Jan

14

Lactose Intolerance is a compelling example of recent evolution. Belies the common belief that evolution takes hundreds of thousands of years, and that human evolution under civilization (rather than the wild) has slowed down.

Lactose intolerance is NOT a defect or disease. The default condition of humans (and others) is lactose intolerance. There is no reason why humans, certainly not adult humans, should be able to easily digest the maternal milk of another species.

Humans as they began in Africa were lactose intolerant. Humans migrated from Africa to the Middle East, Africa and Asia. As humans in the Middle East and then Europe domesticated the cow and the goat, it became a tremendous evolutionary advantage to be able to digest the milk (and cheese) of such species. When a mutant gene for lactose tolerance arose there, it spread incredibly fast because it allowed for far greater nutrition and survival, especially in high diary farming Western European countries. I believe something like 99% of the native population of Denmark is lactose tolerant.

In Asia, diary cows and goats were not highly developed. While a separate (from the European one) lactose tolerance mutant gene also came about in Asia, its spread was much more limited. Thus a majority of Asians share lactose intolerance with Africans. For the same reason. It was the original, default condition of humans, and the mutation did not spread as rapidly and fully as it did in Western Europe.


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