That was the finding of the respected German-American anthropologist Theodor Pösche.
In the same way one can explain common Jewish physical characteristics like the “Jew-fro” by the fact that Jews sometime long ago mixed with Negroes, perhaps also their slaves. The finding that Jews in general have considerable Negro admixture was published by Jew A.E. Mourant in 1978, and in some of them it is obvious. Indeed the Lemba Jews of southern Africa appear entirely Negro; yet they have been authenticated through genetic testing as a genuine Jewish population that bears the Cohenic Y-chromosome. In ancient times the Book of Ezra told them to put away their “foreign wives.” In spite of that, the Jews today are a very racially mixed people.
Why there are blond Jews
Excerpted from Die Arier: ein Beitrag zur historischen Anthropologie, 1878, pp. 31-32
Translated by Hadding Scott, 2014
Finally let us consider the blond Jews, which in Germany are about 11% of Jews according to the surveys in the schools*. These must be declared straightaway as racially mixed, like the blonds of the Turkic peoples. The proof is found in the fact that blond Jews occur only in the countries of the blonds. In Africa there are none; where blonds were prevalent however, miscegenation also happened.
A Polish law around the year 1100 forbids marriages between Jews and Christians, likewise an old Spanish law: proof enough that this took place. From another law of that period it is evident that the Jews converted their servants, slaves that they had bought, to their religion, and thereby totally assimilated them.
About the participation of the Jews in the slave-trade of the Middle Ages, unexpected revelations have recently occurred. I find in the work of my esteemed teacher, Dr. Alfred Schmeckel, the following report about Ditmar von Merseburg (reproduced in the Merseburger Gymnasialprogramm for 1855) on page 10: “In the year 1010 Margrave Guncelin von Meissen was deposed by a court of princes appointed by the Emperor at Merseburg, and imprisoned for a long time because he was found guilty of having sold Christian families to Jews.” Since then Waitz has published in the Anzeiger zur Kunde der deutschen Vorzeit quite a number of cases from which it emerges that in the early Middle Ages Jews took just as much interest in peddling slaves (in most cases Slavs, hence Slav = slave) as now in peddling horses. Waitz cites old municipal tax-schedules [Städtetarife] in which it is set down how much entrance-tax [Eingangssteuer] a Jew had to pay for a slave.
These blond Jews thus are probably not, as Virchow loves to proclaim, “Urgermanen” and their posterity, but probably the mixed progeny of Aryans, especially Slavs, and of Jews.
* Most likely Pösche refers here to the survey of 6,758,827 of Germany’s schoolchildren in respect to color of skin, hair, and eyes that was undertaken in the 1870s by Rudolf Virchow (1821-1902). Virchow had gained fame through contributions to medical science but also held some idiosyncratic views: he was an anti-Darwinist, denying evolution entirely, and also an anti-Nordicist and anti-anti-Semite. Virchow’s survey was apparently intended to prove the opposite of what it did prove. The Jew Franz Boas, founder of “cultural anthropology” (which is essentially anti-racist propaganda in the guise of scholarship) was one of Virchow’s students.
Source: National-Socialist Worldview