Genetic analysis of Sephardic ancestry in the Iberian Peninsula

https://www.biorxiv.org/content/early/2018/05/18/325779

Miguel M Alvarez-Alvarez, Neil Risch, Christopher R Gignoux, Scott Huntsman, Elad Ziv, Laura Fejerman, Maria Esther Esteban, Magdalena Gaya-Vidal, Beatriz Sobrino, Francesca Brisighelli, Nourdin Harich, Fulvio Cruciani, Hassen Chaabani, Angel Carracedo, Pedro Moral, Esteban Gonzalez Burchard, Marc Via, Georgios Athanasiadis

doi: https://doi.org/10.1101/325779

Abstract

The Sephardim are a major Jewish ethnic division whose origins can be traced back to the Iberian Peninsula. We used genome-wide SNP data to investigate the degree of Sephardic admixture in seven populations from the Iberian Peninsula and surrounding regions in the aftermath of their religious persecution starting in the late 14th century. To this end, we used Eastern Mediterranean (from South Italy, Greece and Israel) and North African (Tunisian and Moroccan) populations as proxies for the major ancestral components found in the target populations and carried out unlinked- and linked-marker analyses on the available genetic data. We report evidence of Sephardic ancestry in some of our Iberian samples, as well as in North Italy and Tunisia. We find the Sephardic admixture to be more recent relative to the Berber admixture following an out-of-Iberia geographic dispersal, suggesting Sephardic gene flow from Spain outwards. We also report some of the challenges in assigning Sephardic ancestry to potentially admixed individuals due to the lack of a clear genetic signature.

Quote :

We also report some of the challenges in assigning Sephardic ancestry to potentially admixed individuals due to the lack of a clear genetic signature.

So they don't know? 

It's probably connected to someone's east med or west med component. My mother showed 12% West Asian on Ancestry. It seemed unusually high for someone of her heritage, but it matched my mother's family's rumors of "Converso" heritage, especially since she couldn't explain it any other way.