Autosomal SNPs in different forensic applications

Abstract

The aim of this work was to test a 52 SNP-plex in our laboratory in order to apply it in casework cases, namely in kinship involving relatives of the true father leading to low Parentage Index (PI) values, and in unusual cases such as paraffin-embedded tissue samples or in other cases involving severely degraded samples related to some identification cases. For this, a standard DNA was used, artificially degraded by digestion with DNase I and by different UV exposure times. STR previously-analysed cases were revisited and studied. All the samples were typed for the SNP for ID 52plex using the SNaPshotTM assay. In all the cases, a SNP profile was achieved. In two cases involving paraffin-embedded tissue samples, it was only possible to obtain results for 48% (11 out of 23) and 61% (14 out of 23) STR and mini-STR markers, respectively. Concerning SNPs, results were possible for all the SNPs (52) in one of the cases and for 50 SNPs (96%) in the other. The PI or LR calculated values suffered a minimum of a fourfold increment. Autosomal SNPs can be used as additional markers to the profiling of ‘difficult’ cases that emerge in the routine of many laboratories.