Seascape genomics of eastern oyster (Crassostrea virginica) along the Atlantic coast of Canada.

Interactions between environmental factors and complex life-history characteristics of marine organisms produce the genetic diversity and structure observed within species. Our main goal was to test for genetic differentiation among eastern oyster populations from the coastal region of Canadian Maritimes against expected genetic homogeneity caused by historical events, taking into account spatial and environmental (temperature, salinity, turbidity) variation. This was achieved by genotyping 486 individuals originating from 13 locations using RADSeq. A total of 11 321 filtered SNPs were used in a combination of population genomics and environmental association analyses. We revealed significant neutral genetic differentiation (mean FST= 0.009) between sampling locations, and the occurrence of six major genetic clusters within the studied system. Redundancy analyses (RDA) revealed that spatial and environmental variables explained 3.1% and 4.9% of the neutral genetic variation and 38.6% a...