Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)

This question is quite general, so I'm going to attempt to tie it back to bioinformatics. Background The tree for the current coronavirus is here, showing it is closely related to bat-coronavirus and in particular SARS. Question The bioinformatics question for the current coronavirus is why this virus appears to be able to infect humans…