IBD法在堂表亲缘关系鉴定中的应用

目的 使用血缘一致性(identity by descent,IBD)法计算堂表亲缘关系的堂表关系指数(first cousin index,FCI)和累积堂表关系指数(combined first cousin index,CFCI),为IBD法鉴定两个个体是否具有堂表亲缘关系提供科学手段.方法 取124对堂表兄弟姐...

Application of IBD method in cousinship identification

Objective Identity by descent(IBD) method is used to calculate the first cousin index(FCI) and the combined first cousin index(CFCI) of the cousins, so as to provide a scientific method for identifying whether two individuals have the cousinship by the IBD method. Methods Oral swabs from 124 pairs of cousins and 186 pairs of unrelated individuals were taken to examine the alleles of 18 autosomal STR loci. The FCI and the CFCI of cousin pairs and unrelated individual pairs were calculated by IBD method, and the FCI and the CFCI results of the two groups were analyzed by discriminant analysis. Results The CFCI in cousin pairs and unrelated pairs showed a skew normal distribution. The average and standard deviation of the former were 11.864 and 21.678, while those of the latter were 0.605 and 0.988. There was significant difference between the two groups. Taking CFCI/(CFCI+1) ≥ 0.6 as the standard, the discrimination accuracy of cousin pairs and unrelated individuals is 88.387%. The discriminant equation was established according to the IBD calculation results of each STR locus. The results showed that the discriminant accuracy of multivariate discriminant equation and multivariate stepwise discriminant equation were 92.258% and 91.935%, respectively. Conclusion The IBD method and the discriminant analysis based on IBD method can be used to screen the genetic relationship of the cousins.