GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2005-06 > 1117739083


From: Jim T <>
Subject: Lactose intolerance and Ancestry
Date: Thu, 2 Jun 2005 12:04:43 -0700 (PDT)
In-Reply-To: <200505242126.j4OLQp3K014785@lists5.rootsweb.com>


I found this press release interesting and thought that others
on the list might be interested too.
http://www.news.cornell.edu/stories/June05/lactase.herding.ssl.html
It says that whether or not you are lactose intolerant may give
a clue as to where your distant ancestors lived. Here are some
excerpts from the press release:

"A new Cornell University study finds that it is primarily
people whose ancestors came from places where dairy herds could
be raised safely and economically, such as in Europe, who have
developed the ability to digest milk. On the other hand, most
adults whose ancestors lived in very hot or very cold climates
that couldn't support dairy herding or in places where deadly
diseases of cattle were present before 1900, such as in Africa
and many parts of Asia, do not have the ability to digest milk
after infancy."

"A major challenge in interpreting the data, Sherman noted, was
to resolve the puzzle that about 13 lactose-tolerant populations
live side-by-side with lactose-intolerant populations in some
parts of Africa and the Middle East."

"The most likely explanation is nomadism," Sherman concluded.
All 13 of the populations that can digest dairy yet live in
areas that are primarily lactose intolerant were historically
migratory groups that moved seasonally, Sherman said. Their
nomadism enabled them to find suitable forage for their cattle
and to avoid extreme temperatures. "Also, the fact that these
groups maintained small herds and kept them moving probably
reduced the pathogen transmission rate."


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