Scientific and technical journals in biology and medicine in recent years have extensively covered a debate about whether and how to determine the function and order of human genes on human chromosomes and when to determine the sequence of molecular building blocks that comprise DNA in those chromosomes. In 1987, these issues rose to become part of the public agenda. The debate involves science, technology, and politics. Congress is responsible for "writing the rules" of what various Federal agencies do and for funding their work. This report surveys the points made so far in the debate, focusing on those that most directly influence the policy options facing the U.S. Congress. Topics covered in this report include: (1) DNA mapping; (2) research applications; (3) ethical and social issues; (4) organizations and agencies involved in gene mapping in the United States; (5) project organization; (6) efforts of other countries; and (7) the transfer of technology. Appendices list contract report topics, workshop participants, cost estimates, lists of databases, a bibliometric analysis of research, and a glossary. (CW)