Most of human history has been told by men, and for the most part, about men. But the world’s genetic history was first assembled by the biological legacy of women.
Inside every human cell are hundreds of tiny parcels that only mothers pass down to their children. Known as mitochondria, they were free living bacteria once upon a primordial time.
But today, they contain the machinery human cells need to produce their power. They also contain a unique ring of genetic code, well outside the regular genome, that rarely changes. This means people who do share the same mutations in their mitochondrial DNA, also descend from the same mother at some point back in history. With a simple swab, any man or woman can learn about the ancient geographic origins of their maternal heritage. Both sexes carry it, but only women pass it on.
Mitochondrial DNA has been a powerful guide for people who study evolution. Researchers say it indicates that all humans alive can trace their maternal line back to a woman who lived in Africa about 200,000 years ago, akin to a Genetic Eve. But it’s been far less powerful in revealing the recent past. In part, it’s because mitochondrial DNA tends to change too slowly to indicate when two people are related in a recent time frame.
Using it to try and trace a maternal line is also hampered by the traditional gender wall: Through history, most women changed their names when they married, so there’s no surname to hint whether two people shared a mother, or a stretch of mitochondrial code. New research however is turning up new mutations in Eve’s genetic legacy, which may yet unleash a mother lode of family history.