They argue that some differences exist between the Ashkenazim and the Sephardim (the main ethnic division among Jews), but that essentially Jews are a single people with a limited genetic resemblance to the European populations among whom they dwell. [foonote 632] ??? In blood group data, two major studies, one in 1977 by Bonn??- Tamir, Ashbel, and Kenett and one by Karlin, Kenett, and Bonn??-Tami