Analysis of the viral demographic expansions of polyomavirus JC (JCPyV) and their association with human history

PERESON, M; SANABRIA, DJ; TOTARO, ME; SANCHEZ-FERNANDEZ, C; LIOTTA DJ; BADANO, I

Foz do Iguaçu-PR.

Congreso; XXII International Congress of Genetics (ICG); 2018

Sociedade Brasileira de Genética.

Introduction: Bayesian Skyline (BSK) plots are graphical representations of historical effective population sizes as a function of time, which can be used to trace viral demographic expansions of the polyomavirus JC (JCPyV) and their association with human history. Currently, there are two models for JCPyV demographic history: (i) a viral expansion starting 10,000 years ago, compatible with the Neolithic transition in humans, and (ii) a viral expansion starting 50 years ago, attributed to the end of World War II. Both Models are based on calibration times with viral fixed mean substitution rates of 10-7 substitution/site/year (s/s/y) and 10-5 s/s/y (respectively), and have some drawbacks to fully explain JCPyV evolution. Objective: To estimate an alternative JCPyV model of evolution by using BSK plots calibrated with a theoretical fixed rate of 10-6 s/s/y. Material and methods: BSK plots were estimated on the analysis of 456 sequences of the VP1 gene, obtained by our group (n=21) or available at GenBank (n=435) by using Beast software.Results: The BSK plots showed two phases of growth: (I) Constant (2500-500 years ago) and II) Exponential (from 500 years ago to the present). These two phases can be associated with the development of human civilization and the arrival in the Americas, respectively. Conclusion: We described an alternative hypothesis to the fast and low models of JCPyV evolution. Future epidemiological and phylogeographical studies will be needed to further support this model.Funding: ANPCyT. PICT 2012- 0761. Argentina. Codon Code Aligner License Grant.