Background SARS-CoV-2 is a novel coronavirus that causes COVID-19 infection, with a closest known relative found in bats. For this virus, hundreds of genomes have been sequenced. This data provides insights into SARS-CoV-2 adaptations, determinants of pathogenicity and mutation patterns. A comparison between patterns of mutations that occurred before and after SARS-CoV-2 jumped to human hosts may reveal important evolutionary consequences of zoonotic transmission. Methods We used publically available complete genomes of SARS-CoV-2 to calculate relative frequencies of single nucleotide variations. These frequencies were compared with relative substitutions frequencies between SARS-CoV-2 and related animal coronaviruses. A similar analysis was performed for human coronaviruses SARS-CoV and HKU1. Results We found a 9-fold excess of G–U transversions among SARS-CoV-2 mutations over relative substitution frequencies between SARS-CoV-2 and a close relative coronavirus from bats (RaTG13). This suggests that mutation patterns of SARS-CoV-2 have changed after transmission to humans. The excess of G–U transversions was much smaller in a similar analysis for SARS-CoV and non-existent for HKU1. Remarkably, we did not find a similar excess of complementary C–A mutations in SARS-CoV-2. We discuss possible explanations for these observations.
【저자키워드】 COVID-19, Evolution, SARS-CoV-2, mutations, bioinformatics, transversions, Mutagenesis, 【초록키워드】 coronavirus, Mutation, SARS-CoV, Genome, Transmission, virus, Novel coronavirus, COVID-19 infection, humans, RaTG13, bat, SARS-CoV-2 mutation, pathogenicity, bats, HKU1, Frequency, Analysis, Animal coronaviruses, complementary, relative frequency, determinant, human host, Substitution, zoonotic transmission, single nucleotide variations, Complete, consequence, human coronavirus, Result, occurred, sequenced, was performed, provide, cause, changed, calculate, 【제목키워드】 variant, SARS-CoV-2 genome, allele,