The Eastern side of the Westernmost Europeans: Insights from subclades within Y-chromosome haplogroup J-M304

Characterization of Y chromosome diversity in newfoundland and labrador: evidence for a structured founding population

The population of Newfoundland and Labrador (NL) is largely derived from settlers who migrated primarily from England and Ireland in the 1700s-1800s. Previously described as an isolated founder population, based on historical and demographic studies, data on the genetic ancestry of this population remains fragmentary. Here we describe the largest investigation of patrilineal ancestry in NL. To determine the paternal genetic structure of the population, 1,110 Y chromosomes from an NL-based cohort were analyzed using 5,761 Y-specific SNPs. We identified 160 distinct terminal haplogroups, the majority of which (71.4%) belong to the R1b haplogroup. When compared with global reference populations, the NL population haplogroup composition and frequencies primarily resemble those observed in English and Irish ancestral source populations. There is also evidence of genetic contributions from Basque, French, Portuguese, and Spanish fishermen and early settlers who frequented NL. Interestingly, the observed population structure shows geographical and religious clustering that can be associated with the settlement of the ancestral source populations from predominantly Protestant, England, and Catholic, Ireland respectively. For example, the R1b-M222 haplogroup, seen in people of Irish descent, is found clustered in the Irish-settled Southeast region of NL. The clustering and expansion of Y haplogroups in conjunction with the geographical and religious clusters illustrate that limited subsequent in-migration, geographic isolation, and societal factors have contributed to the genetic substructure of the NL population and its designation as a founder population.

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.

Middle eastern genetic legacy in the paternal and maternal gene pools of Chuetas

Chuetas are a group of descendants of Majorcan Crypto-Jews (Balearic Islands, Spain) who were socially stigmatized and segregated by their Majorcan neighbours until recently; generating a community that, although after the seventeenth century no longer contained Judaic religious elements, maintained strong group cohesion, Jewishness consciousness, and endogamy. Collective memory fixed 15 surnames as a most important defining element of Chueta families. Previous studies demonstrated Chuetas were a differentiated population, with a considerable proportion of their original genetic make-up. Genetic data of Y-chromosome polymorphism and mtDNA control region showed, in Chuetas’ paternal lineages, high prevalence of haplogroups J2-M172 (33%) and J1-M267 (18%). In maternal lineages, the Chuetas hallmark is the presence of a new sub-branching of the rare haplogroup R0a2m as their modal haplogroup (21%). Genetic diversity in both Y-chromosome and mtDNA indicates the Chueta community has managed to avoid the expected heterogeneity decrease in their gene pool after centuries of isolation and inbreeding. Moreover, the composition of their uniparentally transmitted lineages demonstrates a remarkable signature of Middle Eastern ancestry—despite some degree of host admixture—confirming Chuetas have retained over the centuries a considerable degree of ancestral genetic signature along with the cultural memory of their Jewish origin.