A new Nature article came out the other day that addresses a major question in the story of lactase persistence, one of the strongest gene-culture-selection interactions: did hunter-gatherer populations adopt dairy'ing or did dairy'ing cultures migrate and replace these HG populations?
I really love this type of research, not only for its profound insight into the past but also the interdisciplinary team that participated in elucidating these facts. I often find myself thinking I need to be a biochemist/molecular biologist/genomicist/bioinformatician to answer all the questions I have about nutrigenomics - but in this effort alone, there were anthropologists, paleogeneticists, bioarchaeologists, mathematicians, and archaezoologists.
To solve the issue of dairying's origins, researchers looked at the bone remains - since calves need to be killed earlier than a cow raised for slaughter, looking at a bone's age can give insight into whether individuals in the time period were dairy'ing. These bones also provided evidence that the cow remains in Europe were more closely related to cows in the Middle East than wild Europian types - indicating that Middle Easterners herded cows as they expanded into Europe, strong evidence for replacement.
Evolution happens at the population level - the lactase persistence mutation would've taken many generations to pass on. But there's evidence of domestication long before this allele became prevalent. This has lead some to point out that early Neolithic agriculturalists could've manipulated dairy to make it more tolerable/reduce lactose. LeCHE researchers tested pottery and found milk fat residues going back over 7000 yrs - genetic evidence only supports lactase persistence going back 6500 years ago.
The article also talks about why dairy'ing and lactase persistence were selected for - they still mention the role of Vitamin D in milk as potentially having conferred a survival/reproductive advantage. I don't understand this at all - Vitamin D is an area of research that I have zero desire to get involved with - its an all out war between industry funded research, private researchers and government recommendations - but there is so little Vitamin D occurring naturally in milk, compared to natural sources like fish, it's hard to say that it would've given a survival/reproductive advantage.
I really love this type of research, not only for its profound insight into the past but also the interdisciplinary team that participated in elucidating these facts. I often find myself thinking I need to be a biochemist/molecular biologist/genomicist/bioinformatician to answer all the questions I have about nutrigenomics - but in this effort alone, there were anthropologists, paleogeneticists, bioarchaeologists, mathematicians, and archaezoologists.
To solve the issue of dairying's origins, researchers looked at the bone remains - since calves need to be killed earlier than a cow raised for slaughter, looking at a bone's age can give insight into whether individuals in the time period were dairy'ing. These bones also provided evidence that the cow remains in Europe were more closely related to cows in the Middle East than wild Europian types - indicating that Middle Easterners herded cows as they expanded into Europe, strong evidence for replacement.
Evolution happens at the population level - the lactase persistence mutation would've taken many generations to pass on. But there's evidence of domestication long before this allele became prevalent. This has lead some to point out that early Neolithic agriculturalists could've manipulated dairy to make it more tolerable/reduce lactose. LeCHE researchers tested pottery and found milk fat residues going back over 7000 yrs - genetic evidence only supports lactase persistence going back 6500 years ago.
The article also talks about why dairy'ing and lactase persistence were selected for - they still mention the role of Vitamin D in milk as potentially having conferred a survival/reproductive advantage. I don't understand this at all - Vitamin D is an area of research that I have zero desire to get involved with - its an all out war between industry funded research, private researchers and government recommendations - but there is so little Vitamin D occurring naturally in milk, compared to natural sources like fish, it's hard to say that it would've given a survival/reproductive advantage.
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