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.

News
people'It can last and it's terrifying'
Sport
Danny Welbeck's Manchester United future is in doubt
footballGunners confirm signing from Manchester United
Sport
footballFeaturing Bart Simpson
New Articles
Olivia Colman topped the list of the 30 most influential females in broadcasting
tv
PROMOTED VIDEO
News
Kelly Brook
peopleA spokesperson said the support group was 'extremely disappointed'
News
The five geckos were launched into space to find out about the effects of weightlessness on the creatures’ sex lives
i100
Sport
Andy Murray celebrates a shot while playing Jo-Wilfried Tsonga
TennisWin sets up blockbuster US Open quarter-final against Djokovic
Life and Style
techIf those brochure kitchens look a little too perfect to be true, well, that’s probably because they are
Arts and Entertainment
Hare’s a riddle: Kit Williams with the treasure linked to Masquerade
booksRiddling trilogy could net you $3m
Arts and Entertainment
Alex Kapranos of Franz Ferdinand performs live
music Pro-independence show to take place four days before vote
News
ebooksAn unforgettable anthology of contemporary reportage
News
news Video - hailed as 'most original' since Benedict Cumberbatch's
News
i100
Life and Style
The longer David Sedaris had his Fitbit, the further afield his walks took him through the West Sussex countryside
lifeDavid Sedaris: What I learnt from my fitness tracker about the world
Arts and Entertainment
Word master: Self holds up a copy of his novel ‘Umbrella’
booksUnlike 'talented mediocrity' George Orwell, you must approach this writer dictionary in hand
News
i100
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

SQL Implementation Consultant (VB,C#, SQL, Java, Eclipse, integ

£40000 - £50000 per annum + benefits+bonus+package: Harrington Starr: SQL Impl...

SQL Technical Implementation Consultant (Java, BA, Oracle, VBA)

£45000 - £55000 per annum + Benefits + Bonus: Harrington Starr: SQL Technical ...

Head of IT (Windows, Server, VMware, SAN, Fidessa, Equities)

£85000 per annum: Harrington Starr: Head of IT (Windows, Server, VMware, SAN, ...

Lead C# Developer (.Net, nHibernate, MVC, SQL) Surrey

£55000 - £60000 per annum + Benefits + Bonus: Harrington Starr: Lead C# Develo...

Day In a Page

'I’ll tell you what I would not serve - lamb and potatoes': US ambassador hits out at stodgy British food served at diplomatic dinners

'I’ll tell you what I would not serve - lamb and potatoes'

US ambassador hits out at stodgy British food
Radio Times female powerlist: A 'revolution' in TV gender roles

A 'revolution' in TV gender roles

Inside the Radio Times female powerlist
Endgame: James Frey's literary treasure hunt

James Frey's literary treasure hunt

Riddling trilogy could net you $3m
Fitbit: Because the tingle feels so good

Fitbit: Because the tingle feels so good

What David Sedaris learnt about the world from his fitness tracker
Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Second-holiest site in Islam attracts millions of pilgrims each year
Alexander Fury: The designer names to look for at fashion week this season

The big names to look for this fashion week

This week, designers begin to show their spring 2015 collections in New York
Will Self: 'I like Orwell's writing as much as the next talented mediocrity'

'I like Orwell's writing as much as the next talented mediocrity'

Will Self takes aim at Orwell's rules for writing plain English
Meet Afghanistan's middle-class paint-ballers

Meet Afghanistan's middle-class paint-ballers

Toy guns proving a popular diversion in a country flooded with the real thing
Al Pacino wows Venice

Al Pacino wows Venice

Ham among the brilliance as actor premieres two films at festival
Neil Lawson Baker interview: ‘I’ve gained so much from art. It’s only right to give something back’.

Neil Lawson Baker interview

‘I’ve gained so much from art. It’s only right to give something back’.
The other Mugabe who is lining up for the Zimbabwean presidency

The other Mugabe who is lining up for the Zimbabwean presidency

Wife of President Robert Mugabe appears to have her sights set on succeeding her husband
The model of a gadget launch: Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed

The model for a gadget launch

Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed
Alice Roberts: She's done pretty well, for a boffin without a beard

She's done pretty well, for a boffin without a beard

Alice Roberts talks about her new book on evolution - and why her early TV work drew flak from (mostly male) colleagues
Get well soon, Joan Rivers - an inspiration, whether she likes it or not

Get well soon, Joan Rivers

She is awful. But she's also wonderful, not in spite of but because of the fact she's forever saying appalling things, argues Ellen E Jones
Doctor Who Into the Dalek review: A classic sci-fi adventure with all the spectacle of a blockbuster

A fresh take on an old foe

Doctor Who Into the Dalek more than compensated for last week's nonsensical offering