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The use of mitochondrial DNA (mtDNA) in the field of forensic genetics is widely spread mainly due to its advantages when identifying highly degraded samples. In this sense, massive parallel sequencing has made the analysis of the whole mitogenome more accessible, noticeably increasing the informativeness of mtDNA haplotypes. The civil war (1980–1992) in El Salvador caused many deaths and disappearances (including children) all across the country and the economic and social instability after the war forced many people to emigration. For this reason, different organizations have collected DNA samples from relatives with the aim of identifying missing people. Thus, we present a dataset containing 334 complete mitogenomes from the Salvadoran general population. To the best of our knowledge, this is the first publication of a nationwide forensic-quality complete mitogenome database of any Latin American country. We found 293 different haplotypes, with a random match probability of 0.0041 and 26.6 mean pairwise differences, which is similar to other Latin American populations, and which represent a marked improvement from the values obtained with just control region sequences. These haplotypes belong to 54 different haplogroups, being 91% of them of Native American origin. Over a third (35.9%) of the individuals carried at least a heteroplasmic site (excluding length heteroplasmies). Ultimately, the present database aims to represent mtDNA haplotype diversity in the general Salvadoran populations as a basis for the identification of people that disappeared during or after the civil war.

We have genotyped the 58 STRs (27 autosomal, 24 Y-STRs and 7 X-STRs) and 94 autosomal SNPs in Illumina ForenSeq™ Primer Mix A in a sample of 248 men and 143 women from El Salvador, Central America. Regional division (Centro, Oriente, Occidente) showed in almost all cases F values not significantly different from 0, and further analyses were applied only to the undivided, country-wide population. The overall random match probability (RMP) decreased from 6.79 × 10 in length-based genotypes in the 27 autosomal STRs to 1.47 × 10 in repeat-sequence based genotypes. Combining the autosomal loci in this set, RMP reaches 2.97 × 10. In a population genetic analysis, El Salvador showed the lowest F values with US Hispanics both for autosomal and X-STRs; however, it was much closer to Native Americans for the latter than for the former, in accordance with the well-known gender-biased admixture that created most Latin American populations.

Next-generation sequencing technologies have opened new opportunities in forensic genetics. Here, we assess the applicability and performance of the MiSeq FGx™ & ForenSeq™ DNA Signature Prep Kit (Illumina) for the identification of individuals from the mass graves of the Spanish Civil War (1936–1939). The main limitations for individual identification are the low number of possible first-degree living relatives and the high levels of DNA degradation reported in previous studies. Massively parallel sequencing technologies enabling the analysis of hundreds of regions and prioritizing short length amplicons constitute a promising tool for this kind of approaches. In this study, we first explore the power of this new technology to detect first- and second-degree kinship given different scenarios of DNA degradation. Second, we specifically assess its performance in a set of low DNA input samples previously analyzed with CE technologies. We conclude that this methodology will allow identification of up to second-degree relatives, even in situations with low sequencing performance and important levels of allele drop-out; it is thus a technology that resolves previous drawbacks and that will allow a successful approximation to the identification of remains.