Detection of the viral telomerase RNA gene in very virulent (MDV-RB1B) and vaccine (MDV-Rispens and HVT) strains of MDV. Viral genomic DNAs of the MDV-RB1B (RB), MDV-Rispens (RI), and HVT (HV) strains were digested by the BamHI endonuclease, electrophoresed through a 1% agarose gel, and blot hybridized to the vTR gene. The position of the molecular weight marker and the BamHI L fragment from pBMB 8-5 clone are shown at the left and the right, respectively.