Gene expression stasis and plasticity following migration into a foreign environment

Area of Science:

• Evolutionary Biology
• Ecology
• Genomics

Background:

• Maintaining genetic divergence between populations requires selection against migrants.
• Phenotypic plasticity, particularly in gene expression, may allow migrants to adjust to novel environments.
• Previous studies showed limited divergent selection between lake and stream stickleback populations.

Purpose of the Study:

• To investigate the role of gene expression plasticity in migrant adaptation.
• To determine if transplanted stickleback fish exhibit plastic gene expression responses in new habitats.
• To assess the extent to which expression plasticity can facilitate convergence with native populations.

Main Methods:

• Reciprocal transplant experiment with lake and stream stickleback (Gasterosteus aculeatus).
• Measurement of gene expression profiles using TagSeq.
• Analysis of gene expression patterns in relation to habitat of origin and transplantation.

Main Results:

• Extensive gene expression differences exist between genetically distinct lake and stream stickleback populations.
• Gene expression was highly plastic for many genes in response to habitat change.
• Transplanted fish partially converged on the native gene expression profiles of their new habitats.

Conclusions:

• Gene expression plasticity can mitigate the fitness costs associated with migration.
• Plasticity alone is insufficient to fully overcome environmental challenges, as evidenced by differences in survival and parasite load.
• Expression plasticity may soften, but not eliminate, the impact of migration on population divergence.