A phylogenetic tree of the WD domains from Groucho/TLE/Grg family members. The protein sequences of known Gro family members were extracted from Refseq , and searched using BLAT  against the current UCSC genome browser  releases of the assembled genomes of mosquito (ag), honeybee (am), dog (cf), Ciona intestinalis (ci), Ciona savignyi (cs), Drosophila melanogaster (dm), zebrafish (dr), chicken (gg), human (hs), opossum (md), mouse (mm), medaka (ol), Tetraodon (tn), and Xenopus tropicalis (xt). The matching regions of the genomes were extracted and aligned against known RefSeq sequences, using Wise2 , to derive orthologous protein sequences. The WD-domain regions were aligned using ClustalX 2.0  and bootstrapped neighbor-joining trees  were generated and visualized with NJPlot . The branch lengths are proportional to the amount of inferred evolutionary change, and numbers between internal nodes indicate bootstrap values as percentages of 100 replications. Accession numbers for the sequences are in Additional data file 1.