Final answer:
GWAS involves comparing the DNA of two groups, one with a specific disease and one without, to identify significant differences in SNP frequencies. The analysis seeks to find genetic markers for disease susceptibility and targets for further research. However, the associations found do not always indicate causation, and the use of this data in personal genomics services is contentious.
Step-by-step explanation:
Procedure of Genome-Wide Association Studies (GWAS)
The procedure of GWAS involves several stages. Initially, two groups of individuals are selected: one with the disease of interest and the other without (control group). It's crucial that these groups are matched for other characteristics to minimize confounding variables that could influence the results. Once the groups are established, DNA samples are collected from thousands of participants to ensure statistical validity. Modern automated systems then analyze the SNPs, often reviewing over a million, to detect significant differences in the frequency of SNPs between the two groups.
Following the identification of SNP differences, there are two prime applications of this data. Firstly, genetic differences may serve as markers for disease susceptibility in undiagnosed individuals. Secondly, the implicated genes become potential targets for research into the molecular mechanisms of the disease and the development of novel therapies.
The advent of GWAS has also led to the growth of personal genomics companies, which evaluate an individual's susceptibility to various diseases based on SNP analysis. However, the scientific foundation of these services remains a topic of debate, as an association found by GWAS doesn't necessarily imply causation.