PHYSCI 121 Chapter Notes - Chapter N/A: Restriction Enzyme, Bacteriophage, Exon
Document Summary
The dmd transcript is formed by at least 60 exons which have been mapped relative to various reference points within xp21. The first half of the dmd transcript is formed by a minimum of 33 exons spanning nearly 1000 kb, and the remaining portion has at least 27 exons that may spread over a similar distance. The dna isolated from 104 dmd boys was tested with the cdna for detection of deletions and 53 patients exhibit deletion mutations. The majority of deletions are concentrated in a single genomic segment corresponding to only 2 kb of the transcript. The high disease frequency correlates with the high rate of new mutations, estimated to represent one- third of all dmd cases (for review, see moser, 1984). One of these deletion-specific clones, pert87 (dxsl64), was found to be tightly linked to the dmd gene and detected deletions in 6. 5% of dmd patients (monaco et al. , 1985; kunkel et al. , 1986).
