Evolution of head lice leads to clothing date.

I love clever people!

Mark Stoneking, of the Max Planck Institute for Evolutionary Anthropology in Leipzig has figured out a way to determine when humans began wearing clothing using "subtle genetic differences between human body lice that depend on clothing for their survival, and human head lice, which do not". Since body lice are adapted to clothing & can't live on hair, the point that their DNA diverged from head lice should yield a pretty close date for the invention of clothing.

Since most materials rot away after a few ten-thousands of years, it's hard to put a date on many cultural developments. So anthropologists are beginning to turn to indirect measurements like this, but interpreting the results is still controversial.