In April 2010, Craig Venter's team produced a synthetic bacterium. The scientists read the genetic code of a natural bacterium, Mycoplasma mycoides. They transferred this code to a computer, which assembled chemicals to produce an artificial copy of its DNA, the genetic blueprint for life. They then transplanted that synthetic DNA into a different Mycoplasma species with its natural DNA removed. The new life was controlled by the synthetic DNA - an organism whose genome was pieced together from chemical building blocks according to computer design.
Much of the debate that followed centred around whether they had artificially created life, but this question is ethically uninteresting. We now have many ways to produce life using science, such as artificial reproduction. What is ethically important is not whether new life has been produced, but what kind of life it is.
Synthetic biology represents a second ethical quantum leap in biology. The first came about 30 years ago when scientists began to genetically modify life. They moved genes from one species to another, creating experimental models for human diseases and even fluorescent monkeys. They have created a fluorescent human embryo and fused different life forms, for example the "geep", a fusion of a goat and sheep embryo. The human-chimp chimeras of Planet of the Apes are a live possibility.
Genetic engineering involves shuffling the cards of life, moving genes across species; synthetic biology introduces new jokers into the pack. Genetic engineering is limited to genes that naturally exist; synthetic biology provides the technology to create life that has not and could not have naturally existed.
The holy grail of this technology is a second Industrial Revolution, a biological revolution where Man masters the engine of biology to create natural machines that do His work. Asked where this could lead, one leading scientist said: "That's like wondering what a computer could do back in the 1960s - who can tell?"
In the two years since synthetic biology hit the headlines, it has produced anti-malaria drugs and efficient biofuels. Synthetic biological machines could be used to produce "bioremediators" that would break down environmental toxins, or perhaps act as anti-cancer "search and destroy" agents. Biological computing could use human neurons created artificially instead of chips.
However, all power has a dark side.
In 2001, scientists genetically modified mouse pox and created a strain that killed 100 per cent of the mice infected. They published their results on the internet. The same changes could be made to human smallpox, the greatest infectious killer in human history, which kills a third of those infected. Soon, terrorists will not have to get their hands on biological warfare stashes held in the former Soviet Union. With further progress in synthetic biology, it will be possible to cheaply and easily synthesise pathogens, and even modify them to make them perfectly lethal and superinfectious.
This will not require high-tech labs.
In the 1950s and 1960s, only a handful of people had the capacity to destroy the world. Soon, the biological revolution will place that power in the hands of many. One mistake or abuse could be catastrophic. Further into the future, synthetic biology could create radically different life forms that nature and humans have never encountered, with unprecedented risk to natural ecosystems and human health.
In March, 111 organisations led by Friends of the Earth called for a moratorium on the release and commercial use of synthetic organisms until proper regulation is in place. Barack Obama's Commission for the Study of Bioethical Issues has called for a "coordinated evaluation" of public funding for synthetic biology, as well as a review of licensing and control.
Given the potential impact of a catastrophe, there is an absolute moral imperative to review our regulatory structures, international oversight, rules for publication, access to reagents and technology, and so on. Responsible scientists should lead this.
In the meantime, the Bill and Melinda Gates Foundation, the US National Science Foundation, BP and the US Department of Energy have pumped upwards of $500 million (£315 million) into synthetic biology. In the UK, the figure is estimated at £65 million over five years. Technology marches on.
The presidential commission felt that in 2010, the field was "too novel" to produce specific governance. Will any review conducted by government produce useful controls over what is now an industry with a market value of $1.6 billion (expected to be worth $10.8 billion in 2016)? The past two years have seen synthetic biology evolve from a novelty news item to a major research priority, and as such the window for effective governance may have passed.
The biological revolution is at once exciting, even mesmerising, but terrifying. The genie is out of the bottle. Our challenge is to ethically master the machines we are creating. At present, they are relatively simple and benign. But synthetic biology offers the prospect of annihilating life as we know it.