Funds are requested to support the travel of 35 scientists to participate in a workshop to be held in Philadelphia, Pennsylvania, September 1992. This will be the third chromosome 22 workshop. The workshop will be entitled "Mapping Chromosome 22: Progress and Strategies". The small size of this chromosome and its numerous structural rearrangements make it an excellent model for the Human Genome Mapping Project. The completion of a map chromosome 22 will provide invaluable tools for the understanding of the many developmental diseases and malignancies which are associated with structural abnormalities and deletions of this chromosome, and will permit comparisons to be made between its physical and genetic maps. This meeting is designed to bring together scientists with the appropriate biological resources and expertise in many of the scientific disciplines required to expedite completion of the map of chromosome 22. The meeting is intended to broaden collaborative efforts and to foster more extensive scientific interchange. Based on information already generated, resources available and the development of new technologies, the workshop will serve to determine the most efficient methods for completing a detailed genetic and physical map of human chromosome 22.