Molecular relationships in infectious pancreatic necrosis virus.

Infectious pancreatic necrosis virus (IPNV), a Birnaviridae with a double-stranded RNA genome of two segments, is an important aquatic pathogen. Previous characterizations of the RNA and polypeptide patterns of different IPNV isolates have uncovered a wide variety of electropherotypes. We used RNA fingerprinting analysis to study the quasispecies, heterogeneity, and rapid mutation characteristics of IPN viruses. Via cluster analysis of the RNA fingerprints, IPNV standard serotypes as well as T42G-, T24K- and T34G-related isolates were classified into 3 clusters corresponding to the AB, SP, and VR-299 serological types. The IPNV SP cluster represents a different evolutionary route from those of the AB and VR-299 clusters. The VR-299 clusters were separated into two groups, the T34G group were divided into two subgroups. The molecular relationships between these isolates can be correlated with the biological characteristics of these IPN viruses, for example, selective growth in EPC cells and adaptive replication at high temperatures.