What are single nucleotide polymorphisms (SNPs)?

Single nucleotide polymorphisms, frequently called SNPs (pronounced “snips”), are the most common type of genetic variation among people. Each SNP represents a difference in a single DNA building block, called a nucleotide. For example, a SNP may replace the nucleotide cytosine (C) with the nucleotide thymine (T) in a certain stretch of DNA.
SNPs occur normally throughout a person’s DNA. They occur almost once in every 1,000 nucleotides on average, which means there are roughly 4 to 5 million SNPs in a person's genome. These variations may be unique or occur in many individuals; scientists have found more than 100 million SNPs in populations around the world. Most commonly, these variations are found in the DNA between genes. They can act as biological markers, helping scientists locate genes that are associated with disease. When SNPs occur within a gene or in a regulatory region near a gene, they may play a more direct role in disease by affecting the gene’s function.
Most SNPs have no effect on health or development. Some of these genetic differences, however, have proven to be very important in the study of human health. Researchers have found SNPs that may help predict an individual’s response to certain drugs, susceptibility to environmental factors such as toxins, and risk of developing particular diseases. SNPs can also be used to track the inheritance of disease genes within families. Future studies will work to identify SNPs associated with complex diseases such as heart disease, diabetes, and cancer.

مواضيع ذات صلة

Genes in the Cell Nucleus Control Protein Synthesis

RNA Proofreading

Regulation of Transcription by DNA Modification

Electrostatic Forces that Determine Protein Structure

A peptide bond

ادوات قطع ولحم الـ DNA

مصير الـ DNA الغريب في النظام البكتيري

A Common Mechanism for Splicing Reactions

آليات واهمية النقل transduction mechanisms

النقل transduction

Regulation of Transcription by Chromatin

RNA Polymerase Binding and Regulation by Transcription Factors