Shifts in gene expression are a major contributor to phenotypic variation within and across species, Gene expression is the result of multiple regulatory elements (REs) that span transcription to post-translation, leading to a complex interplay in the evolution of different REs. Phylogenetic studies of gene expression have emerged as a powerful approach to test if variation in gene expression across species is consistent with non-adaptive or adaptive evolution. Although useful, phylogenetic studies of are gene expression are often detached from the evolution of the underlying gene regulation. Building off my expertise in evolutionary genetics, transcriptomics, and proteomics, I study gene expression evolution at multiple regulatory levels using a combination of bioinformatics and phylogenetic.