One of the main goals of developmental biology is to understand how the different cell types that constitute a multicellular organism are specified during its development. We are currently exploring the contribution of miRNA-mediated gene expression regulation to diversifying the genetic programs that control cell differentiation. We are interested in both how miRNAs themselves are regulated to achieve highly specific expression patterns in order to generate this cell-type diversity, as well as in how miRNAs were integrated into gene regulatory networks during evolution.