Opsin genes of select treeshrews resolve ancestral character states within Scandentia

Treeshrews are small, squirrel-like mammals in the order Scandentia, which is nested together with Primates and Dermoptera in the superordinal group Euarchonta. They are often described as living fossils, and researchers have long turned to treeshrews as a model or ecological analogue for ancestral primates. A comparative study of colour vision-encoding genes within Scandentia found a derived amino acid substitution in the long-wavelength sensitive opsin gene ( OPN1LW ) of the Bornean smooth-tailed treeshrew ( Dendrogale melanura ). The opsin, by inference, is red-shifted by ca 6 nm with an inferred peak sensitivity of 561 nm. It is tempting to view this trait as a novel visual adaptation; however, the genetic and functional diversity of visual pigments in treeshrews is unresolved outside of Borneo. Here, we report gene sequences from the northern smooth-tailed treeshrew ( Dendrogale murina ) and the Mindanao treeshrew ( Tupaia everetti , the senior synonym of Urogale everetti ). We found that the opsin genes are under purifying selection and that D. murina shares the same substitution as its congener, a result that distinguishes Dendrogale from other treeshrews, including T. everetti. We discuss the implications of opsin functional variation in light of limited knowledge about the visual ecology of smooth-tailed treeshrews.

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Functional preservation and variation in the cone opsin genes of nocturnal tarsiers

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2016.0075 ◽

2017 ◽

Vol 372 (1717) ◽

pp. 20160075 ◽

Cited By ~ 9

Author(s):

Gillian L. Moritz ◽

Perry S. Ong ◽

George H. Perry ◽

Nathaniel J. Dominy

Keyword(s):

Colour Vision ◽

Purifying Selection ◽

Opsin Gene ◽

Long Wavelength ◽

Cone Opsin ◽

Light Levels ◽

Tarsius Bancanus ◽

Dim Light ◽

Two Stages ◽

Functional Preservation

The short-wavelength sensitive (S-) opsin gene OPN1SW is pseudogenized in some nocturnal primates and retained in others, enabling dichromatic colour vision. Debate on the functional significance of this variation has focused on dark conditions, yet many nocturnal species initiate activity under dim (mesopic) light levels that can support colour vision. Tarsiers are nocturnal, twilight-active primates and exemplary visual predators; they also express different colour vision phenotypes, raising the possibility of discrete adaptations to mesopic conditions. To explore this premise, we conducted a field study in two stages. First, to estimate the level of functional constraint on colour vision, we sequenced OPN1SW in 12 wild-caught Philippine tarsiers ( Tarsius syrichta ). Second, to explore whether the dichromatic visual systems of Philippine and Bornean ( Tarsius bancanus ) tarsiers—which express alternate versions of the medium/long-wavelength sensitive (M/L-) opsin gene OPN1MW / OPN1LW —confer differential advantages specific to their respective habitats, we used twilight and moonlight conditions to model the visual contrasts of invertebrate prey. We detected a signature of purifying selection for OPN1SW , indicating that colour vision confers an adaptive advantage to tarsiers. However, this advantage extends to a relatively small proportion of prey–background contrasts, and mostly brown arthropod prey amid leaf litter. We also found that the colour vision of T. bancanus is advantageous for discriminating prey under twilight that is enriched in shorter (bluer) wavelengths, a plausible idiosyncrasy of understorey habitats in Borneo. This article is part of the themed issue ‘Vision in dim light’.

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The evolution of opsin genes in five species of mirid bugs: duplication of long-wavelength opsins and loss of blue-sensitive opsins

BMC Ecology and Evolution ◽

10.1186/s12862-021-01799-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Pengjun Xu ◽

Bin Lu ◽

Jiangtao Chao ◽

Robert Holdbrook ◽

Gemei Liang ◽

...

Keyword(s):

Light Trapping ◽

Phylogenetic Analyses ◽

Management Strategies ◽

Purifying Selection ◽

Color Discrimination ◽

Duplication Event ◽

Economic Losses ◽

Long Wavelength ◽

Phototactic Behavior ◽

Opsin Genes

AbstractBackgroundColor vision and phototactic behavior based on opsins are important for the fitness of insects because of their roles in foraging and mate choice. Related topics, including the duplication and loss of opsin genes, have been well investigated in insect orders such as Coleoptera, Lepidoptera, Hymenoptera, Odonata and Orthoptera, and the findings have been used to develop pest management strategies involving light trapping. Mirid bugs of Hemiptera, which are pests that cause heavy economic losses, show capacity for color discrimination and phototaxis. However, the opsins in mirid bugs remain uncharacterized. Herein, we examined five species to investigate the evolution of opsins in the family Miridae.ResultsUsing RNA-seq, we identified several contigs showing high identity with opsins, including four contigs inApolygus lucorumand three contigs each inAdelphocoris suturalis,Adelphocoris fasciaticollis,Adelphocoris lineolatusandNesidiocoris tenuis. Phylogenetic analyses indicated that one of these genes clustered with ultraviolet-sensitive (UV) opsins and that the others clustered with long-wavelength (LW) opsins, suggesting that duplication of LW opsins and loss of blue light-sensitive (B) opsins occurred in mirid bugs. The existence of introns in the LW opsins of mirid bugs suggested that the duplication events were DNA based. Both LW1 and LW2 opsins of mirid bugs were found to be under strong purifying selection. The LW1 opsins were significantly more highly expressed than the LW2 and UV opsins.ConclusionsWe identified the opsins of mirid bugs using five selected mirid species as a representative sample. Phylogenetic analyses clustered one of the genes with UV opsins and the others with LW opsins, suggesting the occurrence of LW opsin duplication and B opsin loss during the evolution of mirid bugs. Intron detection suggested that the identified duplication event was DNA based. The evidence of strong purifying selection and the relatively high expression levels suggested that these opsins exhibit fundamental functions in mirid bugs.

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

Brain Behavior and Evolution ◽

10.1159/000450746 ◽

2016 ◽

Vol 88 (3-4) ◽

pp. 204-212 ◽

Cited By ~ 6

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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Evidence for UV-green dichromacy in the basal hymenopteran Sirex noctilio (Siricidae)

Scientific Reports ◽

10.1038/s41598-021-95107-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Quentin Guignard ◽

Johannes Spaethe ◽

Bernard Slippers ◽

Martin Strube-Bloss ◽

Jeremy D. Allison

Keyword(s):

Colour Vision ◽

Compound Eye ◽

Phylogenetic Analyses ◽

Ultra Violet ◽

Opsin Gene ◽

Compound Eyes ◽

Sirex Noctilio ◽

Long Wavelength ◽

Opsin Genes ◽

Related Group

AbstractA precondition for colour vision is the presence of at least two spectral types of photoreceptors in the eye. The order Hymenoptera is traditionally divided into the Apocrita (ants, bees, wasps) and the Symphyta (sawflies, woodwasps, horntails). Most apocritan species possess three different photoreceptor types. In contrast, physiological studies in the Symphyta have reported one to four photoreceptor types. To better understand the evolution of photoreceptor diversity in the Hymenoptera, we studied the Symphyta Sirex noctilio, which belongs to the superfamily Siricoidea, a closely related group of the Apocrita suborder. Our aim was to (i) identify the photoreceptor types of the compound eye by electroretinography (ERG), (ii) characterise the visual opsin genes of S. noctilio by genomic comparisons and phylogenetic analyses and (iii) analyse opsin mRNA expression. ERG measurements revealed two photoreceptor types in the compound eye, maximally sensitive to 527 and 364 nm. In addition, we identified three opsins in the genome, homologous to the hymenopteran green or long-wavelength sensitive (LW) LW1, LW2 and ultra-violet sensitive (UV) opsin genes. The LW1 and UV opsins were found to be expressed in the compound eyes, and LW2 and UV opsins in the ocelli. The lack of a blue or short-wavelength sensitive (SW) homologous opsin gene and a corresponding receptor suggests that S. noctilio is a UV-green dichromate.

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Positive selection of the long-wavelength opsin gene in South American cichlid fishes

Hydrobiologia ◽

10.1007/s10750-021-04611-z ◽

2021 ◽

Author(s):

Thomaz Mansini Carrenho Fabrin ◽

Luciano Seraphim Gasques ◽

Rodrigo Junio da Graça ◽

Sônia Maria Alves Pinto Prioli ◽

Weferson Júnio da Graça ◽

...

Keyword(s):

Positive Selection ◽

Opsin Gene ◽

South American ◽

Long Wavelength ◽

Cichlid Fishes ◽

Selection Of

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The Visual Opsin Gene Repertoires of Teleost Fishes: Evolution, Ecology, and Function

Annual Review of Cell and Developmental Biology ◽

10.1146/annurev-cellbio-120219-024915 ◽

2021 ◽

Vol 37 (1) ◽

Author(s):

Zuzana Musilova ◽

Walter Salzburger ◽

Fabio Cortesi

Keyword(s):

Sensory System ◽

Photoreceptor Cells ◽

Opsin Gene ◽

Annual Review ◽

Specific Gene ◽

Publication Date ◽

Teleost Fishes ◽

Opsin Genes ◽

The Rich ◽

Species Specific

Visual opsin genes expressed in the rod and cone photoreceptor cells of the retina are core components of the visual sensory system of vertebrates. Here, we provide an overview of the dynamic evolution of visual opsin genes in the most species-rich group of vertebrates, teleost fishes. The examination of the rich genomic resources now available for this group reveals that fish genomes contain more copies of visual opsin genes than are present in the genomes of amphibians, reptiles, birds, and mammals. The expansion of opsin genes in fishes is due primarily to a combination of ancestral and lineage-specific gene duplications. Following their duplication, the visual opsin genes of fishes repeatedly diversified at the same key spectral-tuning sites, generating arrays of visual pigments sensitive from the ultraviolet to the red spectrum of the light. Species-specific opsin gene repertoires correlate strongly with underwater light habitats, ecology, and color-based sexual selection. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Identification and Expression Patterns of Opsin Genes in a Forest Insect, Dendrolimus punctatus

Insects ◽

10.3390/insects11020116 ◽

2020 ◽

Vol 11 (2) ◽

pp. 116

Author(s):

Sufang Zhang ◽

Xiangbo Kong ◽

Fu Liu ◽

Zhen Zhang

Keyword(s):

Adult Stage ◽

Vision System ◽

Expression Patterns ◽

Coniferous Forest ◽

Light Response ◽

Insect Vision ◽

Long Wavelength ◽

Development Stages ◽

Opsin Genes ◽

Survival And Reproduction

Dendrolimus punctatus walker (Lepidoptera: Lasiocampidae) is the most serious coniferous forest defoliator in China. This species has long life history, and shows different activity rhythms and light response behaviors at larval and adult stages. Insect vision system play important roles for survival and reproduction, and disturbance of photoreception may help us to control this pest. However, we know little about the visual system of D. punctatus. As opsins are the most important genes determining photoreceptor sensitivity of insects, we identified opsins of D. punctatus and analyzed their expression patterns at different development stages in this study. Four opsin genes were identified based on our transcriptome data. Phylogenetic analysis showed that there are three classical ultraviolet (UV), blue, and long-wavelength (LW) light sensitive opsin genes, and another UV-like opsin as homolog of a circadian photoreceptor, Rh7, in Drosophila melanogaster and other insects. Expression analysis indicated that the UV and UV-like opsins expression levels only fluctuated slightly during whole life stages of D. punctatus, while Blue and LW opsins were up-regulated many times at adult stage. Interestingly, the ratio of UV-opsin was much higher in eggs and larvae stages, and lower in pupa and adult stages; reversely, LW-opsin showed extremely high relative ratio in pupa and adult stages. High expression level of LW opsin in the adult stage may correlate to the nocturnal lifestyles of this species at adult stage, and different ratios of UV and LW opsins in larval and adult stages may help to explain the different visual ecologies of these two development stages of D. punctatus. This work is the foundation for further research of opsin functions and vision mechanisms of D. punctatus.

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Longitudinal evaluation of expression of virally delivered transgenes in gerbil cone photoreceptors

Visual Neuroscience ◽

10.1017/s0952523808080577 ◽

2008 ◽

Vol 25 (3) ◽

pp. 273-282 ◽

Cited By ~ 5

Author(s):

MATTHEW C. MAUCK ◽

KATHERINE MANCUSO ◽

JAMES A. KUCHENBECKER ◽

THOMAS B. CONNOR ◽

WILLIAM W. HAUSWIRTH ◽

...

Keyword(s):

Fluorescent Protein ◽

Imaging System ◽

Regulatory Elements ◽

Meriones Unguiculatus ◽

Opsin Gene ◽

Post Injection ◽

Cone Photoreceptors ◽

Long Wavelength ◽

Green Fluorescent

Delivery of foreign opsin genes to cone photoreceptors using recombinant adeno-associated virus (rAAV) is a potential tool for studying the basic mechanisms underlying cone based vision and for treating vision disorders. We used an in vivo retinal imaging system to monitor, over time, expression of virally-delivered genes targeted to cone photoreceptors in the Mongolian gerbil (Meriones unguiculatus). Gerbils have a well-developed photopic visual system, with 11–14% of their photoreceptors being cones. We used replication deficient serotype 5 rAAV to deliver a gene for green fluorescent protein (GFP). In an effort to direct expression of the gene specifically to either S or M cones, the transgene was under the control of either the human X-chromosome opsin gene regulatory elements, i.e., an enhancer termed the locus control region (LCR) and L promoter, or the human S-opsin promoter. Longitudinal fluorescence images reveal that gene expression is first detectable about 14 days post-injection, reaches a peak after about 3 months, and is observed more than a year post-injection if the initial viral concentration is sufficiently high. The regulatory elements are able to direct expression to a subpopulation of cones while excluding expression in rods and non-photoreceptor retinal cells. When the same viral constructs are used to deliver a human long-wavelength opsin gene to gerbil cones, stimulation of the introduced human photopigment with long-wavelength light produces robust cone responses.

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Opsin gene repertoires in northern archaic hominids

Genome ◽

10.1139/gen-2015-0164 ◽

2016 ◽

Vol 59 (8) ◽

pp. 541-549 ◽

Cited By ~ 1

Author(s):

John S. Taylor ◽

Thomas E. Reimchen

Keyword(s):

Colour Vision ◽

Modern Human ◽

Active Species ◽

Opsin Gene ◽

Human Reference Genome ◽

Northern Latitudes ◽

Opsin Genes ◽

Northern Distribution ◽

Dim Light ◽

Additional Support

The Neanderthals’ northern distribution, hunting techniques, and orbit breadths suggest that they were more active in dim light than modern humans. We surveyed visual opsin genes from four Neanderthals and two other archaic hominids to see if they provided additional support for this hypothesis. This analysis was motivated by the observation that alleles responsible for anomalous trichromacy in humans are more common in northern latitudes, by data suggesting that these variants might enhance vision in mesopic conditions, and by the observation that dim light active species often have fewer opsin genes than diurnal relatives. We also looked for evidence of convergent amino acid substitutions in Neanderthal opsins and orthologs from crepuscular or nocturnal species. The Altai Neanderthal, the Denisovan, and the Ust’-Ishim early modern human had opsin genes that encoded proteins identical to orthologs in the human reference genome. Opsins from the Vindija Cave Neanderthals (three females) had many nonsynonymous substitutions, including several predicted to influence colour vision (e.g., stop codons). However, the functional implications of these observations were difficult to assess, given that “control” loci, where no substitutions were expected, differed from humans to the same extent. This left unresolved the test for colour vision deficiencies in Vindija Cave Neanderthals.

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