Sequence-ready 1-Mb YAC, BAC and cosmid contigs covering the distal imprinted region of mouse chromosome 7.

We have constructed approximately 1-Mb contigs of yeast artificial chromosome (YAC), bacterial arti- ficial chromosome (BAC) and cosmid clones covering the imprinted region in mouse chromosome band 7F4/F5. This region is syntenic to human chromosome Ilpl5.5, which is associated with Beckwith- Wiedemann syndrome (BWS) and certain childhood and adult tumors. These contigs provide the basis for genomic sequencing, identification of genes and their regulatory elements, and functional studies in trans- genic and knockout mice, which should be of help to understand not only the mechanisms of imprinting but also the molecular events involved in the genesis of BWS and tumors.