Y-chromosome analysis recapitulates key events of Mediterranean populations.

The remarkable geographical situation of the Mediterranean region, located between Europe, Africa, and Asia, with numerous migratory routes, has made this area a crucible of cultures. Studying the Y-chromosome variability is a very performant tool to explore the genetic ancestry and evaluate scenarios that may explain the current Mediterranean gene pool. Here, six Mediterranean populations, including three Balearic Islands (Ibiza, Majorca, and Minorca) and three Southern Italian regions (Catanzaro, Cosenza, and Reggio di Calabria) were typed using 23 Y-STR loci and up to 39 Y-SNPs and compared to geographically targeted key reference populations to explore their genetic relationship and provide an overview of Y-chromosome variation across the Mediterranean basin. Pairwise RST genetic distances calculated with STRs markers and Y-haplogroups mirror the West to East geographic distribution of European and Asian Mediterranean populations, highlighting the North-South division of Italy, with a higher Eastern Mediterranean component in Southern Italian populations. In contrast, the African populations from the Southern coast of the Mediterranean clustered separately. Overall, these results support the notion that migrations from Magna Graecia or the Byzantine Empire, which followed similar Neolithic and post-Neolithic routes into Southern Italy, may have contributed to maintaining and/or reinforcing the Eastern Mediterranean genetic component in Southern Italian populations.

Development and validation of a new multiplex for upgrading Y-STRs population databases from 12 to 23 markers and its forensic casework application.

Y chromosomal short tandem repeats (Y-STRs) are used in forensic investigations as a useful complementary tool to autosomal markers. The ongoing development of new kits with an increasing number of markers makes it necessary to update populations typed in the Y-STR Haplotype Reference Database to reach at least 23 Y-STRs. A novel Y-STR multiplex panel was developed to offer a cost-efficient alternative to update Y-STR haplotypes from 12 to 23 loci. This panel includes the eleven markers, DYS448, DYS456, DYS458, DYS635, Y-GATA H4, DYS576, DYS481, DYS549, DYS533, DYS570 and DYS643, as well as DYS385a/b for traceability purpose. Developmental validation of this panel was conducted following the recommendations of the Scientific Working Group on DNA Analysis Methods (SWGDAM), showing high sensitivity, tolerance to common inhibitors as well as high species specificity. It was efficient for degraded DNA samples and for detection of male mixtures. When applying it for extending the current data of the Ibiza population, both the discrimination capacity and the haplotype diversity increased from 0.5952 to 0.9048 and from 0.9808 to 0.9977, respectively. Together, the study demonstrates the suitability of this panel in forensic casework.