ISSUES ON EVOLUTION OF CpG ISLANDS IN GENOME OF MAREK’S DISEASE VIRUS

Aim. To study the hypothesis about influence of one form of epigenetic heredity — DNA metyla- tion — on several criteria of pathogenicity of avian herpesviruses using Marek’s disease virus (MDV) as a model. Materials and methods. Nucleotide sequences of genomic DNA of different serotypes of Marek’s disease virus deposited in GenBank were used for the study. Analysis of distribution of CpG islands intra genome was performed with CPGPLOT program. Results. Distribution and number of CpG islands differed markedly in pathogenic serotype 1 and apathogenic serotypes 2 and 3 of MDV. Diagrams of CpG islands distribution showed that serotypes 2 and 3 have significantly higher numbers of islands and they are evenly distributed across genomes. Conclusion. Lower numbers of CpG islands in MDV serotype 1 compared with serotypes 2 and 3 demonstrate pres- ence of evolutionary pressure on pathogenic forms of MDV in order to escape from host cell’s control of expression of viral proteins.

metylation, CpG island, Marek’s disease virus, epigenetic heredity