Phylogeny of the Yellow/MRJP protein family. An unrooted tree was constructed with aligned protein sequences from bees, flies, and bacteria using neighbor-joining (see Methods). The Yellow/MRJP protein family is composed of numerous color-coded subfamilies, each characterized by a group of closely homologous proteins. One of these subfamilies, the MRJPs, has thus far only been found in honey bees. Other subfamilies characterized by similar protein sequences are also known to have similar functions, and are so labeled. (AmY) Apis mellifera yellow; (DmY) Drosophila melanogaster yellow; (Phlepa) Phlebotomus papatasi; (Lutzlo) Lutzomyia longipalpis; (S.ba) Shewanella baltica; (S.aver) Streptomyces avermitilis; (G.met) Geobacter metallireducens; (G.xy) Gluconobacter oxydans; (N.crassa) Neurospora crassa; and (D.rad) Deinococcus radiodurans.