A genome is the genetic material of an organism. In 1981, two different
research groups, Vincent Racaniello and David Baltimore at Massachusetts
Institute of Technology and Eckard Wimmer’s team at State University
of New York, Stony Brook, published the poliovirus genome. They used
an enzyme to switch the single strands of viral ribonucleic acid—RNA—to
double strands of deoxyribonucleic acid—DNA—and then determined
the sequence of adenine, thymine, guanine, and cytosine encoding the
five molecules that are the substance of the virus’s existence.
Poliovirus lacks the ability to correct its mutations, so its genome
evolves at one to two nucleotide substitutions per week. It is always changing.
Left: Eckard Wimmer (left) and colleagues Jeronimo
Cello and Aniko Paul in the Stony Brook lab where they synthesized polio, 2002.
Cello holds a tissue-culture plate in which dilutions of synthesized polio
are growing. Courtesy of Eckard Wimmer
Right: Vincent Racaniello in his lab at Massachusetts
Institute of Technology, around 1985 Courtesy of Vincent Racaniello
In 2002, investigators at the State University of New York in Stony
Brook used the published genetic sequence to synthesize a DNA version
of poliovirus. Then they used an enzyme to convert the DNA to RNA and
grew the virus in a cell-free extract. Animal tests showed that the synthesized
poliovirus caused paralysis.
“The world had better be prepared. This shows you
can re-create a virus from written information.”
—Eckard Wimmer, 2002
Workers in P-4 suits, used for protection from the most virulent pathogens
“I did not use any machine for sequencing the
poliovirus genome. It was all done by hand—my hands! I used what
was known as the ‘Maxam-Gilbert’ method, in which four different
chemical reactions are carried out on the DNA. The products are then
fractionated on thin polyacrylamide gels, which were poured manually,
run, and then carefully removed from the plates, dried, and exposed to
X-ray film. The sequencing ‘ladders’ were then read by myself
on a light box and entered manually into a computer. But we didn’t
have individual computers back then, so I used a terminal hooked up to
an MIT central computer.”
—Vincent Racaniello, 1981
|Who Needs Synthesized Poliovirus?
Viruses like polio, Ebola, and smallpox can never be eradicated because
they can be created in the lab with a DNA synthesizer and the genetic
code. Synthetically made viruses have the potential for both harm and
good. Biological weapons can be created from them. But they might be
altered to create new vaccines or novel systems to deliver genes as therapy.