Arthur Koestler’s book, The Thirteenth Tribe, really popularized the Khazar-Ashkenazim theory. As you note, there is no genetic evidence for it.

It should be mentioned that while it is entirely clear from the genetic evidence at hand that Ashkenazic Jews are not descended primarily from the Khazars, the presence of a small amount of Khazar ancestry hasn’t been completely ruled out. At this point, we simply don’t know much about Khazar genetics (though DNA from Khazar remains may provide answers at some point in the future). It is possible the Khazars were not as Central Asian genetically as their language suggests. After all, even the Turks in Turkey don’t cluster closely to other Central Asian populations. The small number of Turkish invaders from the steppes who overwhelmed Anatolia and Asia Minor were quickly absorbed into the much larger local gene pool. I would advise caution on matters like this. In a similar vein, it was thought just a few years ago that Finns had absolutely no Asian ancestry, that they were entirely Scandinavian, in spite of speaking a Uralic language. Later, more extensive genetic studies changed that view. The Finns are mostly European but do have a minority Asian component to their ancestry.

All the “khazar” dreck spewed by the Arab media is just more dissemblage and lies.

chsw