0090286 Allison, David In what tissues are specific genes expressed? What circumstances alter a gene's expression levels? Which genes "co-express" as functional families? Microarrays can measure expression of thousands of genes simultaneously in tissues of any organism, providing unprecedented power for studying gene expression. However, many questions about microarray technology and the resulting data remain unanswered. Questions surround sample size requirements, measurement quality, testing for group differences in expression levels in the face of vast multiple testing, and optimal grouping (clustering) methods. Few scientists with theoretical/quantitative science expertise are addressing these questions and those that are still struggle for answers. This program offers an interdisciplinary inter-institutional Network of scientists opportunities to work synergistically on such questions. Goals are: a) Facilitate communication and brainstorming among interested scientists who may be geographically or otherwise isolated; b) Stimulate methodological developments in microarray analysis; c) Provide increased opportunities for dissemination of developments to the scientific community; and d) Support entry of new and established quantitative/theoretical scientists into this area. The Network includes computer scientists, geneticists, statisticians, bioinformaticists, measurement theorists, and microarray technology experts plus microarray users. It has two primary activities: a) an annual retreat at a secluded location; b) an inter-institution scholar exchange. Investigators with varying backgrounds but common interests in microarrays will interact in settings facilitating open and contemplative communication. Supplementary activities will disseminate information to the broader scientific community. This program can greatly enhance the practice of microarray analysis thereby generating new basic biological knowledge impacting fields ranging from forestry to agriculture to medicine.