An important aspect of the European approach to the Human Genome project has been its commitment to international collaboration and its support for the Human Genome organisation (HUGO) in its role in co-ordinating the international effort. In recent years, one of the chief approaches of HUGO to the co-ordination of genome projects and the construction of detailed genetic and physical maps has been the organisation of international Single Chromosome Workshops (SCW). At each SCW participants update the genetic and physical maps relating to a specific chromosome, resolve inconsistencies between data sets and arrange collaborations including the sharing of materials. During 1992, CEC have provided core funding for SCWs held in Europe and assistance from European scientists attending SCWs elsewhere. The CEC's support has included co-ordination of SCWs and the development of guidelines for participation and organisation. The contribution of the EC to the success of recent SCWs is widely acclaimed. The present application seeks to extend core support for SCWs and their management for a further 30 months and travel costs to SCWs for participants from European countries without a national genome programme.