 However, in the late 1950s, after the structure of DNA had become more widely understood, chemist Homer Jacobson proposed a cybernetic model of reproduction (Jacobson 1958), going so far as to make a literal model out of train sets and electronic circuits. Later, von Neumann proposed a theory of self-reproducing automata (Neumann 1966), which has become a parallel but influential research program to the issue in biology (Mitchell 2009). Jacob (1973) cemented the logical description of heredity, but the ultimate classical source of the notion that genes are information comes from Williams’ classic 1966 book Adaptation and Natural Selection, in which he referred to genes as “cybernetic abstractions” (1966: 33).