常染色体STR鉴定同胞的应用探讨

Application of Autosomal STR Genetic Markers in Sibling Identification

目的探讨常染色体STR遗传标记鉴定两个体同胞关系的可行性。方法用PowerPlexTM16体系15个常染色体STR基因座检测50对全同胞、25对半同胞和50对无关个体,ITO法计算全同胞关系指数(FSI)、半同胞关系指数(HSI)和FSI∶HSI值,比较3组两个体间等位基因匹配情况,并进行组间差异的χ2检验。结果全同胞的FSI均大于1;19对半同胞的HSI大于1;无关个体FSI均小于1;49对无关个体HSI小于1,1对为1.297。46对全同胞的FSI:HSI值大于1,22对半同胞的FSI:HSI值小于1。全同胞组两个体间1对等位基因全相同、半相同、全不同的基因座数平均值分别为6.06个、7.52个、1.42个;半同胞组分别为2.96个、8.48个、3.56个;无关个体组分别为1.24个、7.22个、6.54个。χ2检验3组两个体间1对等位基因全相同和全不同的基因座数差异有显著意义,半相同的基因座数差异无显著意义。结论PowerPlexTM16体系在全同胞-无关个体的鉴定中效率较高,在鉴定半同胞-无关个体或全同胞-半同胞时效率降低。全同胞-半同胞关系鉴定时,FSI∶HSI值是一个较有效的指标:大于1倾向于为全同胞,小于1倾向于为半同胞。

[Objective] To discuss the feasibility of sibling identification by autosomal short tandem repeat （STR）. [Methods] Fifty pairs of full siblings, 25 pairs of half siblings and 50 pairs of unrelated individuals were genotyped by the 15 STB loci of PowerPlex^TM 16 system. Full sibling index （FSI）, half sibling index （HSI） and the PSI：HSI ratio were calculated with the method of ITO. Allelic matching of the three groups was compared and three sorts of allelic matching in each pair were tested by chi-square test.[Resuhs] In full sibling group, all the PSI were more than 1. In the unrelated individuals, all the PSI were less than 1.In half sibling group, 19 HSI were more than 1. In the unrelated individuals,49 HSI were less than 1, one is 1.297. The ratio of PSI ： HSI was more than 1 for 46 pair of full sibling and it was less than 1 for 22 pair of half sibling. In full siblings, the average locus number of the allele entire-same, one allele identical, the allele entire-different were 6.06, 7.52, 1.42 respectively. In half siblings, those were 2.96, 8.48, 3.56 respectively. In unrelated individuals, those were 1.24, 7.22, 6.54 respectively. By chi-square test, there was significant difference in the locus number of the allele entire-same or the allele entlre-difference and no difference in the one allele identical between the three groups. [Conclusion] In identification of full sibling or unrelated individual, it was high efficient using the 15 autosomal STR loci of PowerPlex^TM 16 system, but it was the lower efficient in identification of full sibling or half sibl/ng and identification of half sibling or unrelated individual. PSI ： HSI was a more effective index in identification of full sibling or half sibling. It suggested that the pair was full siblings when the PSI：HSI ratio was more than 1, and that the pair was half siblings when the ratio was less than 1.