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R2d2 Drives Selfish Sweeps in the House Mouse
John P Didion1, Andrew P Morgan2, Liran Yadgary2
1Department of Genetics, The University of North Carolina at Chapel Hill Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill Carolina Center for Genome Science, The University of North Carolina at Chapel Hill fernando@med.unc.edu.
Molecular Biology and Evolution
|February 18, 2016
Summary
Selfish genetic elements, like the R2d2(HC) variant, can rapidly spread through populations via meiotic drive. This selfish sweep alters genetic diversity, even when detrimental to organismal fitness.
Area of Science:
- Evolutionary genetics
- Population genetics
Background:
- Selective sweeps, driven by positive selection, alter genetic diversity.
- The role of "selfish" genes in fixation and population genetics is debated.
- Meiotic drive can cause nonrandom chromosome segregation, as seen with the R2d2 variant.
Purpose of the Study:
- To investigate evidence for "selfish sweeps" driven by meiotic drive.
- To determine if selfish alleles can fix in natural populations.
- To understand the impact of selfish genes on population genetics and evolution.
Main Methods:
- Analysis of population-genetic data from natural populations.
- Replication in controlled breeding populations across diverse genetic backgrounds.
- Quantification of allele frequency changes and fixation rates.
- Assessment of fitness effects associated with the selfish allele.
Main Results:
- Population-genetic data support a "selfish sweep" driven by high copy number R2d2 alleles (R2d2(HC)).
- R2d2(HC) rapidly increased in frequency and fixed in multiple populations, faster than expected by genetic drift.
- R2d2(HC) exhibited reduced litter sizes in heterozygous mothers, indicating a fitness cost.
- Meiotic drive can rapidly alter genomic landscapes favoring neutral or deleterious mutations.
Conclusions:
- Provides direct evidence of populations undergoing selfish sweeps.
- Demonstrates that meiotic drive can drive fixation of selfish alleles, independent of organismal fitness.
- Highlights the potential for selfish genetic elements to significantly impact evolutionary trajectories.
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