A
tag SNP is a representative
single nucleotide polymorphism (SNP) in a region of the
genome with high
linkage disequilibrium (the non-random association of alleles at two or more loci). It is possible to identify genetic variation without genotyping every SNP in a
chromosomal region. Tag SNPs are useful in whole-genome SNP association studies in which hundreds of thousands of SNPs across the entire genome are genotyped.
The
International HapMap Project is an organization that aims to develop a
haplotype map (
HapMap) of the
human genome, which will describe the common patterns of human
genetic variation. HapMap is a key resource for researchers to find genetic variants affecting health, disease and responses to drugs and environmental factors. The information produced by the project is made freely available to researchers around the world.
A
haplotype (from the
Greek: ?πλο??,
haplo?s, "onefold, single, simple") in
genetics is a combination of
alleles (DNA sequences) at different places (
loci) on the
chromosome that are transmitted together. A haplotype may be one locus, several loci, or an entire chromosome depending on the number of
recombination events that have occurred between a given set of loci