Ashkenazis: Half Middle Eastern, Half European?
September 09, 2014, 07:17 PM
A+
|
a-
Print Friendly and PDF

Ashkenazis: Half Middle Eastern, Half European?

Karen Kaplan reports in the L.A. Times:

DNA ties Ashkenazi Jews to group of just 330 people from Middle Ages

Albert Einstein and all other Ashkenazi Jews can trace their roots to a group of about 330 people who lived during the Middle Ages, a new study finds.

By KAREN KAPLAN

So says a new study in the journal Nature Communications. An international team of scientists sequenced the complete genomes of 128 healthy Ashkenazi Jews and compared each of those sequences with the others, as well as with with the DNA of 26 Flemish people from Belgium. Their analysis allowed them to trace the genetic roots of this population to a founding group in the Middle Ages. …

… Despite their close ties with Europe, no more than half of their DNA comes from ancient Europeans, the researchers found. Only 46% to 50% of the DNA in the 128 samples originated with the group of people who were also the ancestors of the Flemish people in the study. Those ancient people split off from the ancestors of today’s Middle Easterners more than 20,000 years ago, with a founding group of about 3,500 to 3,900 people, according to the study.

The rest of the Ashkenazi genome comes from the Middle East, the researchers reported. This founding group “fused” with the European founding group to create a population of 250 to 420 individuals. These people lived 25 to 32 generations ago, and their descendants grew at a rate of 16% to 53% per generation, the researchers calculated.

The LA Times article comes illustrated with pictures of Einstein and some guy who isn’t Einstein.

Here’s the abstract:

The Ashkenazi Jewish (AJ) population is a genetic isolate close to European and Middle Eastern groups, with genetic diversity patterns conducive to disease mapping. Here we report high-depth sequencing of 128 complete genomes of AJ controls. Compared with European samples, our AJ panel has 47% more novel variants per genome and is eightfold more effective at filtering benign variants out of AJ clinical genomes. Our panel improves imputation accuracy for AJ SNP arrays by 28%, and covers at least one haplotype in ?67% of any AJ genome with long, identical-by-descent segments. Reconstruction of recent AJ history from such segments confirms a recent bottleneck of merely ?350 individuals. Modelling of ancient histories for AJ and European populations using their joint allele frequency spectrum determines AJ to be an even admixture of European and likely Middle Eastern origins. We date the split between the two ancestral populations to ?12–25?Kyr, suggesting a predominantly Near Eastern source for the repopulation of Europe after the Last Glacial Maximum.
There has always been a lot of controversy, scientific and political, over the ancestry of the Ashkenazi Jews who founded Israel: are they from the Holy Land or from Europe? This study comes up with a 50-50 split, which shouldn’t come as a surprise to long-time iSteve readers: arguments that go on for a long time tend to be more or less 50-50 propositions.