Speaker
Description
Gene expression is inherently plastic, and the expression profiles of ectotherm embryos differ substantially between incubation temperatures. We used an experimental approach to understand the relationship between short-term plastic responses and long-term evolutionary responses in transcriptomes. Wall lizards have been introduced to the UK numerous times over the last century, and several populations have adapted independently and repeatedly to the cooler climate by increasing their developmental rate. Using a split-clutch experiment, we asked how expression profiles at an early developmental stage differ between embryos of native and introduced populations at two different incubation temperatures. Accounting for divergence due to drift, we identified a set of genes that showed evidence for positive selection on expression in introduced, compared to native populations. Intersecting this set of genes with temperature-dependent gene expression in the native population shows that genes that evolved a putatively adaptive response to cool climate were predominantly drawn from the pool of genes that exhibits ancestral temperature-dependence in their expression. I discuss how these results contribute to our understanding of evolutionary implications of plasticity.
