Screening of Multi-InDel markers on X-chromosome for forensic purpose

Abstract Many studies have been proposed to identify insertion/deletion (InDel) polymorphisms in humans for forensic genetics. However, the discriminatory power of InDel was limited by the poor polymorphism of diallelic marker. To improve discriminatory power, we designed the Multi-InDel comprising more than two InDel loci that were tightly linked by their physical position as a new marker, which can be amplified by a pair of PCR primers. This strategy gave at least three haplotypes for a Multi-InDel marker. As genetic markers on X-chromosome have been recognized as useful tools to supplement traditional kinship testing, we focused on developing Multi-InDel markers on the X-chromosome (X-Multi-InDel). We explored potential X-Multi-InDel from 1000 genome database, 10 candidates for X-Multi-InDel were selected. The frequencies of the haplotypes were also investigated in Chinese population. The results showed that there were higher levels of heterozygosity in X-Multi-InDel than X-SNP or X-InDel. It implied that X-Multi-InDel markers were useful for individual identification and relationship studies.