Novel (CA)n marker DXYS241 on the nonrecombinant part of the human Y chromosome

The origin of modern humans can be traced by comparing polymorphic sites in either mitochondria or genomic sequences between humans and other primates . The human Y chromosome has both a nonrecombining region and X-Y homologou s pseudo-autosomal regions. In the nonrecombining region events during evol ution can be directly detected. At least a part of homology between Xq21 an d Yp11 is a result of rather recent translocations from the X chromosome to the Y chromosome. DNA markers residing in the nonrecombining region of the human Y chromosome are potentially useful in tracing male-specific gene fl ow in human evolution. However, the number of available markers in the regi on is limited. Here, we report a novel X-Y homologous (CA),, repeat locus i n the nonrecombining region of the Y chromosome. This marker, DXYS241, has several interesting features. Y- and X-chromosome alleles are distinguishab le because the Y-chromosome alleles are shorter than the X-chromosome allel es most of the time. We developed 2 primer sets for specific examination of Y- and X-chromosome alleles. The marker should be useful in establishing r elationships between populations based on patrilineal gene flow. Sequences homologous to DXYS241 are also found on the X chromosome of primates. Four events during primate evolution that led to the modern human Y chromosome w ere identified.