共有基因数在同胞鉴定中应用的研究

目的　探索利用两个体间共有基因数目资料进行同胞关系鉴定的应用价值。方法　根据 80 7对同胞及无关个体的 13个STR基因座的分型结果 ,进行统计学计算。结果　同胞间及无关个体间共有基因数目均符合正态分布 ,分别得到同胞及无关个体关系的判别函数和后验概率 ,以及该方法的平均错判率。其中同胞组判别函数为 :L同胞 =-2 7 0 870 3 +3 2 0 2 3 2S (S为共有基因个数 ) ;无关个体组判别函数为 :L无关 =-7 495 63 +1 685 0 9S ,用上述判别函数进行同胞 /无关个体关系判别时的平均错判率为 0 0 2 65。结论　当共有基因数目大于 17或小于 8时 ,两个体为同胞或无关个体的后验概率分别大于 0 9980和 0 9994。此方法不失为同胞关系鉴定的可信度较高的方法。

Application of the number of alleles identical by state in full sib test

Objective Establish and evaluate the method of number of alleles identical by state in full sib test.Methods Sib pair group and unrelated individual pair group were genotyped in 13 STR loci,statistical calculation was carried out.Results Through analysis by discriminant function the posterior probability of membership in each group and error of the posterior probability was obtained.The discriminant function in sib group is L sib =-27.087 03 3.202 32S(S:number of alleles identical by state);The discriminant function in unrelated individual group is:L unrelated =-7.495 63 1.685 09S.The average error of the posterior probability in sib and unrelated pair group is 0.026 5.Conclusion When the number of alleles identical by state is more than 17 or less than 8,posterior probability of a full sib or unrelated individuals is more than 0.998 0 or 0.999 4,respectively.The method based on the number of alleles identical by state in full sib test is credible in identifying sib pair relationship.