Book excerpt: This thesis focuses on using genetics to better connect complex trait associations to the molecular and cellular processes they affect. Rather than performing top-down post-genome wide association studies (post-GWAS), which has become increasingly popular in recent years as a way to dissect the factors contributing to individual risk loci, we focus here on bottom-up post-GWAS: can we use traits for which the molecular processes governing their concentrations are already well understood, and identify variants affecting them which then might lead to disease or other downstream effects? I hope that you believe this is possible, and useful, in reading these selected works which compose my dissertation.