POPULATION-GENETICS OF Y-CHROMOSOME SHORT TANDEM REPEATS IN HUMANS

Eight human short tandem repeat polymorphisms (STRs) also known as mic rosatellites-DYS19, DYS388, DYS390, DYS391, DYS392, DYS393, DYS389I, a nd DYS389II, mapping in the Y chromosome-were analyzed in two Iberian samples (Basques and Catalans). Allele frequency distributions showed significant differences only for DYS392, Fst and gene diversity index (D) were estimated for the Y STRs. The values obtained are comparable to those of autosomal STR if corrections for the smaller effective pop ulation size on the Y chromosome are taken into account. This suggests that Y-chromosome microsatellites might be as useful as their autosom al counterparts to both human population genetics and forensics. Our r esults also reinforce the hypothesis that selective sweeps in the Y ch romosome in recent times are unlikely, Haplotypes combining five of th e loci were constructed for 71 individuals, showing 29 different haplo types. A haplotype tree was constructed, from which an estimate of 7,0 00 to 60,000 years for the age of the Y-chromosome variation in Iberia was derived, in accordance with previous estimates obtained with mtDN A sequences and nuclear markers.