Milk Drinking: In Our Genes?

A new study led by UCL scientists has found that current genetic data cannot
explain why vast swathes of the world can digest milk.

The ability to digest the milk sugar lactose – also known as lactase persistence
– is a selectively advantageous and recent evolutionary genetic trait, which
emerged about 7,500 years ago in Europe and probably later in other parts of the
world. This means that, once weaned, people in most parts of the world (large
parts of Africa, most of Asia, and Oceania) cannot digest milk for the rest of
their life.

However, the study published in BMC Evolutionary Biology, shows that the four
genetic mutations currently associated with the ability to digest milk cannot
explain why many people in western and southern Africa, south eastern Europe,
the Middle East, and southern and central Asia are able to digest milk. It also
suggests that other genetic variants leading to the ability to digest milk
exist, but have not yet been discovered.

Study co-author Dr Yuval Itan (UCL Genetics, Evolution and Environment) explains
more fully what this study reveals.

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University College London