Sixty seconds on . . . lactose intolerance

Got milk?I do. But have you “herd” the commonly accepted theory of how we came to drink cow’s milk as adults?Moooo?Humans started domesticating animals and using their milk around 10 000 years ago, but probably couldn’t digest lactose, the main sugar in milk. Lactase, the enzyme that digests lactose, is produced naturally by infants and small children but gets turned off as they wean off breastmilk. Instead, a genetic variation in our DNA called lactase persistence (LP) has evolved to allow us to continue to make lactase. LP has rapidly increased in prevalence over the past 10 000 years.How amoosingYep, it’s become a textbook example of natural selection in humans: milk, which contains useful calories, minerals (including calcium), and many beneficial micronutrients, gave advantages to those who had LP, enabling them to pass on their genes to more offspring than those without.So, what’s the moos?A new study published in Nature1…
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