Revisiting SARS-CoV-2: Evolution, polymorphism and compatibility with human tRNA pool in a lineage over a month

Abstract

Introduction: The present study presents a comparative analysis of SARS-CoV-2‟s survival capacity in its human host in an area within a month. Materials and Methods: Codon usage bias study has been carried using Emboss package and evolutionary study has been carried using pn/ps packages in python and R for statistical analysis. Results: The virus has overlapping genes exhibiting a high codon usage bias and optimization with human Lung housekeeping genes. Viral ORFs have near values of minimum folding energies and codon adaptation index with mRNAs of the human Lung housekeeping genes. Then too, viruses showed a greater expression capacity. Polymorphism is in the virus for ORF1ab, surface glycoprotein and nucleocapsid phosphoprotein ORFs. Non-synonymous mutations have shown non-polar substitutions. Out of the twelve mutations nine are for a higher t-RNA copy number. Synonymous mutation simulation mimicking evolution revealed fitter newer strains. Conclusion: Through this study we have explained the inherent codon adaptation of SARS-CoV-2 with human tRNA pool and how the virus shows polymorphism in-order to keep up with its infectious capacity. Hence, giving an insight into viral rapid adaptability.