In contrast, other experts in the field say the two types the Chinese researchers claimed to have identified were a result of both normal viral mutation and errors in data that they were relying on.
University of Queensland virologist Ian Mackay said there were fundamental problems with the study, including that some of the data, which was published on a database shared by researchers, had not yet been "cleaned up".
"[The differences] are sequence errors which in fact were corrected [by the submitting scientist] very soon after they were originally uploaded to the GISAID database," Professor Mackay said.
He said the patterns they identified were no more than normal variation.
"They're almost all identical. It's like us putting on different clothes from day to day," Professor Mackay said.
"I can't believe this has been peer reviewed. It's a weak paper and poor science."