Imagine a future where synthetic jellyfish roam waterways looking for toxins to destroy, where eco-friendly plastics and fuels are harvested from vats of yeast, where viruses are programmed to be cancer killers, and electronic gadgets repair themselves like living organisms.
In synthetic biology, or ‘synbio’, possibilities are limited only by the imagination. Its practitioners don’t view life as a mystery but as a machine – one that can be designed to solve a slew of pressing global health, energy and environmental problems.
It’s a plug-and-play approach. Eager researchers can order DNA sequences online in much the same way electronics enthusiasts buy parts on eBay. Working components are listed in inventories of standardised biological parts. The culture is highly collaborative, with synthetic biologists sharing data and tools in the same spirit that drives the open-source, copyleft and maker movements.
An ongoing, international project called Synthetic Yeast 2.0 is attempting to construct the first eukaryotic organism possessing a chemically-synthesized genome. The most ambitious example of synthetic genome construction to date, each member institute is constructing and troubleshooting one of the 16 yeast chromosomes. In the next few years, they hope to produce a fully ‘synthetic’ yeast possessing all of these chemically-synthesized chromosomes. It’s a plug-and-play approach. Eager researchers can order DNA sequences online in much the same way electronics enthusiasts buy parts on eBay. Working components are listed in inventories of standardised biological parts. The culture is highly collaborative, with synthetic biologists sharing data and tools in the same spirit that drives the open-source, copyleft and maker movements.
The frontman for the field would have to be the audacious Craig Venter.
In 2010 his team created the world’s first synthetic life form – a replica of the cattle bacterium Mycoplasma mycoides. Dubbed ‘JCVI-syn 1.0’, its DNA code was written on a computer, assembled in a test tube and inserted into the hollowed-out shell of a different bacterium. Its creators embedded their names in watermarks in the DNA, along with two quotes. From writer James Joyce: “To live, to err, to fall, to triumph, to recreate life out of life.” From pioneering quantum physicist Richard Feynman: “What I cannot create, I do not understand.”
For Venter, this was just one of many firsts. He holds joint credit for the first sequencing of the three-billion-letter DNA code of the human genome in 2001; in 2007 he became the first human to have their individual genome sequenced. Synthetic biology gets less attention than genetic engineering but practitioners use many of the same techniques. There are long-standing examples like Golden Rice engineered to produce vitamin A, which could be tagged with either label.
Historically, genetic engineers have tinkered with organisms. Synthetic biologists have a far bolder mindset. As Polish geneticist Wacław Szybalski put it at a conference back in 1973: “Up to now we are working on the descriptive phase of molecular biology … But the real challenge will start when we enter the synthetic phase … We will then devise new control elements and add these new modules to the existing genomes or build up wholly new genomes.” In genetics speak, for example, regulatory stretches of DNA are called ‘promoters’; they are in turn regulated by ‘repressor’ or ‘inducer’ molecules. In synbio speak, promoters are called ‘switches’ and the molecules that regulate them ‘actuators’. Working circuits of switches and actuators are ‘logic gates’. Synthetic biologists develop their projects through standard engineering cycles of ‘design, build, test’. The design phase involves computer modelling of the components’ behaviour. The build stage involves genetic engineering.
The test step assesses if it works – and all too often unpredicted DNA interactions and toxicities mean it does not work as expected. Even the simplest biological organisms have DNA sequences no one entirely understands. Take Venter’s minimalist life form, JCVI-syn 3.0, with its 473 genes. While all these genes are necessary for the bacterium to live, the team – which has spent decades studying M. mycoides – has no idea what a third of them do. “As a synthetic biologist I find this so humbling,” Vickers says. If the genetic logic of simple bacteria is mysterious, synthetic biologists are likely to encounter far more spanners in the works as they attempt to move up the evolutionary tree. Life may turn out to be harder to tame than the synthetic biologists initially thought. Nevertheless, they have already scored some impressive runs and their imagination remains unfettered – with a wild array of projects on the drawing board that spans the solidly utilitarian to the truly fantastic.