New life: Scientists create first semi-synthetic organism with 'alien' DNA

Science Editor

Scientists have created the first “semi-synthetic” micro-organism with a radically different genetic code from the rest of life on Earth.

The researchers believe the breakthrough is the first step towards creating new microbial life-forms with novel industrial or medical properties resulting from a potentially massive expansion of genetic information.

The semi-synthetic microbe, a genetically modified E. coli bacterium, has been endowed with an extra artificial piece of DNA with an expanded genetic alphabet – instead of the usual four “letters” of the alphabet its DNA molecule has six.

The natural genetic code of all living things is based on a sequence of four bases – G, C, T, A – which form two sets of bonded pairs, G to C and T to A, that link the two strands of the DNA double helix.

The DNA of the new semi-synthetic microbe, however, has a pair of extra base pairs, denoted by X and Y, which pair up together like the other base pairs and are fully integrated into the rest of the DNA’s genetic code.

The scientists said that the semi-synthetic E. coli bacterium replicates normally and is able to pass on the new genetic information to subsequent generations. However, it was not able to use the new encoded information to produce any novel proteins – the synthetic DNA was added as an extra circular strand that did not take part in the bacterium’s normal metabolic functions.

The study, published in the journal Nature, is the first time that scientists have managed to produce a genetically modified microbe that is able to function and replicate with a different genetic code to the one that is thought to have existed ever since life first started to evolve on Earth more than 3.5 billion years ago.

“Life on earth in all its diversity is encoded by only two pairs of DNA bases, A-T and C-G, and what we’ve made is an organism that stably contains those two plus a third, unnatural pair of bases,” said Professor Floyd Romesberg of the Scripps Research Institute in La Jolla, California.

“This shows that other solutions to storing information are possible and, of course, takes us closer to an expanded-DNA biology that will have many exciting applications, from new medicines to new kinds of nanotechnology,” Professor Romesberg said.

Expanding the genetic code with an extra base pair raises the prospect of building new kinds of proteins from a much wider range of amino acids than the 20 or so that exist in nature. A new code based on six base pairs could in theory deal with more than 200 amino acids, the scientists said.

“In principle, we could encode new proteins made from new, unnatural amino acids, which would give us greater power than ever to tailor protein therapeutics and diagnostics and laboratory reagents to have desired functions,” Professor Romesberg said.

“Other applications, such as nanomaterials, are also possible,” he added.

The researchers emphasised that there is little danger of the new life-forms living outside the confines of the laboratory, as they are not able to replicate with their synthetic DNA strand unless they are continuously fed the X and Y bases – synthetic chemicals called "d5SICS" and "dNaM", that do not exist in nature.

The bacteria also need a special protein to transport the new bases around the cell of the microbe. The transporter protein comes from algae and if it, or the X and Y bases, are lacking, the microbial cells revert back to the natural genetic code, said Denis Malyshev of the Scripps Institute.

“Our new bases can only get into the cell if we turn on the "base transporter" protein. Without this transporter or when the new bases are not provided, the cell will revert back to A, T, G, C and the d5SICS and the dNaM will disappear from the genome,” Dr Malyshev said.

Start your day with The Independent, sign up for daily news emails
News
peoplePair enliven the Emirates bore-draw
Arts and Entertainment
tvPoldark episode 8, review
News
Britain's opposition Labour Party leader Ed Miliband (R) and Boris Johnson, mayor of London, talk on the Andrew Marr show in London April 26
General electionAndrew Marr forced to intervene as Boris and Miliband clash on TV
Arts and Entertainment
Ramsay Bolton in Game of Thrones
tvSeries 5, Episode 3 review
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Ashdown Group: Senior Accounts Assistant - Accounts Payable - St. Albans

£26000 - £28000 per annum + benefits : Ashdown Group: Senior Accounts Assistan...

Ashdown Group: Treasury Assistant - Accounts Assistant - London, Old Street

£24000 - £26000 per annum + benefits : Ashdown Group: A highly successful, glo...

Recruitment Genius: Installation and Service / Security Engineer

£22000 - £40000 per annum: Recruitment Genius: This company is part of a Group...

Recruitment Genius: Service Charge Accounts Assistant

£16000 - £18000 per annum: Recruitment Genius: Are you a a young, dynamic pers...

Day In a Page

Not even the 'putrid throat' could stop the Ross Poldark swoon-fest'

Not even the 'putrid throat' could stop the Ross Poldark swoon-fest'

How a costume drama became a Sunday night staple
Miliband promises no stamp duty for first-time buyers as he pushes Tories on housing

Miliband promises no stamp duty for first-time buyers

Labour leader pushes Tories on housing
Aviation history is littered with grand failures - from the the Bristol Brabazon to Concorde - but what went wrong with the SuperJumbo?

Aviation history is littered with grand failures

But what went wrong with the SuperJumbo?
Fear of Putin, Islamists and immigration is giving rise to a new generation of Soviet-style 'iron curtains' right across Europe

Fortress Europe?

Fear of Putin, Islamists and immigration is giving rise to a new generation of 'iron curtains'
Never mind what you're wearing, it's what you're reclining on

Never mind what you're wearing

It's what you're reclining on that matters
General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

Chuka Umunna: A virus of racism runs through Ukip

The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
Yemen crisis: This exotic war will soon become Europe's problem

Yemen's exotic war will soon affect Europe

Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
Marginal Streets project aims to document voters in the run-up to the General Election

Marginal Streets project documents voters

Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

The real-life kingdom of Westeros

Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
How to survive a social-media mauling, by the tough women of Twitter

How to survive a Twitter mauling

Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

At dawn, the young remember the young

A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

Follow the money as never before

Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

Samuel West interview

The actor and director on austerity, unionisation, and not mentioning his famous parents
General Election 2015: Imagine if the leading political parties were fashion labels

Imagine if the leading political parties were fashion labels

Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence