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Using conventional F-statistics to study unconventional sex-chromosome differentiation
Nicolas Rodrigues1, Christophe Dufresnes1
1Department of Ecology & Evolution, University of Lausanne, Lausanne, Switzerland.
Peerj
|May 3, 2017
Summary
Two simple F-statistics (genetic distance Fst and inbreeding coefficient Fis) can reliably compare sex chromosome differentiation between populations. This method aids in understanding sex determination systems in species with undifferentiated sex chromosomes.
Area of Science:
- Evolutionary biology
- Genetics
- Population genetics
Background:
- Species with undifferentiated sex chromosomes are crucial for understanding sex determination diversity.
- Genomic methods offer new insights but face challenges in characterizing X and Y chromosomes separately.
Purpose of the Study:
- To demonstrate the utility of two F-statistics (Fst and Fis) as proxies for sex chromosome differentiation.
- To facilitate population-level analyses of sex chromosomes in species with undifferentiated systems.
Main Methods:
- Calculation of genetic distance (Fst) between sexes.
- Calculation of inbreeding coefficient (Fis) in the heterogametic sex.
- Correlation of these F-statistics with X-Y differentiation using microsatellite data from frog species (Hyla arborea and Rana temporaria).
Main Results:
- Fst and Fis are reliable proxies for overall X-Y chromosome differentiation in populations.
- These metrics showed a strong correlation with the amount of sex chromosome differentiation.
- High variability in locus-specific fits suggests a need for dense genetic coverage for fine-scale analyses.
Conclusions:
- The proposed F-statistics offer a simplified approach to population-level sex chromosome analysis.
- These methods require minimal sampling, significantly aiding research on sex determination systems.
- Further research with dense genetic data is recommended for detailed sex-chromosome differentiation patterns.
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