Application of SNP-STR Composed by D18S51 and Three SNPs of Its Flanking Region in Paternity Testing

Objective To develop a SNP-STR haplotype by consisting of the SNP and STR genetic markers, both of which locate in a haplotype block. To investigate its distribution in Han population from Chengdu, and explore its application in some special cases of paternity testing. Methods D18S51, one of the high mutation rate STR markers in combined DNA index system （CODIS）, and three SNP loci rs8089331, rs8094489 and rs7236090 in its flanking region, were chosen to establish SNP-STR. Its haplotype was obtained by nested allele-specific polymerase chain reaction, and the relevant distribution of 75 unrelated individuals were investigated in Han population from Chengdu. The SNP-STR haplotype was tentatively applied in duo paternity testing cases with D18S51 incompatibility. Results The SNP-STR typing method was established and a total of 43 haplotypes were obtained successfully in Han population from Chengdu. Its polymorphism was 0.948 6, and duo paternity testing cases were resolved by this method. Conclusion SNP-STR shows high diversity and can be applied in the identifications of some special paternity testing cases.