NEW YORK, April 14 - Just two days after a Canadian team sequenced the coronavirus believed to cause Severe Acute Respiratory Syndrome, a team from the US Centers for Disease Control and Prevention has followed suit, the agency said today.
The draft sequence obtained by scientists at the CDC is "nearly identical" to that determined by the group of Canadian researchers at the British Columbia Cancer Agency in
However, the CDC sequence has 29,727 nucleotides - 15 more than the BC Cancer Agency sequence. The lack of a bigger difference between the sequences, the CDC said, is significant, because the individuals used for the sequences were infected in different countries. This similarity suggests a common source for the virus.
The virus is typical in length for the coronavirus family, which normally has between 29,000 and 31,000 nucleotides, the CDC said.
The CDC researchers used cells that were taken from a throat culture of a SARS patient, and grew them in African green monkey kidney cells (Vero cells), to reproduce the RNA of the virus. They also collaborated with virologists across the
The Canadian group used a microgram of purified viral RNA that they received from the Canadian National Microbiology lab in
Steven Jones, head of bioinformatics at the Genome Sciences Center, led assembly efforts for the Canadian team. The virus bears only "modest" similarity to previously characterized coronaviruses, Jones said.
The scientists at the CDC plan to move on to comparative analysis of this reference sequence and different sequences of those obtained by different tissues taken from SARS patients.
"This is essentially a draft. Now we need to see if what we have identified in the laboratory matches what's causing disease in patients," Bellini said in a statement.
The Canadian group has posted its sequence on its website, http://www.bcgsc.bc.ca
"The next step for the Genome Sciences Centre is to analyze the proteins that the virus produces, to try and find clues for why this is such a virulent pathogen," Jones said in a statement.