Divergent evolution among teleost V1r receptor genes
Patrick Pfister1, Jerome Randall, Juan I Montoya-Burgos
1Department of Zoology and Animal Biology, University of Geneva, Geneva, Switzerland.
Plos One
|April 19, 2007
Summary
Fish V1r1 and V1r2 olfactory receptors show different evolutionary paths. V1r2 is highly conserved, suggesting stable function, while V1r1 evolves faster, potentially adapting to new chemical signals.
Area of Science:
- Olfactory system evolution
- Chemosensory receptor genetics
- Vertebrate olfaction
Background:
- Vertebrate survival relies on social interactions, often mediated by the olfactory system.
- Olfactory receptors (V1rs) detect pheromones, with mammals having large repertoires and teleosts (fish) having limited ones.
Purpose of the Study:
- To analyze the olfactory expression and evolutionary constraints of fish V1r receptor genes (V1r1 and V1r2).
- To identify V1r orthologs in teleosts and understand their evolutionary dynamics.
Main Methods:
- Identified V1r orthologs in zebrafish, medaka, stickleback, and tetraodontidae species.
- Analyzed V1r1 and V1r2 gene sequences from 12 euteleost species.
- Examined evolutionary rates and selective pressures on V1r1 and V1r2.
Main Results:
- V1r orthologs were found in most studied euteleosts, but only one in tetraodontidae.
- V1r2 exhibited a highly conserved evolutionary rate, while V1r1 showed relaxed selective constraint.
- Positively-selected sites were identified in specific V1r1 lineages, indicating adaptation.
Conclusions:
- V1R2 receptor agonist specificity appears conserved across euteleost species.
- The V1R2 receptor was lost in the tetraodontidae lineage.
- V1R1 receptor likely acquired distinct chemosensory characteristics through evolution.
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