To clone the human major histocompatibility complex (MHC), 53 YACs, wi
th an average size of 490 kb, were isolated and characterized from the
CEPH YAC library. These YACs were organized in a single large contig
covering more than 4000 kb. Furthermore, a complete physical map of th
e previously uncloned HLA class I region was established from partial
and/or total digestions of 15 YACs spanning 2000 kb. This resulted in
the establishment of the first YAC contig that spans the entire MHC re
gion and constitutes an essential step in the isolation of all of the
genes present in the region. (C) 1994 Academic Press, Inc.