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Data from a 40,000-year-old man in China reveals complicated genetic history of Asia
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[QUOTE]Originally posted by Djehuti: [QB] ^ Up for the relevance of the implications in regards to populations genetics. Also, since I failed to address some important points before I could address the article. Mind you, the remains in discussion—Tianyuan Man 1 is only comprised of a right mandible and a right femur and right tibia, though the examination of such has yielded some interesting finds: https://www.pnas.org/content/104/16/6573 [IMG]https://www.pnas.org/content/pnas/104/16/6573/F1.medium.gif[/IMG] [IMG]https://www.pnas.org/content/pnas/104/16/6573/F2.medium.gif[/IMG] [i] ABSTRACT 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. Discussion The Tianyuan 1 partial skeleton, as the first east Asian well dated modern human associated skeleton >30 ka 14C BP, provides secure documentation of a suite of derived modern human characteristics in eastern Asia at this time period; among eastern Eurasian early modern remains, only the immature Niah Cave cranium is securely at least as old. These derived modern human features include the strongly projecting tuber symphyseos and high anterior symphyseal angle, the relatively broad scapular glenoid fossa, the reduced hamulus, and the presence of a gluteal buttress and a pronounced pilaster on the femora. Other features that are more common among EMHs include the modest pectoralis major tuberosities of the humeri, the anteriorly rotated radial tuberosity, the relatively straight radial diaphysis, and a modest talar trochlea. These are combined with the absence of several mandibular features (retromolar space, mandibular foramen bridging, mandibular notch asymmetry, and large superior medial pterygoid tubercle) that are common among the Neandertals and rare among Middle and Upper Paleolithic modern humans, but for which the eastern Eurasian late archaic pattern is unknown. At the same time, Tianyuan 1 exhibits several features that place it close to the late archaic humans (represented primarily by the Neandertals) or between them and EMHs. These include the anterior to posterior dental proportions, the proximodistal enlargement of the hamulus, the subcircular and radioulnarly enlarged distal phalangeal tuberosity, and the elevated tibial robusticity despite the linearly elongated body proportions implied by its high crural index. Given the dearth of late archaic human remains in eastern Eurasia, it is not possible to use Tianyuan 1 to support a specific phylogenetic model for the appearance of modern humans in the region, other than to make it likely that there was at least substantial gene flow from earlier modern human populations to the south and west of Tianyuan Cave. This is supported by the derived modern human features previously present in the MPMHs and the high crural index of Tianyuan 1, suggesting some relatively recent ancestry among more equatorial populations. At the same time, the presence of several archaic features, lost or rare in the MPMH sample, implies that a simple spread of modern human morphology eastward from Africa is unlikely, an inference already supported by the south Asian and Australo-melanesian morphology present in the slightly younger remains from Fa Hein, Batadomba lena, and Moh Khiew and especially the contemporaneous Niah Cave 1. More importantly, Tianyuan 1 provides a secure basis for analyzing the morphology and paleobiology of EMHs in eastern Eurasia close to the time of the probable transition from regional late archaic humans to modern humans. With the inevitable addition of more, securely dated, late archaic humans and EMHs from the region, it should become possible to understand the interregional dynamics of this period in human evolution.[/i] What is implied from the morphology of the remains is not a simple demographic spread directly from Africa, but rather demographic admixture with either earlier Sapiens populations and/or Hominid species. [/QB][/QUOTE]
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