Modern genome association studies rarely look for single allele effects anymre. The current views shift towards polygenic or sometimes even omnigenic (meaming m

Modern genome association studies rarely look for single allele effects anymre. The current views shift towards polygenic or sometimes even omnigenic (meaming majority of genes can have indirect effects on the phenotype of disease) associations. No one expects to see big effect sizes because very few people will have differences in any one particular loci. So under these models simple effect sizes are less important than p-values.