In 2014 evo-devo proponent Wallace Arthur admitted this. He expressed a continued faith in common descent and in the evo-devo project, but also confessed that “when the fitness consequences of large-effect mutations in early development have been studied, they have in almost all cases been found to result in major fitness decreases. This is true, for example, of the homeotic mutations studied in Drosophila [fruit flies], and it is one of the main reasons for the rejection of Goldschmidt’s saltational theory of evolution.”26
