Aging and developmental change represent body wide changes in genes. Because many genes change as people age, the relationships between genes also often change, a phenomenon called differential coexpression (of RNA levels). Studying differential coexpression has uncovered changes that cause disease. However, knowledge gaps remain with respect to relationships between disease and aging in neurological diseases, for example. Many diseases have a specific age of onset, schizophrenia for example, typically strikes in early adulthood. This suggests that in multi-gene disorders, where interactions between genes play a role, rewiring may occur between susceptibility genes at the age of disease onset. Dr. Gillis's current research project builds on his earlier work which showed that aging is associated with numerous changes in coexpression, and that genes known to be associated with specific diseases change their relationships with age in healthy individuals. His current project involves studying how the relationships between candidate genes - differential coexpression - in schizophrenia and Alzheimer's Disease, change as a function of age. By understanding how networks of gene interactions might be rewired in diseases, we can identify candidate genes that would be missed otherwise, and beneficially influence the design of treatments and diagnostics.