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Spatial structure alters the site frequency spectrum produced by hitchhiking
Jiseon Min1,2,3, Misha Gupta4, Michael M Desai2,3,4,5
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Genetics
|September 12, 2022
Summary
Spatial structure significantly impacts genetic hitchhiking, altering the site frequency spectrum near selective sweeps. These spatial signatures can be detectable even in largely mixed populations.
Area of Science:
- Population Genetics
- Evolutionary Biology
- Genomics
Background:
- Genetic hitchhiking, the reduction of genetic diversity near selected loci, is a key tool for detecting past selective sweeps.
- The influence of spatial population structure on hitchhiking signatures remains poorly understood.
Purpose of the Study:
- To investigate how spatial structure in a 1D population affects the site frequency spectrum resulting from genetic hitchhiking during a selective sweep.
- To identify characteristic genomic signatures left by sweeps in spatially structured populations.
Main Methods:
- Mathematical modeling of genetic hitchhiking in a 1D population.
- Simulations to analyze the unfolded site frequency spectrum near selective sweeps.
- Comparison of spatial and well-mixed population models.
Main Results:
- Selective sweeps in 1D populations spread as Fisher waves, not logistically.
- A distinct 3-part site frequency spectrum is observed near the swept locus: recent mutations, a transition zone resembling well-mixed populations, and a unique scaling regime at moderate-to-high frequencies.
- Recombination is more effective at restoring diversity in 1D populations compared to well-mixed ones.
Conclusions:
- Spatial structure leaves detectable signatures on the site frequency spectrum during genetic hitchhiking.
- These spatial effects can be significant even in populations with low apparent spatial genetic differentiation.
- Spatial structure may frequently obscure or alter hitchhiking signals in natural populations, impacting the interpretation of genomic data.
Keywords:
genetic diversitygenetic hitchhikingselective sweepssite frequency spectrumspatial structureMore Related Videos
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