本人是新手，现在做课题，想请教一下，什么叫tagSNPs、 HapMap SNPs、 untyped SNPs ？
它们有什么地方不同吗？尤其是untyped SNPs。
先谢谢各位学长学姐们帮助！

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

With the rapid advances in high-throughput genotyping technology, genome-wide association studies have become a viable approach to elucidating the genetic basis of human complex disease. It is now affordable to analyze on the order of 105 to 106 markers throughout the genome. However, because the set of single-nucleotide polymorphisms (SNPs) assayed by the current genotyping platforms covers only a fraction of the total variation in the human genome, it is likely that many disease-susceptibility alleles are not directly genotyped. Therefore, it is of great interest to develop powerful statistical methods to detect association with untyped causal variants. To do this, one can use the linkage disequilibrium (LD) structure of the genome, together with data on typed variants, to detect association between untyped variants and phenotype.