The recipe for artificially creating a mass-killer disease such as smallpox or plague is apparently fairly simple. Take sequencing details conveniently posted on a publicly accessible website, add a sprinkling of commercially available, tailor-made DNA and spend a couple of years in a laboratory cooking-up a lethal concoction.

And there is no doubt laboratory-built microbes that cause disease can be made. Earlier this year a group of scientists at the University of New York announced they had assembled the world's first virus - polio - from scratch using freely available sequencing data. "We did it to prove it can be done," said Eckard Wimmer, research team leader. "This approach has been talked about but not taken seriously."

So how seriously should we take the question of releasing sequencing data to all and sundry? In the USA - the country it might be assumed would be most concerned about this issue - there appear to be conflicting messages from the administration. President Bush's National Security Advisor, Condoleezza Rice, has spoken up for "open and collaborative basic research" while Chief of Staff Andrew Card has ordered federal departments to protect information about weapons of mass destruction and other information that could compromise national security.

In the UK there has been no definite steer on the subject from the Government but the question of vetting everyone who works on the most dangerous human pathogens - including those at biosafety level 4, which have no antidote or vaccine - has been pondered, although, so far, taken no further. One Whitehall official said: "It's a contentious issue but perhaps we should look at the profiles of people working in this area and consider whether they are psychologically suited to the work they are doing or if they might mis-use the information they have."

Access to dangerous pathogens in the UK might be difficult, but do genome sequence data provide a handy second-best, conveniently available at any computer terminal connected to the web? The issue has exercised the minds of pathogen sequencers at the Wellcome Trust Sanger Institute in Hinxton, near Cambridge, such as Dr Julian Parkhill. Although he accepts there might be potential dangers in releasing certain sequencing data, he is convinced that the overall benefits outweigh the risks.

"Information of this sort accelerates research. It makes it more likely that we can produce drugs and vaccines to oppose diseases. You can't undertake something as important as sequencing genomes and then refuse to make those details available just because you feel there might be a few out there who will use them for nefarious purposes. In the end that would be counter-productive."

For a start, says Dr Parkhill, genome sequence data are not going to provide anyone with a ready-made weapon. "The temptation to prohibit sequence release arises from the belief that the data will be used by hostile governments, terrorist groups or even individual bioterrorists. However, most of the problems associated with producing and using biowarfare agents - such as growth, storage and dispersal - will not be assisted by genomic information.

"In contrast, most defensive interventions, including novel drugs, vaccines and surveillance methods, could be vastly improved by genome-based technology. I believe restrictions on data release would compromise the ability of legitimate scientists to study these organisms and investigate new countermeasures, while offering essentially no tangible benefit to the security of the general public."

There are also practical issues, he suggests: "When you release this kind of data it's all or nothing. You can't have partial release. Now, you might say we should vet who gets this information so we can sift out potential terrorists. But who would do the vetting? How would it work? You cannot track data once it has been released on the internet."

And even restricted access brings its own problems: "Fundamentally, the primary issue of data release is control. If genome sequence information is not available openly to the public, it is in the control of someone else, in this case government organisations. When the public know the government is withholding information, they become distrustful of the motives of the scientists involved in the research."

Viruses

Professor Geoffrey Smith, a Wellcome Trust Principal Research Fellow at Imperial College London, who has worked with poxviruses since 1981, is equally adamant there is no substance to the claim that 'sensitive' scientific information should be kept secret in case it falls into the wrong hands.

"There is no question that making pathogen sequencing information publicly available does more good than harm. Genome sequences have been in the public domain for many years and we have had no incident - as far as I know - where a terrorist has made use of them. So why change the situation?" says Professor Smith.

"We know researchers in America have taken the polio sequence from the web and developed a live virus, but this information has been around since 1980 and live polio virus was re-made from cloned DNA in 1981. This was a major breakthrough in polio research and has helped considerably in understanding the virus. Besides, if a terrorist wanted to make something like variola virus, the cause of smallpox, he would need a sophisticated lab - it's not something you can do in your back garden."

One pathogen being studied by Professor Smith is camelpox, an endemic infection of camels throughout the world. Using a viral strain isolated from Iranian camels in the 1970s, Professor Smith's team recently discovered that camelpox is, genetically, quite similar to variola virus. This raised the possibility that it might be used to create a virus that causes a smallpox-like disease in humans. Professor Smith pressed on with publication. "Recently our laboratory sequenced camelpox, and did not hesitate to publish this sequence. I believe there are far more benefits from disseminating scientific information than keeping it under wraps."

The scientific press shares a similar perspective. Dr Rory Howlett, Deputy Biological Sciences Editor at Nature, says: "I don't think we have ever rejected a paper because we thought it would be useful to terrorists or anyone developing biological weapons. Our view is that properly peer-reviewed science should be out there in the public domain."

Global perspectives

It is useful to remind ourselves why pathogen genome sequencing is being undertaken, suggests Dr Parkhill. "Many pathogens considered as theoretical biowarfare agents in the developed world are existing public health threats in the developing world. Diseases such as plague and anthrax are still endemic in some regions so we have to make use of any information we have if we are to eradicate them."

Restricting access could therefore harm the very people pathogen sequencing is intended to benefit. "People engaged in this kind of work will almost certainly not be a small cell of terrorists acting alone. They are more likely to be state-sponsored which means genome sequencing details could be easily available to them. But a scientist engaged in legitimate research on, say, TB, who is working in a remote area of the developing world, will not have easy access to sophisticated equipment and lots of money. He will need scientific data via the web to help his work." In the end, it is much more likely that pathogen genome sequences will save lives rather than cost them.

External links

• Pathogen Sequencing Unit at the Wellcome Trust Sanger Institute: Further details
• Department of Virology at Imperial College of Science, Technology and Medicine: Research interests of Professor Geoffrey Smith