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Modern Human Origins (modern + human_origins)
Selected AbstractsReflections of Our Past; Genetics and the Search for Modern Human OriginsAMERICAN ANTHROPOLOGIST, Issue 4 2004ERIC J. DEVOR No abstract is available for this article. [source] Haplotype Trees and Modern Human OriginsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue S41 2005Alan R. Templeton Abstract A haplotype is a multisite haploid genotype at two or more polymorphic sites on the same chromosome in a defined DNA region. An evolutionary tree of the haplotypes can be estimated if the DNA region had little to no recombination. Haplotype trees can be used to reconstruct past human gene-flow patterns and historical events, but any single tree captures only a small portion of evolutionary history, and is subject to error. A fuller view of human evolution requires multiple DNA regions, and errors can be minimized by cross-validating inferences across loci. An analysis of 25 DNA regions reveals an out-of-Africa expansion event at 1.9 million years ago. Gene flow with isolation by distance was established between African and Eurasian populations by about 1.5 million years ago, with no detectable interruptions since. A second out-of-Africa expansion occurred about 700,000 years ago, and involved interbreeding with at least some Eurasian populations. A third out-of-Africa event occurred around 100,000 years ago, and was also characterized by interbreeding, with the hypothesis of a total Eurasian replacement strongly rejected (P < 10,17). This does not preclude the possibility that some Eurasian populations could have been replaced, and the status of Neanderthals is indecisive. Demographic inferences from haplotype trees have been inconsistent, so few definitive conclusions can be made at this time. Haplotype trees from human parasites offer additional insights into human evolution and raise the possibility of an Asian isolate of humanity, but once again not in a definitive fashion. Haplotype trees can also indicate which genes were subject to positive selection in the lineage leading to modern humans. Genetics provides many insights into human evolution, but those insights need to be integrated with fossil and archaeological data to yield a fuller picture of the origin of modern humans. Yrbk Phys Anthropol 48:33,59, 2005. © 2005 Wiley-Liss, Inc. [source] Putting North Africa on the map of modern human originsEVOLUTIONARY ANTHROPOLOGY, Issue 1 2008Chris Stringer No abstract is available for this article. [source] Genetics and the search for modern human originsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2002Kenneth M. Weiss No abstract is available for this article. [source] Out of Africa with regional interbreeding?BIOESSAYS, Issue 10 2002Modern human origins A central issue in paleoanthropology is whether modern humans emerged in a single geographic area and subsequently replaced the preexisting people in other areas. Although the study of human mitochondrial DNAs supported this single-origin and complete-replacement model, a recent paper1 argues that humans expanded out of Africa more than once and regionally interbred. However, both the genetic antiquity and the impact of the African contribution to modern Homo sapiens are so great as to view Africa as a central place of human evolution. Despite the possibility that out-of-Africa H. sapiens interbred with other populations, this evidence is more consistent with the uniregional hypothesis than the multiregional hypothesis of modern human origins. BioEssays 24:871,875, 2002. © 2002 Wiley Periodicals, Inc. [source] | ||||||||||