Adaptive Evolution of Gene Expression in Drosophila

Publication date: 8 August 2017
Source:Cell Reports, Volume 20, Issue 6
Author(s): Armita Nourmohammad, Joachim Rambeau, Torsten Held, Viera Kovacova, Johannes Berg, Michael Lässig
Gene expression levels are important quantitative traits that link genotypes to molecular functions and fitness. In Drosophila, population-genetic studies have revealed substantial adaptive evolution at the genomic level, but the evolutionary modes of gene expression remain controversial. Here, we present evidence that adaptation dominates the evolution of gene expression levels in flies. We show that 64% of the observed expression divergence across seven Drosophila species are adaptive changes driven by directional selection. Our results are derived from time-resolved data of gene expression divergence across a family of related species, using a probabilistic inference method for gene-specific selection. Adaptive gene expression is stronger in specific functional classes, including regulation, sensory perception, sexual behavior, and morphology. Moreover, we identify a large group of genes with sex-specific adaptation of expression, which predominantly occurs in males. Our analysis opens an avenue to map system-wide selection on molecular quantitative traits independently of their genetic basis.

Graphical abstract

Teaser

Drosophila presents an evolutionary conundrum: there is ubiquitous genomic adaptation, yet it has been impossible to identify system-wide signals of adaptation for gene expression. Nourmohammad et al. develop a method to infer stabilizing and directional selection from expression data. They show that adaptation dominates the evolution of gene expression in Drosophila.


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