WASHINGTON — A new analysis suggests the coronavirus pandemic likely began in China’s Hubei province a month or two earlier than late December 2019, when a cluster of cases tied to a seafood market was first detected.

Scientists traced mutations back in time to estimate when a common ancestral virus first emerged, did modeling exercises on how the new coronavirus spread, and reported their findings Thursday in the journal Science.

Evolutionary biologist Michael Worobey says the study is “pointing pretty strongly to that market not being the original source of the virus but the first place where it encountered sort of one of these superspreading events.”

Public health expert William Hanage, who had no role in the study, says the conclusions are “very, very plausible” and the work “pushes back in time” estimates of the origins of the outbreak.