Abstract: Objective To explore the methods for identification of sibling brothers with Y-STR locus mutation by detection of genetic markers on autosome and Y-biallelic. Methods Goldeneye 20A and 18NC kit were used to genotyped the 35 STRs on autosome from two men. PowerPlex^® Y kit and Yfiler kit were used to genotyped the 16 STRs on Y chromosome full sibling index was calculated by ITO method. Twenty Y-biallelic markers were genotyped by fragment length discrepant allele specific PCR or general PCR. Results Relationship of sibling brothers was found to have mutation of 2 loci on 16 Y-STR and the identical genetype of 20 Y-biallelic markers as well as a cumulative full sibling index of 4.314 9×10⁶ from 35 STRs on autosome. Conclusion In identification of paternal linage of Y-STR mutation, more genetic information can be acquired by detection of Y-biallelic markers including SNP and InDel.

Key words: forensic genetics, siblings, chromosomes, human, Y, STR, mutation, biallelic