How to Argue With a Racist: History, Science, Race and Reality

by Adam Rutherford

The great revelation of the Human Genome Project was that we don’t have very many protein-coding genes; fewer than a water flea, a roundworm or a banana. The count for human genes comes in at around 20,000 (depending on how you define them). This meant that the traditional model held by many geneticists of ‘one gene for one trait’ fell apart at the seams. Instead, for the last fifteen years or so we’ve been building a new model of how genetics works in us, and part of that revelation is that single genes frequently do many things in the body at different times. Genes work in networks and cascades and hierarchies. And so for traits that can be summarised in a simple metric – height, eye or skin colour – what we find via GWAS is that a handful, dozens or even hundreds of genes play a small but cumulative role.