Deciphering Pleiotropic Effects: A molecular characterization of the foraging gene in Drosophila melanogaster

Event Details

December 15, 2015
1:10 pm
RW 432


Speaker: Aaron Allen, Exit seminar

Host: Marla Sokolowski

Abstract: Pleiotropy is defined as the manifold effects of a gene at

the phenotypic level. Understanding the mechanisms of manifold gene

action has important implications for many fields of biology ranging

from evolution and to medicine. The foraging gene, in Drosophila

melanogaster, has long been a pivotal example of a single gene with

natural variants that affect feeding-related phenotypes. One possible

mode of action for foraging’s pleiotropy is through independent

regulation of its gene products. Characterization of the foraging gene

revealed 4 distinct promoters that produce 21 transcripts, and 9 ORFs.

A foraging null mutant of the locus was generated using Ends-out gene

targetting. foraging null mutants had reduced foraging behaviour,

reduced food intake behaviour, and increased lipid levels. A

recombineered full genomic rescue of the gene rescued the effects of

the null mutation. By comparing the effects of the null mutant with

those of the natural variants, I showed that these feeding-related

phenotypes were differentially regulated. A promoter manipulation

strategy identified diverse, and non-overlapping expression patterns

associated with the 4 foraging promoters. Expression was seen in the

nervous and gastric systems of the larva and adult fly, as well as the

reproductive systems of adult fly. This expression suggests potential

new roles for the foraging gene in the larva and adult fly.

Characterizing the regulation of foraging’s gene products will further

our understanding of its role in behaviour, and shed light on the

evolutionary origins of natural variants of the foraging. Not only

will this study further our understanding of this gene’s conserved

function across taxa, but will help elucidate the role for

differential transcriptional regulation in achieving multiple

functions of a gene. This could further serve as fodder for

investigations intro the roles of neo-functionalization versus escape

from adaptive constraint.