One night in 1987 a biochemist from New Zealand, Allan Wilson, and his American colleague Rebecca Cann were examining a so-far ignored part of human DNA at the University of California, Berkeley, and they made the astonishing discovery that all human beings have the same parents. This DNA in our bodies remains intact through the generations and is passed on from mother to daughter, but also leaves behind traces of the changes or mutations. When these scientists examined this DNA component in the family tree of each of the continents of the earth, they could trace it back to one woman who lived in Africa about 200,000 years ago.