In human genetics, a human mitochondrial DNA haplogroup is a haplogroup defined by differences in human mitochondrial DNA. These haplogroups have led some researchers to trace the matrilineal inheritance of modern humans back to human origins in Africa and the subsequent spread across the globe.Known haplogroups are assigned the following letter codes: A, B, C, CZ, D, E, F, G, H, pre-HV, HV, I, J, pre-JT, JT, K, L0, L1, L2, L3, L4, L5, L6, L7, M, N, P, Q, R, S, T, U, UK, V, W, X, Y, and Z.
The woman at the root of all these groups was the most recent common matrilineal (female-lineage) ancestor of all living humans. She is commonly called Mitochondrial Eve.
