Synthetic yeast chromosomes are just the beginning

Expanding this kind of work to human chromosomes could result in important medical breakthroughs

Synthetic biology has the ring of a brave new world about it. The notion of making new kinds of life forms from scratch – rather than just tinkering with the genes of existing ones – sounds like Frankenstein on steroids. But it is not. Scientists’ successful creation of the first complete, functional chromosome of a yeast cell should be celebrated not as a step on the slippery slope to genetic disaster but as a remarkable achievement for the potential good of humanity.

Yeast is a remarkable microbe in that it has an ancient relationship with humans, going back for as long as we have baked bread, brewed beer and made wine. It is in some ways as domesticated as a cat, dog or farm animal. We use genetically modified yeast in many modern biotechnology applications, such as the manufacturing of vaccines and drugs. But its true potential – like many other useful microbes – could be much wider if we could alter its genetic make-up in a more fundamental and controlled manner.

Synthesising complete yeast chromosomes, and even a complete yeast genome made of its full complement of 16 chromosomes, would be a way of designing the overall genetic code of the microbe to do things that would otherwise be impossible. It could, for example, produce more efficient biofuels. Meanwhile, expanding this kind of work to human chromosomes could result in important medical breakthroughs. Scientists have already constructed much simpler, pared-down synthetic copies of human chromosomes, so the full-scale version may well be possible in the near future.

This kind of research will, of course, bring new ethical as well as technical challenges, especially in relation to the human genome. Gene therapy – the deliberate alteration of a patient’s DNA – has not been a great success, but this is largely because of the difficulty of introducing genetic changes accurately enough to damaged cells.

Artificial chromosomes offer a way to make these alterations in a more precise and controlled manner. But the more immediate practical benefit of this technology will come in industrial processing. The humble yeast could therefore soon become even more important for human well-being than it has been so far.