Single-nucleotide polymorphism
hideA single-nucleotide polymorphism (SNP, pronounced snip) is a DNA sequence variation occurring when a single nucleotide — A, T, C, or G — in the genome (or other shared sequence) differs between members of a species (or between paired chromosomes in an individual). For example, two sequenced DNA fragments from different individuals, AAGCCTA to AAGCTTA, contain a difference in a single nucleotide. In this case we say that there are two alleles : C and T. Almost all common SNPs have only two alleles.
Within a population, SNPs can be assigned a minor allele frequency — the lowest allele frequency at a locus that is observed in a particular population. This is simply the lesser of the two allele frequencies for single-nucleotide polymorphisms[1]. There are variations between human populations, so a SNP allele that is common in one geographical or ethnic group may be much rarer in another.
For more information about Single-nucleotide polymorphism, read the full article at
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News tagged with single nucleotide polymorphisms
Inherited risk factors increase odds of developing childhood acute lymphoblastic leukemia
Aug 16, 2009 |
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Scientists at St. Jude Children's Research Hospital have identified inherited variations in two genes that account for 37 percent of childhood acute lymphoblastic leukemia (ALL), including a gene that may help predict drug ...
Researchers identify 'regulatory' genetic sequences that may predict risk for prostate cancer
Aug 14, 2009 |
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Researchers at the Keck School of Medicine of the University of Southern California (USC) have identified a novel genetic mechanism that may govern an individual's risk of developing prostate cancer.
New map of genomic variations will enable disease research
Jul 15, 2009 |
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Genetics researchers have unveiled a powerful new resource for scientists and health providers studying human illnesses--a reference standard of deletions and duplications of DNA found in the human genome. Drawn from over ...
Study shows that a combination of common genetic variations can lead to schizophrenia
Jul 01, 2009 |
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A multi-national group of investigators, including a scientist at the University of North Carolina at Chapel Hill, has discovered that nearly a third of the genetic basis of schizophrenia may be attributed ...
Immune genes adapt to parasites
May 25, 2009 |
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Thank parasites for making some of our immune proteins into the inflammatory defenders they are today, according to a population genetics study that will appear in the June 8 issue of the Journal of Experimental Medicine (onlin ...
Beyond associations: Colorectal cancer culprit found
Apr 23, 2009 |
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Genetics plays a key role in determining risk for colorectal cancer, the second leading cause of cancer-related deaths in the United States. Several common genetic markers have been found to be associated with the disease, ...
Altered gene can increase risk of schizophrenia
Apr 07, 2009 |
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(PhysOrg.com) -- Rutgers geneticist Linda Brzustowicz and her colleagues have identified a specific DNA change that is likely to increase risk for developing schizophrenia in some people. It provides a potential ...
Abnormal DNA repair genes may predict pancreatic cancer risk
Jan 15, 2009 |
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Abnormalities in genes that repair mistakes in DNA replication may help identify people who are at high risk of developing pancreatic cancer, a research team from The University of Texas M. D. Anderson Cancer Center reports ...
