https://www.sciencemag.org/news/2021/01/...-digest-it
EXCERPT: Our history with milk presents a chicken-or-egg conundrum: Humans couldn’t digest the beverage before they evolved mutations that helped them do so, yet they had to already be consuming milk to change their DNA. “There’s always been the question of which came first,” says University of Pennsylvania geneticist Sarah Tishkoff. “The cultural practice or the mutation.”
Now, scientists have found the oldest evidence yet for dairy drinking: People in modern Kenya and Sudan were ingesting milk products beginning at least 6000 years ago. That’s before humans evolved the “milk gene,” suggesting we were drinking the liquid before we had the genetic tools to properly digest it.
All humans can digest milk in infancy. But the ability to do so as an adult developed fairly recently, likely in the past 6000 years. A handful of mutations allows adults to produce the enzyme lactase, which can break down the milk sugar lactose. Genes that enable what’s called lactase persistence are widespread in modern Africa, which has four known lactase persistence mutations. (European populations rely on just one.)
When these lactase mutations evolved, they spread rapidly—evidence that people who carried them had a big advantage... (MORE - details)
EXCERPT: Our history with milk presents a chicken-or-egg conundrum: Humans couldn’t digest the beverage before they evolved mutations that helped them do so, yet they had to already be consuming milk to change their DNA. “There’s always been the question of which came first,” says University of Pennsylvania geneticist Sarah Tishkoff. “The cultural practice or the mutation.”
Now, scientists have found the oldest evidence yet for dairy drinking: People in modern Kenya and Sudan were ingesting milk products beginning at least 6000 years ago. That’s before humans evolved the “milk gene,” suggesting we were drinking the liquid before we had the genetic tools to properly digest it.
All humans can digest milk in infancy. But the ability to do so as an adult developed fairly recently, likely in the past 6000 years. A handful of mutations allows adults to produce the enzyme lactase, which can break down the milk sugar lactose. Genes that enable what’s called lactase persistence are widespread in modern Africa, which has four known lactase persistence mutations. (European populations rely on just one.)
When these lactase mutations evolved, they spread rapidly—evidence that people who carried them had a big advantage... (MORE - details)