Genomics of migration : from marine distributions of salmonids to mechanisms of\ud olfactory and magnetic cue perception for natal homing

Graduation date: 2015Access restricted to the OSU Community, at author's request, from Dec. 15, 2014 - Dec. 15, 2016Substantial scientific investment has been directed towards understanding\ud factors that influence distribution patterns and animals' remarkable ability for precise\ud orientation and navigation, yet fundamental gaps in our knowledge remain. In my\ud dissertation, I applied emerging genetic technologies to conduct a top-down and\ud bottom-up investigation of animal movement and cue perception. First, in partnership\ud with Project CROOS and the California Salmon Genetic Stock Identification project,\ud stock-specific, marine migratory distributions of Chinook salmon (Oncorhynchus\ud tshawytscha) were characterized for five consecutive months (2010) over 1000 km of\ud coastline. A statistical model was developed to provide measures of relative stockspecific\ud abundance, insights into broad factors that influence migratory distribution,\ud and for fisheries management applications. For the second component of my\ud dissertation, I studied specialized olfactory cells of salmonids that are proposed to\ud contain nanometer-sized magnetite crystals that interact with earth strength magnetic\ud fields to transduce them into neural signals. The transcriptome profiles of candidate\ud magnetoreceptor and non-magnetic cells isolated from olfactory rosette tissue, whole\ud olfactory rosettes, and blood and muscle tissue were characterized from ~661 million\ud Illumina RNA-seq reads. A total of 1,006 differentially expressed genes were\ud identified in the magnetic cell sample type. Results, consistent with having identified\ud genes involved in magnetite crystal formation in fish, were used to develop a genetic\ud model of magnetic sensory perception. Finally, to provide insights into olfaction-based\ud homing that takes place in freshwater, the olfactory repertoire of salmonids was\ud inferred from the Rainbow trout (O. mykiss) genome and compared to that of 15 other\ud teleosts and the jawless fish, sea lamprey (Petromyzon marinus), an ancient species.\ud The abundance and diversity of trace amine-associated and V2R-like genes suggests\ud that these classes of chemoreceptors have biological importance. These findings have\ud relevance for resolving if salmon and other marine organisms imprint on magnetic\ud fields, and contribute to our understanding of how magnetic sense, olfaction, and\ud genetic programming are involved in migratory distributions