Meeting Abstract
Heterogeneous environments like the intertidal zone vary in environmental conditions over time and space, potentially leading to high inter-individual variation in physiology within a single population. We used gene and protein expression profiling in Mytilus californianus mussels exposed to five thermal regimes (4 field and 1 common garden) to better understand how thermal stress may expose or mask inter-individual variation. At a global level, thermal stress in the form of transplanting mussels to a high-intertidal site exposed high variation in global gene expression and tended to canalize global protein expression. We then asked whether thermal stress differentially affects variation in expression of individual genes and proteins within specific biochemical networks. We analyzed both canonical (a priori) biochemical pathways and highly interconnected clusters (i.e., empirical or de novo “pathways”) generated from network co-expression analyses. We found 22 genes in six biochemical pathways that have opposing patterns of variation in gene and protein expression across treatments, and 18 genes that have opposing patterns of variation among treatments (for example, only high variation in ambient conditions). Using a dimension reduction analyses, we found expression was most canalized in common garden conditions across biochemical and empirical pathways. Taken together, these analyses suggest that the complexity of interactions between genes is reduced in protein expression, and the suite of genes with increased variation under thermal stress has limited overlap between transcript and protein expression.
