JENA, GERMANY—Science Magazine reports that scientists examined the dental calculus from the teeth of eight skeletons unearthed in Sudan and Kenya that were dated to between 2,000 and 6,000 years old. The presence of milk proteins in the hardened plaque indicates that the people had consumed milk products such as milk, cheese, or yogurt at least 6,000 years ago. However, an earlier study of DNA extracted from these remains did not detect the genes that would have allowed the adults to digest milk products. “It looks like the community was drinking milk before they had lactase persistence,” said team member Madeleine Bleasdale of the Max Planck Institute for the Science of Human History. Fermenting the milk may have made it easier for early farmers to digest, she added. When lactase mutations evolved, however, they spread rapidly, since the ability to digest milk products offers a better chance of survival in harsh conditions. Four known lactase persistence mutations are widely found in Africa today. Read the original scholarly article about this research in Nature Communications. To read about the development of dairy production in the Indus Valley, go to "Around the World: India."