Reflections on Modern Human Origins in the Post-Neandertal Genome Era
September 30, 2013
Academic Building A G008, 5:00 PM
The sequencing of the Neandertal genome answered once and for all the question of whether these hominins played a role in the origins of modern humans – they did, and a majority of humans alive today retain a small portion of Neandertal genes. This finding rejects the strictest versions of the “Recent African Origin” (RAO) model, and has been celebrated by supporters of “Multiregional Evolution” (MRE). However, I will argue that MRE can also be rejected, and that other, intermediate, models of modern human origins better represent the means by which modern humans became the only extant human species. The reason behind this argument is the refutation of one of the major tenets of MRE: global gene flow that prevents cladogenesis from occurring. First, using reconstructions of Pleistocene hominin census size, I maintain that populations were neither large nor dense enough to result in such high levels of gene flow across the Old World. Second, I use mammalian, and in particular, primate, divergence and hybridization data to show that the emergence of Homo is recent enough that member species of this genus were unlikely to have been reproductively isolated from each other,even in the absence of the high levels of global gene flow postulated by MRE supporters.
Trenton W. Holliday, born 1966, in Pensacola, Florida, USA, is Professor of Anthropology at Tulane University in New Orleans, where he has been on the faculty since 1998. Prior to coming to Tulane, Professor Holliday taught at the University ofCentral Florida in Orlando (1997-1998) and the College of William and Mary in Williamsburg, Virginia (1996-1997). He was awarded his B.A. in anthropology magnacum laude from Louisiana State University in 1988, and completed his M.A. (1991) and Ph.D. (1995) degrees in anthropology at the University of New Mexico in Albuquerque.His dissertation and ongoing research interests have focused primarily on modern human origins and the fate of the Neandertals, although he has published work dealing with limb proportions in other fossil hominins, including “Lucy” and Liang Bua 1 (“the Hobbit”).He is the author/co-author multiple journal articles and peer-reviewed book chapters,with work appearing in the Journal of Human Evolution, American Journal of Physical Anthropology, Current Anthropology, American Anthropologist, Nature, and Science. Hespent nearly a decade excavating Upper Paleolithic rock shelters in Portugal, and is a member of the team of scientists studying the newly-discovered species Australopithecus sediba.
Species Concepts, Reticulation, and Human Evolution
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