[Analysis on molecular genetic evolution of Banna virus based on the 12th segment].

Objective: To understand the evolution characteristics of Banna viruses (BAVs) isolated worldwide from 1980 to 2012. Methods: In this study, a phylogenetic analysis using Bayesian Markov Chain Monte Carlo simulations was conducted on all available 12th segment of genes of BAVs isolated worldwide from 1980 to 2012 to investigate the evolutionary and epidemiologic dynamics of BAVs. Results: The Bayesian phylogenetic analysis of BAVs revealed that the common ancestor of BAVs appeared 315 (95%HPD: 63-619) years ago. The evolutionary rate of BAV based on the 12th segment gene was estimated to be 2.33×10-3 (95%HPD: 2.84× 10-4-8.52×10-3) substitution per site per year, indicating BAV belong to an emerging arbovirus with rapid evolution. Conclusion: The evolution of emerging BAVs is rapid and the distribution of BAVs has expanded with new variant being detected, so it is necessary to enhance the surveillance to fully understand the natural distribution and pathogenicity of BAVs.