Evolution, inactivation and loss of short wavelength‐sensitive opsin genes during the diversification of Neotropical cichlids

2021 ◽  
Vol 30 (7) ◽  
pp. 1688-1703
Author(s):  
Frances E. Hauser ◽  
Katriina L. Ilves ◽  
Ryan K. Schott ◽  
Erin Alvi ◽  
Hernán López‐Fernández ◽  
...  
Keyword(s):  
Short Wavelength ◽  
Opsin Genes ◽  
Neotropical Cichlids

scholarly journals Opsin genes: research perspectives with Neotropical cichlids (Perciformes: Cichlidae) and their relevance in floodplain studies

2016 ◽  
Vol 38 (2) ◽  
pp. 241
Author(s):  
Thomaz Mansini Carrenho Fabrin ◽  
Luciano Seraphim Gasques ◽  
Sonia Maria Alves Pinto Prioli ◽  
Alberto José Prioli
Keyword(s):  
Research Perspectives ◽  
Opsin Genes ◽  
Neotropical Cichlids

Losses of functional opsin genes, short-wavelength cone photopigments, and color vision—A significant trend in the evolution of mammalian vision

2013 ◽  
Vol 30 (1-2) ◽  
pp. 39-53 ◽  
Author(s):  
GERALD H. JACOBS
Keyword(s):  
Color Vision ◽  
Short Wavelength ◽  
Mammalian Species ◽  
Gene Families ◽  
Opsin Gene ◽  
Cone Type ◽  
Opsin Genes ◽  
Single Cone ◽  
Cone Pigments ◽  
Cone Photopigments

AbstractAll mammalian cone photopigments are derived from the operation of representatives from two opsin gene families (SWS1 and LWS in marsupial and eutherian mammals; SWS2 and LWS in monotremes), a process that produces cone pigments with respective peak sensitivities in the short and middle-to-long wavelengths. With the exception of a number of primate taxa, the modal pattern for mammals is to have two types of cone photopigment, one drawn from each of the gene families. In recent years, it has been discovered that the SWS1 opsin genes of a widely divergent collection of eutherian mammals have accumulated mutational changes that render them nonfunctional. This alteration reduces the retinal complements of these species to a single cone type, thus rendering ordinary color vision impossible. At present, several dozen species from five mammalian orders have been identified as falling into this category, but the total number of mammalian species that have lost short-wavelength cones in this way is certain to be much larger, perhaps reaching as high as 10% of all species. A number of circumstances that might be used to explain this widespread cone loss can be identified. Among these, the single consistent fact is that the species so affected are nocturnal or, if they are not technically nocturnal, they at least feature retinal organizations that are typically associated with that lifestyle. At the same time, however, there are many nocturnal mammals that retain functional short-wavelength cones. Nocturnality thus appears to set the stage for loss of functional SWS1 opsin genes in mammals, but it cannot be the sole circumstance.

South American Weakly Electric Fish (Gymnotiformes) Are Long-Wavelength-Sensitive Cone Monochromats

2016 ◽  
Vol 88 (3-4) ◽  
pp. 204-212 ◽  
Author(s):  
Da-Wei Liu ◽  
Ying Lu ◽  
Hong Young Yan ◽  
Harold H. Zakon
Keyword(s):  
Short Wavelength ◽  
Electric Fish ◽  
Sister Group ◽  
Weakly Electric Fish ◽  
Opsin Gene ◽  
South American ◽  
Long Wavelength ◽  
Cone Opsin ◽  
Opsin Genes ◽  
Weakly Electric

Losses of cone opsin genes are noted in animals that are nocturnal or rely on senses other than vision. We investigated the cone opsin repertoire of night-active South American weakly electric fish. We obtained opsin gene sequences from genomic DNA of 3 gymnotiforms (Eigenmannia virescens, Sternopygus macrurus, Apteronotus albifrons) and the assembled genome of the electric eel (Electrophorus electricus). We identified genes for long-wavelength-sensitive (LWS) and medium-wavelength-sensitive cone opsins (RH2) and rod opsins (RH1). Neither of the 2 short-wavelength-sensitive cone opsin genes were found and are presumed lost. The fact that Electrophorus has a complete repertoire of extraretinal opsin genes and conservation of synteny with the zebrafish (Danio rerio) for genes flanking the 2 short-wavelength-sensitive opsin genes supports the supposition of gene loss. With microspectrophotometry and electroretinograms we observed absorption spectra consistent with RH1 and LWS but not RH2 opsins in the retinal photoreceptors of E. virescens. This profile of opsin genes and their retinal expression is identical to the gymnotiform's sister group, the catfish, which are also nocturnally active and bear ampullary electroreceptors, suggesting that this pattern likely occurred in the common ancestor of gymnotiforms and catfish. Finally, we noted an unusual N-terminal motif lacking a conserved glycosylation consensus site in the RH2 opsin of gymnotiforms, a catfish and a characin (Astyanax mexicanus). Mutations at this site influence rhodopsin trafficking in mammalian photoreceptors and cause retinitis pigmentosa. We speculate that this unusual N terminus may be related to the absence of the RH2 opsin in the cones of gymnotiforms and catfish.

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