By Carey Gillam Since the outbreak of COVID-19 in the Chinese city of Wuhan in December 2019, scientists have searched for clues about what led to the emergence of its causative agent, the novel coronavirus SARS-CoV-2. Uncovering the source of SARS-CoV-2 could be crucial for preventing future outbreaks. A series of four high profile studies … Validity of key studies on origin of coronavirus in doubt; science journals investigating