Life

Did lactose tolerance evolve more than once?

Did lactose tolerance evolve more than once?

Culture had dramatic effect on our ability to digest lactose Now, a new study indicates that the ability to digest milk arose more than once in humans descended from cattle herders–a finding that sheds light on how culture can have a rapid and dramatic effect on our genome.

When was lactose intolerance first discovered?

It is not until relatively recently that medicine recognised the worldwide prevalence of lactose intolerance and its genetic causes. Its symptoms were described as early as Hippocrates (460–370 BC), but until the 1960s, the prevailing assumption was that tolerance was the norm.

Is lactose intolerance an evolution?

The ability to digest lactose is also evidence that humans are still evolving. In those 10,000 years, it arose independently in at least four places around the globe. Today, more than 90 percent of all people have some degree of lactose tolerance.

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Where did lactose tolerance probably first originate?

The genetic mutation conferring this advantage—shared by most lactose tolerant Europeans—was commonly thought to have occurred first in the northern part of the continent, where the sun shines less and people may be in greater need of the vitamin D found in cow’s milk.

Who found out about lactose intolerance?

Now Leena Peltonen’s team at the University of California, Los Angeles, has discovered the genetic basis for lactose intolerance. The discovery supports the theory that retaining the ability to digest milk evolved only in some peoples in the past ten thousand years, as an adaptation to dairy farming.

Why did humans develop lactose tolerance?

Thousands of years ago, a mutation in the human genome allowed many adults to digest lactose and drink milk. But at that time, they lacked a genetic mutation that would have allowed them to digest raw milk’s dominant sugar, lactose, after childhood. …

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Why is everyone becoming lactose intolerant?

Lactose intolerance in adulthood is caused by gradually decreasing activity (expression) of the LCT gene after infancy, which occurs in most humans. LCT gene expression is controlled by a DNA sequence called a regulatory element, which is located within a nearby gene called MCM6.