In human mitochondrial genetics, Haplogroup L3 is a human mitochondrial DNA (mtDNA) haplogroup. Haplogroup L3 has played a pivotal role in the history of the human species. Soon after the haplogroup arose in East Africa a relatively small number of migrants carried it across the Red Sea to Arabia, inaugurating an intercontinental migration that eventually settled every major land mass on Earth except Antarctica. That small group also gave rise to every non-African haplogroup.