Mitochondrial Eve and Y-Chromosome Adam

1. Mitochondrial Eve

   • Represents

• the most recent common matrilineal ancestor of all living humans,

1. Mitochondrial Eve

   • traced through

• mitochondrial DNA (mtDNA)

1. Mitochondrial Eve

   • inherited

• exclusively from mothers.

1. Mitochondrial Eve

   • Lived in

• Africa ~150,000–200,000 years ago.

1. Mitochondrial Eve

   • Not the only woman alive at the time, but the only one

• whose mtDNA lineage survives today.

1. Y-Chromosome Adam

   • Represents

• the most recent common patrilineal ancestor of all living males,

1. Y-Chromosome Adam

   • traced through

• the Y chromosome passed from fathers to sons.

1. Y-Chromosome Adam

   • Lived in

• Africa ~200,000–300,000 years ago (not necessarily contemporaneous with Eve).

1. Y-Chromosome Adam

   • Not the only male alive at the time, but

• the only one with an unbroken Y-chromosome lineage to the present.

Key Points:

• Both reflect

• genetic bottlenecks, not population bottlenecks.

Key Points:

• Their estimated timelines differ because of

• varied inheritance patterns (mtDNA vs. Y chromosome).

Key Points:

• Support the

• "Out of Africa" model of human origins.

evidence for out of africa model

African Origins:

Genetic Bottlenecks:

Time Depth:

Lack of Archaic Lineages:

Diversity Gradient:

1. African Origins:

   • Both figures trace back to Africa (Eve ~150,000–200,000 years ago; Adam ~200,000–300,000 years ago), aligning with

• fossil evidence of Homo sapiens origins there.

1. Genetic Bottlenecks:

   • Their existence reflects a

• small founding population in Africa,

  • consistent with the model's prediction of a recent African origin followed by migration.

1. Time Depth:

• The younger age of non-African mtDNA/Y lineages (<100,000 years)

• supports a late dispersal from Africa,

  • replacing archaic humans (Neanderthals/Denisovans).

1. Lack of Archaic Lineages:

• No mtDNA/Y lineages from older Homo species (e.g., Neanderthals) persist in modern humans,

  • implying replacement rather than assimilation outside Africa.

1. Diversity Gradient:

• Higher mtDNA/Y diversity in Africans aligns with the model’s prediction that

• longer evolutionary history in Africa generated more variation.