Evolutionary Origins of SARS-CoV-2

Understanding the origins of the COVID-19 pandemic will help us to prevent coronavirus pandemics happening in the future.

This animation from evolutionary virologists Spyros Lytras and Professor David L. Robertson explores the origins of SARS-CoV-2, and explains how we can work out where new viruses come from.

 

 

How are researchers understanding the evolutionary origins of SARS-CoV-2?

Understanding the origins of the COVID-19 pandemic will help us to prevent coronavirus pandemics happening in the future. We do this by searching for viruses in wild animal populations and comparing their genome sequences to SARS-CoV-2, the virus which causes COVID-19.

Comparing the similarities and differences between these virus genomes enables us to understand which viruses are most closely related to SARS-CoV-2 and how long ago they shared a common ancestor. It also helps us to work out the different types of viruses we might expect to see in a group.

Our research at the CVR is looking at the genome sequences of related viruses to help us to determine their evolutionary histories. Coronaviruses undergo 'recombination' - this is the process of two different viruses swapping parts of their genetic material. Due to recombination, each coronavirus genome does not just represent a single evolutionary history.

We separate out the recombinant parts of a genome sequence, to help us to reconstruct the evolutionary history of each virus. This computational analysis gives us a clearer picture of how these viruses are related to one another.

The search for the origins of SARS-CoV-2 has shown that there are a number of related coronaviruses currently circulating in horseshoe bat populations in China and Southeast Asia. These closely related viruses shared a common ancestor with SARS-CoV-2 about 40 years ago. Some of these unknown missing viruses circulating in wild animal populations are almost certainly capable of infecting humans.

Assessing this risk and finding these pathogens is a priority. By connecting the evolutionary history of the known coronaviruses with their sampling locations and hosts, we can draw a detailed picture of how these viruses are distributed in the environment and make predictions about the risk of pathogen emergence.

Examining how these coronaviruses evolved will give us crucial insights into where the viruses capable of infecting humans are, giving us the knowledge we need to manage and prepare for future coronavirus spillovers to the human population.

Journal articles relating to this research include:

https://www.nature.com/articles/s41564-020-0771-4

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001115

https://www.biorxiv.org/content/10.1101/2021.01.22.427830v3