Visual adaptation in Lake Victoria cichlid fishes: depth-related variation of color and scotopic opsins in species from sand/mud bottoms
| Autor: | Yohey Terai, Semvua I. Mzighani, Hillary D. J. Mrosso, Hiroo Imai, Norihiro Okada, Shiho Takahashi-Kariyazono, Herbert Tichy, Takashi Okitsu, Mitsuto Aibara, Akimori Wada, Ryutaro Miyagi, Shinji Mizoiri, Akie Sato |
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| Rok vydání: | 2017 |
| Předmět: |
Male
0106 biological sciences 0301 basic medicine Visual adaptation Geologic Sediments Opsin media_common.quotation_subject Color Lake Victoria 010603 evolutionary biology 01 natural sciences Evolution Molecular 03 medical and health sciences Species Specificity Cichlid parasitic diseases Animals Scotopic vision Eye Proteins Alleles Ecology Evolution Behavior and Systematics media_common Depth Perception Natural selection Base Sequence Geography biology Adaptation Ocular Pigmentation Ecology Environmental heterogeneity Color vision Cichlids biology.organism_classification Lakes Speciation 030104 developmental biology Habitat sense organs Adaptation Research Article |
| Zdroj: | BMC Evolutionary Biology |
| ISSN: | 1471-2148 |
| Popis: | Background For Lake Victoria cichlid species inhabiting rocky substrates with differing light regimes, it has been proposed that adaptation of the long-wavelength-sensitive (LWS) opsin gene triggered speciation by sensory drive through color signal divergence. The extensive and continuous sand/mud substrates are also species-rich, and a correlation between male nuptial coloration and the absorption of LWS pigments has been reported. However, the factors driving genetic and functional diversity of LWS pigments in sand/mud habitats are still unresolved. Results To address this issue, nucleotide sequences of eight opsin genes were compared in ten Lake Victoria cichlid species collected from sand/mud bottoms. Among eight opsins, the LWS and rod-opsin (RH1) alleles were diversified and one particular allele was dominant or fixed in each species. Natural selection has acted on and fixed LWS alleles in each species. The functions of LWS and RH1 alleles were measured by absorption of reconstituted A1- and A2-derived visual pigments. The absorption of pigments from RH1 alleles most common in deep water were largely shifted toward red, whereas those of LWS alleles were largely shifted toward blue in both A1 and A2 pigments. In both RH1 and LWS pigments, A2-derived pigments were closer to the dominant light in deep water, suggesting the possibility of the adaptation of A2-derived pigments to depth-dependent light regimes. Conclusions The RH1 and LWS sequences may be diversified for adaptation of A2-derived pigments to different light environments in sand/mud substrates. Diversification of the LWS alleles may have originally taken place in riverine environments, with a new mutation occurring subsequently in Lake Victoria. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-1040-x) contains supplementary material, which is available to authorized users. |
| Databáze: | OpenAIRE |
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