PhD student discovers key genetic SARS link

Month-long project leads to four-month investigation and revolutionary discovery

A U of T student had no idea his class project would end up unravelling the history of SARS. But when he was assigned an open-ended study, John Stavrinides jumped at the chance to tackle public enemy number one.

“I chose the SARS genome because it was obviously very important from a medical perspective,” said Stavrinides, a PhD candidate in comparative genomics.

Under the supervision of Professor David Guttman of botany, Stavrinides turned a month-long project into four months. It would involve 10-hour days in front of the computer, using computational tools to trace the coronavirus’ checkered past.

The detective work paid off. As Stavrinides and Guttman unravelled the history of the genome, they discovered that SARS was formed by a combination of mammalian and avian viruses. This recombination event created an entirely new coronavirus, unrecognizable to human immune systems.

Similar genetic exchange events are believed responsible for some of the most devastating viral epidemics and pandemics such as the 1918 Spanish flu pandemic that killed over 20 million people worldwide. Guttman said this type of genetic change can have far more dramatic consequences than simple genetic mutations, in
which only small features in genes are changed at any one time.

“These recombination events have the potential to create an entirely new structure essentially instantaneously,” he said. “Since our immune systems have never seen this new viral form, it is more difficult for them to respond to it in a timely and effective manner.”

Stavrinides and Guttman’s findings were published in the January issue of the Journal of Virology. Although an effective vaccine for SARS is years away, the study offers another piece to the puzzle.

“We hope that this work will contribute to the design of specific and effective vaccines,” Guttman said, “but perhaps it will be most useful in the development of tests for the diagnosis of new SARS outbreaks. We will be in a much better position to recognize new and potentially deadly viral outbreaks if we can identify the specific evolutionary changes that made SARS so deadly.”

The project garnered Stavrinides an A and received extensive international coverage in media outlets as far-reaching as Al-Jazeera and BBC News, but he’s not resting on his laurels. While his PhD work centres on bacteria instead of viruses, he said what he learned working with SARS was invaluable.

“In our field, you can apply all the tools and concepts to virtually any system,” said Stavrinides, who is studying plant pathogens. “That’s the power of evolutionary study.”

Karen Kelly is an assistant news services officer with the department of public affairs.
U of T Public Affairs, ph: (416) 978-0260; email: k.kelly@utoronto.ca