March 2, 2007
Neolithic lactose intolerance
Looks like I'm just an old-fashioned guy:
The first direct evidence that early Europeans were unable to digest milk has been found by scientists at UCL (University College London) and Mainz University.In a study, published in the journal 'PNAS', the team shows that the gene that controls our ability to digest milk was missing from Neolithic skeletons dating to between 5840 and 5000 BC. However, through exposure to milk, lactose tolerance evolved extremely rapidly, in evolutionary terms. Today, it is present in over ninety per cent of the population of northern Europe and is also found in some African and Middle Eastern populations but is missing from the majority of the adult population globally. . .
Dr Thomas said: "To go from lactose tolerance being rare or absent seven to eight thousand years ago to the commonality we see today in central and northern Europeans just cannot be explained by anything except strong natural selection. Our study confirms that the variant of the lactase gene appeared very recently in evolutionary terms and that it became common because it gave its carriers a massive survival advantage. Scientists have inferred this already through analysis of genes in today's population but we've confirmed it by going back and looking at ancient DNA."
This study challenges the theory that certain groups of Europeans were lactose tolerant and that this inborn ability led the community to pursue dairy farming. Instead, they actually evolved their tolerance of milk within the last 8000 years due to exposure to milk.
Full story here.
Posted by David on March 2, 2007 9:27 AM
I have a mental picture of my northern European ancestors (Welsh and Swedish)--they survived because they could drink milk and I imagine more importantly, each cheese (cured milk) a food with a longer shelf life, during those long cold wet winter months, when other people starved because they could not tolerate milk products and the root vegetables produced dduring the short growing season and the dried fish were used up. The weather is so fierce in the winter fishing is out of the question, and the growing season so short in a rocky land with minimal top soil....a hard life and many did not survive to reproduce.
Posted by: Sarah
on March 2, 2007 11:03 AM