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From: "brian quinn" <>
Subject: Re: [DNA] Lactose tolerance evolved recently cf +tb
Date: Sat, 3 Mar 2007 16:48:22 +1100
In-Reply-To: <mailman.6179.1172878715.2838.genealogy-dna@rootsweb.com>


As I recall Northern Europeans have more of the Cystic Fibrosis gene.
Northern Europeans are more lactose tolerant than other people. Cystic
fibrosis gene- (the half strength version) confers protection against
Tuberculosis.

Anyone drinking unpasteurised milk can get TB and coughing spreads it.

So maybe much of Europe once had the lactose tolerance. They got TB but
higher percent of those with CF gene survived and they happen to be more
northern Europeans.

The southern Europeans that kept cows etc were decimated by TB along with
their lactose tolerant genes.


Below from:
http://www.newscientist.com/channel/life/genetics/dn10013-cystic-fibrosis-ge
ne-protects-against-tuberculosis.html

"Unparalleled epidemic
However, between 1600 and 1900, TB caused 20% of all deaths in Europe, an
epidemic unparalleled elsewhere. The model showed that even if it gave only
partial protection against TB, the CF gene would easily have reached its
current levels in Europeans.

"The stage was set (in Europe) by the long-term presence of tuberculosis,
which allowed CF mutations to establish themselves, albeit at some lower
level. But then the TB pandemic starting in the seventeenth century allowed
CF to really take off." says Poolman.

By contrast, TB only became a major cause of death in India after 1800 - in
which time a protective effect would give CF its modern incidence in India,
of about one person in 40,000.

Global resurgence
CF patients and carriers of the gene have some resistance to TB. This could
be because TB bacteria need a nutrient that CF patients do not make, Poolman
and Galvani suggest."



I suspect there were many TB epidemics in the past. I wonder if Stone Age
people ever milked an Aurochs? Hmm here is an Iron Age one.



from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1153742


"The earliest known case of human tuberculosis in Britain dates to the
middle period of the Iron Age, approximately 2,200 years before present.
Bone lesions on the spine of a male skeleton excavated at Tarrant Hinton in
Dorset, United Kingdom, show evidence of Pott's disease and are supported by
molecular evidence of Mycobacterium tuberculosis complex DNA amplified by
IS6110 PCR (19).........

.....The extent of M. bovis infection in Iron Age herds-and hence the risk
of human exposure-is unknown. M. bovis has the greatest host range of any
other member of the Mycobacterium tuberculosis complex, and in this middle
period of the British Iron Age (600 to 100 BC), cattle, sheep, pigs, goats,
and wild species, such as deer, would have been typical elements of the
mixed farming economy. In fact, faunal remains from sites across Wessex
indicate that sheep were predominant by this time, having taken over from
cattle. This was probably due to their ability to survive on higher pastures
with minimal requirement for water and for their wool, an important raw
material for Iron Age spindle looms. However, cattle would have still been
important as symbols of status and kept as beasts of traction as well as for
their milk and other dairy products which might have been stored for
consumption outside periods of lactation (8)."

(8)= Cunliffe, B. 1993 . Wessex to AD 1000. Longman Group, United Kingdom
Ltd., London, United Kingdom.

Pre 1400 Native Americans have been shown to have had TB so not necessarily
cow related. Forget the ref.

Ellen I think mentioned cows on the highlands in Europe- only summer
transhumance I think. Rest of times cows/goats kept in byres through the
winter, sheep on the highlands in the summer but near the farm house in the
winter/spring.

Brian Quinn





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