Meeting Abstract

20.5  Saturday, Jan. 4 14:30  Genetic correlates of local adaptation in the globally invasive European green crab, Carcinus maenas TEPOLT, C. K.*; PALUMBI, S. R.; Hopkins Marine Station, Stanford University; Hopkins Marine Station, Stanford University carolyn.tepolt@gmail.com

The European green crab (Carcinus maenas) is a globally invasive species, with established populations across a wide range of thermal environments in both its native and invasive ranges. This demonstrated ability to survive and thrive across novel environments makes the species ideal for examining the mechanisms underpinning success in a rapidly changing climate. Previously, we have demonstrated differences in heat tolerance after common-temperature acclimation between seven diverse populations of green crabs in both the native and invasive range. This work suggested the existence of local adaptation to temperature. In this study, we use transcriptome sequencing to examine the genomic mechanisms associated with these differences. Using a panel of 10,809 nuclear SNPs generated by mRNA-Seq, we are able to distinguish significant differentiation between populations with different heat tolerances. An outlier F_ST analysis identifies 51 genes likely to be under selection between these populations. The outlier genes are significantly enriched for Gene Ontology terms associated with mitochondrial cellular components, including the mitochondrial inner membrane. We directly sequenced several candidate genes from this group in crabs tested for heat tolerance during physiological experiments, examining the relationship between genotype and phenotype on the level of the individual animal. Despite high potential gene flow, green crabs can be locally adapted to their environments, and show genetic differences at particular loci that seems to indicate the action of selection. Adaptive differences between populations are likely to include selection on energy production via nuclear-encoded mitochondrial proteins.