 In 1977, recombinant DNA technology enabled biologists to start to explore the genetic control of development.The growth of evolutionary developmental biology from 1978, when Edward B. Lewis discovered homeotic genes, showed that many so-called toolkit genes act to regulate development, influencing the expression of other genes.It also revealed that some of the regulatory genes are extremely ancient, so that animals as different as insects and mammals share control mechanisms; for example, the "Pax6" gene is involved in forming the eyes of mice and of fruit flies.