Phylogenetic relationships among CRWN proteins. A maximum likelihood tree of CRWN homologs constructed from an alignment of amino acid sequences that correspond to the coiled-coil domains. Bootstrap values (of 1000 replicates) are indicated on each branch. The A. thaliana CRWN proteins are indicated in bold, and homologs are labeled with the genus name and an assigned number (Additional file 1: Table S1). Two major clades are marked by blue and green; the yellow inset oval indicates a subgroup of CRWN4-like proteins from dicots that lack the conserved C-terminal domain (Additional file 2).