Haplotype Trees and Modern Human Origins
Article first published online: 20 DEC 2005
Copyright © 2005 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Supplement: Yearbook of Physical Anthropology
Volume 128, Issue Supplement 41, pages 33–59, 2005
How to Cite
Templeton, A. R. (2005), Haplotype Trees and Modern Human Origins. Am. J. Phys. Anthropol., 128: 33–59. doi: 10.1002/ajpa.20351
- Issue published online: 20 DEC 2005
- Article first published online: 20 DEC 2005
- NIH. Grant Number: GM065509
- gene flow;
- natural selection;
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.