Whales Evolved Swiftly to Become Deep Divers

Awesome news article from the CSB department at UofT highlighting a recent PNAS paper from the Chang lab, featuring the work of former PhD student Sarah Dungan!

Many cetacean species can dive to extraordinary depths on a single breath, but the evolutionary origins of deep-sea foraging in ancestral cetaceans remain unclear. In their publication, they present a resurrected ancestral cetacean visual protein (rhodopsin).

Their findings suggest that ancient whales were active at mesopelagic depths and had evolved a faster dark adaptation rate, a trait that allows diving mammals to rapidly adjust to dimming light. Their results also indicate that the ancestor of modern cetaceans was a deeper diver.

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This Fish Has Adapted to Canada’s Deepest Coldest Lakes. UTSC Researchers are Unravelling it’s Genetics to Find Out How.

Great article from UTSC covering the incredible work Alex Van Nynatten, a postdoc in the Lovejoy lab, has been doing with the Deepwater Sculpin in collaboration with the Chang lab! This fish is quite impressive as they are known to live almost exclusively in lakes with temperatures below 8 °C, and at depths greater than 35 metres.

The entire genome of this fascinating species is currently being sequenced to see how this otherwise unassuming fish has adapted to such harsh conditions. Alex has special interest in in studying the fish’s vision genes and their adaptations to this cold and dark environment.

Alex Van Nynatten, a postdoc in the Lovejoy lab.
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Convergent patterns of evolution of mitochondrial oxidative phosphorylation (OXPHOS) genes in electric fishes

The ability to generate and detect electric fields is vital for the survival of several groups of fishes. Authors Ahmed A. Elbassiouny, Nathan R. Lovejoy and Belinda S.W. Chang speculated that electric fish may be able to meet the high metabolic demands of bioelectrogenesis, as a result of the adaptive evolution of genes encoding for the mitochondrial OXPHOS cellular machinery. Evidence for this was found in two independently derived clades of weakly electric fishes, South American Gymnotiformes and African Mormyroidea.

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Screening of Chemical Libraries Using a Yeast Model of Retinal Disease

Pathogenic mutations cause rhodopsin to misfold and disrupt its function. In this study, a yeast-based assay was used to screen for compounds that have the potential to rescue the function of mutant rhodopsin. It was confirmed that 9-cis retinal could partially rescue light-dependent activation of disease-associated rhodopsin mutation (P23H). A phenotypic screen was also done with yeast assays to screen compounds from the LOPAC1280 library and a peptidomimetic library.

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Evolutionary signatures of photoreceptor transmutation in geckos reveal potential adaptation and convergence with snakes

A recent study by Ryan K. Schott, Nihar Bhattacharyya, and Belinda S.W. Chang analysed the patterns of evolution in the gecko phototransduction gene and compared them to those of other reptiles. Parallel shifts in selective constraint on phototransduction genes were found in geckos and snakes.

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To see or not to see: molecular evolution of the rhodopsin visual pigment in neotropical electric fishes

What do visual disease in humans and dim-light adaptation in fishes have in common? Read our publication on Proceedings of the Royal Society B, and find out more!

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Coupling of human rhodopsin to a yeast signaling pathway

In this new assay, light dependent activation of the human rhodopsin protein initiates the yeast mating pathway and results in the signaling of a fluorescent reporter. This innovative technique allowed the authors to characterize a panel of known rhodopsin mutations and to explore the molecular mechanisms that lead to their to pathogenicity.

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Functional trade-offs and environmental variation shaped ancient trajectories in the evolution of dim-light vision

How did epistasis affect the evolution of tetrapod dim-light vision? How does this compare with fishes? Find out more by reading our lab’s recent paper published in eLIFE.

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Bat cone opsin evolution

How is bat color vision shaped by ecological factors? Check out our new paper in Proc B!

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Convergence in the visual system at high altitudes

Can convergence in evolutionary rates predict convergence in protein function? Check out our new paper in Evolution!

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