Covid origins: Clues point to a ‘modified' close relative

In the summer of last year, two Pune scientists, Monali Rahalkar and husband Rahul Bahulikar, wrote a paper titled ‘Lethal Pneumonia Cases in Mojiang Miners (2012) and the Mineshaft Could Provide Important Clues to the Origin of SARS-CoV-2’. The research, first reported by TOI on June 16, 2020, theorised a link between Covid-19 and a pneumonia-like illness that claimed the lives of three miners in China’s Yunnan province. Their probe into the deaths and the bat coronavirus RaTG13, discovered in 2013 and currently the closest known relative of SARS-CoV-2, soon became a key part of investigations by DRASTIC, a group of scientists and analysts looking into the origins of Covid-19. The couple’s work gained momentum after a member of this group — known as ‘The Seeker’ — found other vital information that boosted the ‘lab leak theory’. Rahalkar has hypothesised that the miners’ illness was not transmissible at the time because friends, relatives and others near the mine were not sickened. But after their samples reached the Wuhan Institute of Virology (WIV), reports emerged of a fast-moving infection. Excerpts from an interview with Swati Shinde Gole:

- Swati Shinde Gole

What made you so curious about SARS-CoV-2 origins?

Its exact origin is still unknown. It’s said bats are the source of this beta coronavirus, mainly because the next relative, named RaTG13, comes from bat feces. RaTG13 is a virus sequenced from bat fecal swab collected in 2013. Not many details have been given about this interesting relative, though we know that SARS-CoV-2 and RaTG13 share 96.2% genome similarities. SARS-CoV-2 or 2019-nCoV was first described in a Nature paper (Zhou et al 2020), but the authors did not provide details on RaTG13, only mentioning that it came from China’s Yunnan province. The paper’s lead author is Zheng-li Shi, from the WIV. We later found out that RaTG13 was discovered by Zheng-li Shi’s group in 2012-13 during surveillance of an abandoned mineshaft. After going through several online sources, we found the exact location of this mine — TongGuan, Mojiang county, Yunnan.

Why is the Mojiang mineshaft link so special?