The development of organisms is a complex process that continues to drive intrigue and exploration. In a new paper from Developmental and Cell Biology Assistant Professor Zeba Wunderlich and graduate student Rachel Waymack, in collaboration with Alvaro Fletcher and Professor German Enciso from the Department of Mathematics, the researchers shed new light on organismal development and the purpose of unique regions of the genome referred to as “shadow” enhancers. These special enhancers help provide an extra set of instructions for when and where to turn genes on.

Species from insects to plants to mammals rely on enhancers to specify patterns of gene expression. A subset of enhancers, shadow enhancers, work in groups of two or more to drive overlapping spatiotemporal expression of the same gene. While this unique group of enhancers is common in genes important for development, their precise mechanism of action was previously unclear.

Professor Wunderlich, Ms. Waymack and the team sought to test the hypothesis that shadow enhances can buffer against upstream noise, that is, variability of gene expression. Using a mathematical model to help decode gene expression in the developing fruit fly, the team determined that shadow enhancer pairs drive lower noise than standard enhancers. Additionally, the shadow enhancers were able to maintain low levels of expression noise across a wide range of temperatures. Together, their results help to further the understanding of how development can proceed normally under a wide range of varying conditions like temperature gradients.