 2, 3, 4) are identical in size and comparable in abundance whether isolated from monkey cells infected with adenovirus type 2 or with the host range mutant Ad2hr400 or coinfected with adenovirus type 2 plus simian virus 40. The mRNA species isolated from monkey cells are identical in size to those isolated from human cells. Production of virus-associated RNA is also identical in productive and abortive infections of monkey cells. Synthesis of virus-associated RNA is, however, significantly greater in HeLa cells than in CV1 cells at late times after infection regardless of which virus is used in the infection. Images PMID:6283181

  12. Uptake of Plasmin-PN-1 Complexes in Early Human Atheroma.

    PubMed

    Boukais, Kamel; Bayles, Richard; Borges, Luciano de Figueiredo; Louedec, Liliane; Boulaftali, Yacine; Ho-Tin-Noé, Benoit; Arocas, Véronique; Bouton, Marie-Christine; Michel, Jean-Baptiste

    2016-01-01

    Zymogens are delivered to the arterial wall by radial transmural convection. Plasminogen can be activated within the arterial wall to produce plasmin, which is involved in evolution of the atherosclerotic plaque. Vascular smooth muscle cells (vSMCs) protect the vessels from proteolytic injury due to atherosclerosis development by highly expressing endocytic LDL receptor-related protein-1 (LRP-1), and by producing anti-proteases, such as Protease Nexin-1 (PN-1). PN-1 is able to form covalent complexes with plasmin. We hypothesized that plasmin-PN-1 complexes could be internalized via LRP-1 by vSMCs during the early stages of human atheroma. LRP-1 is also responsible for the capture of aggregated LDL in human atheroma. Plasmin activity and immunohistochemical analyses of early human atheroma showed that the plasminergic system is activated within the arterial wall, where intimal foam cells, including vSMCs and platelets, are the major sites of PN-1 accumulation. Both PN-1 and LRP-1 are overexpressed in early atheroma at both messenger and protein levels. Cell biology studies demonstrated an increased expression of PN-1 and tissue plasminogen activator by vSMCs in response to LDL. Plasmin-PN-1 complexes are internalized via LRP-1 in vSMCs, whereas plasmin alone is not. Tissue PN-1 interacts with plasmin in early human atheroma via two complementary mechanisms: plasmin inhibition and tissue uptake of plasmin-PN-1 complexes via LRP-1 in vSMCs. Despite this potential protective effect, plasminogen activation by vSMCs remains abnormally elevated in the intima in early stages of human atheroma. PMID:27445860

  13. Uptake of Plasmin-PN-1 Complexes in Early Human Atheroma

    PubMed Central

    Boukais, Kamel; Bayles, Richard; Borges, Luciano de Figueiredo; Louedec, Liliane; Boulaftali, Yacine; Ho-Tin-Noé, Benoit; Arocas, Véronique; Bouton, Marie-Christine; Michel, Jean-Baptiste

    2016-01-01

    Zymogens are delivered to the arterial wall by radial transmural convection. Plasminogen can be activated within the arterial wall to produce plasmin, which is involved in evolution of the atherosclerotic plaque. Vascular smooth muscle cells (vSMCs) protect the vessels from proteolytic injury due to atherosclerosis development by highly expressing endocytic LDL receptor-related protein-1 (LRP-1), and by producing anti-proteases, such as Protease Nexin-1 (PN-1). PN-1 is able to form covalent complexes with plasmin. We hypothesized that plasmin-PN-1 complexes could be internalized via LRP-1 by vSMCs during the early stages of human atheroma. LRP-1 is also responsible for the capture of aggregated LDL in human atheroma. Plasmin activity and immunohistochemical analyses of early human atheroma showed that the plasminergic system is activated within the arterial wall, where intimal foam cells, including vSMCs and platelets, are the major sites of PN-1 accumulation. Both PN-1 and LRP-1 are overexpressed in early atheroma at both messenger and protein levels. Cell biology studies demonstrated an increased expression of PN-1 and tissue plasminogen activator by vSMCs in response to LDL. Plasmin-PN-1 complexes are internalized via LRP-1 in vSMCs, whereas plasmin alone is not. Tissue PN-1 interacts with plasmin in early human atheroma via two complementary mechanisms: plasmin inhibition and tissue uptake of plasmin-PN-1 complexes via LRP-1 in vSMCs. Despite this potential protective effect, plasminogen activation by vSMCs remains abnormally elevated in the intima in early stages of human atheroma. PMID:27445860

  14. 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.

  15. 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

    2014-01-01

    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

  16. 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

  17. 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…

  18. 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

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

    PubMed

    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

  20. 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

  1. 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

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

    PubMed

    Piperno, Dolores R; Dillehay, Tom D

    2008-12-16

    Previous research indicates that the Nanchoc Valley in northern Peru was an important locus of early and middle Holocene human settlement, and that between 9200 and 5500 (14)C 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 (14)C 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 Nanchoc region by 8000 (14)C 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

  3. 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. PMID:15598488

  4. DNA analysis of an early modern human from Tianyuan Cave, China

    PubMed Central

    Fu, Qiaomei; Meyer, Matthias; Gao, Xing; Stenzel, Udo; Burbano, Hernán A.; Kelso, Janet; Pääbo, Svante

    2013-01-01

    Hominins with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 y ago. The genetic relationships between these early modern humans and present-day human populations have not been established. We have extracted DNA from a 40,000-y-old anatomically modern human from Tianyuan Cave outside Beijing, China. Using a highly scalable hybridization enrichment strategy, we determined the DNA sequences of the mitochondrial genome, the entire nonrepetitive portion of chromosome 21 (∼30 Mbp), and over 3,000 polymorphic sites across the nuclear genome of this individual. The nuclear DNA sequences determined from this early modern human reveal that the Tianyuan individual derived from a population that was ancestral to many present-day Asians and Native Americans but postdated the divergence of Asians from Europeans. They also show that this individual carried proportions of DNA variants derived from archaic humans similar to present-day people in mainland Asia. PMID:23341637

  5. DNA analysis of an early modern human from Tianyuan Cave, China.

    PubMed

    Fu, Qiaomei; Meyer, Matthias; Gao, Xing; Stenzel, Udo; Burbano, Hernán A; Kelso, Janet; Pääbo, Svante

    2013-02-01

    Hominins with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 y ago. The genetic relationships between these early modern humans and present-day human populations have not been established. We have extracted DNA from a 40,000-y-old anatomically modern human from Tianyuan Cave outside Beijing, China. Using a highly scalable hybridization enrichment strategy, we determined the DNA sequences of the mitochondrial genome, the entire nonrepetitive portion of chromosome 21 (∼30 Mbp), and over 3,000 polymorphic sites across the nuclear genome of this individual. The nuclear DNA sequences determined from this early modern human reveal that the Tianyuan individual derived from a population that was ancestral to many present-day Asians and Native Americans but postdated the divergence of Asians from Europeans. They also show that this individual carried proportions of DNA variants derived from archaic humans similar to present-day people in mainland Asia. PMID:23341637

  6. 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. PMID:22305470

  7. 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. PMID:26061688

  8. 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

  9. 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

  10. 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

  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. PMID:21047863

  12. 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. PMID:22826222

  13. 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

  14. The backbone of the post-synaptic density originated in a unicellular ancestor of choanoflagellates and metazoans

    PubMed Central

    2010-01-01

    Background Comparative genomics of the early diverging metazoan lineages and of their unicellular sister-groups opens new window to reconstructing the genetic changes which preceded or accompanied the evolution of multicellular body plans. A recent analysis found that the genome of the nerve-less sponges encodes the homologues of most vertebrate post-synaptic proteins. In vertebrate excitatory synapses, these proteins assemble to form the post-synaptic density, a complex molecular platform linking membrane receptors, components of their signalling pathways, and the cytoskeleton. Newly available genomes from Monosiga brevicollis (a member of Choanoflagellata, the closest unicellular relatives of animals) and Trichoplax adhaerens (a member of Placozoa: besides sponges, the only nerve-less metazoans) offer an opportunity to refine our understanding of post-synaptic protein evolution. Results Searches for orthologous proteins and reconstruction of gene gains/losses based on the taxon phylogeny indicate that post-synaptic proteins originated in two main steps. The backbone scaffold proteins (Shank, Homer, DLG) and some of their partners were acquired in a unicellular ancestor of choanoflagellates and metazoans. A substantial additional set appeared in an exclusive ancestor of the Metazoa. The placozoan genome contains most post-synaptic genes but lacks some of them. Notably, the master-scaffold protein Shank might have been lost secondarily in the placozoan lineage. Conclusions The time of origination of most post-synaptic proteins was not concomitant with the acquisition of synapses or neural-like cells. The backbone of the scaffold emerged in a unicellular context and was probably not involved in cell-cell communication. Based on the reconstructed protein composition and potential interactions, its ancestral function could have been to link calcium signalling and cytoskeleton regulation. The complex later became integrated into the evolving synapse through the

  15. Human chronic gonadotropin concentrations in very early pregnancy and subsequent preeclampsia.

    PubMed

    Rabie, Nader Z; Magann, Everett F

    2014-09-01

    Evaluation of: Asvold BO, Vatten LJ, Tanbo TG, Eskild A. Concentrations of human chorionic gonadotrophin in very early pregnancy and subsequent pre-eclampsia: a cohort study. Hum. Reprod. 29(6), 1153-1160 (2014). A total of 2405 consecutive singleton pregnancies were followed to determine if early HCG levels were associated with the development of preeclampsia. All pregnancies were conceived by in vitro fertilization, which allowed very accurate gestational age dating. HCG levels were obtained on day 12, and grouped into 4 categories (<50, 50-99, 100-149, ≥ 150). HCG levels less than 50 were associated with an odds ratio of 2.3 (95% CI: 1.2-4.7) for preeclampsia and and odds ratio of 4.2 (95% CI: 1.4-12.2) for severe preeclampsia. Early HCG levels may serve as a marker for the detection of preeclampsia. PMID:25335537

  16. [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. PMID:25872313

  17. Transcriptional Factor PU.1 Regulates Decidual C1q Expression in Early Pregnancy in Human.

    PubMed

    Madhukaran, Shanmuga Priyaa; Kishore, Uday; Jamil, Kaiser; Teo, Boon Heng Dennis; Choolani, Mahesh; Lu, Jinhua

    2015-01-01

    C1q is the first recognition subcomponent of the complement classical pathway, which in addition to being synthesized in the liver, is also expressed by macrophages and dendritic cells (DCs). Trophoblast invasion during early placentation results in accumulation of debris that triggers the complement system. Hence, both early and late components of the classical pathway are widely distributed in the placenta and decidua. In addition, C1q has recently been shown to significantly contribute to feto-maternal tolerance, trophoblast migration, and spiral artery remodeling, although the exact mechanism remains unknown. Pregnancy in mice, genetically deficient in C1q, mirrors symptoms similar to that of human preeclampsia. Thus, regulated complement activation has been proposed as an essential requirement for normal successful pregnancy. Little is known about the molecular pathways that regulate C1q expression in pregnancy. PU.1, an Ets-family transcription factor, is required for the development of hematopoietic myeloid lineage immune cells, and its expression is tissue-specific. Recently, PU.1 has been shown to regulate C1q gene expression in DCs and macrophages. Here, we have examined if PU.1 transcription factor regulates decidual C1q expression. We used immune-histochemical analysis, PCR, and immunostaining to localize and study the gene expression of PU.1 transcription factor in early human decidua. PU.1 was highly expressed at gene and protein level in early human decidual cells including trophoblast and stromal cells. Surprisingly, nuclear as well as cytoplasmic PU.1 expression was observed. Decidual cells with predominantly nuclear PU.1 expression had higher C1q expression. It is likely that nuclear and cytoplasmic PU.1 localization has a role to play in early pregnancy via regulating C1q expression in the decidua during implantation. PMID:25762996

  18. Expression of immediate early genes after treatment of human astrocytoma cells with radiation and taxol

    SciTech Connect

    Gubits, R.M.; Geard, C.R.; Schiff, P.B.

    1993-10-20

    The promising chemotherapeutic agent, taxol, has been shown to sensitize the G18 line of human astrocytoma cells to ionizing radiation. The present studies were performed to identify specific changes in gene expression associated with this altered sensitivity. The products of immediate early genes, which are induced transiently in cells in response to a variety of treatments, including growth factors, neurotransmitters, and irradiation with UV light or X rays, are thought to initiate a cascade of genetic responses to alterations in cellular environment. The present results demonstrate a dramatic attenuation in one immediate early gene response in association with a treatment that enhances radiosensitivity in a refractory human brain tumor line. 22 refs., 5 figs., 1 tab.

  19. Some early uses of evoked brain responses in investigations of human visual function.

    PubMed

    Regan, D

    2009-05-01

    In the context of the technical possibilities of the time, this paper describes early attempts to employ visual-evoked potentials (VEPs) as a tool for investigating human visual function, focussing on the contributions of Henk Spekreijse and his colleagues. The topics covered are as follows: attempts to distinguish between true pattern-specific VEPs and the effects of responses to changes in local luminance; retinal rivalry and interocular sustained suppression; the implications of VEPs elicited by equiluminant chromatic patterns; VEPs specific to real and apparent motion; stereo VEPs; identification of a visual-auditory convergence area in the human brain. PMID:18304602

  20. 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. PMID:17218523

  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. Behavioral inferences from the Skhul/Qafzeh early modern human hand remains

    PubMed Central

    Niewoehner, Wesley A.

    2001-01-01

    Two groups of humans are found in the Near East ≈100,000 years ago, the late archaic Neanderthals and the early modern Skhul/Qafzeh humans. Observations that Neanderthals were more heavily muscled, had stronger upper-limb bones, and possessed unusual shapes and orientations of some upper-limb joint complexes relative to the Skhul/Qafzeh hominids, have led some researchers to conclude that significant between-group upper-limb-related behavioral differences must have been present, despite the association of the two groups with similar Middle Paleolithic archeological complexes. A three-dimensional morphometric analysis of the hand remains of the Skhul/Qafzeh hominids, Neanderthals, early and late Upper Paleolithic humans, and Holocene humans supports the dichotomy. The Skhul/Qafzeh carpometacarpal remains do not have any unique morphologies relative to the other fossil samples remains examined. However, in the functionally significant metacarpal 1 and 3 bases they resemble Upper Paleolithic humans, not Neanderthals. Furthermore, the Skhul/Qafzeh sample differs significantly from the Neanderthals in many other aspects of hand functional anatomy. Given the correlations between changes in tool technologies and functional adaptations seen in the hands of Upper Paleolithic humans, it is concluded that the Skhul/Qafzeh hand remains were adapted to Upper Paleolithic-like manipulative repertoires. These results support the inference of significant behavioral differences between Neanderthals and the Skhul/Qafzeh hominids and indicate that a significant shift in human manipulative behaviors was associated with the earliest stages of the emergence of modern humans. PMID:11248017

  3. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex.

    PubMed

    Self, Matthew W; Peters, Judith C; Possel, Jessy K; Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C; Roelfsema, Pieter R

    2016-03-01

    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

  4. 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

    2016-01-01

    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. 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

  6. 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

  7. 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. PMID:23045659

  8. James L. German, a pioneer in early human genetic research turned 90.

    PubMed

    Passarge, Eberhard

    2016-06-01

    In the early 1960s, J. German established the non-synchronous human DNA replication pattern in metaphases of cultured lymphocytes and fibroblasts. This could be used to distinguish several chromosomes of similar morphology. From 1965 on over the next 30 years, he and his coworkers systematically studied Bloom's syndrome in depth, cumulating in the identification in 1995 of the BLM gene as encoding a DNA helicase. © 2016 Wiley Periodicals, Inc. PMID:27016306

  9. Early human cultural and skeletal remains from guitarrero cave, northern peru.

    PubMed

    Lynch, T F; Kennedy, K A

    1970-09-25

    An early man site in highland Peru yielded a rich cultural assemblage in stratigraphic association with faunal remains, botanical remains, and campfire remnants that furnished secure radiocarbon dates. A human mandible and teeth, showing interesting patterns of occlusal wear, were found in a stratum dated by a charcoal sample to 10,610 B.C., the oldest such date in South America. PMID:17772515

  10. Human Herpesvirus 6 Latently Infects Early Bone Marrow Progenitors In Vivo

    PubMed Central

    Luppi, Mario; Barozzi, Patrizia; Morris, Christine; Maiorana, Antonio; Garber, Richard; Bonacorsi, Goretta; Donelli, Amedea; Marasca, Roberto; Tabilio, Antonio; Torelli, Giuseppe

    1999-01-01

    We have studied the in vivo tropism of human herpesvirus 6 (HHV-6) for hemopoietic cells in patients with latent HHV-6 infection. Having used a variety of cell purification, molecular, cytogenetic, and immunocytochemical procedures, we report the first evidence that HHV-6 latently infects early bone marrow progenitor cells and that HHV-6 may be transmitted longitudinally to cells which differentiate along the committed pathways. PMID:9847383

  11. 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…

  12. 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.

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

    PubMed

    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

  14. 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

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

    DOE PAGESBeta

    Yang, Dongqing; Pomraning, Kyle; Kopchinskiy, Alexey; Karimi, Aghcheh Razieh; Atanasova, Lea; Chenthamara, Komal; Baker, Scott E.; Zhang, Ruifu; Shen, Qirong; Freitag, Michael; et al

    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.

  16. Early Parental Care Is Important for Hippocampal Maturation: Evidence from Brain Morphology in Humans

    PubMed Central

    Rao, Hengyi; Betancourt, Laura; Giannetta, Joan M.; Brodsky, Nancy L.; Korczykowski, Marc; Avants, Brian B.; Gee, James C.; Wang, Jiongjiong; Hurt, Hallam; Detre, John A.; Farah, Martha J.

    2009-01-01

    The effects of early life experience on later brain structure and function have been studied extensively in animals, yet the relationship between childhood experience and normal brain development in humans remains largely unknown. Using a unique longitudinal data set including ecologically valid in-home measures of early experience during childhood (at age 4 and 8 years) and high-resolution structural brain imaging during adolescence (mean age 14 years), we examined the effects on later brain morphology of two dimensions of early experience: parental nurturance and environmental stimulation. Parental nurturance at age 4 predicts the volume of the left hippocampus in adolescence, with better nurturance associated with smaller hippocampal volume. In contrast, environmental stimulation did not correlate with hippocampal volume. Moreover, the association between hippocampal volume and parental nurturance disappears at age 8, supporting the existence of a sensitive developmental period for brain maturation. These findings indicate that variation in normal childhood experience is associated with differences in brain morphology, and hippocampal volume is specifically associated with early parental nurturance. Our results provide neuroimaging evidence supporting the important role of warm parental care during early childhood for brain maturation. PMID:19595774

  17. Early Regulation of Profibrotic Genes in Primary Human Cardiac Myocytes by Trypanosoma cruzi

    PubMed Central

    Dykan, Andrey; Rachakonda, Girish; Villalta, Fernando; Mandape, Sammed N.; Lima, Maria F.; Pratap, Siddharth; Nde, Pius N.

    2016-01-01

    The molecular mechanisms of Trypanosoma cruzi induced cardiac fibrosis remains to be elucidated. Primary human cardiomyoctes (PHCM) exposed to invasive T. cruzi trypomastigotes were used for transcriptome profiling and downstream bioinformatic analysis to determine fibrotic-associated genes regulated early during infection process (0 to 120 minutes). The identification of early molecular host responses to T. cruzi infection can be exploited to delineate important molecular signatures that can be used for the classification of Chagasic patients at risk of developing heart disease. Our results show distinct gene network architecture with multiple gene networks modulated by the parasite with an incline towards progression to a fibrogenic phenotype. Early during infection, T. cruzi significantly upregulated transcription factors including activator protein 1 (AP1) transcription factor network components (including FOSB, FOS and JUNB), early growth response proteins 1 and 3 (EGR1, EGR3), and cytokines/chemokines (IL5, IL6, IL13, CCL11), which have all been implicated in the onset of fibrosis. The changes in our selected genes of interest did not all start at the same time point. The transcriptome microarray data, validated by quantitative Real-Time PCR, was also confirmed by immunoblotting and customized Enzyme Linked Immunosorbent Assays (ELISA) array showing significant increases in the protein expression levels of fibrogenic EGR1, SNAI1 and IL 6. Furthermore, phosphorylated SMAD2/3 which induces a fibrogenic phenotype is also upregulated accompanied by an increased nuclear translocation of JunB. Pathway analysis of the validated genes and phospho-proteins regulated by the parasite provides the very early fibrotic interactome operating when T. cruzi comes in contact with PHCM. The interactome architecture shows that the parasite induces both TGF-β dependent and independent fibrotic pathways, providing an early molecular foundation for Chagasic cardiomyopathy

  18. Early Regulation of Profibrotic Genes in Primary Human Cardiac Myocytes by Trypanosoma cruzi.

    PubMed

    Udoko, Aniekanabassi N; Johnson, Candice A; Dykan, Andrey; Rachakonda, Girish; Villalta, Fernando; Mandape, Sammed N; Lima, Maria F; Pratap, Siddharth; Nde, Pius N

    2016-01-01

    The molecular mechanisms of Trypanosoma cruzi induced cardiac fibrosis remains to be elucidated. Primary human cardiomyoctes (PHCM) exposed to invasive T. cruzi trypomastigotes were used for transcriptome profiling and downstream bioinformatic analysis to determine fibrotic-associated genes regulated early during infection process (0 to 120 minutes). The identification of early molecular host responses to T. cruzi infection can be exploited to delineate important molecular signatures that can be used for the classification of Chagasic patients at risk of developing heart disease. Our results show distinct gene network architecture with multiple gene networks modulated by the parasite with an incline towards progression to a fibrogenic phenotype. Early during infection, T. cruzi significantly upregulated transcription factors including activator protein 1 (AP1) transcription factor network components (including FOSB, FOS and JUNB), early growth response proteins 1 and 3 (EGR1, EGR3), and cytokines/chemokines (IL5, IL6, IL13, CCL11), which have all been implicated in the onset of fibrosis. The changes in our selected genes of interest did not all start at the same time point. The transcriptome microarray data, validated by quantitative Real-Time PCR, was also confirmed by immunoblotting and customized Enzyme Linked Immunosorbent Assays (ELISA) array showing significant increases in the protein expression levels of fibrogenic EGR1, SNAI1 and IL 6. Furthermore, phosphorylated SMAD2/3 which induces a fibrogenic phenotype is also upregulated accompanied by an increased nuclear translocation of JunB. Pathway analysis of the validated genes and phospho-proteins regulated by the parasite provides the very early fibrotic interactome operating when T. cruzi comes in contact with PHCM. The interactome architecture shows that the parasite induces both TGF-β dependent and independent fibrotic pathways, providing an early molecular foundation for Chagasic cardiomyopathy

  19. A Novel Fully Humanized 3D Skin Equivalent to Model Early Melanoma Invasion.

    PubMed

    Hill, David S; Robinson, Neil D P; Caley, Matthew P; Chen, Mei; O'Toole, Edel A; Armstrong, Jane L; Przyborski, Stefan; Lovat, Penny E

    2015-11-01

    Metastatic melanoma remains incurable, emphasizing the acute need for improved research models to investigate the underlying biologic mechanisms mediating tumor invasion and metastasis, and to develop more effective targeted therapies to improve clinical outcome. Available animal models of melanoma do not accurately reflect human disease and current in vitro human skin equivalent models incorporating melanoma cells are not fully representative of the human skin microenvironment. We have developed a robust and reproducible, fully humanized three-dimensional (3D) skin equivalent comprising a stratified, terminally differentiated epidermis and a dermal compartment consisting of fibroblast-generated extracellular matrix. Melanoma cells incorporated into the epidermis were able to invade through the basement membrane and into the dermis, mirroring early tumor invasion in vivo. Comparison of our novel 3D melanoma skin equivalent with melanoma in situ and metastatic melanoma indicates that this model accurately recreates features of disease pathology, making it a physiologically representative model of early radial and vertical growth-phase melanoma invasion. PMID:26330548

  20. Immunohistochemical Markers of Neural Progenitor Cells in the Early Embryonic Human Cerebral Cortex

    PubMed Central

    Vinci, L.; Ravarino, A.; Fanos, V.; Naccarato, A.G.; Senes, G.; Gerosa, C.; Bevilacqua, G.; Faa, G.; Ambu, R.

    2016-01-01

    The development of the human central nervous system represents a delicate moment of embryogenesis. The purpose of this study was to analyze the expression of multiple immunohistochemical markers in the stem/progenitor cells in the human cerebral cortex during the early phases of development. To this end, samples from cerebral cortex were obtained from 4 human embryos of 11 weeks of gestation. Each sample was formalin-fixed, paraffin embedded and immunostained with several markers including GFAP, WT1, Nestin, Vimentin, CD117, S100B, Sox2, PAX2, PAX5, Tβ4, Neurofilament, CD44, CD133, Synaptophysin and Cyclin D1. Our study shows the ability of the different immunohistochemical markers to evidence different zones of the developing human cerebral cortex, allowing the identification of the multiple stages of differentiation of neuronal and glial precursors. Three important markers of radial glial cells are evidenced in this early gestational age: Vimentin, Nestin and WT1. Sox2 was expressed by the stem/progenitor cells of the ventricular zone, whereas the postmitotic neurons of the cortical plate were immunostained by PAX2 and NSE. Future studies are needed to test other important stem/progenitor cells markers and to better analyze differences in the immunohistochemical expression of these markers during gestation. PMID:26972711

  1. 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. PMID:24236171

  2. 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

  3. 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.

  4. 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.

  5. 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. PMID:26500820

  6. 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

  7. 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

  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. Matriptase regulates proliferation and early, but not terminal, differentiation of human keratinocytes

    PubMed Central

    Chen, Ya-Wen; Wang, Jehng-Kang; Chou, Fen-Pai; Wu, Bai-Yao; Hsiao, Hui-Chung; Chiu, Han; Xu, Zhonghong; Baksh, Adrienne NH; Shi, Galen; Kaul, Malvika; Barndt, Robert; Shanmugam, Victoria K.; Johnson, Michael D.; Lin, Chen-Yong

    2013-01-01

    Genetic defects in matriptase are linked to two congenital ichthyosis, autosomal recessive ichthyosis with hypotrichosis (ARIH, OMIM 610765) and, ichthyosis, follicular atrophoderma, hypotrichosis, and hypohidrosis (IFAH, OMIM602400). 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, 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 suggests that, unlike mouse matriptase, human matriptase may be involved in regulation of keratinocyte growth and early differentiation, rather than terminal differentiation, providing mechanistic insights for the pathology of the two congenital ichthyoses, ARIH and IFAH. PMID:23900022

  10. 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

  11. Genetic programs in human and mouse early embryos revealed by single-cell RNA sequencing

    PubMed Central

    Xue, Zhigang; Huang, Kevin; Cai, Chaochao; Cai, Lingbo; Jiang, Chun-yan; Feng, Yun; Liu, Zhenshan; Zeng, Qiao; Cheng, Liming; Sun, Yi E.; Liu, Jia-yin; Horvath, Steve; Fan, Guoping

    2016-01-01

    Mammalian pre-implantation development is a complex process involving dramatic changes in the transcriptional architecture1–4. We report here a comprehensive analysis of transcriptome dynamics from oocyte to morula in both human and mouse embryos, using single-cell RNA sequencing. Based on single-nucleotide variants in human blastomere messenger RNAs and paternal-specific single-nucleotide polymorphisms, we identify novel stage-specific monoallelic expression patterns for a significant portion of polymorphic gene transcripts (25 to 53%). By weighted gene co-expression network analysis5,6, we find that each developmental stage can be delineated concisely by a small number of functional modules of co-expressed genes. This result indicates a sequential order of transcriptional changes in pathways of cell cycle, gene regulation, translation and metabolism, acting in a step-wise fashion from cleavage to morula. Cross-species comparisons with mouse pre-implantation embryos reveal that the majority of human stage-specific modules (7out of 9) are notably preserved, but developmental specificity and timing differ between human and mouse. Furthermore, we identify conserved key members (or hub genes) of the human and mouse networks. These genes represent novel candidates that are likely to be key in driving mammalian pre-implantation development. Together, the results provide a valuable resource to dissect gene regulatory mechanisms underlying progressive development of early mammalian embryos. PMID:23892778

  12. Defining the genomic signature of totipotency and pluripotency during early human development.

    PubMed

    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

  13. 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

  14. 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. PMID:26580202

  15. From the Cover: Feature Article: Water, plants, and early human habitats in eastern Africa

    NASA Astrophysics Data System (ADS)

    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.

  16. Early Detection of Human Epileptic Seizures Based on Intracortical Local Field Potentials.

    PubMed

    Park, Yun S; Hochberg, Leigh R; Eskandar, Emad N; Cash, Sydney S; Truccolo, Wilson

    2013-01-01

    The unpredictability of re-occurring seizures dramatically impacts the quality of life and autonomy of people with epilepsy. Reliable early seizure detection could open new therapeutic possibilities and thus substantially improve quality of life and autonomy. Though many seizure detection studies have shown the potential of scalp electroencephalogram (EEG) and intracranial EEG (iEEG) signals, reliable early detection of human seizures remains elusive in practice. Here, we examined the use of intracortical local field potentials (LFPs) recorded from 4×4-mm(2) 96-microelectrode arrays (MEA) for early detection of human epileptic seizures. We adopted a framework consisting of (1) sampling of intracortical LFPs; (2) denoising of LFPs with the Kalman filter; (3) spectral power estimation in specific frequency bands using 1-sec moving time windows; (4) extraction of statistical features, such as the mean, variance, and Fano factor (calculated across channels) of the power in each frequency band; and (5) cost-sensitive support vector machine (SVM) classification of ictal and interictal samples. We tested the framework in one-participant dataset, including 4 seizures and corresponding interictal recordings preceding each seizure. The participant was a 52-year-old woman suffering from complex partial seizures. LFPs were recorded from an MEA implanted in the participant's left middle temporal gyrus. In this participant, spectral power in 0.3-10 Hz, 20-55 Hz, and 125-250 Hz changed significantly between ictal and interictal epochs. The examined seizure detection framework provided an event-wise sensitivity of 100% (4/4) and only one 20-sec-long false positive event in interictal recordings (likely an undetected subclinical event under further visual inspection), and a detection latency of 4.35 ± 2.21 sec (mean ± std) with respect to iEEG-identified seizure onsets. These preliminary results indicate that intracortical MEA recordings may provide key signals to quickly and

  17. 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. PMID:24612646

  18. [Early human transplants: 60th anniversary of the first successful kidney transplants].

    PubMed

    Gentili, Marc E

    2015-11-01

    First kidney transplant attempts begin with the 20th century: improving vascular sutures, understanding the phenomena of rejection or tolerance, then progress in HLA groups enable early success in the second half of the century. Definition of brain death, use of corticosteroids, radiotherapy and prime immunosuppressors promote the development of transplants. Discover of cyclosporine in the 1980s, and legislative developments augur a new era. Many advances are arising: use of stem cells from the donor, enhancement of Maastricht 3 donor or living donation. Finally organ transplantation remains an immense human adventure, but also scientific and ethic. PMID:26206772

  19. Differential diagnosis of early human pregnancies: impact of different diagnostic measures.

    PubMed

    Thorburn, J; Bryman, I; Hahlin, M; Lindblom, B

    1992-01-01

    A total of 261 women in early pregnancy, either with mild symptoms of ectopic pregnancy (EP) or being at an increased risk for this condition, were included in a longitudinal study. The effectiveness of different diagnostic measures in obtaining correct final diagnoses was analyzed. In addition to clinical findings and symptoms, the use of serum human chorionic gonadotropin, serum progesterone, endovaginal sonography and a risk score for EP were all proven to be valuable in distinguishing normal intrauterine pregnancies from pathological pregnancies. PMID:1505809

  20. 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. PMID:25278927

  1. Early influence of auditory stimuli on upper-limb movements in young human infants: an overview

    PubMed Central

    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. PMID:25278927

  2. 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

  3. Human in vitro reporter model of neuronal development and early differentiation processes

    PubMed Central

    Couillard-Despres, Sebastien; Quehl, Eike; Altendorfer, Katrin; Karl, Claudia; Ploetz, Sonja; Bogdahn, Ulrich; Winkler, Juergen; Aigner, Ludwig

    2008-01-01

    Background During developmental and adult neurogenesis, doublecortin is an early neuronal marker expressed when neural stem cells assume a neuronal cell fate. To understand mechanisms involved in early processes of neuronal fate decision, we investigated cell lines for their capacity to induce expression of doublecortin upon neuronal differentiation and develop in vitro reporter models using doublecortin promoter sequences. Results Among various cell lines investigated, the human teratocarcinoma cell line NTERA-2 was found to fulfill our criteria. Following induction of differentiation using retinoic acid treatment, we observed a 16-fold increase in doublecortin mRNA expression, as well as strong induction of doublecortin polypeptide expression. The acquisition of a neuronal precursor phenotype was also substantiated by the establishment of a multipolar neuronal morphology and expression of additional neuronal markers, such as Map2, βIII-tubulin and neuron-specific enolase. Moreover, stable transfection in NTERA-2 cells of reporter constructs encoding fluorescent or luminescent genes under the control of the doublecortin promoter allowed us to directly detect induction of neuronal differentiation in cell culture, such as following retinoic acid treatment or mouse Ngn2 transient overexpression. Conclusion Induction of doublecortin expression in differentiating NTERA-2 cells suggests that these cells accurately recapitulate some of the very early events of neuronal determination. Hence, the use of reporter genes under the control of the doublecortin promoter in NTERA-2 cells will help us to investigate factors involved early in the course of neuronal differentiation processes. Moreover the ease to detect the induction of a neuronal program in this model will permit to perform high throughput screening for compounds acting on the early neuronal differentiation mechanisms. PMID:18312642

  4. 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

  5. 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.

  6. 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

    2015-10-01

    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

  7. 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

  8. Heterokont Predator Develorapax marinus gen. et sp. nov. - A Model of the Ochrophyte Ancestor.

    PubMed

    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

  9. Early-onset binocularity in preterm infants reveals experience-dependent visual development in humans

    PubMed Central

    Jandó, Gábor; Mikó-Baráth, Eszter; Markó, Katalin; Hollódy, Katalin; Török, Béla; Kovacs, Ilona

    2012-01-01

    Although there is a great deal of knowledge regarding the phylo- and ontogenetic plasticity of the neocortex, the precise nature of environmental impact on the newborn human brain is still one of the most controversial issues of neuroscience. The leading model–system of experience-dependent brain development is binocular vision, also called stereopsis. Here, we show that extra postnatal visual experience in preterm human neonates leads to a change in the developmental timing of binocular vision. The onset age of binocular function, as measured by the visual evoked response to dynamic random dot correlograms (DRDC-VEP), appears to be at around the same time after birth in preterm (4.07 mo) and full-term (3.78 mo) infants. To assess the integrity of the visual pathway in the studied infants, we also measured the latency of the visual-evoked response to pattern reversal stimuli (PR-VEP). PR-VEP latency is not affected by premature birth, demonstrating that the maturation of the visual pathway follows a preprogrammed developmental course. Despite the immaturity of the visual pathway, clearly demonstrated by the PR-VEP latencies, our DRCD-VEP data show that the visual cortex is remarkably ready to accept environmental stimulation right after birth. This early plasticity makes full use of the available extra stimulation time in preterm human infants and results in an early onset of cortical binocularity. According to our data, the developmental processes preceding the onset of binocular function are not preprogrammed, and the mechanisms turning on stereopsis are extremely experience-dependent in humans. PMID:22711824

  10. Differences between human and mouse alpha-fetoprotein expression during early development

    PubMed Central

    JONES, ELIZABETH A.; CLEMENT-JONES, MARK; JAMES, OLIVER F. W.; WILSON, DAVID I.

    2001-01-01

    Alpha-fetoprotein (AFP) is the major serum protein during development. AFP is one of the earliest proteins to be synthesised by the embryonic liver. The synthesis of AFP decreases dramatically after birth and only trace amounts are expressed in the adult liver. The tissue distribution of AFP in early human embryogenesis has not been defined. We have studied the expression pattern of AFP mRNA in human and mouse embryos by in situ hybridisation. In humans, AFP is expressed in the hepatic diverticulum at 26 d postovulation as it differentiates from the foregut endoderm (i.e. in the most primitive hepatocytes). It is also expressed in the endoderm of the gastrointestinal tract and in the yolk sac at this age. AFP is subsequently expressed in the mesonephros and transiently in the developing pancreas. In the mouse, no expression of AFP was observed in the mesonephros but other sites of expression were similar. Thus AFP has a distinct temporospatial expression pattern during the embryonic period and this differs between human and mouse species. It is interesting that AFP is expressed by tumours such as primitive gastrointestinal, renal cell and pancreatic tumours as well as those of hepatocyte origin. This distribution reflects the sites of AFP expression during development. PMID:11430694