Unstable environmental conditions constrain the fine-tune between opsin sensitivity and underwater light in an Amazon forest stream fish.

Autor:	de Almeida Borghezan E; Wildlife Research Center of the Kyoto University, Kyoto, Japan.; National Institute for Amazonian Research, Manaus, Brazil., da Silva Pires TH; National Institute for Amazonian Research, Manaus, Brazil., Zuanon J; National Institute for Amazonian Research, Manaus, Brazil., Sugiura H; Wildlife Research Center of the Kyoto University, Kyoto, Japan., Kohshima S; Wildlife Research Center of the Kyoto University, Kyoto, Japan., Kishida T; Wildlife Research Center of the Kyoto University, Kyoto, Japan.; College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
Jazyk:	angličtina
Zdroj:	Journal of evolutionary biology [J Evol Biol] 2024 Feb 14; Vol. 37 (2), pp. 212-224.
DOI:	10.1093/jeb/voae001
Abstrakt:	Visual adaptations can stem from variations in amino acid composition, chromophore utilization, and differential opsin gene expression levels, enabling individuals to adjust their light sensitivity to environmental lighting conditions. In stable environments, adaptations often involve amino acid substitutions, whereas in unstable conditions, differential gene expression may be a more relevant mechanism. Amazon forest streams present diverse underwater lighting conditions and experience short-term water colour fluctuations. In these environments, it is less likely for genetic and amino acid sequences to undergo modifications that tailor opsin proteins to the prevailing lighting conditions, particularly in species having several copies of the same gene. The sailfin tetra, Crenuchus spilurus, inhabits black and clear water Amazon forest streams. The long-wavelength sensitivity (LWS) is an important component for foraging and courtship. Here, we investigated LWS opsin genes in the sailfin tetra. Three copies of LWS1 and two copies of LWS2 genes were found. The maximum absorbance wavelength (λmax) estimated from the amino acid sequences of LWS1 genes exhibited variation among the different copies. In contrast, the copies of LWS2 genes showed identical expected λmax values. Although the amino acid positions affecting λmax varied among LWS genes, they remained consistent among populations living in different water colours. The relative expression levels of LWS genes differed between gene copies. While not formally tested, our results suggest that in fluctuating environments, visual adaptations may primarily stem from alterations in gene expression profiles and/or chromophore usage rather than precise genetic tuning of protein light sensitivity to environmental lighting conditions. (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Evolutionary Biology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Databáze:	MEDLINE
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