The genetic map of coronaviruses in bats – Claudia Grisanti


June 05, 2020 12:02 PM

An international team of researchers has created a genetic map of coronaviruses that infect bats in China. A virus identical to Sars-cov-2, which causes covid-19, could not be found. Researchers from the United States and China studied 41 bat species in six biogeographical regions. The most important regions for this study were southern China and southwestern China. 781 different rna sequences were identified and an evolutionary tree was built.

One of these viruses shares 96.2 percent of its rna sequence with the covid-19 coronavirus. Sars-cov-2 is thought to have originated from a bat coronavirus decades ago and passed on to another species before infecting people. The study was published online on bioRxiv and its data, methods and results have not yet been verified. It is therefore a preliminary report.

Funding for this research was recently withdrawn by the U.S. administration. “One of the study’s co-authors is Shi Zheng Li,” writes Science, “the expert on bats from the Wuhan Institute of Virology who received a lot of attention because of the accusations of President Donald Trump and others – not accompanied by any evidence so far – that the covid-19 pandemic originated in his laboratory. Shi categorically denied the insinuation that his laboratory ever treated a virus closely related to Sars-cov-2 “.

Population density and herds
According to the authors of the study, some factors may explain why bats in the two regions of China host many coronaviruses, very different from each other and evolutionarily ancient. The south-western area of ​​the country constituted a refuge for many mammals during the recent glacial period. The long-term presence of bats could explain the diversity of coronaviruses that infect them.

The two regions are also characterized by a large population density, many farms and a subtropical to tropical climate. According to the authors, it would be necessary to monitor the spread of coronaviruses, extending the examination also to neighboring regions in Vietnam, Laos and Burma.


One of the limitations of this study, Science specifies, is the small part of genetic material analyzed for each species. Coronaviruses have a large genome and it would have been very expensive to study the whole sequence.

The world must change its approach: instead of reacting to pandemics it should try to identify dangerous coronaviruses before they emerge, says Peter Daszak, president of the EcoHealth alliance and co-author of the study. Many other viruses closely related to Sars-cov-2 are just waiting to be detected in wildlife and studied, says Daszak. “But of course, if history repeats itself, when we have found all the rest of the clade (biological group) of Sars-2, something else will emerge.”

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