A chromosomal inversion acts as a hotspot for divergence in multiple ecologically relevant traits
Chromosomal inversions are proposed to aid local adaptation to divergent habitats when there is gene flow by creating regions of low recombination that can maintain tight linkage between multiple locally adaptive alleles. However, key theoretical predictions about the role of chromosomal inversions in local adaptation remain largely untested in empirical systems. Here, we test the prediction that…
A chromosomal inversion can act as a focal point for adaptation to different environments by concentrating small genetic effects across multiple traits, according to a study on threespine stickleback (Gasterosteus aculeatus). Researchers tested the hypothesis that inversions maintain tight linkage between locally adaptive alleles despite high gene flow.
By examining associations between inversions and traits in both wild-caught and lab-raised populations, they found that a specific inversion on chromosome XXI impacts several ecologically relevant traits. The inversion's effects, ranging from small to moderate, align with predictions for polygenic adaptation. Interestingly, heterozygous individuals exhibit intermediate phenotypes, suggesting that the phenotypic consequences of inversions depend on genomic and environmental backgrounds.
While most associations were consistent across datasets and approaches, some were specific to individual studies, highlighting the influence of context on inversion-driven phenotypic changes. The findings bolster the notion that chromosome XXI inversions contribute to ecological divergence in threespine stickleback, demonstrating that inversions can play a significant role in local adaptation by preserving linkage between small-effect adaptive alleles amidst widespread gene flow.
Written by urgent.news from bioRxiv's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
