I belong to a genealogy-dna list.  There have been some interesting
discussions on lactose tolerance/intolerance recently.  I thought I would
post one of messages since it touches on a couple of issues that we discuss
here.  I didn't know about the higher latitude/cholesterol connection.  Have
we discussed this and I've missed it?  I don't remember reading it in any of
"our" books.  I have left off the poster's name since I'm posting without
his explicit permission; however, the list is archived and fully searchable
at rootsweb.com.

Theola

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I think dairying arose with goats. There are lots of studies on the goat
dna.

>From http://www.ansi.okstate.edu/breeds/goats/Goats-w.htm

"The goat, along with sheep, were among the earliest domesticated animals.
Goat remains have been found at archaeological sites in western Asia, such
as Jericho, Choga, Mami, Djeitun and Cayonu, which allows domestication of
the goats to be dated at between 6000 and 7000 B.C.

 However, unlike sheep, their ancestry is fairly clear. The major
contributor of modern goats is the Bezoar goat which is distributed from the
mountains of Asia Minor across the Middle East to Sind.

Unlike sheep, goats easily revert to feral or wild condition given a chance.
In fact, the only domestic species which will return to a wild state as
rapidly as a goat is the domestic cat."

Interesting that the Swedes have the highest percent lactose tolerance when
it was the Anatolians and Middle Easterners who had dairy animals way
earlier. Why didn't the people who domesticated these creatures first have
the higher tolerance? What is it about high latitude people that means they
had high tolerance of lactose before they had goats etc.

High latitude Europeans have high cholesterol which is an advantage in low
light levels as the higher cholesterol in skin is converted by sunlight to
vitamin D. So maybe they really needed the extra fat for the low light
levels and vitamin D. Which is all an advantage for the babies rather than
the adults who get the cholesterol disadvantages.

Swedes have a lot of Coeliac disease compared even to Danes. Must be a link
to dna I would say. So Swedes show intolerance of glutens/cereals.

So maybe the Swedes have a mutation that gives you lactose tolerance in
adulthood but unrelated originally to dairying, maybe very late weaning
originally an advantage to low light level latitude people, because get
extra cholesterol and thus extra vitamin D.

A thought anway.