effect size

Why we expect genetic differences between populations to be zero

We expect the genetic difference between two (or an arbitrary number of) groups that diverged from some common ancestral population to be zero under neutrality. This is a well-known result that I feel like isn’t discussed enough, especially in discussions around mean differences in traits such as IQ and educational attainment.

A general model for the bias in variant effect sizes due to population structure

Motivation The effects of population structure in GWAS (genome-wide association studies) have been well-studied. It’s one of those problems that on a surface level is quite easy to grasp intuitively.

Effect size of a tag variant

Motivation Ever wondered why the effect size of a tag variant is $$r\beta_{causal}$$? Here, $$r$$ is the correlation (measure of LD) between the tag and causal variant, and $$\beta_{causal}$$ is the effect size of the causal variant.