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

Event date: Tuesday, December 15, 2015, at 1:10 PM
Location: 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.