We constructed a yeast artificial chromosome (YAC) framework map of human chromosome 4 by screening a YAC library with 63 polymorphic DNA markers located on the chromosome. These genetic markers are from two framework melotic maps that had previously been constructed by two research groups, and are placed on the two maps with odds for their order of 1000: 1 or greater. In addition to Isolating and determining the sizes of 141 YAC clones for 54 of these markers, we combined the two framework melotic maps to produce a single Integrated map. These combined maps and the YAC clones provide a set of extended DNA loci ordered at high odds that can be used to isolate additional polymorphic loci and genes, and to serve as a framework for obtaining a higher resolution physical map of the chromosome. © 1994 Oxford University Press.