The presence of this conserved motif in different viral families is suggested to be the result of at least two separate recombination events.

[2] To date s2m has been described in four families of positive sense single-stranded RNA viruses; Astroviridae, Caliciviridae, Picornaviridae and Coronaviridae.

The viruses that contain s2m can infect a wide range of higher vertebrates, including birds, bats, horses, dogs and humans, and display different tissue tropisms.

[11] In three patients in Diamond Princess cruise, two mutations, 29736G > T and 29751G > T ("G13" and "G28") were found in s2m of SARS-CoV-2, as "G28" was predicted as recombination hotspots in Australian SARS-CoV-2 mutants.

[12] Molecular dynamics simulations shows that both S2M variants, 29734G>C (G11C) and 29742G>U (G19U), of SARS-CoV-2 change RNA structure stability, raising questions as to the functional relevance of s2m in SARS-CoV-2 replication.