A novel transcript containing homology to exons 5, 9, 10, and 11 of th
e beta-glucuronidase gene has been shown to be derived from Chromosome
(Chr) 5. In situ hybridization analysis has shown that this transcrip
t is homologous to four loci on Chr 5 (5p13.3, 5p15.1, 5q13.1, and 5q1
5), two loci on Chr 6 (6p11.2 and 6p21.3), and one on Chr 22 at 22q11.
2. Analysis of cosmid clones from Chr 5 has defined three distinct con
tigs in which there are tandem genomic repeats of a unit containing se
quences homologous to exons 5, 9, and 10 but not 11. Pulsed-field gel
electrophoresis (PFGE) analysis has shown that the length of these rep
eats is highly variable between unrelated individuals, indicating that
these regions of Chr 5 are prone to rearrangement. These sequences ma
y be important with respect to stability around the Chr 5 centromere.