Identification of a candidate adaptive polymorphism for Drosophila life history by parallel independent clines on two continents

Abstract

Life history traits are critical components of fitness and frequently reflect adaptive responses to environmental pressures. However, few genes that contribute to natural life history variation have been identified. Insulin signalling mediates the determination of life history traits in many organisms, and single gene manipulation in Drosophila melanogaster suggests that individual genes in the pathway have the potential to produce major effects on these quantitative traits. We evaluated allelic variation at two insulin signalling genes, the Insulin-like Receptor (InR) and its substrate, chico, in natural populations of D. melanogaster. We found different patterns of variation: InR shows evi..