Phenotypic data for clinal populations, foxo genotypes

The insulin/insulin-like growth factor signaling pathway has been
hypothesized as a major determinant of life-history profiles that vary
adaptively in natural populations. In Drosophila melanogaster,
multiple components of this pathway vary predictably with latitude; this
includes foxo, a conserved gene that regulates insulin signaling
and has pleiotropic effects on a variety of fitness-associated traits. We
hypothesized that allelic variation at foxo contributes
to genetic variance for size-related traits that vary adaptively with
latitude. We first examined patterns of variation among natural
populations along a latitudinal transect in the eastern United States and
show that thorax length, wing area, wing loading, and starvation tolerance
exhibit significant latitudinal clines for both males and females but that
development time does not vary predictably with latitude. We then
generated recombinant outbred populations and show that naturally
occurring allelic variation at foxo, which exhibits stronger
clinality than expected, affects the same traits that vary with latitude
in the natural populations. Our results suggest that allelic variation
at foxo contributes to adaptive patterns of life-history
variation in natural populations of this genetic model.
Keywords: foxo, cline, body size, starvation tolerance, genetic
architecture.