1. The adolescent genome

genetic imperfection Disease is a normal and inevitable part of life that arises from the way that organisms are put together.

unselfish genes The way that different flavors (alleles) of thousands of genes work together establishes how an organism looks or behaves, or how healthy it is.

how genes work and why they come in different flavors We all differ from one another at millions of places in the genome.

three reasons why genes might make us sick Rare alleles that have a large impact, common alleles that have a moderate one, or hundreds of alleles with very small effects can all contribute.

a unified theory of complex disease The combination of rapid human evolution and recent cultural change has pushed us out of a genetic comfort zone, predisposing many more people to disease.