A friend who works in a research lab performed a GWAS and discovered a tight association between a SNP allele and the disease she is studying. She concluded that the SNP allele must be the mutation that causes the disease. Explain why she is likely to be wrong.

Verified step by step guidance

1. Understand the concept of SNP (Single Nucleotide Polymorphism): SNPs are variations at a single position in DNA among individuals. They are the most common type of genetic variation in humans.
2. Recognize the nature of GWAS (Genome-Wide Association Studies): GWAS are studies that involve scanning markers across the genomes of many people to find genetic variations associated with a particular disease. However, these studies only show associations and do not prove causation.
3. Consider Linkage Disequilibrium: SNPs found to be associated with a disease in GWAS may be in linkage disequilibrium with the actual causal mutation. This means the SNP is near the true causal genetic variant and inherited together with it, but is not itself the cause of the disease.
4. Evaluate the need for further research: To establish causality, further studies such as functional genomics or experimental validation are needed. These studies can help determine if the SNP directly affects the biological pathway of the disease.
5. Explore alternative explanations: It's also possible that multiple SNPs or a combination of genetic and environmental factors contribute to the disease, rather than a single SNP being the sole cause.