Many of the maternal ancestors of modern Ashkenazi Jews were European converts, according to a research project headed by a University of Huddersfield professor.

The young science of archaeogenetics has been used to settle a long-standing controversy -- the origin of Europe's Ashkenazi Jews. Are they principally descended from forbears who migrated from Palestine in the first century AD? Or were their ancestors Europeans who converted to Judaism?

A new article in the leading journal Nature Communications claims to have settled the question. Analysis of DNA samples has shown that on the female line, the Ashkenazim are descended not from the Near East but from southern and western Europe.

Professor Martin Richards heads the Archaeogenetics Research Group based at the University of Huddersfield and he is a co-author of the new article, entitled "A substantial prehistoric European ancestry amongst Ashkenazi maternal lineages."

In Hebrew, the word "Ashkenazi" means "Germans" and the term is used for Jews of eastern European origin who historically spoke the Yiddish or Judeo-German language. Professor Richards says that the new explanation for their origins was one of the most significant findings from a wider project in which he and his colleagues -- principally the Portuguese PhD students Marta Costa and Joana Pereira -- were analysing mitochondrial DNA samples (i.e. DNA that traces the maternal line) in order to investigate the prehistoric settlement of Europe by migrants from the Near East.

Ashkenazi Jewish lineages were among the large quantity of publicly available mitochondrial genomes of people from Europe, the Caucasus and the Middle East that entered the analysis. It was discovered that in the vast majority of cases, Ashkenazi lineages are most closely related to those of southern and western Europe and that they had been present in Europe for many thousands of years.

‌"This suggests that, even though Jewish men may indeed have migrated into Europe from Palestine around 2000 years ago, they seem to have married European women," states Professor Richards.

This seems to have happened first along the Mediterranean, especially in Italy, and later -- but probably to a lesser extent -- in western and central Europe. This suggests that, in the early years of the Diaspora, Judaism took in many converts from amongst the European population, but they were mainly recruited from amongst women. Thus, on the female line of descent, the Ashkenazim primarily trace their ancestry neither to Palestine nor to Khazaria in the North Caucasus -- as has also been suggested -- but to southern and western Europe.

"The origins of the Ashkenazim is one of the big questions that people have pursued again and again and never really come to a conclusive view," said Prof Richards, who has described the new data as "compelling."