How far back can you trace your maternal line? To your mother? Your grandmother? How about your maternal great-great-great-grandmother? Whether you know your maternal-line genealogy back ten generations or none at all, you can discover the history of your ancestors going back tens of thousands of years. Their story is in your DNA — your mitochondrial DNA, to be precise.
Each generation, mothers pass down their mitochondrial DNA (mtDNA) to their children. Both their daughters and their sons inherit mtDNA, but only women pass it on. As a result, you inherited your mtDNA from the long, unbroken line of women who make up your maternal line.
Researchers study the genetic markers in mtDNA to trace the histories of our maternal lines. Using these markers, they can identify maternal haplogroups, families of maternal lineages that descend from the same woman.
In fact, they’ve discovered that we are all direct maternal-line descendants of a single woman who lived in eastern Africa between 150,000 and 200,000 years ago! As her daughters and their daughters migrated out of the cradle of modern humans, they branched out into different groups that crossed Africa and the globe. Many of these migrations can be traced using haplogroups.
At 23andMe, we’ve just released a redesigned version of our Maternal Haplogroup report, placing customers’ own ancestral stories within the context of the broader human story. We determine each customer’s maternal haplogroup by looking at the genetic markers in their mtDNA. Then, we walk each customer step by step through the points at which their maternal line branched off from others over thousands of years. Furthermore, the report lets you know if you share a maternal haplogroup with a notable individual or groups of individuals in history.