Evolution of flowering in response to day length: flipping the CONSTANS switch

Day length provides an important environmental cue by signalling conditions favourable for flowering. While Arabidopsis promotes flowering in response to long days, rice promotes flowering in response to short days. Despite this difference, a recent paper reveals that the network controlling this response is highly conserved in these distantly related plants, only the activity of one component is reversed. This reveals how an important developmental process can be diversified for adaptation by using the same set of genes, but regulating them differently.