Studies of cichlid evolution have highlighted the importance visual pigment genes in spectacular radiation African rift lake cichlids. Recent work, however, has also provided strong evidence for adaptive diversification riverine cichlids Neotropics, which inhabit environments markedly different spectral properties from lakes. These ecological and/or biogeographic differences may imposed divergent selective pressures on system. To test these hypotheses, we investigated molecular dim-light...

Cichlids encompass one of the most diverse groups fishes in South and Central America, show extensive variation life history, morphology, colouration. While studies visual system evolution cichlids have focussed largely on African rift lake species flocks, Neotropical offer a unique opportunity to investigate at broader temporal geographic scales. American cichlid colonization America has likely promoted accelerated rates morphological lineages as they encountered reduced competition,...

Understanding the origins and impacts of novel traits has been a perennial interest in many realms ecology evolutionary biology. Here, we build on previous philosophical treatments this subject to encompass novelties across biological scales eco-evolutionary perspectives. By defining as new features at one scale that have emergent effects other scales, incorporate forms novelty previously treated isolation (such from genetic mutations, developmental pathways, morphological features,...

Significance Protein evolution in response to different environments has long been of interest both evolutionary biologists and biochemists. High-altitude specialist catfishes the Andes mountains offer an opportunity examine molecular adaptations accompanying adaptation cold environments. Rhodopsins other visual pigments form first step vision have a model system for studying basis sensory adaptations; however, many these studies focused solely on spectral shifts. Recent suggest that aspects...

Natural variation in the number, expression and function of sensory genes an organism's genome is often tightly linked to different ecological evolutionary forces. Opsin genes, which code for first step visual transduction, are ideal models testing how factors such as light environment may influence system adaptation. Neotropical cichlid fishes a highly ecologically diverse group that evolved variety aquatic habitats, including black (stained), white (opaque) clear waters. We used...

Retinal neurogenesis in fish facilitates cellular rearrangement throughout ontogeny, potentially allowing for optimization of the visual system to shifts habitat and behaviour. To test this possibility, we studied developmental trajectory photopic process Nile tilapia. We examined ontogenetic changes lens transmission, photoreceptor sensitivity post-receptoral sensitivity, used these estimate cone pigment frequency retinal circuitry. observed an decrease ultraviolet (UV) which resulted from...

Abstract Rhodopsin is the visual pigment responsible for initiating phototransduction cascade in vertebrate rod photoreceptors. Although well‐characterized a few model systems, comparative studies of rhodopsin function, particularly nonmammalian vertebrates are comparatively lacking. Bowerbirds rare among passerines possessing key substitution, D83N, at site that otherwise highly conserved G protein‐coupled receptors. While this substitution present some dim‐light adapted vertebrates, often...

Abstract Extreme environments, such as Antarctic habitats, present major challenges for many biological processes. icefishes (Crynotothenioidea) represent a compelling system to investigate the molecular basis of adaptation cold temperatures. Here, we explore how sub-zero habitats have impacted rhodopsin (RH1) function, temperature-sensitive dim-light visual pigment found in rod photoreceptors. Using likelihood models and ancestral reconstruction, find that accelerated evolutionary rates...

Convergent evolution in response to similar selective pressures is a well-known phenomenon evolutionary biology. Less well understood how selection drives convergence protein function, and the underlying mechanisms by which this can be achieved. Here, we investigate functional visual system of two distantly related lineages high-altitude adapted Andean Himalayan catfishes. Statistical analyses revealed lineages, parallel acceleration rates rhodopsin, dim-light pigment. However, elevated were...

Rhodopsin is the visual pigment that mediates dim‐light vision in vertebrates and a model system for study of retinal disease. The majority rhodopsin experiments are performed using bovine rhodopsin; however, recent evidence suggests significant functional differences exist among mammalian rhodopsins. In this study, we identify both thermal decay light‐activated release rates between human perform mutagenesis studies to highlight two clusters substitutions contribute these differences. We...

Polarization sensitivity (PS) in vertebrate vision is controversial, perhaps because its underlying mechanism has remained obscure. An issue that might have added to the controversy rainbow trout ( Oncorhynchus mykiss ), which served as primary model system for polarization-based orientation, lose their ability orient relative celestial polarized-light patterns when parr (fry) transform into migratory smolts (juveniles), would benefit most from orientation. Here we addressed two key...

Active electroreception-the ability to detect objects and communicate with conspecifics via the detection generation of electric organ discharges (EODs)-has evolved convergently in several fish lineages. South American fishes (Gymnotiformes) are a highly species-rich group, possibly part due evolution an (EO) that can produce diverse EODs. Neofunctionalization voltage-gated sodium channel gene accompanied electrogenic tissue from muscle resulted novel (scn4aa) uniquely expressed EO. Here, we...

Abstract Retinitis pigmentosa (RP) comprises several heritable diseases that involve photoreceptor, and ultimately retinal, degeneration. Currently, mutations in over 50 genes have known links to RP. Despite advances clinical characterization, molecular characterization of RP remains challenging due the heterogeneous nature causal genes, mutations, phenotypes. In this study, we compiled large datasets two important visual associated with RP: rhodopsin, which initiates phototransduction...

We describe a new Geophagus from the Berbice River of Guyana, bringing total number described species in genus to 19, and Guianese six.. crocatus, species, is distinguished all outside G. surinamensis group by presence an incomplete suborbital stripe (vs. complete), six lateral bars, with bars 2 3 slightly sloping toward each other fusing dorsally at base dorsal fin. crocatus only known River, it present above below Itabru Falls.

Abstract Visual signals are involved in many fitness‐related tasks and therefore essential for survival species. Aquatic organisms ideal systems to study visual evolution, as the high diversity of spectral properties aquatic environments generates great potential adaptation different light conditions. Flatfishes an economically important group, with over 800 described species distributed globally, including halibut, flounder, sole, turbot. The flatfish wide array they occupy provides...

Abstract We used mitochondrial DNA to assess the genetic structure of endangered lake chubsucker Erimyzon sucetta across its Canadian range. found unique haplotypes in Lyons Creek, a tributary Niagara River that faces strong potential for habitat deterioration. Creek may therefore serve as reservoir diversity. The sensitivity combined with uniqueness E. population, call further investigation into whether this population should be considered separate designatable unit conservation purposes.

Understanding the origins and impacts of novel traits has been a perennial interest in many realms ecology evolutionary biology. Here, we build on previous philosophical treatments subject to encompass novelties across biological scales eco-evolutionary perspectives. By defining as new features at one scale that have emergent effects other scales, incorporate forms novelty previously treated isolation (such from genetic mutations, developmental pathways, morphological features, species). Our...

A new nonlinear FM function has been applied to the design of pulse compression EMAT's used in surface wear and SAW velocity variation measurements. The experimentally obtained compressed mainto-sidelobe ratio is 19 dB. Furthermore, it shown that detection s urface on carbonsteel pipes, at point their support, with feasible.