RANDOM AMPLIFIED POLYMORPHIC DNA-FINGERPRINTING OF MOSQUITO-PATHOGENIC AND NONPATHOGENIC STRAINS OF BACILLUS-SPHAERICUS

Random amplified polymorphic DNA fingerprinting was used to examine 31 mosquito-pathogenic and 14 nonpathogenic strains of Bacillus sphaeric us. We verified that DNA bands that migrated the same distance in an a garose gel were homologous by using PCR-generated probes made from the random amplified polymorphic DNA bands. The band patterns obtained wi th eight primers were analyzed by using the Jaccard coefficient and un weighted pair group with arithmetic average clustering. Pathogenic str ains belonging to DNA homology group IIA were similar to strains belon ging to nonpathogenic homology groups at an average level of similarit y of 6.3%. Individual serotypes were clearly identified among the path ogenic strains. This suggests that there is overall genetic homogeneit y among strains within serotypes. It is also consistent with the unifo rm toxicity pattern found for each serotype (unlike the toxin diversit y found in Bacillus thuringiensis serotypes). These results, together with DNA homology data, support the proposal that a new species should be described for the pathogenic strains.