TO CREATE life is the prerogative of gods. Deep in the human psyche, whatever the rational pleadings of physics and chemistry, there exists a sense that biology is different, is more than just the sum of atoms moving about and reacting with one another, is somehow infused with a divine spark, a vital essence. It may come as a shock, then, that mere mortals have now made artificial life.

Craig Venter and Hamilton Smith, the two American biologists who unravelled the first DNA sequence of a living organism (a bacterium) in 1995, have made a bacterium that has an artificial genome—creating a living creature with no ancestor (see article). Pedants may quibble that only the DNA of the new beast was actually manufactured in a laboratory; the researchers had to use the shell of an existing bug to get that DNA to do its stuff. Nevertheless, a Rubicon has been crossed. It is now possible to conceive of a world in which new bacteria (and eventually, new animals and plants) are designed on a computer and then grown to order.

That ability would prove mankind's mastery over nature in a way more profound than even the detonation of the first atomic bomb. The bomb, however justified in the context of the second world war, was purely destructive. Biology is about nurturing and growth. Synthetic biology, as the technology that this and myriad less eye-catching advances are ushering in has been dubbed, promises much. In the short term it promises better drugs, less thirsty crops (see article), greener fuels and even a rejuvenated chemical industry. In the longer term who knows what marvels could be designed and grown?

On the face of it, then, artificial life looks like a wonderful thing. Yet that is not how many will view the announcement. For them, a better word than “creation” is “tampering”. Have scientists got too big for their boots? Will their hubris bring Nemesis in due course? What horrors will come creeping out of the flask on the laboratory bench?

Such questions are not misplaced—and should give pause even to those, including this newspaper, who normally embrace advances in science with enthusiasm. The new biological science does have the potential to do great harm, as well as good. “Predator” and “disease” are just as much part of the biological vocabulary as “nurturing” and “growth”. But for good or ill it is here. Creating life is no longer the prerogative of gods.

Children of a lesser god

It will be a while, yet, before lifeforms are routinely designed on a laptop. But this will come. The past decade, since the completion of the Human Genome Project, has seen two related developments that make it almost inevitable. One is an extraordinary rise in the speed, and fall in the cost, of analysing the DNA sequences that encode the natural “software” of life. What once took years and cost millions now takes days and costs thousands. Databases are filling up with the genomes of everything from the tiniest virus to the tallest tree.

These genomes are the raw material for synthetic biology. First, they will provide an understanding of how biology works right down to the atomic level. That can then be modelled in human-designed software so that synthetic biologists will be able to assemble new constellations of genes with a reasonable presumption that they will work in a predictable way. Second, the genome databases are a warehouse that can be raided for whatever part a synthetic biologist requires.

The other development is faster and cheaper DNA synthesis. This has lagged a few years behind DNA analysis, but seems to be heading in the same direction. That means it will soon be possible for almost anybody to make DNA to order, and dabble in synthetic biology.

That is good, up to a point. Innovation works best when it is a game that anyone can play. The more ideas there are, the better the chance some will prosper. Unfortunately and inevitably, some of those ideas will be malicious. And the problem with malicious biological inventions—unlike, say, guns and explosives—is that once released, they can breed by themselves.

Biology really is different

The Home Brew computing club launched Steve Jobs and Apple, but similar ventures produced a thousand computer viruses. What if a home-brew synthetic-biology club were accidentally to launch a real virus or bacterium? What if a terrorist were to do the same deliberately?

The risk of accidentally creating something bad is probably low. Most bacteria opt for an easy life breaking down organic material that is already dead. It doesn't fight back. Living hosts do. Creating something bad deliberately, whether the creator is a teenage hacker, a terrorist or a rogue state, is a different matter. No one now knows how easy it would be to turbo-charge an existing human pathogen, or take one that infects another type of animal and assist its passage over the species barrier. We will soon find out, though.

It is hard to know how to address this threat. The reflex, to restrict and ban, has worked (albeit far from perfectly) for more traditional sorts of biological weapons. Those, though, have been in the hands of states. The ubiquity of computer viruses shows what can happen when technology gets distributed.

Thoughtful observers of synthetic biology favour a different approach: openness. This avoids shutting out the good in a belated attempt to prevent the bad. Knowledge cannot be unlearned, so the best way to oppose the villains is to have lots of heroes on your side. Then, when a problem arises, an answer can be found quickly. If pathogens can be designed by laptop, vaccines can be, too. And, just as “open source” software lets white-hat computer nerds work against the black-hats, so open-source biology would encourage white-hat geneticists.

Regulation—and, especially, vigilance—will still be needed. Keeping an eye out for novel diseases is sensible even when such diseases are natural. Monitoring needs to be redoubled and co-ordinated. Then, whether natural or artificial, the full weight of synthetic biology can be brought to bear on the problem. Encourage the good to outwit the bad and, with luck, you keep Nemesis at bay.