 One source of confusion, according to the critics, were the metaphors that got embedded in molecular genetics in the mid-twentieth century. Computing and architectural metaphors suggesting that the genome was a “program” or “blueprint” for development conveyed misleading ideas about how cells operated (Kay 2000). Informational metaphors may capture some features of biology, but the error was in thinking that only DNA carried that biological information (Griffiths 2001; Jablonka 2002; entry:  biological information).  