Mark Thomas, University College, London, England, and Joachim Burger, Mainz University, Germany, have reported these results online on February 26, 2007 in Nature.com and in the journal Proceedings of the National Academy of Sciences. They stated that European adults did not possess the lactase gene possibly up to eight thousand years ago, which allows the human body to digest milk by breaking down lactose.

The scientists based their research on the study of DNA (deoxyribonucleic acid, which carries an organism’s genetic material) from several Neolithic skeletons found in Hungary, Lithuania, Germany, and Poland, which lived about 8,000 years ago. In this DNA, the gene that allows milk consumption was absent.

Based partly on this study, scientists believe that early humans began to farm and began to raise and domesticate diary cows before they became tolerant of milk. They are not sure how European adults got the milk gene that allowed them to tolerate the digestion of milk. However, geneticists think that a genetic mutation was first introduced 3,000 to 7,000 years ago in eastern Africa or northern Europe. In any case, they consider the ability to drink milk to be one of the major contributors to human survival and prosperity over the past tens of thousands of years.

Generally, babies can tolerate milk but sometimes lose that ability between the ages of two and five years. Today, most people in Asia, sub-Saharan Africa, native-Americans, and Pacific Islanders are lactose intolerant, while many people in Europe and those outside sub-Saharan Africa continue to possess the lastase gene into adulthood.

In all, about 70% of people today can tolerate milk—a vast improvement from 8,000 years ago when almost no adults could tolerate milk.

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Genetics  Research  Science  William Atkins