Final answer:
Mitochondrial Eve refers to the most recent common ancestor of all humans through the maternal line, believed to have lived in Africa around 200,000 years ago. She is identified via mtDNA analysis, which traces maternal ancestry.
Step-by-step explanation:
Mitochondrial Eve, also known as the mtMRCA (mitochondrial most recent common ancestor), is the name given to the woman from whom all living humans descend on their mother's side. She is believed to have lived in Africa around 200,000 years ago. Mutations in mtDNA (mitochondrial DNA), which are passed on maternally, occur at regular intervals, allowing researchers to trace our genetic lineage back to this one woman.
The matrilineal descent of other Homo sapiens females living at the time of Mitochondrial Eve ended as their descendants died without female offspring or only had male children, resulting in the extinction of their maternal line and mtDNA. Mitochondrial DNA is unique in that it is passed down unchanged from mother to child unless a mutation occurs. This mtDNA heritage represents a direct line back to Mitochondrial Eve, serving as a significant clue to human evolutionary history.