Community-wide genome sequencing reveals 30 years of Darwin's finch evolution

A fundamental goal in evolutionary biology is to understand the genetic architecture of adaptive traits. Using whole-genome data of 3955 of Darwin's finches on the Galapagos Island of Daphne Major, we identified six loci of large effect that explain 45% of the variation in the highly heritable beak size of Geospiza fortis, a key ecological trait. The major locus is a supergene comprising four genes. Abrupt changes in allele frequencies at the loci accompanied a strong change in beak size caused by natural selection during a drought. A gradual change in Geospiza scandens occurred across 30 years as a result of introgressive hybridization with G. fortis. This study shows how a few loci with large effect on a fitness-related trait contribute to the genetic potential for rapid adaptive radiation.

Automated summary

This study used whole-genome data of Darwin's finches to identify six loci associated with beak size variation in Geospiza fortis. The major locus is a supergene composed of four genes. Changes in allele frequencies at these loci accompanied a significant change in beak size caused by natural selection during a drought, while introgressive hybridization with another species resulted in gradual changes in beak size in another population.