Today it's a desert. Two hundred thousand years ago, perhaps it was home. The San people of southern Africa carry one of the oldest maternal DNA lineages on Earth. Now, researchers think they know the precise place our earliest maternal ancestor called home. (Image credit: Shutterstock) Two hundred thousand years ago, the earliest shared ancestors of every living human on Earth rested their feet at a verdant oasis in the middle of Africa's Kalahari Desert. Here, in a patchwork of now-extinct lakes, forests and grasslands known as the Makgadikgadi paleowetland, our greatest grandmothers and -grandfathers hunted, gathered and raised families...