BBC News:
A research team in China has published analysis of samples taken more than three years ago from the market linked to the outbreak of Covid-19.
The Huanan seafood and wildlife market has been a focal point in the search for the origin of the coronavirus.
But this is the first peer-reviewed study of biological evidence gathered from the market back in 2020.
By linking the virus with animals sold in the market, it could open new lines of inquiry into how the outbreak began.
The research reveals swabs that tested positive for the virus also contained genetic material from wild animals.
Some scientists say this is further evidence that the disease was initially transmitted from an infected animal to a human.
But others have urged caution in interpreting the findings and it remains unclear why it took three years for the genetic content of the samples to be made public.
Another theory has centred on the suggestion that the virus accidentally leaked from a laboratory in Wuhan.
