title: The time and place of European admixture in Ashkenazi Jewish history.
abstract: The Ashkenazi Jewish (AJ) population is important in genetics due to its high rate of Mendelian disorders. AJ appeared in Europe in the 10th century, and their ancestry is thought to comprise European (EU) and Middle-Eastern (ME) components. However, both the time and place of admixture are subject to debate. Here, we attempt to characterize the AJ admixture history using a careful application of new and existing methods on a large AJ sample. Our main approach was based on local ancestry inference, in which we first classified each AJ genomic segment as EU or ME, and then compared allele frequencies along the EU segments to those of different EU populations. The contribution of each EU source was also estimated using GLOBETROTTER and haplotype sharing. The time of admixture was inferred based on multiple statistics, including ME segment lengths, the total EU ancestry per chromosome, and the correlation of ancestries along the chromosome. The major source of EU ancestry in AJ was found to be Southern Europe (≈60-80% of EU ancestry), with the rest being likely Eastern European. The inferred admixture time was ≈30 generations ago, but multiple lines of evidence suggest that it represents an average over two or more events, pre- and post-dating the founder event experienced by AJ in late medieval times. The time of the pre-bottleneck admixture event, which was likely Southern European, was estimated to ≈25-50 generations ago.
authors.affiliation: Department of Computer Science, Columbia University, New York, New York, United States of America.|Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America.
authors.forename: James
authors.initials: J
authors.lastname: Xue
authors.affiliation: Center for Psychiatric Neuroscience, The Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Manhasset, New York, United States of America.|Department of Psychiatry, Division of Research, The Zucker Hillside Hospital Division of the North Shore-Long Island Jewish Health System, Glen Oaks, New York, United States of America.|Departments of Psychiatry and Molecular Medicine, Hofstra Northwell School of Medicine, Hempstead, New York, United States of America.
authors.forename: Todd
authors.initials: T
authors.lastname: Lencz
authors.affiliation: Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Ariel
authors.initials: A
authors.lastname: Darvasi
authors.affiliation: Department of Computer Science, Columbia University, New York, New York, United States of America.|Department of Systems Biology, Columbia University, New York, New York, United States of America.
authors.forename: Itsik
authors.initials: I
authors.lastname: Pe'er
authors.affiliation: Braun School of Public Health and Community Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem, Israel.
authors.forename: Shai
authors.identifier: 0000-0002-0188-2610
authors.initials: S
authors.lastname: Carmi
mesh_terms: D005060:Europe; D005260:Female; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D007585:Jews / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D044465:White People / Q000235:genetics*