More Like this

1. Light environment drives evolution of color vision genes in butter!ies and moths

   https://doi.org/https://doi.org/10.1038/s42003-021-01688-z  

   Sondhi, Y.; Ellis, E.A.; Bybee, S.M.; Theobald, J.C.; Kawahara, A.Y. (February 2021, Communications biology)

   null (Ed.)

   Opsins, combined with a chromophore, are the primary light-sensing molecules in animals and are crucial for color vision. Throughout animal evolution, duplications and losses of opsin proteins are common, but it is unclear what is driving these gains and losses. Light availability is implicated, and dim environments are often associated with low opsin diversity and loss. Correlations between high opsin diversity and bright environments, however, are tenuous. To test if increased light availability is associated with opsin diversi"cation, we examined diel niche and identi"ed opsins using transcriptomes and genomes of 175 butter!ies and moths (Lepidoptera). We found 14 independent opsin duplications associated with bright environ- ments. Estimating their rates of evolution revealed that opsins from diurnal taxa evolve faster —at least 13 amino acids were identi"ed with higher dN/dS rates, with a subset close enough to the chromophore to tune the opsin. These results demonstrate that high light availability increases opsin diversity and evolution rate in Lepidoptera. 

   more » « less
2. Evolution of Opsin Genes in Caddisflies (Insecta: Trichoptera)

   https://doi.org/10.1093/gbe/evae185  

   Powell, Ashlyn; Heckenhauer, Jacqueline; Pauls, Steffen U; Ríos-Touma, Blanca; Kuranishi, Ryoichi B; Holzenthal, Ralph W; Razuri-Gonzales, Ernesto; Bybee, Seth; Frandsen, Paul B (September 2024, Genome Biology and Evolution)

   Wheat, Christopher (Ed.)

   Abstract Insects have evolved complex and diverse visual systems in which light-sensing protein molecules called “opsins” couple with a chromophore to form photopigments. Insect photopigments group into three major gene families based on wavelength sensitivity: long wavelength (LW), short wavelength (SW), and ultraviolet wavelength (UV). In this study, we identified 123 opsin sequences from whole-genome assemblies across 25 caddisfly species (Insecta: Trichoptera). We discovered the LW opsins have the most diversity across species and form two separate clades in the opsin gene tree. Conversely, we observed a loss of the SW opsin in half of the trichopteran species in this study, which might be associated with the fact that caddisflies are active during low-light conditions. Lastly, we found a single copy of the UV opsin in all the species in this study, with one exception: Athripsodes cinereus has two copies of the UV opsin and resides within a clade of caddisflies with colorful wing patterns. 

   more » « less
3. Vision using multiple distinct rod opsins in deep-sea fishes

   https://doi.org/10.1126/science.aav4632  

   Musilova, Zuzana; Cortesi, Fabio; Matschiner, Michael; Davies, Wayne I.; Patel, Jagdish S.; Stieb, Sara M.; Busserolles, Fanny; Malmstrom, Martin; Torresen, Ole K.; Brown, Celeste J.; et al (May 2019, Science magazine)

   Vertebrate vision is accomplished through light-sensitive photopigments consisting of an opsin protein bound to a chromophore. In dim light, vertebrates generally rely on a single rod opsin [rhodopsin 1 (RH1)] for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their RH1 gene repertoires. Among these, the silver spinyfin (Diretmus argenteus) stands out as having the highest number of visual opsins in vertebrates (two cone opsins and 38 rod opsins). Spinyfins express up to 14 RH1s (including the most blueshifted rod photopigments known), which cover the range of the residual daylight as well as the bioluminescence spectrum present in the deep sea. Our findings present molecular and functional evidence for the recurrent evolution of multiple rod opsin–based vision in vertebrates. 

   more » « less
4. Crustacean conundrums: a review of opsin diversity and evolution

   https://doi.org/10.1098/rstb.2021.0289  

   Palecanda, Sitara; Iwanicki, Thomas; Steck, Mireille; Porter, Megan L. (October 2022, Philosophical Transactions of the Royal Society B: Biological Sciences)

   Knowledge of crustacean vision is lacking compared to the more well-studied vertebrates and insects. While crustacean visual systems are typically conserved morphologically, the molecular components (i.e. opsins) remain understudied. This review aims to characterize opsin diversity across crustacean lineages for an integrated view of visual system evolution. Using publicly available data from 95 species, we identified opsin sequences and classified them by clade. Our analysis produced 485 putative visual opsins and 141 non-visual opsins. The visual opsins were separated into six clades: long wavelength sensitive (LWS), middle wavelength sensitive (MWS) 1 and 2, short wavelength or ultraviolet sensitive (SWS/UVS) and a clade of thecostracan opsins, with multiple LWS and MWS opsin copies observed. The SWS/UVS opsins were relatively conserved in most species. The crustacean classes Cephalocarida, Remipedia and Hexanauplia exhibited reduced visual opsin diversity compared to others, with the malacostracan decapods having the highest opsin diversity. Non-visual opsins were identified from all investigated classes except Cephalocarida. Additionally, a novel clade of non-visual crustacean-specific, R-type opsins (Rc) was discovered. This review aims to provide a framework for future research on crustacean vision, with an emphasis on the need for more work in spectral characterization and molecular analysis. This article is part of the theme issue ‘Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods’. 

   more » « less
5. Evolution of Phototransduction Genes in Lepidoptera

   https://doi.org/10.1093/gbe/evz150  

   Macias-Muñoz, Aide; Rangel Olguin, Aline G; Briscoe, Adriana D (August 2019, Genome Biology and Evolution)

   Abstract Vision is underpinned by phototransduction, a signaling cascade that converts light energy into an electrical signal. Among insects, phototransduction is best understood in Drosophila melanogaster. Comparison of D. melanogaster against three insect species found several phototransduction gene gains and losses, however, lepidopterans were not examined. Diurnal butterflies and nocturnal moths occupy different light environments and have distinct eye morphologies, which might impact the expression of their phototransduction genes. Here we investigated: 1) how phototransduction genes vary in gene gain or loss between D. melanogaster and Lepidoptera, and 2) variations in phototransduction genes between moths and butterflies. To test our prediction of phototransduction differences due to distinct visual ecologies, we used insect reference genomes, phylogenetics, and moth and butterfly head RNA-Seq and transcriptome data. As expected, most phototransduction genes were conserved between D. melanogaster and Lepidoptera, with some exceptions. Notably, we found two lepidopteran opsins lacking a D. melanogaster ortholog. Using antibodies we found that one of these opsins, a candidate retinochrome, which we refer to as unclassified opsin (UnRh), is expressed in the crystalline cone cells and the pigment cells of the butterfly, Heliconius melpomene. Our results also show that butterflies express similar amounts of trp and trpl channel mRNAs, whereas moths express ∼50× less trp, a potential adaptation to darkness. Our findings suggest that while many single-copy D. melanogaster phototransduction genes are conserved in lepidopterans, phototransduction gene expression differences exist between moths and butterflies that may be linked to their visual light environment. 

   more » « less