Testing long-term evolutionary change and stasis in the pioneer factor Grainyhead
Authors: Henry Ertl; Patricia Wittkopp
Affiliation: University of Michigan, Ann Arbor, MI
Keywords: l. evo-devo; a. core promoters and general transcription factors
A comprehensive understanding of morphological evolution must entail studying both evolutionary change and stasis in the developmental mechanisms that produce organismal form. Grainyhead (Grh) is a transcription factor critical for epithelial cell formation in the epidermis of flies, mice, and nematodes, suggesting the developmental role of Grh is conserved over 700 million years. To determine whether the underlying molecular functionality of Grh is also conserved, we constructed transgenic flies and tested whether the nematode Grh ortholog could rescue the weak epidermis phenotype of flies lacking functional Grh. We then collected gene expression, chromatin accessibility, and Grh binding data to provide a mechanistic explanation for any divergence between these distantly related Grh orthologs.