Nature Genetics
20, 278 - 280 (1998)
doi:10.1038/3088
Genetic evidence for a higher female migration rate in humansMark T. Seielstad1, Eric Minch2
& L. Luca Cavalli-Sforza21
Program for Population Genetics, Harvard School of
Public Health, 665 Huntington Avenue, Boston,
Massachusetts 02115, USA. 2
Department of Genetics, Stanford University School
of Medicine, Stanford, California 94305-5120, USA.
Correspondence should be addressed to Mark T. Seielstad mark@ppg.harvard.edu
Mitochondrial DNA and the Y chromosome have been used extensively in
the study of modern human origins and other phylogenetic questions, but not
in the context of their sex-specific modes of transmission. mtDNA is transmitted
exclusively by females, whereas the Y chromosome is passed only among males.
As a result, differences in the reproductive output or migration rate of males
and females will influence the geographic patterns and relative level of genetic
diversity on the Y chromosome, autosomes and mtDNA (ref. 1). We have found that Y chromosome variants tend to be more localized
geographically than those of mtDNA and the autosomes2,
5. The
fraction of variation within human populations for Y chromosome single nucleotide
polymorphisms (SNPs) is 35.5%, versus 80−85% for the autosomes
and mtDNA (refs 6, 7, 8). A higher female than male migration rate (via
patrilocality, the tendency for a wife to move into her husband's natal household)
explains most of this discrepancy, because diverse Y chromosomes would enter
a population at a lower rate than mtDNA or the autosomes. Polygyny may also
contribute, but the reduction of variation within populations that we measure
for the Y chromosome, relative to the autosomes and mitochondrial DNA, is
of such magnitude that differences in the effective population sizes of the
sexes alone are insufficient to produce the observation.
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