Resumen:
Understanding how organisms adapt to their local environment is central to evolution. With
new whole-genome sequencing technologies and the explosion of data, deciphering the
genomic basis of complex traits that are ecologically relevant is becoming increasingly
feasible. Here we study the genomic basis of wing shape in two Neotropical butterflies that
inhabit large geographical ranges. Heliconius butterflies at high elevations have been shown
to generally have rounder wings than those in the lowlands. We reared over 1100 butterflies
from 71 broods of H. erato and H. melpomene in common-garden conditions and show that
wing aspect ratio, i.e. elongatedness, is highly heritable in both species and elevationassociated wing shape differences are maintained. Genome-wide associations with a
published dataset of 666 whole genomes from across a hybrid zone, uncovered a highly
polygenic basis to wing shape variation in the wild. We identify several genes that have roles
in wing morphogenesis or wing shape variation in Drosophila flies, making them promising
candidates for future studies. There was little evidence for molecular parallelism in the two
species, with only one shared candidate gene, nor for a role of the four known colour pattern
loci, except for optix in H. erato. Thus, we present the first insights into the heritability and
genomic basis of within-species wing shape in two Heliconius species, adding to a growing
body of evidence that polygenic adaptation may underlie many ecologically relevant traits.
