Phylogenetic tree of the family of insect OBPs and related proteins. Sequences were aligned stepwise using the CLUSTAL Xpackage. The proteins were then truncated by removing the signal sequence-bearing N termini as in Figure 3. This alignment was then used to construct the unrooted distance (neighbor-joining) tree shown. Branch lengths are proportional and reflect the mean distance (percentage difference) between the various sequences. The symbols for bootstrap values are as shown in Figure 3. Proteins with known olfactory system expression are indicated by asterisks. GenBank accession nos. of the non-Drosophila insect protein sequences are as follows: T. mol B1 (Tenebrio molitor B1, M97916); T. mol B2, M97917; T. molThp12, 6573610; G. mel SER, (Galleria mellonella sericotropin, L41640); P. reg CRLBP,Phormia regina CRLBP, S78710; A. per PBP1, (Antheraea pernyi PBP1, X96773); A. pol PBP (Antheraea polyphemusPBP, X17559; A. per PBP2, X96860); M. sex PBPA (Manduca sexta PBPA, M21797; M. sex PBPB, M21798); B. mor PBP (Bombyx mori PBP, X94987); H. vir PBP (Heliothis virescens PBP,X96861); L. dis PBP2 (Lymantria dispar PBP2, 2444187); A. per GOBP2, X96772); M. sex GOBP2, M73798; H. vir GOBP2, 96863; B. mor GOBP2, X94989; B. mor GOBP1, X94988; M. sex GOBP1, M73797; H. vir GOBP1, X96862; B. mor ABPX, X94990, H. zea PBP (Helicoverpa zea PBP, 3639083); L. lin LAP (Lygus lineolaris,3644030); L. dis PBP1, 2444185; H. vir ABPX, AJ002518); P. japPBP (Popillia japonica PBP, 3721994); A. osa PBP (Anomala osakana PBP, 3721996); A. per ABPX, AJ002519; M. bra GOBP2 (Mamestra brassicae GOBP2, 2961244); R. pal Rpa12′ (Rhynchophorus palmarum Rpa12‘, AF141865); R.palRpa12,AF139912; M. bra PBP2, 2961240; C. cap MSP (Ceratitis capitata MSP, Y08954); M. bra PBP1, 2961242; A. gam D7r1 (Anopheles gambiae D7r1, AJ133852); A. gam D7r3, AJ000035; A. gam D7r2, AJ000036; L. lon SL1 (Lutzomyia longipalpias SL1,AF132517); A. mel ASP1 Apis mellifera ASP1, AF166496; A. mel ASP2, AF166497; Y. cag PBP (Yponomeuta cagnagellus PBP,AF177661); P. gos PBP (Pectinophora gossypiella PBP,AF177656); C. ros PBP (Choristoneura rosaceana PBP,AF177654); A. vel PBP (Argyrotaenia velutinana PBP,AF177639); S. exi PBP (Synanthedon exitiosa PBP, AF177660); O. nub PBP (Ostrinia nubilalis PBP, AF133631); C. pin PBP (Choristoneura pinus PBP, AF177650); C. mur PBP (Choristoneura murinana PBP, AF177645; C. par PBP (Choristoneura parallela PBP, AF177648); P. div OBP1 (Phyllopertha diversa PBP, PC7028; P. div OBP2, PC7029.