A genetic polymorphism or SNP is a variation in a specific position of the DNA which, in addition, is present in a significant proportion of the population, at least 1%. These variations consist of the change of one nucleotide (adenine, guanine, cytosine, or thymine) for another different one within the genome.
A polymorphism may have no effect, but some, generally located in coding or regulatory regions of the genome, can have consequences on the phenotype. The phenotype is understood as the expression of the genotype that can be observed (not only externally, but also, for example, at a biochemical level) and is determined, in part, by the environment. These polymorphisms would affect, for example, our vulnerability to suffering from certain conditions or the metabolization of drugs, thus being the basis of the tellmeGen study.
By consensus, each of these variants is assigned an rs code (Reference SNP cluster ID or rsID) used in research and reference databases (such as dbSNP). You can find this code within the technical details of each of the items.
Genome-wide association studies or GWAS are an approach used in genetic research to associate specific genetic variations with certain diseases or conditions. This method involves the analysis of the genomes of a large number of different people and the search for predictive markers for a given condition.