Tracking cytosine depletion in SARS-CoV-2

Motivation: Danchin et al. have pointed out that cytosine drives the evolution of SARS-CoV-2. A depletion of cytosine might lead to the attenuation of SARS-CoV-2. Results: We built a website to track the composition change of mono-, di-, and tri-nucleotide of SARS- CoV-2 over time. The website downloads new strains available from GISAID and updates its results daily. Our analysis suggests that the composition of cytosine in coronaviruses is related to their reported mortality. Using 137,315 SARS-CoV-2 strains collected in ten months, we observed cytosine depletion at a rate of about one cytosine loss per month from the whole genome. Availability: The website is available at http://www.bio8.cs.hku.hk/sarscov2/.