a1 National Institute of Environmental Health Sciences, P. O. Box 12233, Research Triangle Park, N. C. 27709, USA
a2 Department of Ecology and Evolutionary Biology, University of California at Irvine, Irvine, CA 92717, USA
a3 General Education Course, Chikushi Jogakuen Junior College, Ishizaka 2-12-1, Dazaifu-shi, Fukuoka-ken 818-01, Japan
A population genetic model with a single locus at which balancing selection acts and many linked loci at which neutral mutations can occur is analysed using the coalescent approach. The model incorporates geographic subdivision with migration, as well as mutation, recombination, and genetic drift of neutral variation. It is found that geographic subdivision can affect genetic variation even with high rates of migration, providing that selection is strong enough to maintain different allele frequencies at the selected locus. Published sequence data from the alcohol dehydrogenase locus of Drosophila melanogaster are found to fit the proposed model slightly better than a similar model without subdivision.
(Received February 14 1990)
(Revised April 23 1990)
c1 Corresponding author.