Variation in gene expression underpins variation in organismal traits and diversity. Therefore, understanding how gene expression evolves will allow us to better understand the mechanisms of evolutionary change. The strength and form of selection on gene expression and its role in evolution is difficult to estimate, however, because of the high dimensional and highly correlated nature of gene expression data. In this project the SUDS scholar will estimate selection on gene expression traits and compare the results from different methods that are commonly used to study selection on gene expression.