If you need an accessible version of this item please contact JSTOR User Support

Drift, Admixture, and Selection in Human Evolution: A Study with DNA Polymorphisms

Anne M. Bowcock, Judith R. Kidd, Joanna L. Mountain, Joan M. Herbert, Luciano Carotenuto, Kenneth K. Kidd and Luca Cavalli-Sforza
Proceedings of the National Academy of Sciences of the United States of America
Vol. 88, No. 3 (Feb. 1, 1991), pp. 839-843
Stable URL: http://www.jstor.org/stable/2356081
Page Count: 5
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Drift, Admixture, and Selection in Human Evolution: A Study with DNA Polymorphisms
Preview not available

Abstract

Accuracy of evolutionary analysis of populations within a species requires the testing of a large number of genetic polymorphisms belonging to many loci. We report here a reconstruction of human differentiation based on 100 DNA polymorphisms tested in five populations from four continents. The results agree with earlier conclusions based on other classes of genetic markers but reveal that Europeans do not fit a simple model of independently evolving populations with equal evolutionary rates. Evolutionary models involving early admixture are compatible with the data. Taking one such model into account, we examined through simulation whether random genetic drift alone might explain the variation among gene frequencies across populations and genes. A measure of variation among populations was calculated for each polymorphism, and its distribution for the 100 polymorphisms was compared with that expected for a drift-only hypothesis. At least two-thirds of the polymorphisms appear to be selectively neutral, but there are significant deviations at the two ends of the observed distribution of the measure of variation: a slight excess of polymorphisms with low variation and a greater excess with high variation. This indicates that a few DNA polymorphisms are affected by natural selection, rarely heterotic, and more often disruptive, while most are selectively neutral.

Page Thumbnails

  • Thumbnail: Page 
839
    839
  • Thumbnail: Page 
840
    840
  • Thumbnail: Page 
841
    841
  • Thumbnail: Page 
842
    842
  • Thumbnail: Page 
843
    843