LOV domain sequences are conserved across multiple kingdoms. Tree adapted from Krauss and colleagues . LOV sequences of different families are color coded: the archaea in turquoise, alphaproteobacteria (α) in pink, betaproteobacteria (β) and gammaproteobacteria (γ) in yellow, actinobacteria (actino) are in brown, chloroflexi (chloro) in dark green, firmicutes (firmi) in grey, cyanobacteria (cyano) in light blue, fungal sequences from the white-collar 1 (WC-1) protein are in green (fungi), plant phototropin and neochrome (Phot/Neo) LOV domains (LOV1 and LOV2) are in blue, algal aureochrome LOV sequences (aureo) in dark purple, the ZTL/ADO/FKF1-LOV family of plant regulators are in purple, and putative animal LOV domains are in red. Branches have been collapsed; triangle size is proportional to the number of collapsed branches. Numbers of collapsed branches are indicated at the base of each triangle.