According to a Sunday 9:14 pm Reuters article, an Israeli geneticist says
modern Ashkenazis came >from an even smaller gene pool than previously
thought.

The article refers to an estimation of 1500 Jewish families - dating back
to the 14th century - being the source for the total Ashkenazi population
today. But it says Ísraeli Ariel Darvasi - president of a pharmaceutical
company and geneticist at Jerusalem's Hebrew University - believes the
source of the total (Ashkenazi) population might have really been only
500 families.

I don't know what the basis for this result is, but a similar,
and possibly even more extreme conclusion can be drawn >from the
occurrence of the mutant BRCA1 gene that is associated with
breast cancer and the gene connected with Tay-Sachs disease, both
of which are associated with Eastern European Ashkenazi Jews.
The BRCA1 gene occurs in about 1% of this population and the
Tay-Sachs gene occurs in about 3%. For genes that do not affect
reproductive capacity, which these genes apparently do not, one
can assume that the frequency of occurrence will remain stable

from one generation to the next. Since these mutant genes are

identical in all the persons who have them, it can be assumed
that they each originated >from a single individual. This implies
that a single individual once constituted 1% or 3% of the Eastern
European Ashkenazi population, meaning that the population would
have had to be about 30-100 persons. On the other hand, the
Eastern European group was not separate >from other Jewish groups
until around the 14th-15th centuries, so this small population
must have occurred sometime around or after that period.

Nathan Reiss
Highland Park, NJ

Researching: REISS, BAUM, LILIENSTEIN, EDELMUTH, GRIESHEIM,
METZGER, GOTTLIEB, MAY, LIPPMANN, all >from Hesse, Germany;
GOLDBLUM, DYNER, MELLER, FREYLICH, >from Olkusz, Russo-Poland;
KRIEGER, >from Oswiecim (Auschwitz), Austro-Poland.