Right in the middle of a scare over milk products containing potentially deadly bacteria comes a new study showing how the consumption of milk and other dairy products has driven the evolution of human society.
Up until around 11,000 years ago adult humans couldn't consume dairy products at all. But the near-simultaneous development of yoghurt and cheese-making and a random genetic mutation changed everything.
"Probably one of the biggest single selective events in recent human evolution has been the ability to digest milk as adults," Steve Pointing, director of the AUT Institute for Applied Ecology, said on Firstline this morning.
"As infants we all digest milk – all mammals in fact – but as adults, there's huge variability. If we look around society today, some people are able to tolerate lactose – the milk carbohydrate – and others are not, and it causes quite severe symptoms when you consume it."
According to a new study published in journal Nature, ancient societies with both dairy farming and a population tolerant of lactose produced around 19 percent more offspring than those without. Prof Pointing says this is a "quite significant amount for a single mutation".
"The ability to process and preserve milk products essentially led us to be more able to withstand hard times," he says.
The study's authors call it "gene-culture co-evolution", and say it allowed lactose-tolerant populations to "sweep through Europe and displace the hunter-gatherer cultures that had lived there for millennia".
Dairy products were also able to be stored longer in colder European climes, giving lactose tolerance a further push north.
"What this study suggests is that these two events, which essentially led to the prevalence of agrarian societies in human evolution, allowed us to basically even out times of famine," says Prof Pointing.
Even nowadays, about two-thirds of the world is lactose intolerant to some degree. Most of those able to drink fresh milk can trace their genetic ancestry can back to northern Europe, or small pockets in Africa and the Middle East.
source: newshub archive