DNA fingerprinting method was applied to identify inbred strains of la
boratory rats. By Southern blot hybridization with core sequence of mi
nisatellite DNA as a probe, typical hypervariable patterns of DNA fing
erprint were obtained in inbred rat strains. The patterns were complet
ely different among 15 rat strains examined, and the patterns of the D
NA fingerprint of samples obtained from the same strain were completel
y identical. The patterns of the DNA fingerprint of two substrains der
ived from the same strain were identical, indicating relative stabilit
y of the patterns over a large number of generations. Therefore, we co
ncluded that the DNA fingerprinting method was useful for the identifi
cation of inbred strains in genetic monitoring of laboratory rats.