20 SNPs as supplementary markers in kinship testing

Abstract

Single Nucleotide Polymorphisms (SNPs) are having an increasingly role in Forensic Genetics due to very low SNP mutation rates and the possibility to multiplex a great number of loci. The purpose of this study was to evaluate the use of 20 autosomal SNPs as additional markers in the resolution of kinship casework where the alleged father was not available for testing and close relatives were used instead. A total of six caseworks which included alleged paternal grandparents, alleged uncles or alleged brothers were studied. All individuals studied in these cases were typed before with 17 autosomal STRs using Identifiler(Plus) ® and Powerplex 16 ® systems. Twenty SNPs were typed using SNaPshot ® methodology with two 10-plex, previously shown useful in paternity testing. LRs were calculated with “ Familias” using South Portugal STR and SNP frequency databases. This study confirms that even as few as 20 autosomal SNP loci can be very useful in kinship analysis as a complement to standard methodologies. Moreover, SNaPshot ® methodology can be easily implemented in any Forensic Laboratory.