Genetic differences among human populations are usually larger for the Y ch
romosome than for mtDNA(1-3). one possible explanation is the higher rate o
f female versus male migration due to the widespread phenomenon of patriloc
ality, in which the woman moves to her mate's residence after marriage. To
test this hypothesis, we compare mtDNA and Y-chromosome variation in three
matrilocal (in which the man moves to his mate's residence after marriage)
and three patrilocal groups among the hill tribes of northern Thailand. Gen
etic diversity in these groups shows a striking correlation with residence
pattern, supporting the role of sex-specific migration in influencing human
genetic variation.