title: Triglyceride pools, flight and activity variation at the Gpdh locus in Drosophila melanogaster.
abstract: We have created a set of P-element excision-derived Gpdh alleles that generate a range of GPDH activity phenotypes ranging from zero to full activity. By placing these synthetic alleles in isogenic backgrounds, we characterize the effects of minor and major activity variation on two different aspects of Gpdh function: the standing triglyceride pool and glycerol-3-phosphate shuttle-assisted flight. We observe small but statistically significant reductions in triglyceride content for adult Gpdh genotypes possessing 33-80% reductions from normal activity. These small differences scale to a notable proportion of the observed genetic variation in triglyceride content in natural populations. Using a tethered fly assay to assess flight metabolism, we observed that genotypes with 100 and 66% activity exhibited no significant difference in wing-beat frequency (WBF), while activity reductions from 60 to 10% showed statistically significant reductions of approximately 7% in WBF. These studies show that the molecular polymorphism associated with GPDH activity could be maintained in natural populations by selection in the triglyceride pool.
authors.affiliation: Department of Ecology and Evolution, State University of New York, Stony Brook, New York 11794, USA.
authors.forename: Thomas J S
authors.initials: TJ
authors.lastname: Merritt
authors.forename: Efe
authors.initials: E
authors.lastname: Sezgin
authors.forename: Chen-Tseh
authors.initials: CT
authors.lastname: Zhu
authors.forename: Walter F
authors.initials: WF
authors.lastname: Eanes
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D004734:Energy Metabolism; D005260:Female; D005426:Flight, Animal; D018507:Gene Expression Regulation, Developmental; D014644:Genetic Variation; D005838:Genotype; D005993:Glycerolphosphate Dehydrogenase / Q000235:genetics*; D005994:Glycerophosphates / Q000378:metabolism; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D005994:Glycerophosphates; D014280:Triglycerides; D005993:Glycerolphosphate Dehydrogenase