1. Genome-Wide Association Studies: Present Status and Future Directions
Judy H. Cho 
Gastroenterology 
Volume 138, Issue 5, Pages e1 (May 2010)
DOI: /j.gastro
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2. Figure 1
Selection of SNPs to include in GWAS genotyping platforms. Depicted are 5 adjacent SNPs (SNPs 1–5) that have been phased to depict haplotypes (closely linked markers inherited together; for autosomal chromosomes, each individual will have paternal and maternal haplotypes). The more common (1) and less common (2) alleles can be designated at each SNP. SNPs 1 and 4 are in complete linkage disequilibrium (ie, correlated) with each other (SNP group *); similarly SNPs 2, 3, and 5 are also completely correlated (SNP group ‡). Therefore, only 2 markers (ie, one each from SNP group * and ‡) would need to be genotyped to capture the variation from all 5 markers. The HapMap project, by genotyping trios (both parents and child; defines phasing patterns) from various population groups has defined linkage disequilibrium patterns throughout the genome; this has made possible efficient, parsimonious selection of SNPs to include in GWAS genotyping platforms.
Gastroenterology  , e1DOI: ( /j.gastro )
Copyright © 2010 AGA Institute Terms and Conditions