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Comparative Genomics Provides Insights into Adaptive Evolution in Tactile-Foraging Birds
Li Wang1, Li Sun1, Qiu-Hong Wan1
1MOE Key Laboratory of Biosystems Homeostasis & Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Genes
|April 23, 2022
Summary
Tactile foragers like kiwi and mallards show gene expansion in smell, while crested ibis show it in hearing. This study explores sensory evolution and potential visual degradation in these birds.
Area of Science:
- Evolutionary biology
- Neuroscience
- Comparative genomics
Background:
- Tactile-foraging birds exhibit an enlarged principal sensory nucleus (PrV) and reduced visual brain regions, suggesting sensory trade-offs.
- The adaptive evolution of sensory systems in tactile foragers remains incompletely understood.
Purpose of the Study:
- To investigate the genetic mechanisms underlying sensory system evolution in three tactile foragers: kiwi, mallard, and crested ibis.
- To explore the potential trade-offs between different sensory modalities and their corresponding brain structures.
Main Methods:
- Comparative genomic analysis of genes related to sensory systems (olfaction, hearing, vision).
- Identification of genes under positive selection or convergent evolution.
- Analysis of candidate genes associated with visual degradation, such as PDLIM1.
Main Results:
- Kiwi and mallard show gene expansion in olfaction-related genes; crested ibis show expansion in hearing-related genes.
- Genes crucial for visual development underwent positive selection or convergent amino acid substitutions across all three species, suggesting visual degradation.
- The gene PDLIM1, involved in visual degradation, exhibited dense convergent amino acid substitutions.
Conclusions:
- Specialized tactile foraging is linked to adaptive evolution of sensory abilities and brain structures.
- Evidence suggests a potential trade-off between enhanced tactile senses and visual degradation in these birds.
- Genes regulating neuronal progenitor cell proliferation and differentiation may influence the relative sizes of brain sensory areas.
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