Report of the Fourth International Workshop on Human Chromosome 21

This report summarizes progress toward completing the mapping of human chromosome 21, as presented and discussed at the Fourth International Workshop on Human Chromosome 21. The overall goal of the workshop was to use both previous and new data to construct the genetic linkage map, the pulsed-field macrorestriction map, the YAC, cosmid, and P1 maps, and the gene and clinical disorders maps. Because of the large amount of mapping data now available on chromosome 21, a special effort was made to integrate all mapping information.