No abstract

Background: The recent emergence of viral pneumonia was caused by the novel coronavirus (SARS-Cov-2), which has spread to many countries and threated the global public health.Results: In the current study, we provide a primary evolutionary analysis based on the codon usage patterns of SARS-Cov-2 genome sequences. We employed bioinformatics technologies to measure the nucleotide compositions, the relative synonymous codon usage (RSCU), the codon adaptation index (CAI), and other indices. Our results reflected that there were some similarities of codon usage bias between SARS-Cov-2 and its natural reservoirs, suggesting that SARS-Cov-2 was tended to evolve its codon usage which was comparable to that of its hosts. Additionally, various degree of adaptation to the SARS-Cov-2 host and vector were estimated, even different genes have different codon adaptation to their reservoirs. We further suggested that SARS-Cov-2 isolates were evolving at a rapid substitution rate under their translation selection pressure of their hosts.Conclusions: The findings of the present study will provide help for the understanding of the elements leading to viral evolution and adaptation to reservoirs.