Along with family-based studies, dozens of genome-wide association studies (GWAS) have clearly identified the genetic basis of common diseases and complex traits. There are currently hundreds of single nucleotide polymorphisms (SNP) associated with human disease as well as biochemical and physiological phenotypes. Although this is only the tip of the iceberg, we are now confronted with a general lack of understanding of how these trait-associated variants act. How do these genetic changes lead to overt clinical phenotypes? What are the molecular mechanisms? Can we harness this information to develop better preventive and curative strategies? Current efforts are shifting to focus on these questions as we move from identifying variants to understanding their effects. Here I provide a broad overview of the main technical concerns and current bottlenecks as we approach this new phase.
Keywords: Complex traits; Fine-mapping; Functional genomics; GWAS; Genotype; Human disease; Phenotype; Variant function.