Figure 1.

System genetics strategies. Molecular phenotypes across multiple biological scales — including the genome (G), transcripts (T), proteins (P), metabolites (M) and microbiome — are examined using “omics” technologies in populations exhibiting natural variation. Interactions (shown as arrows) can then be identified using genetic mapping, correlation structure, causal modeling, and network modeling. For example, based on natural variations of genes 1–4 (G1–4), interactions between the genes and related molecules can be modelled. These molecular interactions are then examined in the context of clinical variation in the population. Modified from Civelek and Lusis, Nat Rev Genet 2014.