About Single nucleotide polymorphisms (SNPs)

Single nucleotide polymorphisms (SNPs)

Single nucleotide polymorphisms or SNPs (pronounced "snips") are DNA sequence variations that occur when a single nucleotide (A,T,C,or G) in the genome sequence is altered. For example a SNP might change the DNA sequence AAGGCTAA to ATGGCTAA. For a variation to be considered a SNP, it must occur in at least 1% of the population. SNPs, which make up about 90% of all human genetic variation, occur every 100 to 300 bases along the 3-billion-base human genome. Two of every three SNPs involve the replacement of cytosine (C) with thymine (T). SNPs can occur in both coding (gene) and noncoding regions of the genome. Many SNPs have no effect on cell function, but scientists believe others could predispose people to disease or influence their response to a drug.

Although more than 99% of human DNA sequences are the same across the population, variations in DNA sequence can have a major impact on how humans respond to disease; environmental insults such as bacteria, viruses, toxins, and chemicals; and drugs and other therapies. This makes SNPs of great value for biomedical research and for developing pharmaceutical products or medical diagnostics. SNPs are also evolutionarily stable --not changing much from generation to generation --making them easier to follow in population studies.

Scientists believe SNP maps will help them identify the multiple genes associated with such complex diseases as cancer, diabetes, vascular disease, and some forms of mental illness. These associations are difficult to establish with conventional gene-hunting methods because a single altered gene may make only a small contribution to the disease.

Several groups worked to find SNPs and ultimately create SNP maps of the human genome. Among these groups were the U.S. Human Genome Project (HGP) and a large group of pharmaceutical companies called the SNP Consortium or TSC project. The likelihood of duplication among the groups was small because of the estimated 3 million SNPs, and the potential payoff was high.

In addition to the pharmacogenomic, diagnostic, and biomedical research implications, SNP maps are helping to identify thousands of additional markers along the genome, thus simplifying navigation of the much larger genome map generated by researchers in the HGP.

SNPs: Variations on a Theme 

A basic introduction to SNPs from the National Center for Biotechnology Information (NCBI).

Understanding SNPs and Cancer - An online tutorial from the National Cancer Institute.

Diseases and Medical Response 

 An animated tutorial describing how DNA markers are used in medical applications.

Genome Variations 

Questions and answers about genome variation from the Genome News Network.

HGP.

Single nucleotide polymorphism - Wikipedia, the free encyclopedia

This is simply the lesser of the two allele frequencies for single nucleotide polymorphisms[1]. It is important to note that there are variations between ...
en.wikipedia.org/wiki/Single_nucleotide_polymorphism

Nature Protocols: Single nucleotide polymorphism (SNP) allele ...

Identifying the genetic variation underlying complex disease requires analysis of many single nucleotide polymorphisms (SNPs) in a large number of samples. ...
www.natureprotocols.com/2007/01/11/single_nucleotide_polymorphism.php

Springer Protocols: Abstract: SAGE Analysis in Identifying ...

Furthermore, we provide a detailed, day-by-day based protocol for SAGE. ... A general approach to single-nucleotide polymorphism discovery. (1999) Nat. ...
www.springerprotocols.com/Abstract/doi/10.1007/978-1-59745-463-6_5

TaqMan SNP Genotyping Assays Protocol (PN 4332856C)
SNP Genotyping Assays Protocol. work should be conducted in properly equipped .... SNP Genotyping Assays Protocol. 3. Store multiple aliquots of the SNP ...
docs.appliedbiosystems.com/pebiodocs/04332856.pdf

Assays-by-Design Service For SNP Assays Protocol
PDF of Assays-by-Design Service For SNP Assays Protocol. �C PDF of Assays-by-Design Service Submission Guidelines. Protocol. �C PDF of product insert ...
www.rockefeller.edu/genomics/pdf/Applied_Biosystems_SNP_Assay-by-design.pdf

SeqWright | SNP Discovery/Exon Resequencing

Single Nucleotide Polymorphisms (SNPs) are the most common type of sequence variation and account for about 90% of sequence differences in humans. ...
www.seqwright.com/resequencing.htm

GSC: C. elegans SNP Data

C. elegans Single Nucleotide Polymorphism Data ... Rapid gene mapping in Caenorhabditis elegans using a high density polymorphism map. ...
genome.wustl.edu/genome/celegans/celegans_snp.cgi

Patterns of single-nucleotide polymorphisms in candidate genes for ...

Sequence variation in human genes is largely confined to single-nucleotide polymorphisms (SNPs) and is valuable in tests of association with common diseases ...
www.nature.com/ng/journal/v22/n3/full/ng0799_239.html

Polymorphisms

Most* RFLPs are created by a change in a single nucleotide in the gene, and so these are called single nucleotide polymorphisms (SNPs). ...
users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Polymorphisms.html

JG-SNP - A Database of Japanese Single Nucleotide Polymorphism for ...

Developments of geriatric autopsy database and Internet-based database of Japanese single nucleotide polymorphisms for geriatric research (JG-SNP). ...
www.tmgh.metro.tokyo.jp/jg-snp/english/E_top.html

High-resolution single-nucleotide polymorphism array and clustering
Single-nucleotide polymorphisms (SNPs) are the most. common form of sequence variation in the human. genome, occurring approximately every 1200 base pairs ...
www.broad.mit.edu/mpr/publications/projects/SNP_Analysis/Janne.pdf