Estimating sex-specific processes in human populations: Are XY-homologous markers an effective tool?
Homologous markers on the sex-specific regions of the X- and Y-chromosomes are differentially inherited through males and females, and have similar molecular characteristics. They may therefore be useful as a complement to the comparison of mtDNA and Y-chromosomal haplotypes for estimating sex-specific processes shaping human population structure. To test this idea, we analyzed XY-homologous microsatellite diversity in 33 human populations from Africa, Asia and Europe. Interpopulation comparisons suggest that the generally discordant pattern of genetic variation observed for X- and Y-linked markers could be an outcome of sex-specific migration processes (m(females)/m(males) approximately 3) or sex-specific demographic processes (N(females)/N(males) approximately 11) or a combination of both. However, intrapopulation diversity estimated by the X/Y ratio Watterson estimator (theta(H(Y))/theta(H(X))) suggests that the scenarios required to explain the global genetic variation of XY-homologous markers are many and complex, and that the sex-specific processes (effective population size and migration rate) shaping human population structures are likely to be specific to each population under study. XY-homologous markers provide an insight into the genuine complexity of sex-specific processes, and their further exploitation in human population studies seems worthwhile.
Balaresque
P
P
Eco-anthropologie et Ethnobiologie, UMR5145 Department Hommes Natures Societes, MNHN, Paris, France. plb7@le.ac.uk
Manni
F
F
Dugoujon
J M
JM
Crousau-Roy
B
B
Heyer
E
E
D000349:Africa / Q000453:epidemiology; D000465:Algorithms; D001208:Asia / Q000453:epidemiology; D002877:Chromosomes, Human / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D005060:Europe / Q000453:epidemiology; D005260:Female; D014644:Genetic Variation; D005828:Genetics, Population / Q000379:methods*; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D017385:Sequence Homology; D012727:Sex Characteristics