Genome 4 stress

In this chapter Ridley talks about how the genome isnt the only one helping ones health. He states chromosome 10 also helps by converting cholsterol to cortesol. Cortesol is released when stress is present and that the brain sends a signal in chains  of triggers that holds down the immune system. he says that "the main purpose of most genes in the human genome is regulating the expression of other genes in the genome". Ridley in the chapter states the world is interconnected without a control center and he uses the example of the economy.