The Last Influx

[X99Lynx at aol.com]

TO THE LIST, FYI:
The following, a news story and two abstracts, seem to state that the last
major migration into Europe occurred in the Neolithic period, accounting for
about 20% of the current population.  Judging past events based on current
genes has its problems, but
note that Cavalli-Sforza, L.L is listed in the head of one of the two studies.
This was originally posted on the Mother Tongue list.
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>From the Associated Press:
DNA Study Traces Europeans Ancestry

By PAUL RECER
The Associated Press
WASHINGTON (AP) - Four out of five of the men in Europe shared a common male
ancestor that lived as a primitive hunter on a wild continent some 40,000
years ago, researchers say.

In a study appearing Friday in the journal Science, researchers say that an
analysis of a pattern found in the Y chromosome taken from 1,007 men from 25
places in Europe shows that about 80 percent of Europeans arose from the
Paleolithic people who first migrated to Europe.

Peter A. Underhill, a senior researcher at the Stanford Genome Technology
Center in Palo Alto, Calif., and co-author of the study, said the research
supports conclusions from archaeological, linguistic and other DNA evidence
about the settlement of Europe by ancient peoples.

``When we can get different lines of evidence that tell the same story, then
we feel we are telling the true history of the species,'' said Underhill.

Underhill said the researchers used the Y chromosome in the study because its
rare changes establish a pattern that can be traced back hundreds of
generations, thus helping to plot the movement of ancient humans.

The Y chromosome is inherited only by sons from their fathers. When sperm
carrying the Y chromosome fertilizes an egg it directs the resulting baby to
be a male. An X chromosome from the father allows a fertilized egg to be
female.

The Y chromosome has about 60 million DNA base pairs. Changes in those base
pairs happen infrequently, said Underhill, but they occur often enough to
establish patterns that can be used to trace the ancestry of people.

He said researchers looking at the 1,007 chromosome samples from Europe
identified 22 specific markers that formed a specific pattern. Underhill said
the researchers found that about 80 percent of all European males shared a
single pattern, suggesting they had a common ancestor thousands of
generations ago.

The basic pattern had some changes that apparently developed among people who
once shared a common ancestor and then were isolated for many generations,
Underhill said.

This scenario, he said, supports other studies about the Paleolithic European
groups. Those studies suggest that a primitive, stone-age human came to
Europe, probably from Central Asia and the Middle East, in two waves of
migration beginning about 40,000 years ago. Their numbers were small and they
lived by hunting animals and gathering plant food. They used crudely
sharpened stones and fire.

About 24,000 years ago, the last ice age began, with mountain-sized glaciers
moving across most of Europe. Underhill said the Paleolithic Europeans
retreated before the ice, finding refuge for hundreds of generations in three
areas: what is now Spain, the Balkans and the Ukraine.

When the glaciers melted, about 16,000 years ago, the Paleolithic tribes
resettled the rest of Europe. Y chromosome mutations occurred among people in
each of the ice age refuges, said Underhill. He said the research shows a
pattern that developed in Spain is now most common in northwest Europe, while
the Ukraine pattern is mostly in Eastern Europe and the Balkan pattern is
most common in Central Europe.

About 8,000 years ago, said Underhill, a more advanced people, the Neolithic,
migrated to Europe from the Middle East, bringing with them a new Y
chromosome pattern and a new way of life: agriculture. About 20 percent of
Europeans now have the Y chromosome pattern from this migration, he said.
---------------------
Semino, O., Passarino, G., Oefner, P.J., Lin, A.A.,
Arbuzova, S., Beckman, L.E., De Benedictis, G.,
Francalacci, P., Kouvatsi, A., Limborska, S., Marcikia, M.,
Mika, A., Mika, B., Primorac, D., Santachiara-Benerecetti,
A.S., Cavalli-Sforza, L.L. & Underhill, P.A. (2000) The
genetic legacy of Paleolithic Homo sapiens sapiens in
extant Europeans: A Y chromosome perspective. Science. 290
(5494). 1155 - 9
(http://www.sciencemag.org/cgi/content/abstract/290/5494/1155)

Abstract:
A genetic perspective of human history in Europe was
derived from 22 binary markers of the  nonrecombining Y
chromosome (NRY). Ten lineages account for >95% of the 1007
European Y  chromosomes studied. Geographic distribution
and age estimates of alleles are compatible with  two
Paleolithic and one Neolithic migratory episode that have
contributed to the modern European  gene pool. A
significant correlation between the NRY haplotype data and
principal components  based on 95 protein markers was
observed, indicating the effectiveness of NRY binary
polymorphisms in the characterization of human population
composition and history.
------------------------------
Gibbons, A. (2000) Europeans Trace Ancestry to Paleolithic
People. Science. 290 (5494). 1080 - 1.
(http://www.sciencemag.org/cgi/content/summary/290/5494/1080)

Summary:
Y chromosome data show that living Europeans have deep
 roots in the region--and researchers say genetic markers
may  be linked to cultures known from archaeological
remains. In a  report on page 1155, an international team
reports that a  wealth of data from the Y chromosome show
that more than  80% of European men have inherited their Y
 chromosomes--which are transmitted only from father to
son--from Paleolithic ancestors who lived 25,000 to 40,000
years ago. Thus, the genetic template for European men was
set as early as 40,000 years ago, then modified--but not
recast--by the Neolithic farmers who  arrived in the region
about 10,000 years ago.
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