Tinman

He seemed to feel quite at home at the tinman's, although they were hammering and tapping away there all day, but people said that the gudewife put a dish of porridge up in the garret for him every Thursday evening; and it's no wonder that they got on well and became rich when they had a brownie in the house.

Tinman belongs to a special class of genes. [...] But some genes make proteins that control other genes. Some act like master switches, triggering many different genes to work together to build a structure. Tinman is one such “master gene” for the fruit fly.