Ancient DNA can be a powerful tool for helping us reconstruct the long-dead past. Most surviving genetic material comes from the bones and teeth of animals that lived in cold environments, where freezing temperatures help prevent decay. While hotter climates are seen as hostile to preservation, rese archers have recently extracted DNA from a tooth found in South Africa that may date to around 50,000 years ago—the oldest yet retrieved from sub-Saharan Africa. ...read more read less