Abstract
Yellowtail ascites virus and related strains isolated from marine fish have been shown to be similar to infectious necrosis virus (IPNV) in terms of biological and serological characteristics. This paper explores the relationship of aquatic birnaviruses at the genetic level. The junction region on the genome segment A coding viral capsid protein VP2 and viral protease NS was amplified by PCR in six marine strains. Analysis of nucleotide and the deduced amino acid sequences revealed that the six marine strains have amino acid variations in the possible amino terminus of NS when compared to IPNV. The six marine strains form a new genogroup which is distinguished from three serotypes ofPNV.