Length and repeat-sequence variation in 58 STRs and 94 SNPs in two Spanish populations

We have genotyped the 58 STRs (27 autosomal, 24 Y-STRs and 7 X-STRs) and 94 autosomal SNPs in Illumina ForenSeq (TM) Primer Mix A in 88 Spanish Roma (Gypsy) samples and 143 Catalans. Since this platform is based in massive parallel sequencing, we have used simple R scripts to uncover the sequence variation in the repeat region. Thus, we have found, across 58 STRs, 541 length-based alleles, which, after considering repeat-sequence variation, became 804 different alleles. All loci in both populations were in Hardy-Weinberg equilibrium. F-ST between both populations was 0.0178 for autosomal SNPs, 0.0146 for autosomal STRs, 0.0101 for X-STRs and 0.1866 for Y-STRs. Combined a priori statistics showed quite large; for instance, pooling all the autosomal loci, the a priori probabilities of discriminating a suspect become 1 - (2.3 x 10(-70)) and 1 - (5.9 x 10(-73)), for Roma and Catalans respectively, and the chances of excluding a false father in a trio are 1 - (2.6 x 10(-20)) and 1 - (2.0 x 10(-21)). (C) 2017 Elsevier B.V. All rights reserved.