Can you please explain what you mean by Khazar Jews? It seems that a number of...people critical of Israels existence refer to Jews, specifically Ashkenazi Jews as being descendants of Khazaria. While there is some truth to Khazar leadership converting to Judaism, what evidence is there to claim that the majority of Ashkenazi Jews are Khazars? Despite recent genetic evidence to the contrary, (evidence:
http://www.familytreedna.com/pdf/43026_Doron.pdf) and a lack of any real mainstream scholarly support, this belief is still popular among groups such as the Christian Identity Movement, Black Hebrews, British Israelitists and others (particularly Arabs), who claim that they, rather than Jews, are the true descendants of the Israelites, or who seek to who usurp the connection between Ashkenazi Jews and Israel in favor of their own.
Most Jews, including Ashkenazi Jews, do not exhibit the oriental features of the Khazars, who were likely of Central Asian Turkish origin. Modern DNA studies on the Y chromosome of Jews worldwide have also discredited the Khazar origin theory for the vast majority of Jews, including the Ashkenazi.
A study published by the National Academy of Sciences found that "The results support the hypothesis that the paternal gene pools of Jewish communities from Europe, North Africa, and the Middle East descended from a common Middle Eastern ancestral population, and suggest that most Jewish communities have remained relatively isolated from neighboring non-Jewish communities during and after the Diaspora." [2]. Researchers express surprise at the remarkable genetic uniformity they found among modern Jews, no matter where the diaspora has become dispersed around the world. Contradicting the "mongrel" theory, DNA demonstrated substantially less inter-marriage among Jews over the last 3000 years than found in other populations.
"The results accord with Jewish history and tradition and refute theories like those holding that Jewish communities consist mostly of converts from other faiths, or that they are descended from the Khazars, a medieval Turkish tribe that adopted Judaism." [3] [43]
Morever, "The analysis provides genetic witness that these communities have, to a remarkable extent, retained their biological identity separate from their host populations, evidence of relatively little intermarriage or conversion into Judaism over the centuries." Id. And another finding, paradoxical but unsurprising, is that by the yardstick of the Y chromosome, the world's Jewish communities are closely related to Syrians and Palestinians[44], suggesting that all are descended from a common ancestral population that inhabited the Middle East some four thousand years ago. Id.
This study found that "The extremely close affinity of Jewish and non-Jewish Middle Eastern populations observed ... supports the hypothesis of a common Middle Eastern origin.",[45] as does the mitochondrial DNA (mtDNA) of at least 40% of the current Ashkenazi population.[19] So although Khazars could possibly have been absorbed into the modern Jewish population as we know it today, it is unlikely that they formed a large percentage of the ancestors of modern Jews.[46]
DNA analysis further determined that modern Jews of the priesthood tribe -- or "Cohanim" -- share a common ancestor in Israel dating back about 3000 years, 1700 years older than the Khazar conversion to Judaism. This result is consistent for all Jewish populations around the world.[45] [4]
"Using a combination of molecular genetics and mathematical analysis, the scientists arrived at an estimated date for the most recent common ancestor of contemporary Cohanim. According to this analysis, the common ancestor lived between the Exodus (approx. 1000 B.C.E) and the destruction of the first Temple (586 B.C.E.), consistent with the biblical account. Similar results were obtained based on analysis of either Sephardi or Ashkenzi communities, confirming the ancestral link of the two communities which had been separated for more than 500 years." [47] [5] "To date the original high priest, the research team used a formula based on a commonly accepted mutation rate. This formula yieded some 106 generations for both Ashkenazi and Sephardi Jews, or between 2,650 and 3,180 years, depending on whether a generation is counted as 25 or 30 years."