Figure 1. The Hamilton Eye Institute (HEI) Retina Database and GeneNetwork can reveal the covariance in gene expression that establishes genetic networks in the retina. A: Input: A systems biology approach and the microarray data from 75 BXD RI mouse retinas feed into the HEI Retina Database. B: Databases: The HEI Retina Database links to the interactive GeneNetwork Database website. C: Analysis: The analytical tools within GeneNetwork are used to interrogate the data set and detect the co-variance among sets of genes that map to a common genetic locus and collectively control a complex trait. D: Outcomes: Identify the unique genomic loci that co-vary with the trait of interest, which lends to the discovery of quantitative trait loci (QTL), cellular, and tissue signatures. These signatures allow the construction of schema for genetic networks.