Mitochondrial Eve — where the tree closes

Follow every living person's maternal line back far enough and the branches converge. Because each of us has exactly one mother, the matrilineal tree can only narrow going backward, and eventually every thread arrives at one woman. She is called Mitochondrial Eve, and current estimates put her somewhere around 150,000–200,000 years ago, in Africa.

⚠ She was not the first woman, not the only woman of her time, and not anyone's idea of a first parent. She is a graph property: the most recent common ancestor along one particular kind of link. Thousands of her contemporaries have living descendants — just not by an unbroken chain of daughters. And that is the room's universal frame demonstrated rather than asserted. Zoom the worm-tree out far enough and every reader of this app, without exception, shares a node. The tree that seemed to be about ancestry turns out to be about everyone.