Effects of DNA Methylation on Adenovirus genome evolution

Abstract

DNA Methylation is a form of epigenetic modification which plays important role in regulating many cellular processes including gametogenesis, early embryogenesis, cellular differentiation and development, genomic imprinting in the mammals. Vertebrates have been reported to show CpG suppression. Viruses infecting these vertebrates have co-evolved with their hosts and thus show similar under-representation of CpGs within their genomes. We attempted to study genomes of Adenoviral strains causing infection in humans. Our data shows that in Human Adenoviruses, CpG dinucleotides are underrepresented while TpG and CpA being over-represented. The Adenovirus genome sequences were subjected to Multiple Sequence Alignment for identifying the CG dinucleotide conserved positions. Mutations of CGs at conserved positions provide strong evidence that CpG mutations have bias for TpG/CpA in comparison with any other dinucleotide sequence thereby indicating a strong association with DNA methylation in Adenoviral genome.