Additive effect of SNPs on the platelet response. Each panel shows the additive association (r²) between SNPs and each platelet functional trait. To generate these models, all SNPs were added stepwise into a linear regression model in order of the significance of their individual associations (most significant first) and rejected if no longer significant (P > .01) when part of the combined model. All genotyped SNPs were entered into this model if they had an individual association with functional trait of P < .01.