http://www.sciencemag.org/news/2020/03/mutations-can-reveal-how-coronavirus-moves-they-re-easy-overinterpret

Tables are empty at St. Mark’s Square in Venice after the Italian government adopted emergency measures to contain the novel coronavirus.

Immediately after Christian Drosten published a genetic sequence of the novel coronavirus online on 28 February, he took to Twitter to issue a warning. As the virus has raced around the world, more than 350 genome sequences have been shared on the online platform GISAID. They hold clues to how the new virus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading and evolving. But because the sequences represent a tiny fraction of cases and show few telltale differences, they are easy to overinterpret, as Drosten realized.