I have found article like this on the topic:There are generally three types of Jews, Mizrahi, Sephardic and Ashkenazi. Ashkenazis may be the descendants of Khazars.
The majority of Ashkenazi Jews are descended from prehistoric European women, according to study published today (October 8) in Nature Communications. While the Jewish religion began in the Near East, and the Ashkenazi Jews were believed to have origins in the early indigenous tribes of this region, new evidence from mitochondrial DNA, which is passed on exclusively from mother to child, suggests that female ancestors of most modern Ashkenazi Jews converted to Judaism in the north Mediterranean around 2,000 years ago and later in west and central Europe
Looks like same thing what Laura wrote