Polymorphism and Genetic Instability of Microsatellite Markers on Human Sex Chromosomes.

到目前为止，人类性染色体上的微卫星标记还没有被广泛研究。我们研究了人类X和Y染色体上微卫星的多态特征如下：1)基因组DNA标本取自日本和德国人群中随机抽取的个体。微卫星标记DYS388、DYS389、DYS390、DYS391、DYS392和DYS393分别有6、10、8、10、6和6个多态等位基因。其中，DYS388、DYS391、DYS392和DYS393等位基因频率分布不均匀，杂合度较低，不能作为法医学应用的多态标记。DYS384有多达20个等位基因，不是Y染色体的特异标记，因为以雌性DNA为模板可扩增出DYS384的扩增产物，部分个体的雄性DNA也可扩增出相当于两个等位基因的产物。2)关于X染色体上的STR，来自PAT…的dna样本根据先前研究中获得的这些SIRS的等位基因频率，对更多患有几种X连锁疾病的患者进行了可能与特定遗传不稳定微卫星标记的关联测试。事实上，我们可以将特定的遗传不稳定的微卫星标记与感兴趣的疾病联系起来。3)根据前人研究中获得的Y染色体STR等位基因频率，对Y染色体多个基因座微卫星的多态多样性进行了检测，以期在性别犯罪嫌疑人的鉴别或特定男性DNA样本的血缘关系确定中发挥潜在的作用。DYS390和DYS389-1在各自的LAD上表现出足以区分个体的杂合性。4)将本研究获得的日本人群的等位基因频率与文献数据库中已有的其他亚洲人群的等位基因频率进行比较，发现日本人群的DYS388和DYS392基因座的等位基因频率在日本人群和其他亚洲人群(包括中国人、蒙古族和台湾少数民族)之间存在显著差异。这些结果将为在这些基因座上识别日本特有的多态遗传标记提供一个独特的框架。这些发现将有助于从Y染色体变异的角度研究亚洲种族迁移和日本种族起源的人口问题。较少

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 … More 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