To provide funding of the NSF-supported Living Stock collection entitled ?Collection of Mutant Types of Drosophila melanogaster? located at Bloomington, Indiana. The NSF will add funds contributed by the NCRR, NIGMS and the NICHD of NIH, to the NSF-supported Living Stock Collection entitled ?Collection of Mutant Types of Drosophila melanogaster? to assist in assuring that documented strains are readily available to all qualified NIH users. The Stock Center will, in all publications and news releases to the scientific community and general public, state the involvement of the NCRR, NIGMS and NICHD of the NIH in supporting this resource. The Stock Center will provide to NCRR a list of users of the resource for each calendar year. The Bloomington Drosophila Stock Center collects, maintains, and distributes genetic stocks of the fly Drosophila melanogaster. The high degree of conservation between insects and vertebrates of many proteins and cellular and developmental pathways combined with the Drosophila extensive set of well developed genetic tools make it one of the foremost model organisms for investigating many fundamental problems in biology. The collection consists of over 24,800 different stocks that carry more than 39,600 unique genetic components. Mutant alleles of over 9,000 genes account for 45% of these unique components. Insertions of transgene constructs (engineered transposable elements) make up 45% of unique components and chromosome aberrations account for the remaining 9%. Stock information is incorporated into FlyBase, the primary Drosophila community database, and is available from the Center's web site, providing full access to up-to-date information about stocks available from the collection. In addition, Center scientists are available to answer questions and provide advice on the use of these materials. Stocks in the collection are in demand, with approximately 165,300 stock samples being requested from the Center last year. Academia-based researchers receive 98% of the samples distributed, 56% working in the U.S. and the remaining 44% spread among 52 countries. This resource contributes to scientific progress by assuring that a wide variety of documented strains of current research value are readily available to all researchers, and by promoting the effective use of available research materials through information services. Drosophila resource activities impact all areas of research with major contributions from Drosophila studies, including gene regulation, cell biology, developmental biology, neurobiology, behavioral biology, population biology, ecology and evolution. Given that 77% of human genes that have been associated with a heritable disease have a clearly related gene in Drosophila, research using Drosophila can be expected to have a direct impact on our understanding of human health in the coming years, including development of disease treatments.