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Microsatellite markers on human sex chromosomes have not extensively been studied to date. We characterized polymorphic features of microsatellites on human X and Y chromosomes as follows.
1) Genomic DNA specimens were prepared from blood samples collected from individuals randomly selected from Japanese and German populations. Microsatellite markers DYS388, DYS389, DYS390, DYS391, DYS392, and DYS393 had 6, 10, 8, 10, 6, and 6 polymorphic alleles, respectively. Among them, DYS388, DYS39l, DYS392, and DYS393 were inadequate as polymorphic markers for use in forensic medicine, since allele frequencies were not evenly distributed at these loci resulting in less sufficient heterozygosity. DYS384 had as many as 20 alleles and was found not to be a specific marker of Y chromosome, since female DNA as a template yielded PCR products of DYS384 and male DNA from some individuals also yielded products in an amount equivalent to two alleles. 2) Regarding STRs on X chromosomes, DNA samples from pat
ients with several X-linked diseases were tested for a possible association with a particular genetically unstable microsatellite marker based on allele frequencies of these SIRs obtained in the previous study. Indeed, We could link a particular genetically unstable microsatellite marker to a disease of interest. 3) Based on allele frequencies of STRs on Y chromosomes obtained in the previous study, polymorphic diversity of microsatellite at several loci of Y chromosome were tested for potential usefulness in distinguishing individuals suspected of a sex crime or for determining blood relationship with regard to specific male DNA samples. DYS390 and DYS389-1 showed heterozygosity at respective lad sufficient for distinguishing individuals. 4) We found significant allele frequency variations at DYS388 locus and DYS392 locus, respectively, between Japanese population and other Asian populations including Chinese, Mongolian, and the minority race in Taiwan (Ami tribe) when data obtained from the Japanese population in the present study were compared with those from other Asian populations, which were available in the literature database. These results will provide a unique framework for identifying Japanese specific polymorphic genetic markers at these loci. These finding should be useful for population study on racial migration in Asia and the origin of Japanese race in terms of Y chromosome variation. Less