"For a more scientific take on the Jewish origin debate, recent DNA analysis of Ashkenazic Jews – a Jewish ethnic group – revealed that their maternal line is European. It has also been found that their DNA only has 3% ancient ancestry which links them with the Eastern Mediterranean (also known as the Middle East) – namely Israel, Lebanon, parts of Syria, and western Jordan. This is the part of the world Jewish people are said to have originally come from – according to the Old Testament. But 3% is a minuscule amount, and similar to what modern Europeans as a whole share with Neanderthals. So given that the genetic ancestry link is so low, Ashkenazic Jews’ most recent ancestors must be from elsewhere."
"The tolerance of the Persians encouraged the Jews to adopt Persian names, words, traditions, and religious practices, and climb up the social ladder gaining a monopoly on trade. They also converted other people who were living along the Black Sea, to their Jewish faith. This helped to expand their global network.
Among these converts were the Alans (Iranian nomadic pastoral people), Greeks, and Slavs who resided along the southern shores of the Black Sea. Upon conversion, they translated the Old Testament into Greek, built synagogues, and continued expanding the Jewish trade network."
"The Asian group of these DNA mutations, found in Ashkenazic Jews, likely originated from the Ashina elite and other Khazar clans, who converted from Shamanism to Judaism. This means that the Ashina and core Khazar clans were absorbed by the Ashkenazic Jews." - ["Ashkenazic Jews’ mysterious origins unravelled by scientists thanks to ancient DNA" (2018)](https://theconversation.com/ashkenazic-jews-mysterious-origi...)
I can’t comment about the DNA evidence as I am hardly an expert, but they go both ways (cohen lines genes).
However, the entire ‘Ashkenazi Jews are Khazar’ theory has antisemite origins, and it is well known that Jews were already all over Europe at the times of the Roman Empire, way before any Khazar entity
"For a more scientific take on the Jewish origin debate, recent DNA analysis of Ashkenazic Jews – a Jewish ethnic group – revealed that their maternal line is European. It has also been found that their DNA only has 3% ancient ancestry which links them with the Eastern Mediterranean (also known as the Middle East) – namely Israel, Lebanon, parts of Syria, and western Jordan. This is the part of the world Jewish people are said to have originally come from – according to the Old Testament. But 3% is a minuscule amount, and similar to what modern Europeans as a whole share with Neanderthals. So given that the genetic ancestry link is so low, Ashkenazic Jews’ most recent ancestors must be from elsewhere."
"The tolerance of the Persians encouraged the Jews to adopt Persian names, words, traditions, and religious practices, and climb up the social ladder gaining a monopoly on trade. They also converted other people who were living along the Black Sea, to their Jewish faith. This helped to expand their global network.
Among these converts were the Alans (Iranian nomadic pastoral people), Greeks, and Slavs who resided along the southern shores of the Black Sea. Upon conversion, they translated the Old Testament into Greek, built synagogues, and continued expanding the Jewish trade network."
"The Asian group of these DNA mutations, found in Ashkenazic Jews, likely originated from the Ashina elite and other Khazar clans, who converted from Shamanism to Judaism. This means that the Ashina and core Khazar clans were absorbed by the Ashkenazic Jews." - ["Ashkenazic Jews’ mysterious origins unravelled by scientists thanks to ancient DNA" (2018)](https://theconversation.com/ashkenazic-jews-mysterious-origi...)