Evaluation of DNA homology of Marek's disease virus, herpesvirus of turkeys and Epstein-Barr virus under varied stringent hybridization conditions.

Marek's disease virus (MDV) showed only 0.3-0.6% homology in DNA sequence with herpesvirus of turkeys (HVT) at Tm-24.4 degrees C in spite of its antigenic similarity to the latter. Southern blot hybridization under stringent conditions showed that the homology between MDV and HVT is located in the restricted portion of these viral genomes. At Tm-49.6 degrees C, which permits the detection of homology with one base mismatch in three between the MDV and HVT DNAs, sequences with weak homology were found to be distributed over most of these viral genomes. No homology was detected between Epstein-Barr virus and either MDV or HVT DNA.