Evolutionary dynamics of Rh2 opsins in birds demonstrate an episode of accelerated evolution in the New World warblers (Setophaga).
Mol Ecol
; 24(10): 2449-62, 2015 May.
Article
em En
| MEDLINE
| ID: mdl-25827331
ABSTRACT
Low rates of sequence evolution associated with purifying selection can be interrupted by episodic changes in selective regimes. Visual pigments are a unique system in which we can investigate the functional consequences of genetic changes, therefore connecting genotype to phenotype in the context of natural and sexual selection pressures. We study the RH2 and RH1 visual pigments (opsins) across 22 bird species belonging to two ecologically convergent clades, the New World warblers (Parulidae) and Old World warblers (Phylloscopidae) and evaluate rates of evolution in these clades along with data from 21 additional species. We demonstrate generally slow evolution of these opsins both Rh1 and Rh2 are highly conserved across Old World and New World warblers. However, Rh2 underwent a burst of evolution within the New World genus Setophaga, where it accumulated substitutions at 6 amino acid sites across the species we studied. Evolutionary analyses revealed a significant increase in dN /dS in Setophaga, implying relatively strong selective pressures to overcome long-standing purifying selection. We studied the effects of each substitution on spectral tuning and found they do not cause large spectral shifts. Thus, substitutions may reflect other aspects of opsin function, such as those affecting photosensitivity and/or dark-light adaptation. Although it is unclear what these alterations mean for colour perception, we suggest that rapid evolution is linked to sexual selection, given the exceptional plumage colour diversification in Setophaga.
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Texto completo:
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aves Canoras
/
Evolução Biológica
/
Opsinas
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article