Ashkenazic and Sephardic Jews were first identified as distinct less than a millenium ago. That is fast. It took tens of thousands of years for Europeans to diverge from Africans. If Ashkenazim look different from Sephardim, it’s because people living in northern Europe are more likely to marry northern Europeans, and people living in the Near East are more likely to marry Arabs.
Askenazi Jews seem to be about ~40 to 50% Southern European, the second largest component is basically classical Near Eastern (think Druze or Syrians) and they (according to the current interpretation of genetic data) seem to have been this way for centuries.
Its rather surprising that they seem to have Southern European admixture while there is only a few extra % of Eastern and Northern Admixture, they are among European peoples closest to Italians. Perhaps the mixture stabilised in the Late Roman Empire after Europe became less cosmopolitan? Perhaps both Italians and Jews had much in common to start with due to ancient Greek admixture (they are remarkably close to modern Greeks as well)? Also Germanic migrations in the 5th century where there are already some indications of Jews settling in what is now Germany might be another common imprint.
Recent admixture that occurred after Jewish and Christians started integrating seems to have gone mostly into the gentile population, though naturally in places like America with its massive out marriage rate and considering the large population of marginally Jewish Soviet immigrants in Israel this has probably changed recently.
As to the Shepardim, depends on how the word is used. In the narrow sense of “Spanish Jews” I don’t think the differences are that pronounced (though I must admit I don’t recall much of the data regarding them). But if one under the term includes Mizrahi Jews as often it is, then the differences are rather significant and yes they do seem to have non-negligible Arab admixture or rather a greater similarity to them (someone really needs to recover some Jewish DNA from the Roman and Hellenic period, lots of interesting stuff might be found).
Ashkenazic and Sephardic Jews were first identified as distinct less than a millenium ago. That is fast. It took tens of thousands of years for Europeans to diverge from Africans. If Ashkenazim look different from Sephardim, it’s because people living in northern Europe are more likely to marry northern Europeans, and people living in the Near East are more likely to marry Arabs.
Askenazi Jews seem to be about ~40 to 50% Southern European, the second largest component is basically classical Near Eastern (think Druze or Syrians) and they (according to the current interpretation of genetic data) seem to have been this way for centuries.
Its rather surprising that they seem to have Southern European admixture while there is only a few extra % of Eastern and Northern Admixture, they are among European peoples closest to Italians. Perhaps the mixture stabilised in the Late Roman Empire after Europe became less cosmopolitan? Perhaps both Italians and Jews had much in common to start with due to ancient Greek admixture (they are remarkably close to modern Greeks as well)? Also Germanic migrations in the 5th century where there are already some indications of Jews settling in what is now Germany might be another common imprint.
Recent admixture that occurred after Jewish and Christians started integrating seems to have gone mostly into the gentile population, though naturally in places like America with its massive out marriage rate and considering the large population of marginally Jewish Soviet immigrants in Israel this has probably changed recently.
As to the Shepardim, depends on how the word is used. In the narrow sense of “Spanish Jews” I don’t think the differences are that pronounced (though I must admit I don’t recall much of the data regarding them). But if one under the term includes Mizrahi Jews as often it is, then the differences are rather significant and yes they do seem to have non-negligible Arab admixture or rather a greater similarity to them (someone really needs to recover some Jewish DNA from the Roman and Hellenic period, lots of interesting stuff might be found).