Found: the origin of life

Scientists solve the mystery of how the Earth was transformed

Of all the scientific mysteries, this is probably the greatest one of all – how did life on Earth begin? We are not talking about how it evolved into the diversity of lifeforms we see today. We are talking about how it originated in the first place.

For all his immense insight into evolution, Charles Darwin himself was stumped. He suggested that whatever the mechanism was that had led to the first replicating lifeforms, it most probably arose in some "warm little pond", a primordial soup of pre-biotic ingredients where the seed of life first germinated on the early Earth.

Now scientists have developed an experiment demonstrating how the very first self-replicating molecules may have formed about 4 billion years ago when the Earth was like any other lifeless planet that had yet to experience the radical transformation of living, breathing creatures.

John Sutherland and colleagues at Manchester University have broken new ground by being able to synthesise almost from scratch two of the four building blocks of RNA, the self-replicating molecule that many scientist believe to be the most likely contender for the original molecule of life. Dr Sutherland believes that he has shown how it was possible to make all the building blocks of RNA from the simple chemicals that would have existed on Earth 4 billion years ago.

"We've made the building blocks of RNA from what was around on the early Earth and is still around in interstellar space and in the atmosphere of Saturn's moon Titan," Dr Sutherland said.

"We haven't yet made the RNA molecule itself but we've made two of the four sub-units or building blocks. It suggests that making the molecule is possible. The building blocks are strung together and doing that is actually easier than making the building blocks themselves," he said.

RNA is the less familiar cousin of DNA, the genetic blueprint of life. Like DNA, the RNA molecule can carry and transmit information from one generation to the next. But unlike DNA, RNA is a relatively simple molecule that many scientists believed could have been quite easy to synthesise in the harsh environment of the early Earth. The trouble with this idea – which is more than 40 years old – is that no one has been able to join up the three components, the sugars, bases and phosphates that make up each of the four building blocks of RNA, under the sort of conditions that existed 4 billion years ago. Dr Sutherland, however, has shown in a study published in the journal Nature that this is indeed possible.

"The trouble is, the human eye sees the three components of RNA and so the human brain assumes that to make the molecule you should combine those three components. People have found that they can make the sugars and the bases but the key thing they can't do is to join them together," Dr Sutherland said.

"And so for 40 or so years they have worked on the problem and have become so frustrated that they have decided that RNA, although very desirable, is just too complicated and so there must have been a simpler molecule that spawned RNA. We've just changed the order of assembly of the pieces, but it's overcome the dogma that it cannot be done," he said.

In trying to explain how life began on Earth, scientists have attempted to formulate theories to account for how the first self-replicating molecule came into existence. One of the earliest theories was the "primordial soup", where simple molecules mixed together in a broth that was regularly energised by ultraviolet light and electric storms.

Over time, these simple molecules would have combined to form more complex substances containing the all-important atomic ingredients of life – oxygen, carbon, hydrogen and nitrogen. Although scientists were able to make the building blocks of proteins in this way, they failed to do the same with DNA or RNA.

Scientists first proposed that RNA preceded proteins in the 1960s, but it was not until the 1980s that they received strong support for the idea. Thomas Cech at the University of Colorado and Sidney Altman at Yale, found that RNA could act as a catalyst by speeding up a chemical reaction and yet being unchanged in the process – a feat normally reserved for enzymes.

This was the first hard evidence that RNA, a molecule that can replicate and store genetic information, could also have triggered the first synthesis of life's proteins. Most scientists now believe that there was an "RNA world" early in the Earth's history from which all present-day life is ultimately descended.

Start your day with The Independent, sign up for daily news emails
Life and Style
Mary Beard received abuse after speaking positively on 'Question Time' about immigrant workers: 'When people say ridiculous, untrue and hurtful things, then I think you should call them out'
Life and Style
Most mail-order brides are thought to come from Thailand, the Philippines and Romania
Life and Style
Margaret Thatcher, with her director of publicity Sir Gordon Reece, who helped her and the Tory Party to victory in 1979
voicesThe subject is being celebrated by the V&A museum, triggering some happy memories for former PR man DJ Taylor
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

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

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
Public relations as 'art'? Surely not

Confessions of a former PR man

The 'art' of public relations is being celebrated by the V&A museum, triggering some happy memories for DJ Taylor
Bill Granger recipes: Our chef succumbs to his sugar cravings with super-luxurious sweet treats

Bill Granger's luxurious sweet treats

Our chef loves to stop for 30 minutes to catch up on the day's gossip, while nibbling on something sweet
London Marathon 2015: Paula Radcliffe and the mother of all goodbyes

The mother of all goodbyes

Paula Radcliffe's farewell to the London Marathon will be a family affair
Everton vs Manchester United: Steven Naismith demands 'better' if Toffees are to upset the odds against United

Steven Naismith: 'We know we must do better'

The Everton forward explains the reasons behind club's decline this season
Arsenal vs Chelsea: Praise to Arsene Wenger for having the courage of his convictions

Michael Calvin's Last Word

Praise to Wenger for having the courage of his convictions