[Application of the number of allele shared among autosomal STR loci in full sibling identification]

Abstract

Objective: To establish and evaluate the method of full sibling identification based on the number of allele shared among autosomal STR Loci.

Methods: Two hundred and eighty full sibling pairs and 2,003 unrelated individual pairs were genotyped in 15 STR loci with Identifiler Kit, and the number of allele shared among the 15 STR loci (S15) and full sibling index (FSI) were calculated. Fisher discriminant functions were established with SAS 8.2 software based on S15, the power of which were compared with ITO method.

Results: The distribution of S15, in full sibling pair group and unrelated individual pair group were in accord with normal distribution. The established Fisher discriminant functions for each group were Z(FS)= 3.26970S15-31.51174 and Z(UI)=1.70058S15-8.524 11, respectively. The average error of probability in sibling and unrelated pair group was 0.0298. There was no statistically significant difference on the power of full sibling discriminant between the method based on the number of allele shared among the 15 STR loci or the CODIS 13 STR loci and the ITO method.

Conclusion: The method based on the number of allele shared among the 15 STR loci in full sibling identification is convenient, credible, easy to handling and unaffected by the allele frequency of STR loci.