Amino acid substitution models represent substitution rates among amino acids during the evolution. The models play an important role in analyzing protein sequences, especially inferring phylogenies. The rapid evolution of flaviviruses is expanding the threat in public health. A number of models have been estimated for some viruses, however, they are unable to properly represent amino acid substitution patterns of flaviviruses. In this study, we collected protein sequences from the flavivirus genus to specifically estimate an amino acid substitution model, called FLAVI, for flaviviruses. Experiments showed that the collected dataset was sufficient to estimate a stable model. More importantly, the FLAVI model was remarkably better than other existing models in analyzing flavivirus protein sequences. We recommend researchers to use the FLAVI model when studying protein sequences of flaviviruses or closely related viruses.
Keywords: Amino acid substitution model; Dengue virus; Evolution; Flaviviruses; West nile virus; Zika virus.