This proposal requests funds for the purchase of an ABI 3100 DNA Analyzer in support of the Department of Pediatrics Molecular Biology Core Laboratory. A new Molecular Biology Core Laboratory will be open not only for all of the Scholars and Mentors of the CHRC but to other researchers based in (or who collaborate with programs) in the Department of Pediatrics. The laboratory will continue to operate as a charge back unit, billing investigators accounts via the office of Grants Accounting at Baylor College of Medicine, as occurs now with the CHRC Core. In 1991, an ABI 373 sequencer was purchased for the CHRC laboratory and upgraded twice in an attempt to keep up with the increasing demands of our CHRC Mentors and Scholars. With obsolescence, the instrument will be increasingly difficult to maintain, but the actual and anticipated throughput of the laboratory cannot be met with existing equipment. We have identified 19 users all of whom are independently funded. The 8 major users have sequencing needs of 44,500 and genotyping needs of 10,000 sequences. Our minor users and future Scholars of the CHRC will need approximately 16,000 sequencing reactions and an additional 2000 for genotyping. In total, we anticipate a demand for approximately 71,500 samples in the first year of operating the new instrument.