Yang et al. (14) developed a new method, Genome-wide Complex Trait Analysis (GCTA), that focuses on the estimation of the phenotypic variance explained by genome-wide similarity at genotyped single nucleotide polymorphism (SNPs). Rather than testing each SNP individually, GCTA decomposes the phenotypic variance into two components: (1) effects due to the additive influences of all measured SNPs (h2SNP) and (2) the effects due to unmeasured environmental influences, random noise, or the effects of genetic variants that were not measured by the genotyping array. This approach allows for an estimate of phenotypic variability explained by genome-wide SNP data.
