Explain what a Single nucleotide polymorphism is and give an example thereof
A single nucleotide polymorphism (SNP) is a variation in a single nucleotide (A, T, C, or G) of DNA that occurs at a specific position in the genome, which can be observed in a population. SNPs can affect a variety of traits, such as susceptibility to certain diseases, behavior, and physical characteristics.
An example of a SNP is the A/G polymorphism in the MTHFR gene. The MTHFR gene is involved in folate metabolism and the A/G polymorphism results in an amino acid change in the MTHFR protein. This SNP has been associated with several diseases, such as cardiovascular disease, stroke, and cancer. Additionally, it has been linked to the effectiveness of certain medications, such as methotrexate, which is used to treat certain cancers and autoimmune diseases.
A Single Nucleotide Polymorphism, or SNP, is a common type of genetic variation in which a single nucleotide (A, T, C, or G) at a specific position in the DNA sequence differs among individuals. These variations occur in more than 1% of the population.
SNPs can be categorized into three types based on their impact: silent, missense, and nonsense. Silent SNPs do not cause any change in the amino acid sequence of proteins. Missense SNPs lead to the substitution of one amino acid for another, potentially altering the protein's function. Nonsense SNPs introduce a premature stop codon, causing the protein synthesis to be terminated early.
Here's an example of an SNP: rs1800497. This particular SNP is located in the gene encoding TNF-alpha, a cytokine involved in the immune response. The SNP results in a change from guanine (G) to adenine (A) at position 308 of the DNA sequence. This SNP is associated with altered levels of TNF-alpha production and has been implicated in various diseases, including rheumatoid arthritis, inflammatory bowel disease, and certain cancers.