Physical mapping of the cystic fibrosis region by pulsed-field gel electrophoresis.

The gene for cystic fibrosis (CF) is known to be flanked by the closely linked DNA markers met and J3.11 on chromosome 7. Using the technique of pulsed-field gel electrophoresis, we have constructed a complete overlapping restriction map of approximately 3000 kb of DNA in this region. The met and J3.11 probes are found to be between 1300 and 1800 kb apart, which compares well with their genetic distance of 1-2 cM. The CF gene must be located within this interval, and the availability of this physical map should be of considerable utility in mapping additional clones as the search for the gene proceeds.