scholarly journals LOSS OF BOTH SHORT WAVELENGTH CONE OPSIN GENES IN REPRESENTATIVES OF THE NOCTURNALLY-ACTIVE GYMNOTIFORM WEAKLY ELECTRIC FISHES AND THEIR SISTER GROUP, THE CATFISHES.

2012 ◽  
Vol 6 ◽  
Author(s):  
Samanta Manoj
Keyword(s):  
Short Wavelength ◽  
Sister Group ◽  
Cone Opsin ◽  
Opsin Genes ◽  
Electric Fishes ◽  
Weakly Electric

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.

scholarly journals Convergent mosaic brain evolution is associated with the evolution of novel electrosensory systems in teleost fishes

2021 ◽  
Author(s):  
Erika L. Schumacher ◽  
Bruce A. Carlson
Keyword(s):  
Brain Region ◽  
Brain Size ◽  
Brain Evolution ◽  
Brain Regions ◽  
Torus Semicircularis ◽  
Micro Computed Tomography ◽  
Electrosensory System ◽  
Electric Fishes ◽  
Weakly Electric ◽  
Region Size

AbstractBrain region size generally scales allometrically with total brain size, but mosaic shifts in brain region size independent of brain size have been found in several lineages and may be related to the evolution of behavioral novelty. African weakly electric fishes (Mormyroidea) evolved a mosaically enlarged cerebellum and hindbrain, yet the relationship to their behaviorally novel electrosensory system remains unclear. We addressed this by studying South American weakly electric fishes (Gymnotiformes) and weakly electric catfishes (Synodontis spp.), which evolved varying aspects of electrosensory systems, independent of mormyroids. If the mormyroid mosaic increases are related to evolving an electrosensory system, we should find similar mosaic shifts in gymnotiforms and Synodontis. Using micro-computed tomography scans, we quantified brain region scaling for multiple electrogenic, electroreceptive, and non-electrosensing species. We found mosaic increases in cerebellum in all three electrogenic lineages relative to non-electric lineages and mosaic increases in torus semicircularis and hindbrain associated with the evolution of electrogenesis and electroreceptor type. These results show that evolving novel electrosensory systems is repeatedly and independently associated with changes in the sizes of individual brain regions independent of brain size, which suggests that selection can impact structural brain composition to favor specific regions involved in novel behaviors.

A Novel Missense Mutation in Both OPN1LW and OPN1MW Cone Opsin Genes Causes X-Linked Cone Dystrophy (XLCOD5)

2011 ◽  
pp. 595-601 ◽  
Author(s):  
Jessica C. Gardner ◽  
Tom R. Webb ◽  
Naheed Kanuga ◽  
Anthony G. Robson ◽  
Graham E. Holder ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Cone Dystrophy ◽  
Cone Opsin ◽  
Opsin Genes

Three cone opsin genes and cone cell arrangement in retina of juvenile Pacific bluefin tuna Thunnus orientalis

2008 ◽  
Vol 74 (2) ◽  
pp. 314-321 ◽  
Author(s):  
Taeko MIYAZAKI ◽  
Jun KOHBARA ◽  
Kenji TAKII ◽  
Yasunori ISHIBASHI ◽  
Hidemi KUMAI
Keyword(s):  
Bluefin Tuna ◽  
Pacific Bluefin Tuna ◽  
Thunnus Orientalis ◽  
Cone Cell ◽  
Cone Opsin ◽  
Cell Arrangement ◽  
Opsin Genes

Coding of Stimuli by Ampullary Afferents in Gnathonemus petersii

2010 ◽  
Vol 104 (4) ◽  
pp. 1955-1968 ◽  
Author(s):  
J. Engelmann ◽  
S. Gertz ◽  
J. Goulet ◽  
A. Schuh ◽  
G. von der Emde
Keyword(s):  
Frequency Tuning ◽  
Low Frequency ◽  
Weakly Electric Fish ◽  
Behavioral Experiments ◽  
Low Frequencies ◽  
Similar Frequency ◽  
Linear Feature ◽  
Reconstruction Methods ◽  
Electric Fishes ◽  
Weakly Electric

Weakly electric fish use electroreception for both active and passive electrolocation and for electrocommunication. While both active and passive electrolocation systems are prominent in weakly electric Mormyriform fishes, knowledge of their passive electrolocation ability is still scarce. To better estimate the contribution of passive electric sensing to the orientation toward electric stimuli in weakly electric fishes, we investigated frequency tuning applying classical input-output characterization and stimulus reconstruction methods to reveal the encoding capabilities of ampullary receptor afferents. Ampullary receptor afferents were most sensitive (threshold: 40 μV/cm) at low frequencies (<10 Hz) and appear to be tuned to a mix of amplitude and slope of the input signals. The low-frequency tuning was corroborated by behavioral experiments, but behavioral thresholds were one order of magnitude higher. The integration of simultaneously recorded afferents of similar frequency-tuning resulted in strongly enhanced signal-to-noise ratios and increased mutual information rates but did not increase the range of frequencies detectable by the system. Theoretically the neuronal integration of input from receptors experiencing opposite polarities of a stimulus (left and right side of the fish) was shown to enhance encoding of such stimuli, including an increase of bandwidth. Covariance and coherence analysis showed that spiking of ampullary afferents is sufficiently explained by the spike-triggered average, i.e., receptors respond to a single linear feature of the stimulus. Our data support the notion of a division of labor of the active and passive electrosensory systems in weakly electric fishes based on frequency tuning. Future experiments will address the role of central convergence of ampullary input that we expect to lead to higher sensitivity and encoding power of the system.

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