Re: Homo heidelbergensis
Ethan Vishniac (ethan@astro.as.utexas.edu)
31 May 1994 13:51:53 GMT
Ken Brown <rkjb@cix.compulink.co.uk> wrote:
>
>What evidence is there that Jews are or ever were a seperate breeding
>community from anybody else?
>
>There are of course well-known genes whose frequency differs between Jewish
>communities & adjacent Gentiles. But, on the whole, Jews are surely more
>closely related to Gentiles living nearby than to remote Jewish populations.
Actually, this is wrong. Should I start an FAQ on this topic? Having gone
through the effort to look up the references I'd hate to see the work wasted.
Recent genetic evidence indicates that Jews form a distinct gene pool. Of
course `distinct' in this context means that we tend to be more related to
each other than to any other group, including those we have had as close
neighbors. At all times, in every place, there has been some intermarriage.
The degree of intermarriage has tended to be exaggerated by people who looked
at adaptive genetic characteristics (white skin, Rh factor frequency etc.) as
an indication of ancestry.
In other words, Stanley may be guilty of exaggeration, but he's basically
right.
References below:
I have not read all these articles, merely the two that seemed
most important and easily accessible. I note that there seems
to be a strong consensus though. I couldn't find any modern
dissenting articles.
1."Y-chromosome specific haplotype diversity in Ashkenazic and
Sephardic Jews" Gerard Lucotte, Human Biology Oct 1993 v65 n5 pg 835
This is what is sounds like. The conclusions were that the Jewish
populations showed strong affinities with each other, but exhibited
types also found in some non-Jewish populations. In other words,
they were about what you would expect if you believed that Jews
derived from a single historical population, but had undergone a
moderate amount of intermarriage in the last few thousand years.
The results were grossly inconsistent with the notion that the Jewish
subjects of the study were about as much related as any random
collection of Europeans and North Africans.
2. "mtDNA Polymorphisms in Two Communities of Jews" Tikopchinski et al.
American Journal of Human Genetics, v48, pg 129, 1991
Again, this is what it sounds like, i.e. similar results from
mitochrondrial studies. In this case they examined 39 subjects,
roughly half Sephardic and half Ashkenazic. The mitochondria
represented at least 21 distinct lineages (with common ancestry about
4 to 5 thousand years back). All primary, secondary and tertiary
branches led to both Sephardim and Ashkenazim. Of the four types
of mtDNA that occured more than once in the sample, 3 were similar
to types previously found in non-Jewish Caucasian populations.
There was insufficient data to determine whether this was due to
similar origins for these groups, or from intermarriage during the
diaspora. The mtDNA genetic diversity was higher than one would
expect given the size of Israel, but much lower than one would obtain
from a random group of East Asians or Africans. It was roughly
comparable to that shown by Papuans, who inhabit an area much larger
than Israel. The conclusion was that either the early Jews had
an abnormally high mtDNA diversity (doubtful) or Jews have acquired
maternal lineages since their emergence as a distinct group (quite
likely).
3. Mourant, A.E., Kopec, A.L., and Domaniewski-Sobszak, K.
"The Genetics of the Jews", Clarendon Press, 1978.
4. Karlin, S., Kenett, R., and Bonne-Tamir B.
"Analysis of Biochemical Genetic Data on Jewish Populations"
American Journal of Human Genetics, v31, pg 341 1979.
5. Livshits, T., Sokal, R.P., and Kobliansky, E.
"Genetic Affinities of Jewish Populations"
American Journal of Human Genetics, v49, 131, 1991.
6. Szeinberg "Polymorphic Evidence for a Mediterranean Origin
of the Ashkenazi Community" in "Genetic Diseases Among Ashkenazi
Jews" Goodman and Matulsky (eds.) 1979.
7. Bonne-Tamir et al. "Human Mitochrondrial DNA Types in 2
Israeli Populations", American Journal of Human Genetics,
v38, pg. 341. 1986.
8.The article that first sparked my recent interest in this topic was
a column in Natural History (November 1993) by Jared Diamond called
`Who Are the Jews'. It summarizes a number of recent studies on
the genetics of the Ashkenazim and comments about the affect of
diseases in establishing blood group frequencies through natural
selection. It's a nice article, but it gives no primary references.
9.Among the Jews: Diseases and Markers at the DNA Level' edited
by Batsheva Bonne-Tamir (New York, Oxford University Press 1992,
ISBN 0195068173).
The broad consensus that has emerged from this work is that the
Ashkenazic and Sephardic Jewish communities represent a single
ethnic group with a history of some intermarriage. This parent
population apparently originated in the Eastern Mediterranean.
This conclusion is, of course, completely incompatible with the
notion that the Ashkenazim are largely descended from the Khazari.
It is not inconsistent with the notion that there is some small
amount of Khazari ancestry among Eastern European Jews. The
most surprising thing about this conclusion (at least, to me,
but also to most people I know) is not what it says about the
Khazari, but what it says about the kinship between the
Ashkenazim and Sephardim. The notion of Khazari ancestry has
always been the province of a rather small minority. The
idea that Jews are primarily related to their neighbors, rather
than to each other, has been an extremely popular view. There
is much that one can say in its favor, but it happens not to
be true.
This consensus appears to have emerged only in the last twenty
years. The earliest reference here (Mourant et al.) included
the comment that `each major [Jewish] community as a whole
bears some resemblance to indigenous peoples of the region
where it first developed'. For example, the Ashkenazim
were (in Mourant's view) primarily Rhineland Germans.
Contrast that with Livshits et al.'s statement that
Jewish communities `consistently show
lower distance.. than with their non-Jewish neighbors'
This shift in view has coincided with a shift from the use of
blood groups and similar adaptive traits, to the detailed
analysis of nonfunctional DNA features.
--
"Quis tamen tale studium, quo ad primam omnium rerum causam evehimur,
tamquam inutile aut contemnendum detractare ac deprimere ausit?"-Bridel
Ethan T. Vishniac, Dept. of Astronomy, The University of Texas at Austin
Austin, Texas, 78712 ethan@astro.as.utexas.edu
|