GWAS

http://www.genomesunzipped.org/2010/07/how-to-read-a-genome-wide-association-study.php

The basic GWAS approach is to look at approximately a million positions in the human genome (called ‘SNPs’) where different people carry different versions of the genetic code (so at some particular position I might have an ‘A’ and you might have a ‘C’). I’m going to focus here on the most common GWAS design, called case-control, where the goal is to compare the frequencies of these different versions between a group of healthy individuals (controls) and another group of people with a specific disease (cases). The places where the frequencies between cases and controls are significantly different are therefore associated with risk of developing the disease.