7-11-heptacosadiene and Starvation

To understand the role of adaptation in speciation, one must characterize the ecologically relevant phenotypic effects of naturally occurring alleles at loci potentially causing reproductive isolation. The desaturase2 gene of Drosophila melanogaster is such a locus. Two geographically differentiated ds2 alleles underlie a pheromonal difference between the Zimbabwe and Cosmopolitan races. We used a site-directed gene replacement technique to introduce an allele of ds2 from the Zimbabwe population into Cosmopolitan flies. We show that the Cosmopolitan allele confers resistance to cold as well as susceptibility to starvation when the entire genetic background is otherwise identical. We conclude that ecological adaptation likely accompanies sexual isolation between the two behavioral races of D. melanogaster.

Topics: Adaptation, Physiological; Africa; Alkadienes; Alkenes; Alleles; Animals; Biological Evolution; Body Constitution; Caribbean Region; Cold Temperature; Drosophila melanogaster; Drosophila Proteins; Ecosystem; Fatty Acid Desaturases; Female; Gene Targeting; Genes, Insect; Genotype; Male; Phenotype; Pheromones; Polymorphism, Genetic; Sex Characteristics; Sexual Behavior, Animal; Species Specificity; Starvation; Wings, Animal