The objectives of the core component are three-fold: (1) to provide administrative support for participants in the Program; (2) to establish centralized facilities for chemical analysis and oligodeoxynucleotide synthesis; and (3) to conduct a seminar series in which visiting scientists will be invited to discuss their research with Program members. The administrative structure of the Program is substantially unchanged. The Core Project has been expanded to include sophisticated mass spectrometer analysis as well as automated DNA synthesis and purification. Mass spectrometry will play a critical role in the analysis of adducts and synthetic intermediates; we hope to add an important new component, a LC/MS thermospray system, to our current facilities. Synthesis of oligodeoxynucleotides is essential for all investigators in the Program; this can most effectively be accomplished by a centralized service facility. Synthesis of certain chemically-modified oligodeoxynucleotides will require large scale preparation of modified deoxynucleoside phosphoramidites. This will be conducted in the core facility.