Application of bacterial artificial chromosomes to the generation of contiguous physical maps: a pilot study of human ryanodine receptor gene (RYR1) region.

In order to increase the rate of generation of a contiguous human chromosome 19 physical map, we have investigated the advantages of using a bacterial artificial chromosome (BAC) library in comparison with other systems. This cloning system, recently described, can faithfully propagate DNA fragments greater than 300 kb in size. We have screened a total human genomic BAC library with a complex cosmid probe, specific for the ryanodine receptor gene (RYR1) located at 19q13.1. One 150-kb BAC was positive for the ryanodine receptor probe. The ryanodine receptor BAC hybridized to a 150-kb overlapping set of nine chromosome 19-specific cosmids at the 3' terminus of the RYR1 gene as well as two established cosmid contigs which can be linked to the same physical region. The hybridization of the BAC to a 150-kb set of chromosome 19 cosmids suggests that this BAC is nonchimeric in structure.