中国南方汉族群体九个短片段长度Y-STR基因座的遗传多态性及其法医学应用

目的研究中国南方汉族群体中，扩增产物片段长度在180bp以下的9个Y染色体的短串联重复（Y-short tandem repeal，Y-STR）基因座的遗传多态性，并用于法医学鉴定。方法采用PCR复合扩增和基因测序仪荧光检测方法，检测213个无关男性个体，调查南方汉族的9个Y-SIR基因座的等位基因频率和单倍型频率，并对84对真父子和36对非父子的亲子鉴定样本进行检测。结果213个无关男性个体中，DYS426基因座检出3个等位基因，DYS393、DYS460、DYS391和DYS389 Ⅰ基因座均检出了5个等位基因，DYS456基因座检出6个等位基因，H4和DYS388基因座检出7个等位基因，DYS458基因座检出8个等位基因。除DYS426基因座的基因多样性（gene diversity，GD）值（0．1489）较低外，其余8个基因座的GD值介于0．5064～0．9133。9个Y-SIR基因座的单倍型共有178种，其中154种单倍型仅出现1次，单倍型多样性达0．9983。在84对真父子中，未观察到基因座突变。检测36对非父子，有2个Y-STR基因座排除的案例有2例（5．56％）；有3个和3个以上的Y-STR基因座可以排除父子关系的案例为33例（91．67％）；9个Y-SIR基因座不能排除父子关系的有1例。结论9个Y-SIR基因座具有丰富的遗传多态性，该短片段长度Y-STR基因复合荧光扩增系统可用于法医学个体识别和亲子鉴定。

The genetic polymorphisms of nine Y- STR loci with short fragment size alleles in southern Chinese Han population and its applicatioin in forensic science

OBJECTIVE: To study the genetic polymorphisms of 9 Y-chromosome specific STR loci that the allele size is less than 180 bp in length in the southern Chinese Han population, and to utilize the studied result to forensic science. METHODS: Nine Y-STR loci were amplified by single multiplex PCR, and the PCR products were sequenced by using ABI Prism 3100 DNA Sequencer. The allele and haplotype frequencies at 9 Y-STR loci were determined in a total of 213 unrelated males from southern Chinese Han population. Eighty-four father/son pairs with demonstrated paternity and thirty-six non-paternity father/son pairs were detected by using our Y-STR multiplex system. RESULTS: Three Y-STR alleles for DYS426, five alleles for DYS393, DYS460, DYS391 and DYS389 I respectively, six alleles for DYS456, seven alleles for both H4 and DYS388, and eight alleles for DYS458 loci were detected in 213 unrelated male individuals. Except for the DYS426 locus with a low GD value of 0.1489, the GD values for other 8 Y-STR loci ranged from 0.5064 to 0.9133. A total of 178 haplotypes were found at 9 Y-STR loci, of which 154 haplotypes were observed only once, and the haplotype diversity was 0.9983. None of Y-STR allele mutation was observed in the 84 father/son pairs with demonstrated paternity. Among the 36 non-paternity father/son pairs, two cases could get the paternity exclusions at 2 Y-STR loci; and the paternity of 33 cases could be ruled out by 3 or more Y-STR loci; only one case was found no exclusion of paternity regardless of detecting 9 Y-STR loci. CONCLUSION: This result indicates that the 9 Y-STR loci with short fragment size alleles are highly polymorphic. The fluorescent multiplex amplification system that we developed is suitable for personal identification and paternity testing.