COS 77-1 - Identifying the genetic basis for tolerance to an emerging conservation threat

Thursday, August 15, 2019: 8:00 AM
L004, Kentucky International Convention Center
Avril M. Harder1, William Ardren2 and Mark R. Christie1,3, (1)Department of Biological Sciences, Purdue University, West Lafayette, IN, (2)Western New England Complex, U.S. Fish and Wildlife Service, Essex Junction, VT, (3)Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
Background/Question/Methods

Disruptions in vitamin-producing communities within an ecosystem can lead to altered vitamin availabilities at higher trophic levels. Across the Northern Hemisphere, evidence is mounting that populations of many taxa, including birds, fishes, and bivalves, are deficient in thiamine (vitamin B1). Thiamine is an essential vitamin that is required for metabolism, energy production, and proper neurological function and development. Because of thiamine’s central roles in these processes, thiamine deficiency can impair an individual’s capacity to forage, avoid predation, and reproduce. While the root causes of thiamine deficiency may vary among systems, one possible outcome is reduced population viability. Some research suggests that fish populations with diets low in thiamine may have genetically adapted to low thiamine availability, reducing the probability of demographic loss in response to thiamine deficiency. We evaluated the potential for such an adaptive response in a thiamine-deficient population of Atlantic salmon (Salmo salar). We generated 9 distinct families and treated half of the eggs in each family with thiamine, leaving the remaining half untreated. We identified differentially expressed genes between the treated and untreated groups across all 9 families and combined these results with survival analyses to describe how patterns of expression vary with patterns in survivorship.

Results/Conclusions

We identified 3,616 differentially expressed genes (DEGs) between thiamine treated and untreated individuals, and the top DEGs were related to neurological function and development, metabolic processes and energy production, and behavior. Examining gene expression patterns across families that were ranked according to survivorship revealed two main categories of DEGs: i) genes constitutively expressed across families with expression magnitude shifted according to treatment and ii) genes adaptively expressed across families with higher family survivorship corresponding to higher similarity in treated and untreated individual expression profiles. Together, the results of transcriptomic and survival analyses suggest a genetic basis for differences in among-family survivorship in response to thiamine deficiency. We will discuss how these findings relate to populations’ capacities to genetically adapt to conditions of low thiamine availability and the conservation implications of a heritable basis for thiamine acquisition.