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Range size variably predicts genetic diversity in Gehyra geckos
Ching Ching Lau1, Keith Christian2, Jessica Fenker1
1Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia.
Evolution; International Journal of Organic Evolution
|March 20, 2025
Summary
Larger range sizes correlate with higher genetic diversity in Gehyra geckos. However, population fluctuations and gene flow also significantly impact genetic diversity, deviating from simple neutral theory predictions.
Area of Science:
- Population genetics
- Evolutionary biology
- Genomics
Background:
- Genetic diversity is crucial for species' adaptive capacity.
- Neutral theory predicts a positive correlation between population size and genetic diversity.
- Demographic factors can confound this relationship.
Purpose of the Study:
- Investigate the influence of range size, population fluctuation, and introgression on genetic diversity.
- Analyze genomic-scale SNP data from Australian Gehyra geckos.
- Examine deviations from neutral theory predictions.
Main Methods:
- Generated population-level SNP data for 21 Gehyra gecko species.
- Analyzed 769 samples across a wide range of geographic distributions.
- Employed best-practice methods for heterozygosity estimation.
Main Results:
- Found a significant positive correlation between range size and heterozygosity overall.
- Observed a stronger range size-heterozygosity link in the 'australis' clade than the 'nana' clade.
- Detected population expansion (Tajima's D) and introgression in the 'nana' group.
Conclusions:
- Range size is a key, but not sole, determinant of genetic diversity.
- Population fluctuations and introgression play significant roles in shaping genetic diversity.
- Results offer insights into demographic processes beyond neutral expectations.
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