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Natural selection at linked sites in humans
Bret A Payseur1, Michael W Nachman
1Department of Ecology and Evolutionary Biology, Biosciences West Building, University of Arizona, Tucson, AZ 85721, USA. payseur@email.arizona.edu
Gene
|December 7, 2002
Summary
Neutral genetic diversity in humans is impacted by linked mutations. Distinguishing between background selection and genetic hitchhiking remains challenging with current data, unlike in Drosophila.
Area of Science:
- Population Genetics
- Evolutionary Biology
- Human Genetics
Background:
- Neutral polymorphism patterns are influenced by linked selected mutations.
- Background selection reduces neutral diversity by removing deleterious mutations.
- Genetic hitchhiking lowers neutral polymorphism during beneficial mutation fixation.
Purpose of the Study:
- To review evidence for selection at linked sites affecting human neutral polymorphism.
- To discuss methods for differentiating background selection from genetic hitchhiking in humans.
Main Methods:
- Analysis of polymorphism levels relative to recombination rates.
- Comparison of variation on X chromosomes versus autosomes.
- Examination of neutral polymorphism frequency distributions.
- Assessment of population-specific genetic variation patterns.
Main Results:
- Clear evidence exists for selection impacting linked sites in human neutral polymorphism.
- Current data and methods are insufficient to determine the relative importance of background selection versus genetic hitchhiking in humans.
- Human findings contrast with stronger positive selection signals observed in Drosophila.
Conclusions:
- Selection at linked sites demonstrably affects human genetic diversity.
- Further research is needed to quantify the contributions of background selection and genetic hitchhiking.
- Comparative genomics studies highlight differences in evolutionary forces across species.