Mediator complex proteins are required for diverse developmental processes

► Mediator complex gene mutants have diverse phenotypes affecting many developmental processes. ► Mutants in the same Mediator complex gene in different species have distinct phenotypes. ► Mutant phenotypes reveal that Med12 and Med13 have similar functions in multiple species. ► Mutant phenotypes reveal that Cdk8 and CycC do not overlap in function with Med12 and Med13. ► At present no overall correlation exists between complex location and mutant phenotype.