SNPSTR rs59186128_D7S820 polymorphism distribution in European Caucasoid, Hispanic, and Afro-American populations.

ABSTRACT

Single nucleotide polymorphisms (SNPs) in the flanking regions of microsatellite loci (SNPSTRs) help to increase the power of discrimination of short tandem repeat (STR) loci. SNPs are positions in the genome that have been well-conserved over the course of evolution, so analysing them can help distinguish between STR alleles in which the number of repetitions matches due to descent from those which match by chance. This provides support for the determination of biological paternity and other kinship analyses in which mutation needs to be ruled out as grounds for exclusion. Locus D7S820 shows a variable position, SNP rs59186128, in the 5' flanking region. This study is set out (1) to determine the frequencies of SNP rs59186128 in populations with various geographical origins and (2) to estimate the possible contribution of rs59186128 to the allele discrimination of locus D7S820. To that end, individuals from European Caucasoid, Hispanic, and Afro-American populations are studied using denaturing high-performance liquid chromatography, which enables locus rs59186128 to be quickly and highly cost-effectively screened. Moreover, a method is established for determining the haplotypes of SNPSTR rs59186128_D7820. The results show that SNP rs59186128 has a T allele frequency of more than 0.15 in one of the Afro-American populations studied, and the haplotype analysis shows that there is no preferential association between the alleles of SNPSTR rs59186128_D7S820, which supports the idea that they could be useful in forensic applications.