Posted on 02/26/2007 3:28:35 PM PST by blam
Early Europeans unable to stomach milk
22:00 26 February 2007
NewScientist.com news service
Roxanne Khamsi
Researchers analysing the DNA in Neolithic human remains claim to have uncovered the first direct evidence that modern humans have evolved changes in response to natural selection.
Just 7000 years ago, Europeans were unable to digest milk, according to a new analysis of fossilised bone samples – nowadays more than 90% of this population can.
Europeans must have incurred a rapid change in their genetic make-up because it held an evolutionary advantage for them to be able to digest milk, says Mark Thomas at University College London in the UK, who carried out the study with colleagues.
However, other experts caution that larger studies are needed to support the conclusions of this research.
Milking it
The majority of humans around the world lose the ability to digest lactose – a sugar in milk – before reaching adulthood. This is because their gene for the enzyme lactase, which breaks lactose down, is switched off during adolescence. Symptoms of this “lactose intolerance” include bloating and diarrhoea after drinking milk.
However, over 90% of northern Europeans have a version of the lactase gene that remains active throughout life, enabling them to continue drinking milk as adults.
To determine when this special lactose tolerance evolved in Europe, Thomas’s team analysed the DNA from 55 bone samples belonging to eight Neolithic Europeans. The skeletons were dated to between 5840 BC and 5000 BC.
Constant supply
After extracting the DNA from the fossils, researchers identified the sequence of the lactase gene for each of the eight Neolithic individuals. Surprisingly, says Thomas, none of the early Europeans had the gene mutation associated with lactose tolerance in modern-day Europeans.
(Excerpt) Read more at newscientist.com ...
GGG Ping.
It seems I have read that adults have no need to drink milk.
Me on the other hand have a problem with drinking milk. I can process it okay it just always tastes spoiled no matter how cold or fresh. I've tried all kinds from Skim to Whole milk. I'm not sure why but I never liked it, even as a kid. To each his own I guess.
Ahhh, my kin folk.
EIGHT individuals studied. Yeah, they've really proved something.
Most likely, the ones who couldn't tolerate milk starved to death one rough winter.
Some does everyone else in my family. I've tried to like milk but just can't seem to get past the taste. I must have different taste bud wiring.
You skipped school the day they taught statistics?
Take a sample of eight modern Europeans at random, On average 7 will be capable of digesting milk - the result may vary slightly.
If none of them have that capability that's honking big significant.
Europeans are more likely to tolerate milk and less likely to tolerate wheat and soy, when compared to Asians and Africans. Some researchers estimate 95% of all caucasian lactose intolerance is actually a secondary condition caused by another food damaging the digestive system.
Considering how a 200% mortality-rate is related to untreated food intolerance even in the modern world with all the best treatment and freedom from natural threats, you don't need to find thousands of dead ancestors with seldom-seen DNA to have a firm hypothesis that one's traditional cultural diet is an important part of maintaining health.
I get about 500 calories from milk just in my coffee each day - but if I get near a milligram of wheat, rye, or barley, I'll be deathly ill for half a week. This happens a lot in Ireland. Culturally-genetically? I (We) are adapted to get our starches from potatos and other tubers. We kept the cows around because we adapted to that, and lo and behold, steak and potatos was born.
If you have 100,000 people and only 500 of them can handle milk, and then you create a world where those that can handle milk have a tremendous survival advantage, it won't take long where the vast majority will be able to handle milk.
Reverse the advantage and you will eventually end up where you started.
This is evolution of a population. It is not evolution of the individual members of a species.
Look up Celiac Disease. Also called Sprue. Affects the Irish and the Italians. Mamma Begorra!
bookmark
Few cattle, goats and sheep were domesticated 7000 years ago, so there was little opportunity and almost no need to handle milk.
When they did tame the critters, it must have been something like this: "You're gonna' do WHAT with that cow?"
;^)
Nah. Read this book about the DNA of the Europeans and especially the Brits.
Actually Southern Europeans have trouble drinking milk. That's why Italians don't usually add milk or cream to their coffee. I remember visiting Argentina and getting strange looks when I once drank milk in public.
That's possible. The data indicates, if nothing else, that the percentage of individuals in the population with the gene for the lactose-processing enzyme has increased. One would expect this, knowing that Northern Europe grew to depend on dairy products as a main source of protein. Less-tolerant individuals would be less likely to thrive, and the stronger genetic type - for that environment - would come to dominate the population.
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