Crohn's disease-isolated mycobacteria are identical to Mycobacterium paratuberculosis, as determined by DNA probes that distinguish between mycobacterial species

Abstract
DNA extracted from an unclassified Crohn9s disease-isolated Mycobacterium strain was cloned. The recombinant clones were radiolabeled and hybridized to restriction digests of mycobacterial DNA transferred to nylon membranes. Restriction fragment length polymorphisms (RFLPs) were identified that distinguished between mycobacterial DNA samples. Quantitative estimates of frequencies of DNA base substitution were also obtained. No RFLPs were detected between the DNA of three unclassified Crohn9s disease-isolated mycobacteria and Mycobacterium paratuberculosis, although several RFLPs were detected that distinguished between M. paratuberculosis and both M. avium complex serovars 2 and 5. The frequency of DNA base substitution between M. paratuberculosis and M. avium complex serovar 2 was measured as 0.87 (+/- 1.2)%. Images