The molecular basis of electroreception across diverse organisms

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The goals for my research program are to determine the mechanisms by which unique organisms detect low amplitude sensory signals to guide fundamental behaviours and to train HQP from diverse backgrounds. One of the most remarkable examples of convergent evolution among vertebrates is illustrated in the multiple independent origins of the electric senses. These include the capacity to passively detect weak electric fields as noted in marine elasmobranchs and amphibians. Furthermore, S. American and African weakly electric fishes independently evolved complex active electroreception for navigation, object localization, and communication via the generation and reception of weak electric fields. Despite decades of behavioural and neuroanatomical studies, the molecular mechanisms by which these animal detect electric fields have remained unknown. Recently, my work has established the first mechanistic foothold into understanding how the detection of electric fields is initiated, showing that specific isoforms of voltage-gated calciums channels and functionally coupled potassium channels are critical to initiating electroreception in two distantly related elasmobranchs Yet, among the multitude of other electroreceptive vertebrates, which are acutely tuned to diverse electric signals, how they detect important electric signals remains unanswered. Is there a common convergent mechanism or have diverse species co-opted specific signalling mechanisms among the multiple independent origins of electroreception? Rapidly changing technologies now allow me to ask these questions with an unparalleled level of precision and specificity. There are three primary objectives for this Discovery Grant. These research will focus on sturgeon - members of the primitive Chondrostei fish with an elaborate passive electrosensory system - and weakly electric S. American knife fish (Gymnotiformes) and African elephant fish (Mormyroidea) which independently evolved high frequency weakly electric systems. These studies will use species from both sexes as there is sexual dimorphism in active electric signals. Objective 1 is to determine the suite of genes expressed within specific electrosensory receptors, via single cell transcriptomics, and will be performed by one MSc student. Objective 2 is to determine the electrical response properties of electrosensory cells using patch clamp electrophysiology on native cells and heterologous systems and is to be performed by two PhD students. Objective 3 is to determine the molecular contributions to electric field detection through pharmacological manipulation of electrosensory cells combined with novel, quantitative behavioural analyses and will be performed by one MSc student. In sum, these experiments will identify molecular mechanisms of electroreception at genetic, cellular, and behavioural dimensions in the context of its phenotypic diversity.