“It's alive, IT'S ALIVE!” exclaimed Dr Frankenstein upon creating a living being from spare parts. This classic tale of horror takes root within the dark arts of science fiction. Though far from being science fact, this movie masterpiece is no longer entirely based on fiction either. Fast forward to the twenty-first century and the burgeoning field of synthetic biology combines the natural and the artificial to generate biological organisms that previously did not exist.
Synthetic biologists study living organisms to uncover how life works and how we can harness it to our benefit. In the first instance, scientists are attempting to recreate biology using manmade parts, providing us with a deeper understanding of what it minimally takes to generate life. In the second instance, scientists have rebooted existing biology after building in new specs to transform living organisms into biological machines with practical applications.
Whichever the approach, it all begins with DNA – the genetic code to life. For decades we have been artificially manufacturing the building blocks of DNA represented by the letters A, T, C and G. We have cloned genes into and out of different organisms, in a process called genetic engineering. Biomedical engineer Jim Collins famously referred to synthetic biology as “genetic engineering on steroids”. Manufacturing a single gene is quite different from creating an entire genome of thousands, millions or even billions of As, Ts, Cs and Gs strung together without a single typo.
Biologist Craig Venter met this challenge in 2008 by being the first to manufacture the whole genome of a bacterium. Two years later Venter went one step further by manufacturing the genome of one bacterium and implanting it into the shell of another, whose own DNA had been removed. The manmade DNA was distinguished from the natural DNA by encoding a few lines of verse from English poet James Joyce: “To live, to err, to fall, to triumph, to recreate life out of life”.
This new bacterium, spurred to life by a manmade genome, was controversially hailed as the world’s first synthetic life form and nicknamed Synthia. Some religious groups declared Venter was trying to play God. However man is a long way from creating life from scratch. Although the instruction manual for Synthia was produced in a lab, Nature made the body it commanded.
Inverting this scenario has also resulted in a new creature - the eight-armed, artificial jellyfish - made by implanting rat heart cells containing Nature's own DNA into a silicone body suit. In this feat of reverse engineering, heart cells grew into a silicone body by following paths marked out by scientists using special proteins. This hybrid organism was released into liquid and with the help of some electrical shocks, began to swim in patterns similar to its natural counterpart, the ocean-dwelling jellyfish.
The development of curious new creatures is touted as the next phase in medical and industrial development, with spider-goats and micro-organic drug factories making the headlines. Before the image of a half-goat-half-spider-like beast is conjured up in your mind, rest assured that the spider-goat looks just like every other goat. The difference is genetic, as slotted amongst a stretch of DNA normally responsible for milk production; scientists have placed a spider gene encoding dragline silk.
Ever seen a spider fall? You’ll find it catches itself by shooting out a substance as strong as steel called dragline silk. Medical research has already shown it to hold potential for use as stitches, artificial tendons and scaffolds for growing ligaments and skin grafts. Harvesting copious amounts of dragline silk from thousands of tiny spiders is an impossibly difficult task. The spider-goat however just requires milking. The milk is then processed to extract the silk, providing a potential source for mass production of Nature’s very own Kevlar.
Mass production is also the goal of micro-organic drug factories. Yeast has long been used to leaven our bread and brew our beers, but its benefits stretch far beyond filling our bellies. Biochemical engineer Jay Keasling constructed a unique genetic circuit combining genes from bacteria, plants and yeast. This novel piece of genetic technology, when inserted into yeast, allows them to produce a chemical called artemisinic acid – a vital precursor to the anti-malarial drug artemisinin.
Artemisinin is normally extracted from the plant sweet wormwood, with yields that vary with the weather. It is cheaper however to extract its precursor from these genetically rebooted yeast factories. This yeast-manufactured drug is set to hit the market this year, with hopes of making anti-malarial treatments more affordable in countries that desperately need it.
Affordability is also at the forefront of Keasling’s next biological reboot. If yeast can make drugs, how about bacteria that make jet fuel? With the cost of flights soaring as the world’s oil supplies dry up, micro-organic fuel factories would be a timely salvation. Keasling's experiments have shown the bacterium, E.coli, commonly known to cause stomach upsets, can be genetically hijacked to produce a variety of fuels. Inserting an extra set of genes poached from other bacteria equipped E.coli to churn out chemicals that can be processed into petrol, diesel and jet fuel.
In a far-flung future where jet planes are fuelled by a stomach bug, a laptop made from bacteria would not seem out of place. Early efforts in organic electronics have produced a primitive 96-pixel screen made from electrically sensitive yeast and hard drives made from E.coli chromosomes. The list of products that may sprout from synthetic biology is growing, but are we ready for it?
Strict regulations are in place to ensure that manipulated bacteria are rendered harmless to the human body, that hybrid organisms are kept safely within a lab, and that new drugs or chemicals produced are rigorously tested. It is nonetheless difficult to predict the consequences of such major modifications to biology. With this in mind, synthetic biologists cautiously venture on, and Frankenstein's creation will stay put in the fiction aisle of your local library.
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