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Published on: September 22, 2021
The great human expansion
Brenna M Henn1, L L Cavalli-Sforza, Marcus W Feldman
1Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
Summary
Modern human origins trace back to a major African expansion 45,000-60,000 years ago, leading to reduced genetic diversity globally due to the serial founder effect.
Area of Science:
- Human Evolution
- Population Genetics
- Paleoanthropology
Background:
- Human origins involve a significant demographic and geographic expansion from Africa.
- This expansion, starting 45,000-60,000 years ago, led to global human settlement.
- Genomic data reveal a continuous loss of genetic diversity, known as the serial founder effect.
Purpose of the Study:
- To review advances in understanding human genetic diversity within Africa.
- To examine the great human expansion out of Africa.
- To propose hypotheses for a synthetic view of modern human evolution.
Main Methods:
- Analysis of genetic and paleoanthropological evidence.
- Examination of genomic data from contemporary humans.
- Integration of data from human parasites, morphology, and linguistics.
Main Results:
- African populations retain exceptional genetic variants due to substructure.
- Populations outside Africa show a dramatic reduction in genetic diversity.
- The serial founder effect model is supported by diverse evidence.
Conclusions:
- Human population history, shaped by hunter-gatherer factors, explains current genetic variation patterns.
- Reconciling major expansion with subsequent stability requires further investigation.
- Understanding these patterns is crucial for medical genetics and evolutionary studies.
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