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Opsin evolution in damselfish: convergence, reversal, and parallel evolution across tuning sites.

Christopher M Hofmann¹, N Justin Marshall, Kawther Abdilleh

¹Department of Biology, University of Maryland, College Park, MD, USA. chofma1@gmail.com

Journal of Molecular Evolution

|October 20, 2012

Summary

Opsin evolution in damselfish reveals repeated adaptation in visual pigments, similar to cichlids. This suggests the aquatic light environment strongly influences how visual systems evolve over time.

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Area of Science:

Evolutionary biology
Genetics
Marine biology

Background:

The visual system is crucial for survival, with direct links between visual pigments and opsin genes.
Previous studies on African cichlids showed positive selection on opsins, particularly those for short and long wavelengths.

Purpose of the Study:

To investigate opsin evolution in damselfish (Pomacentridae), a widely distributed reef fish family.
To compare opsin variation in damselfish with that of African cichlids to understand evolutionary patterns.

Main Methods:

Examined opsin evolution in damselfish, considering their 50 million-year fossil record.
Reconstructed amino acid substitutions at opsin spectral tuning sites.

Main Results:

Found increased functional variation in short- and long-wavelength opsins in damselfish, mirroring findings in African cichlids.
Identified multiple instances of parallel evolution, convergent evolution, and an evolutionary reversal at opsin tuning sites.

Conclusions:

Amino acids at spectral tuning sites are highly mutable and evolve repeatedly.
The aquatic light environment significantly shapes opsin sequence evolution.
Phylogenetic methods reveal natural selection's role in shaping visual phenotypes.