Assignment of 55 novel cosmids to seven subregions of chromosome 13 using fluorescence in situ hybridization.

Fifty-five individual cosmids isolated from a chromosome 13-specific library have been regionally assigned using fluorescence in situ hybridization. These cosmids represent novel DNA markers that can be added to the limited number of DNA probes already available for this chromosome. Individual cosmids mapped along the length of the chromosome with almost equal distribution except that there appears to be an excess of probes from the distal 13q33-q34 region. Only two cosmids did not map back to chromosome 13, indicating that at least 96% of cosmids in this library are from this chromosome. The library is generally available as gridded colonies on nylon membranes suitable for hybridization screening.