The use of random fragments of DNA from a defined region of the human X chromosome has led to the identification of a region of DNA that exhibits deletion in patients with DMD. The same region is tightly linked to the disorder in families segregating the disease. A systematic search of the region has failed to detect reproducible transcription in any of the tissues tested, including both human adult and fetal tissue. A possibly more simple and straightforward approach is to utilize nucleotide sequence conservation between species to identify presumably important segments. Two conserved DNA fragments were found, and DNA sequence analysis of both the mouse and human segments should soon determine if indeed these regions are important to the normal expression of the DMD gene
