Maximum likelihood tree of archaeal and bacterial biotin carboxylase (BC) domainsequences. This tree is based on 196 representative sequences and 322 conserved sites and wasarbitrarily rooted on the PYC-related sequences. Numbers at nodes indicate bootstrap robustnessvalues higher than 50. Colors on leaves represent the affiliation of the sequences to theirrespective domain of life: archaea (red), bacteria (blue) and eukaryotes (green). Bars on the rightreport the functional assignment of the sequences; sequences that are not in front of any bar areassumed to bear an acyl-CoA carboxylase activity.