Dissecting the nature of developmental time: candidate genes for altitudinal variation

MENSCH JULIÁN; CARREIRA VALERIA; FOLGUERA GUILLERMO; LAVAGNINO NICOLÁS; GOENAGA JULIETA; HASSON ESTEBAN; FANARA JUAN JOSÉ

Punta del Este, Uruguay

Congreso; 150 years of Darwin´s Evolutionary Theory: a southamerican celebration; 2009

Facultad de Ciencias_Universidad de la República

 Understanding the genetic architecture of ecologically relevant adaptive traits requires the contribution of developmental and evolutionary biology. The time to reach the age of reproduction is a complex life history trait commonly known as developmental time. In particular, in holometabolous insects that occupy ephemeral habitats, like fruit flies, the impact of developmental time on fitness is further exaggerated. In the present work we study several aspects of the nature of developmental time concerning geographical variation, climatic factors and candidate genes affecting the trait. Our results showed an altitudinal clinal variation for second chromosome natural substitution lines derived from western Argentinean populations. Furthermore, developmental time was not only positively correlated with altitude but also with mean thermal amplitude temperature at the site of origin of population. In order to identify genes responsible for this potentially adaptive variation we performed genetic complementation tests for a number of heterochronic mutants that has been previously characterized. Our results demonstrate that allelic variation at genes invected, mastermind, criclket and CG14591 contribute to altitudinal variation in developmental time. Clinal variation of developmental time over short geographical distances, together with climatic temperature association of the trait suggest a strong adaptive differentiation of the populations. Taken together, our results stress the need to take into account the effect of metabolic and neurogenic signaling pathways on the genetic architecture of this complex life-history trait.