Echoes from Sepharad: signatures on the maternal gene pool of crypto-Jewish descendants

Genetic landscape of homologous recombination repair genes in early-onset/familial prostate cancer patients

Prostate cancer (PrCa) is one of the three most frequent and deadliest cancers worldwide. The discovery of PARP inhibitors for the treatment of tumors with deleterious variants in homologous recombination repair (HRR) genes has placed PrCa on the roadmap of precision medicine. However, the overall contribution of HRR genes to the 10%-20% of carcinomas arising in men with early-onset/familial PrCa has not been fully clarified. We used targeted next-generation sequencing (T-NGS) covering eight HRR genes (ATM, BRCA1, BRCA2, BRIP1, CHEK2, NBN, PALB2, and RAD51C) and an analysis pipeline querying both small and large genomic variations to clarify their global and relative contribution to hereditary PrCa predisposition in a series of 462 early-onset/familial PrCa cases. Deleterious variants were found in 3.9% of the patients, with CHEK2 and ATM being the most frequently mutated genes (38.9% and 22.2% of the carriers, respectively), followed by PALB2 and NBN (11.1% of the carriers, each), and finally by BRCA2, RAD51C, and BRIP1 (5.6% of the carriers, each). Using the same NGS data, exonic rearrangements were found in two patients, one pathogenic in BRCA2 and one of unknown significance in BRCA1. These results contribute to clarify the genetic heterogeneity that underlies PrCa predisposition in the early-onset and familial disease, respectively.

Ancestral patterns of recessive dystrophic epidermolysis bullosa mutations in Hispanic populations suggest sephardic ancestry

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare genodermatosis caused by mutations in the gene coding for type VII collagen (COL7A1). More than 800 different pathogenic mutations in COL7A1 have been described to date; however, the ancestral origins of many of these mutations have not been precisely identified. In this study, 32 RDEB patient samples from the Southwestern United States, Mexico, Chile, and Colombia carrying common mutations in the COL7A1 gene were investigated to determine the origins of these mutations and the extent to which shared ancestry contributes to disease prevalence. The results demonstrate both shared European and American origins of RDEB mutations in distinct populations in the Americas and suggest the influence of Sephardic ancestry in at least some RDEB mutations of European origins. Knowledge of ancestry and relatedness among RDEB patient populations will be crucial for the development of future clinical trials and the advancement of novel therapeutics.

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.

Y chromosome diversity in a linguistic isolate (Mirandese, NE Portugal)

OBJECTIVES

The purpose of this study was to genetically characterize the male lineages of people who speak Mirandese, an interesting case of a linguistic relict that can still be found in the municipality of Miranda do Douro, NE Portugal. This region lies within the area of the Leonese dialects, which are remnants of the Romance dialects spoken in the Kingdom of Leon currently grouped in the Astur-Leonese linguistic continuum. We intended to disclose affinities with surrounding populations, namely from Spain where the Astur-Leonese is also spoken.

METHODS

Eighty-eight unrelated males (58 from Miranda and 30 from Bragança, the broad Portuguese region where Miranda is located) were genotyped with the combined use of 17 Y chromosome short tandem repeats (Y-STRs) and a high resolution Y chromosome single nucleotide polymorphism (Y-SNPs) strategy. Moreover, 236 males from Miranda and neighboring regions, previously classified as R-M269, were also genotyped.

RESULTS

R-P312 was the most frequent haplogroup in the Mirandese, followed by J-12f2.1 and T-M70. The male lineages J-12f2.1 and T-M70 were also well represented, and both were shared with descendants of Sephardic Jews. No signs of diversity reduction were detected.

CONCLUSIONS

Mirandese speakers display a Y chromosome gene pool that shows a subtle differentiation from neighboring populations, mainly attributable to the assimilation of lineages ascribed to be of Jewish ancestry. Although not revealing signs of geographic/linguistic isolation, no clear affinities with other Astur-Leonese populations were detected. The results suggest that in Miranda language sharing is not accompanied by significant gene flow between populations from both sides of the political border. Am. J. Hum. Biol. 28:671-680, 2016. © 2016 Wiley Periodicals, Inc.

Portuguese crypto-Jews: the genetic heritage of a complex history

The first documents mentioning Jewish people in Iberia are from the Visigothic period. It was also in this period that the first documented anti-Judaic persecution took place. Other episodes of persecution would happen again and again during the long troubled history of the Jewish people in Iberia and culminated with the Decrees of Expulsion and the establishment of the Inquisition: some Jews converted to Catholicism while others resisted and were forcedly baptized, becoming the first Iberian Crypto-Jews. In the 18th century the official discrimination and persecution carried out by the Inquisition ended and several Jewish communities emerged in Portugal. From a populational genetics point of view, the worldwide Diaspora of contemporary Jewish communities has been intensely studied. Nevertheless, very little information is available concerning Sephardic and Iberian Crypto-Jewish descendants. Data from the Iberian Peninsula, the original geographic source of Sephardic Jews, is limited to two populations in Portugal, Belmonte, and Bragança district, and the Chueta community from Mallorca. Belmonte was the first Jewish community studied for uniparental markers. The construction of a reference model for the history of the Portuguese Jewish communities, in which the genetic and classical historical data interplay dynamically, is still ongoing. Recently an enlarged sample covering a wide region in the Northeast Portugal was undertaken, allowing the genetic profiling of male and female lineages. A Jewish specific shared female lineage (HV0b) was detected between the community of Belmonte and Bragança. In contrast to what was previously described as a hallmark of the Portuguese Jews, an unexpectedly high polymorphism of lineages was found in Bragança, showing a surprising resistance to the erosion of genetic diversity typical of small-sized isolate populations, as well as signs of admixture with the Portuguese host population.