Finding correlated mutations among RNA segments in H3N2 influenza viruses

In order to capture a selective packaging mechanism among eight RNA segments in influenza A viruses, we assume that almost nucleotides in the positions of packaging signals must be simultaneously changed. In this paper, we formulate such positions as correlated mutations based on a joint entropy ratio, develop a method of finding all of them by using set enumeration with pruning and apply to nucleotide sequences among RNA segments in H3N2 influenza viruses.