SNPs in disease gene mapping, medicinal drug development and evolution.

Single nucleotide polymorphism (SNP) technologies can be used to identify disease-causing genes in humans and to understand the inter-individual variation in drug response. These areas of research have major medical benefits. By establishing an association between the genetic make-up of an individual and drug response it may be possible to develop a genome-based diet and medicines that are more effective and safer for each individual. Additionally, SNPs can be used to understand the molecular mechanisms of sequence evolution. It has been found that throughout the given gene, the rate, type and site of nucleotide substitutions as well as the selection pressure on codons is not uniform. The residues that evolve under strong selective pressures are found to be significantly associated with human disease. Deleterious mutations that affect biological function of proteins are effectively being rejected by natural selection from the gene pool. If substituted nucleotides are fixed during evolution then they may have selection advantages, they may be neutral, or they may be deleterious and cause pathology. Therefore, it is possible that disease-associated SNPs (or pathology) and evolution can be related to one another.