On the Malabar coast in southwest India, the Jews of Cochin make up a small and distinct population. While any putative Jewish forebears of the community are thought to have arrived as early as biblical times (King Solomon’s era), a Jewish community on the Malabar coast has only been attested since the 9th century CE. We investigate the genetic history of Cochin Jews by genotyping 21 members of the community and comparing the results with data from 707 individuals from 72 other Indian, Jewish, and Pakistani groups, as well as individuals from other populations throughout the world. We used principal component analysis, FST, ADMIXTURE, identity-by-descent sharing, admixture linkage disequilibrium decay, haplotype sharing, allele sharing autocorrelation decay, and contrasting the X chromosome with the autosomes to conduct comprehensive genome-wide investigations. Several prior studies have found that the genetics of Cochin Jews are similar to that of indigenous Indian communities. However, we find significant Jewish genetic heritage in this community that is not found in any other Indian or Pakistani population (except the Jewish Bene Israel, which we characterized previously). Cochin Jews are descended from both Jewish and Indian ancestors. According to historical sources, we see a considerable recent Jewish gene flow into this group 13–22 generations (470–730 years) ago, with contributions from Yemenite, Sephardi, and Middle-Eastern Jews. High endogamy and a recent population bottleneck have also been discovered in this population, which could explain the elevated occurrence of various recessive disorders in Cochin Jews.
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5020127/
