title: Evolution of the integral membrane desaturase gene family in moths and flies.
abstract: Lepidopteran insects use sex pheromones derived from fatty acids in their species-specific mate recognition system. Desaturases play a particularly prominent role in the generation of structural diversity in lepidopteran pheromone biosynthesis as a result of the diverse enzymatic properties they have evolved. These enzymes are homologous to the integral membrane desaturases, which play a primary role in cold adaptation in eukaryotic cells. In this investigation, we screened for desaturase-encoding sequences in pheromone glands of adult females of eight lepidopteran species. We found, on average, six unique desaturase-encoding sequences in moth pheromone glands, the same number as is found in the genome database of the fly, Drosophila melanogaster, vs. only one to three in other characterized eukaryotic genomes. The latter observation suggests the expansion of this gene family in insects before the divergence of lepidopteran and dipteran lineages. We present the inferred homology relationships among these sequences, analyze nonsynonymous and synonymous substitution rates for evidence of positive selection, identify sequence and structural correlates of three lineages containing characterized enzymatically distinct desaturases, and discuss the evolution of this sequence family in insects.
authors.affiliation: Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, New York 14456, USA. dck2@cornell.edu
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Knipple
authors.forename: Claire-Lise
authors.initials: CL
authors.lastname: Rosenfield
authors.forename: Rasmus
authors.initials: R
authors.lastname: Nielsen
authors.forename: Kyung Man
authors.initials: KM
authors.lastname: You
authors.forename: Seong Eun
authors.initials: SE
authors.lastname: Jeong
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005260:Female; D017344:Genes, Insect; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007915:Lepidoptera / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D012724:Sex Attractants / Q000378:metabolism; D013045:Species Specificity
chemical_list: D018076:DNA, Complementary; D029721:Drosophila Proteins; D019476:Insect Proteins; D012724:Sex Attractants; D044943:Fatty Acid Desaturases