Rare C-to-G mutations occurred at an unexpectedly high frequency during emergence of SARS-CoV-2 delta variant

SARS-CoV-2 possesses a diagnostic aboveground protein, the spike protein, which plays a cardinal relation successful viral introduction into big cells. The improvement of spike macromolecule mutations has been an important origin successful the emergence of viral variants with altered transmissibility and immune-evasion properties. Previous studies person shown that SARS-CoV-2 improvement is powerfully biased toward definite types of nucleotide substitutions, with C-to-G substitutions occurring lone rarely.