Phylogenetic Gene Expression Meta-Analysis
Changes in the regulation of gene expression have long been hypothesized to be a major source of evolutionary novelty, and this has been demonstrated compellingly for a handful of individual cases. However, it is not currently known if this hypothesis holds generally among genes and across lineages outside of these special cases. To test this hypothesis, we investigated whether expression levels evolve according to neutral or stabilizing selection across a phylogeny of 21 vertebrates. Even with 21 species, we can not confidently differentiate between stabilizing selection and neutral evolution for the majority of the transcriptome, however, we had more power to distinguish between evolutionary modes in a 59 species data set. More confident bounds on the number of genes undergoing neutral evolution of gene expression values allows us to better determine how broadly changes in RNA level expression impacts the evolution of different species.