Selection of a sublibrary enriched for a chromosome from total human bacterial artificial chromosome library using DNA from flow sorted chromosomes as hybridization probes

摘要

The division of total genomic libraries into chromosome-specific sublibraries is critical for efficient analysis and mapping of the genome. A new colony hybridization-based approach to rapidly identify chromosome-specific clones from a ihuman genomicbacterial artificial chromosome (BAG) library (1,2) is described. The most ideal hybridization probe for identifying all of the chromosome-specific clones from a genomic library in a single hybridization would be the chromosome itself. Using flow sortedchromosome 22 DNA as a probe, which was obtained as previously described (3,4), we screened a 4x human genomic BAG library gridded onto 42 hybridization filters at 5 x 5 density using a Biomek 1,000 gridding tool (2). 100 ng of sorted DNA was labeled with [alpha-~(32)P]dCTP and [alpha-~(32)P]dATP by random priming and hybridized to the filters under suppressive condition (2). Chromosomes 21 and 22 are similar in size, and they both are acrocentric chromosomes carryine ribosomal repeats.