Cis-regulatory variation in plant genomes and the impact of natural selection.

Understanding the molecular mechanisms that allow phenotypic diversification in response to natural or artificial selection is one of the major challenges of modern biology (Barrett and Hoekstra, 2011). The evolution of gene regulation is a prominent pillar for adaptation in sessile organisms like plants because the activity of genes must be tuned to the environment. Today, we can accurately document the genome-wide distribution of -regulatory variants. Here, I summarize how current data show that both positive selection and purifying selection contribute to shape -regulatory variation. To disentangle their relative impact, I argue that -regulatory and amino-acid evolutionary rates should be analyzed jointly.