I am reading a GWAS paper that found a SNP associated to predisposition to colon cancer and was assessed for gene expression of the nearby gene. They found that the genotype accounted for 55% of the variation in the nearby gene expression. 55% sounds like a lot to me, what is the usual percent accounted for a significant SNP in a study like this?

http://www.nature.com/ng/journal/v44/n7/full/ng.2293.html

I am reading a GWAS paper that found a SNP associated to predisposition to colon cancer and was assessed for gene expression of the nearby gene. They found that the genotype accounted for 55% of the variation in the nearby gene expression. 55% sounds like a lot to me, what is the usual percent accounted for a significant SNP in a study like this?

• Dunlop MG, Dobbins SE, Farrington SM, Jones AM, Palles C, Whiffin N, Tenesa A, Spain S, Broderick P, Ooi L-Y, et al.. 2012. Common variation near CDKN1A, POLD3 and SHROOM2 influences colorectal cancer risk. Nature genetics 44: 770–776.