A new study, published online in The American Journal of
Human Genetics, indicates on genetic grounds that the
first European Jews originated in the same area as their
wives. The secular bias of most researchers had led them to
assume up until now that the Ashkenazi communities of
Northern and Central Europe were founded by men who came from
the Middle East, and then took wives from each local
population whom they perhaps converted to Judaism. Even a
superficial familiarity with the current social and religious
strictures of Jewish life, and the simple knowledge that
these mores were observed unchanged for thousands of years,
should have suggested that the men and women traveled
together.
Doron Behar and Karl Skorecki of the Technion and Ramban
Medical Center in Haifa, and colleagues elsewhere, reported
that just four women, who may have lived 2,000 to 3,000 years
ago, appear genetically to have been the ancestors of 40
percent of Ashkenazis alive today. The Technion team's
analysis was based on mitochondrial DNA, a genetic element
that is separate from the genes held in the cell's nucleus
and that is inherited only through the female line. Because
of changes that build up on the mitochondrial DNA —
which do not have any known observable physical consequences
— people can be assigned to branches that are defined
by which mutations they carry.
The researchers found that many branches of current Ashkenazi
Jews coalesced to single trees, and they were able to reduce
them to four female ancestors. The similarity to the four
Matriarchs is striking, but the genetic evidence indicates
that these four women lived one or two thousand years after
the time of the Matriarchs.
They found that some people in Egypt, Arabia and the Levant
also carried the set of mutations that defines one of the
four women and they thus argue that all four probably came
originally from the Middle East.
A study by Michael Hammer of the University of Arizona five
years ago showed that the men in many Jewish communities
around the world bear Y chromosomes that were Middle Eastern
in origin. This finding is widely accepted by geneticists as
genetic proof of the Middle Eastern origin of the men, and
also of the purity of the Jewish family throughout the ages
in exile, but there is less consensus about the women's
origins.
David Goldstein, now of Duke University, said in 2002 that
the mitochondrial DNA of women in Jewish communities around
the world did not seem to be Middle Eastern. According to
him, each community has its own genetic pattern and in some
cases the mitochondrial DNA is related to that of the host
community. It was Dr. Goldstein and his colleagues who
publicly suggested that Jewish men had arrived from the
Middle East, taken wives from the host population and
converted them to Judaism, after which he conceded that the
genetic evidence showed clearly that there was no further
intermarriage with non-Jews.
The Technion team suggests that the women too are of Middle
Eastern origin, and would presumably have accompanied their
husbands to Europe. Though this has not yet been shown for
all Jewish communities around the world, at least the
Ashkenazi Jewish community would have been formed by families
of Jewish men and women migrating together.
Dr. Hammer told the New York Times that the new study
"moves us forward in trying to understand Jewish population
history." His own recent research, he said, suggests that the
Ashkenazi population expanded through a series of bottlenecks
— events that squeeze a population down to small
numbers — perhaps as it migrated from the Middle East
after the destruction of the Second Temple in around 70 CE to
Italy, reaching the Rhine Valley in the 10th century.
Dr. Goldstein told the New York Times that the new
report did not force him to alter his previous conclusion. In
his view, the Technion team has shown that genetic drift - -
that mitochondrial DNA's of a small, isolated population tend
to change rapidly as some lineages fall extinct and others
become more common — has played a major role in shaping
Ashkenazi mitochondrial DNA, but the linkage with Middle
Eastern populations is not statistically significant.
Dr. Goldstein argues that because of genetic drift, Ashkenazi
mitochondrial DNAs have developed their own pattern, which
makes it very hard to tell their source. In the patrilineal
case, however, even Dr. Goldstein concedes that there is no
question of a Middle Eastern origin.
