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Distinct latitudinal patterns of molecular rates across vertebrates
Tianlong Cai1,2,3, Zhixin Wen4, Zhongguan Jiang5
1Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China.
Summary
The evolutionary speed hypothesis suggests temperature drives biodiversity gradients via molecular rates. This study found limited support, with varying effects across vertebrate groups and thermoregulatory strategies.
Area of Science:
- Evolutionary Biology
- Biodiversity Science
- Genomics
Background:
- The latitudinal diversity gradient (LDG) is a major biodiversity pattern with unresolved mechanisms.
- The evolutionary speed hypothesis (ESH) links molecular rates, temperature, and speciation to explain the LDG.
Purpose of the Study:
- To systematically test the ESH's predictions across major vertebrate groups using molecular data.
- To investigate the influence of thermoregulatory strategies on molecular rates and their latitudinal patterns.
Main Methods:
- Analyzed mitochondrial and nuclear genome data from over 5,400 vertebrate species.
- Calculated absolute synonymous (dS) and nonsynonymous (dN) substitution rates.
- Examined correlations between molecular rates, latitude, temperature, and diversification rates.
Main Results:
- Synonymous substitution rates (dS) increased with temperature and decreased with latitude in ectotherms, but not endotherms.
- Mitochondrial nonsynonymous rates (dN) increased with temperature, influenced by mutation rates or selection.
- Neither mitochondrial dS nor dN correlated with diversification rates; ESH was supported only in reptiles and amphibians for nuclear rates.
Conclusions:
- Provides limited support for the evolutionary speed hypothesis in vertebrates.
- Highlights the complex interplay of factors, including thermoregulation, shaping biodiversity gradients.
- Suggests temperature's role in molecular evolution varies significantly across vertebrate taxa.
Keywords:
evolutionary speed hypothesislatitudinal diversity gradientmolecular ratetemperaturethermoregulationMore Related Videos
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