Definition: A Single Nucleotide Polymorphism (SNP, pronounced “snip”) is a variation in a single nucleotide — the fundamental building blocks of DNA — that occurs at a specific position in the genome. Despite the human genome being largely identical across the population, SNPs represent variations in a single DNA building block, such as an adenine (A) replacing a cytosine (C). These variations are the most prevalent type of genetic variation among individuals, with millions of SNPs identified in the human genome.
Key Concepts:
- Genetic Variation: SNPs constitute a primary source of human genetic diversity, influencing individuals’ responses to diseases, vaccines, pharmaceuticals, and environmental factors. A SNP may lead to a different amino acid being produced in a protein sequence, potentially altering the protein’s function.
- Genetic Markers: SNPs act as biological markers, aiding scientists in identifying genes associated with diseases. They can help predict an individual’s susceptibility to certain diseases, their reaction to medications, and other traits.
- Population Genetics: The distribution and frequency of SNP variations can provide insights into the genetic history of populations, tracing ancestry and evolutionary changes.
Applications:
- Personalised Medicine: SNPs are utilised in pharmacogenomics to customise medical treatments to an individual’s genetic profile, enhancing drug efficacy and minimising adverse reactions.
- Disease Risk Assessment: Analysing SNPs allows researchers to identify genetic predispositions to various diseases, such as cancer, diabetes, and cardiovascular conditions, facilitating early intervention and tailored prevention strategies.
- Nutrigenetics and Diet: SNPs affect how individuals metabolise nutrients, impacting dietary requirements and predispositions to diet-related health issues. This knowledge enables personalised dietary recommendations.
- Forensic Science: SNPs can be employed in forensic investigations to identify individuals or biological relationships, owing to their high variability in the population.
Challenges and Considerations:
Interpreting the impact of SNPs requires a comprehensive analysis due to the complex interaction of multiple genes and environmental factors. Additionally, ethical considerations regarding privacy, consent, and the potential for genetic discrimination arise with the use of genetic information.
Conclusion:
Single Nucleotide Polymorphisms (SNPs) are foundational to genetic research and personalised medicine, offering profound insights into human diversity, disease predisposition, and response to environmental factors. Their study advances our understanding of genetics, facilitating progress in medical treatments, nutritional advice, and disease prevention, all tailored to the unique genetic profiles of individuals.
Finding the Data
- Useful SNP Databases:
- dbSNP: (https://www.ncbi.nlm.nih.gov/snp/) A public repository of SNPs maintained by the National Center for Biotechnology Information (NCBI).
- ClinVar: (https://www.ncbi.nlm.nih.gov/clinvar/) Holds information about SNPs with potential clinical significance.
- Population Frequency Databases:
- 1000 Genomes: (https://www.internationalgenome.org/) A large-scale reference set of human genome sequences.
- gnomAD: (https://gnomad.broadinstitute.org/) Another extensive genomic database, aggregating information from different sequencing projects.
