Gene expression plasticity evolves in response to colonization of freshwater lakes in threespine stickleback

Abstract

Phenotypic plasticity is predicted to facilitate individual survival and/or evolve in response to novel environments. Plasticity that facilitates survival should both permit colonization and act as a buffer against further evolution, with contemporary and derived forms predicted to be similarly plastic for a suite of traits. On the other hand, given the importance of plasticity in maintaining internal homeostasis, derived populations that encounter greater environmental heterogeneity should evolve greater plasticity. We tested the evolutionary significance of phenotypic plasticity in coastal British Columbian postglacial populations of threespine stickleback (Gasterosteus aculeatus) that evolved under greater seasonal extremes in temperature after invading freshwater lakes from the sea. Two ancestral (contemporary marine) and two derived (contemporary freshwater) populations of stickleback were raised near their thermal tolerance extremes, 7 and 22 °C. Gene expression plasticity was estimated for more than 14,000 genes. Over five thousand genes were similarly plastic in marine and freshwater stickleback, but freshwater populations exhibited significantly more genes with plastic expression than marine populations. Furthermore, several of the loci shown to exhibit gene expression plasticity have been previously implicated in the adaptive evolution of freshwater populations, including a gene involved in mitochondrial regulation (PPARAa). Collectively, these data provide molecular evidence that highlights the importance of plasticity in colonization and adaptation to new environments.

Temperature Stress Mediates Decanalization and Dominance of Gene Expression in Drosophila melanogaster

“…Many studies have used expression profiling to study genetically diverged individuals/populations at two environments (e.g. :[16–20]), but the canalization of gene expression across the entire transcriptome still remains understudied. Allele specific gene expression analysis in two inbred lines and their progeny is a popular approach to gain insight into the regulatory architecture of gene expression [21–24].…”

Genetic Basis of Differential Heat Resistance between Two Species of Congeneric Freshwater Snails: Insights from Quantitative Proteomics and Base Substitution Rate Analysis

“…For the same thermal exposure, protein fold-change ratios between the two species were calculated and Student t-test was then applied with a P-value of 0.02 instead of using 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 analyzed with Fisher's exact test and Adrian Alexa's improved weighted scoring algorithm, with the significance level of enrichment set as 0.01 as there was no multi-test adjustment. 56 …”

Toward the genetic origins of a potentially non-native population of threespine stickleback (Gasterosteus aculeatus) in Alberta

“…These findings suggest that threespine stickleback introduced to Alberta could have survived in these extreme habitats only through selective sweeps leading to the rapid evolution of thermal tolerance or the evolution of phenotypic plasticity. Rapid evolution and phenotypic plasticity are well documented in threespine stickleback (McKinnon and Rundle 2002), including with respect to temperature tolerance (Morris et al 2014).…”