 Although he featured genetic control, Waddington’s designation of the landscape as “epigenetic” suggests a view of development allowing more of a role for epigenesis than more gene-focused contemporaries. Scott Gilbert (1991) argues that the branching-track lineage structure unifies development and genetics, visualizing a formal analogy between cellular, genetic, and organismal development. Fagan (2012, 2013a) extends this argument, focusing on Waddington’s unification of two complementary landscape images: robust pathways above, and interacting gene products below, with genes at the bottom, metaphorically “pulling the strings”. Nicoglou and Merlin (2017) and Nicoglou (2018) discuss this unifying, integrative feature of Waddington’s landscape model as one strand of twentieth-century epigenetics.