DNA is a dazzling, if dull, language. With only four chemical building blocks — known in short form as A, C, G, and T—repeated over and over in different orders some six billion times, it’s not the sort of story anyone curls up with. But it is the story of you, biologically speaking. Inherited as 23 pairs of chromosomes from your parents, DNA is a compilation of the generations of parents who also came before them.
Changes can spring up in DNA each time it’s passed down to the next generation. And for various reasons, certain changes only became common in specific regions of the world. The first person to carry the change, or mutation, may have had many children, who in turn passed it down to many future generations in the area.
The mutation may have resulted in a survival advantage, such as the ability to digest milk into adulthood, or the power to resist malaria. Many of these mutations are now associated with specific continents, and some with countries. By learning about the mutations in your DNA, you can learn something about where in the world your ancestors once lived. Researchers liken these markers to sign posts across the genome, and often, they can point the way back — way back – to unexpected places.