CONSTRUCTION OF HIGH-RESOLUTION PHYSICAL MAPS FROM YEAST ARTIFICIAL CHROMOSOMES USING RESTRICTION LANDMARK GENOMIC SCANNING (RLGS)

We have established a new system for chromosome-specific yeast artific ial chromosome (YAC) contig construction using restriction landmark ge nomic scanning (RLGS-based YAC contig mapper). RLGS is a powerful tool for detecting more than 1000 restriction landmarks distributed on an entire genome in one procedure. In this system, RLGS is applied to sor ted chromosomes to cover the target chromosome. Using these landmarks as guideposts, chromosome-specific YAC clones are then ordered. In thi s paper, we report the construction of a map for a human chromosome 21 YAC contig spanning q22.1 using this new approach. Applying RLGS to s orted chromosomes 21 enables detection of approximately 1400 spots (eq uivalent of 1050 PacI landmarks), covering the entire region of this c hromosome. We constructed the 2.5-Mb YAC contig encompassing 21q22.1 w ith 66 spots (equivalent of 50 PacI landmarks). With this contig map, we could detect two deleted regions and chimerism in the YAC insert DN A. Our results demonstrated the usefulness of this approach for findin g DNA alterations of YACs, such as deletions and chimerism. (C) 1996 A cademic Press, Inc.