Belinda Chang's Lab

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.

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.

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.

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.

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!

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.

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.

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

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