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Rhodopsin molecular evolution in mammals inhabiting low light environments
Huabin Zhao1, Binghua Ru, Emma C Teeling
1School of Life Sciences, East China Normal University, Shanghai, China.
Plos One
|December 18, 2009
Summary
Mammalian vision adapted to diverse light environments through changes in the rhodopsin gene. Molecular evolution in rhodopsin occurred independently in bats and rodents inhabiting low-light conditions.
Area of Science:
- Evolutionary biology
- Molecular biology
- Mammalian vision
Background:
- Mammalian adaptation to varied light environments is linked to visual system evolution.
- The rod pigment rhodopsin is crucial for vision, especially in dim light.
Purpose of the Study:
- Investigate molecular adaptation of the rhodopsin gene in mammals.
- Determine if evolutionary shifts to dim-light niches correlate with rhodopsin gene changes.
Main Methods:
- Sequenced the rhodopsin gene in 22 mammals (bats, mole-rats).
- Compared sequences with 37 published mammal rhodopsin sequences.
- Reconstructed phylogenetic trees and performed selection tests.
Main Results:
- All studied mammals possess functional rhodopsin.
- Phylogenetic analysis revealed accelerated evolution in bats and rodents inhabiting low-light environments.
- Divergent selection pressures were identified in subterranean rodents, bats, and marine mammals.
Conclusions:
- Independent molecular evolution of rhodopsin occurred in specialized mammal groups.
- These changes are linked to adaptation to distinct light environments.
- Molecular changes in rhodopsin may not directly dictate spectral sensitivity.
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