As the current number of Covid-19 cases keeps rising across the globe, researchers aren’t only concerned about finding a vaccine or effective treatment – they also want to track the virus to find out how it spreads, mutates and adapts over time.
A team from Arizona State University (ASU) lead by Efrim Lim, assistant professor at ASU's Biodesign Institute, traced the trail of the virus across the world by using advanced technology that can decode the entire genetic code of SARS-CoV-2.
Their research was announced in a news release and published in the Journal of Virology.
What is genome sequencing and why is it important?
We’ve been hearing the term “genome sequencing” frequently in coronavirus-related content, but it’s often hard to understand, especially if you are not an expert in epidemiology.
Genome sequencing is the process of “figuring out” the exact order of DNA nucleotides in a virus, almost like letters in a sentence, but without punctuation and capitals.
People often compare genome sequencing with “decoding” a virus, but it’s not really the same – all the letters of the DNA nucleotides are already coded – sequencing is simply “reading” this long order of letters to understand what’s behind the virus.
Each virus contains its own unique genome, which will help researchers understand more about that virus. For researchers, a database of each and every sequence is important to help them track and trace SARS-CoV-2.
For this purpose, each sequence is deposited into a worldwide gene bank, which currently shows that SARS-CoV-2 originated from a single source in Wuhan, China and slowly developed different strains as it spread across the globe – first to Europe, and then to the States and Africa through travel.
A unique mutation
From this database of sequences, the team at ASU discovered a mutation that has never been seen before.
The mutation showed that 81 of those letters from the DNA nucleotides simply disappeared.
"One of the reasons why this mutation is of interest is because it mirrors a large deletion that arose in the 2003 SARS outbreak," said Lim in the press release.
Apparently, the same happened during the middle and late stages of the SARS outbreak in 2003, which made the virus significantly weaker. Scientists believe that a weakened virus has more potential to spread through a community without causing severe symptoms and complications.
In the case of this mutation, it has never appeared in the existing database before and could provide more insight into how the virus makes people sick. According to experts, it could also be a new starting point for others who are developing vaccines from scratch.
But, with SARS-CoV-2, only time will tell how exactly this pandemic will play out.
Lim stated that only 16 000 SARS-CoV-2 genomes have been sequenced to date, which is a minuscule portion of the strains that are currently out there. The ASU team will continue tracking different strains to provide more information and more ways of fighting the virus.
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