Scientists have created synthetic clones of the novel coronavirus SARS-CoV-2, the highly infectious virus responsible for the Covid-19 pandemic, within the space of just one week.
The synthetic clones of SARS-CoV-2 were created at the high-security laboratory at the University of Bern’s Institute of Virology and Immunology in Switzerland. By recreating the little-understood virus, the researchers hope to offer other researchers the opportunity to find new methods to fight the ongoing disease outbreak. For example, the clones can be used as a tool to develop diagnostic tests, antiviral treatments, and vaccines.
Viruses are effectively just genetic material, either DNA or RNA, wrapped in a protein shell. In the case of SARS-CoV-2, genome sequencing has shown that its “genetic code” is made up of a single-strand RNA molecule of about 30,000 bases containing 15 genes. Just for context, the human genome is in the form of a double helix of DNA molecules made of around 6.4 billion bases and about 25,000 genes.
Reported in the journal Nature this week, scientists used the “blueprint” of the genome sequence to reconstruct most of SARS-CoV-2's genetic material from synthetic DNA. The genetic material was then reassembled and introduced into Brewer’s yeast cells (Saccharomyces cerevisiae), creating a synthetic version of SARS-CoV-2 that closely resembles the real deal. However, the researchers did observe some differences in replication.
Some viruses can be cloned using a method involving the bacteria Escherichia coli, but coronaviruses can prove tricky to clone using this technique. So, the researchers looked to a pre-existing method using yeast cells previously developed at the University of Bern, known as transformation-associated recombination.
"We replicated the virus within the space of a week," Professor Volker Thiel, an organic geochemist at the University of Bern’s Institute of Virology and Immunology, said in a statement.
"Our model system using yeast cells shows that it is ideally suited for reconstructing coronaviruses and other viruses," he added.
The speedy nature of this method could allow health authorities, pharmaceutical companies, and research labs to gain access to clinical samples without the need for transporting viral samples from elsewhere, which is often considered risky and can take a fair amount of time. While there is no word yet on how or when these newly developed synthetic clones will be used, the University of Bern said in their press release that the research "attracted the interest of the World Health Organization (WHO)" after it was published on the pre-print server medRxiv back in February 2020.