Exclusive: 'Jaw-dropping' breakthrough hailed as landmark in fight against hereditary diseases as Crispr technique heralds genetic revolution

Development to revolutionise study and treatment of a range of diseases from cancer, incurable viruses such as HIV to inherited genetic disorders such as sickle-cell anaemia and Huntington’s disease

Science Editor

A breakthrough in genetics – described as “jaw-dropping” by one Nobel scientist – has created intense excitement among DNA experts around the world who believe the discovery will transform their ability to edit the genomes of all living organisms, including humans.

Click image above to enlarge graphic

The development has been hailed as a milestone in medical science because it promises to revolutionise the study and treatment of a range of diseases, from cancer and incurable viruses to inherited genetic disorders such as sickle-cell anaemia and Down syndrome.

For the first time, scientists are able to engineer any part of the human genome with extreme precision using a revolutionary new technique called Crispr, which has been likened to editing the individual letters on any chosen page of an encyclopedia without creating spelling mistakes. The landmark development means it is now possible to make the most accurate and detailed alterations to any specific position on the DNA of the 23 pairs of human chromosomes without introducing unintended mutations or flaws, scientists said.

The technique is so accurate that scientists believe it will soon be used in gene-therapy trials on humans to treat incurable viruses such as HIV or currently untreatable genetic disorders such as Huntington’s disease. It might also be used controversially to correct gene defects in human IVF embryos, scientists said.

Until now, gene therapy has had largely to rely on highly inaccurate methods of editing the genome, often involving modified viruses that insert DNA at random into the genome – considered too risky for many patients.

The new method, however, transforms genetic engineering because it is simple and easy to edit any desired part of the DNA molecule, right down to the individual chemical building-blocks or nucleotides that make up the genetic alphabet, researchers said.

“Crispr is absolutely huge. It’s incredibly powerful and it has many applications, from agriculture to potential gene therapy in humans,” said Craig Mello of the University of Massachusetts Medical School, who shared the 2006 Nobel Prize for medicine for a previous genetic discovery called RNA interference.

“This is really a triumph of basic science and in many ways it’s better than RNA interference. It’s a tremendous breakthrough with huge implications for molecular genetics. It’s a real game-changer,” Professor Mello told The Independent.

“It’s one of those things that you have to see to believe. I read the scientific papers like everyone else but when I saw it working in my own lab, my jaw dropped. A total novice in my lab got it to work,” Professor Mello said.

In addition to engineering the genes of plants and animals, which could accelerate the development of GM crops and livestock, the Crispr technique dramatically “lowers the threshold” for carrying out “germline” gene therapy on human IVF embryos, Professor Mello added.

The new method of gene therapy makes it simple and easy to edit any desired part of the DNA molecule (Getty Creative) The new method of gene therapy makes it simple and easy to edit any desired part of the DNA molecule (Getty Creative)
Germline gene therapy on sperm, eggs or embryos to eliminate inherited diseases alters the DNA of all subsequent generations, but fears over its safety, and the prospect of so-called “designer babies”, has led to it being made illegal in Britain and many other countries.

The new gene-editing technique could address many of the safety concerns because it is so accurate. Some scientists now believe it is only a matter of time before IVF doctors suggest that it could be used to eliminate genetic diseases from affected families by changing an embryo’s DNA before implanting it into the womb.

“If this new technique succeeds in allowing perfectly targeted correction of abnormal genes, eliminating safety concerns, then the exciting prospect is that treatments could be developed and applied to the germline, ridding families and all their descendants of devastating inherited disorders,” said Dagan Wells, an IVF scientist at Oxford University.

“It would be difficult to argue against using it if it can be shown to be as safe, reliable and effective as it appears to be. Who would condemn a child to terrible suffering and perhaps an early death when a therapy exists, capable of repairing the problem?” Dr Wells said.

The Crispr process was first identified as a natural immune defence used by bacteria against invading viruses. Last year, however, scientists led by Jennifer Doudna at the University of California, Berkeley, published a seminal study showing that Crispr can be used to target any region of a genome with extreme precision with the aid of a DNA-cutting enzyme called CAS9.

Since then, several teams of scientists showed that the Crispr-CAS9 system used by Professor Doudna could be adapted to work on a range of life forms, from plants and nematode worms to fruit flies and laboratory mice.

Earlier this year, several teams of scientists demonstrated that it can also be used accurately to engineer the DNA of mouse embryos and even human stem cells grown in culture. Geneticists were astounded by how easy, accurate and effective it is at altering the genetic code of any life form – and they immediately realised the therapeutic potential for medicine.

“The efficiency and ease of use is completely unprecedented. I’m jumping out of my skin with excitement,” said George Church, a geneticist at Harvard University who led one of the teams that used Crispr to edit the human genome for the first time.

“The new technology should permit alterations of serious genetic disorders. This could be done, in principle, at any stage of development from sperm and egg cells and IVF embryos up to the irreversible stages of the disease,” Professor Church said.

David Adams, a DNA scientist at the Wellcome Trust Sanger Institute in Cambridge, said that the technique has the potential to transform the way scientists are able to manipulate the genes of all living organisms, especially patients with inherited diseases, cancer or lifelong HIV infection.

“This is the first time we’ve been able to edit the genome efficiently and precisely and at a scale that means individual patient mutations can be corrected,” Dr Adams said.

“There have been other technologies for editing the genome but they all leave a ‘scar’ behind or foreign DNA in the genome. This leaves no scars behind and you can change the individual nucleotides of DNA – the ‘letters’ of the genetic textbook – without any other unwanted changes,” he said.

Timeline: Landmarks in DNA science

Restriction enzymes: allowed scientists to cut the DNA molecule at or near a recognised genetic sequence. The enzymes work well in microbes but are more difficult to target in the more complex genomes of plants and animals. Their discovery in the 1970s opened the way for the age of genetic engineering, from GM crops to GM animals, and led to the 1978 Nobel Prize for medicine.

Polymerase chain reaction (PCR): a technique developed in 1983 by Kary Mullis (below, credit: Getty) in California allowed scientists to amplify the smallest amounts of DNA – down to a single molecule – to virtually unlimited quantities. It quickly became a standard technique, especially in forensic science, where it is used routinely in analysing the smallest tissue samples left at crime scenes. Many historical crimes have since been solved with the help of the PCR test. Mullis won the Nobel Prize for chemistry in 1993.

 

RNA interference: scientists working on the changing colour of petunia plants first noticed this phenomenon, which was later shown to involve RNA, a molecular cousin to DNA. In 1998, Craig Mello and Andrew Fire in the US demonstrated the phenomenon on nematode worms, showing that small strands of RNA could be used to turn down the activity of genes, rather like a dimmer switch. They shared the 2006 Nobel Prize for physiology or medicine for the discovery.

Zinc fingers: complex proteins called zinc fingers, first used on mice in 1994, can cut DNA at selected sites in the genome, with the help of enzymes. Another DNA-cutting technique called Talens can do something similar. But both are cumbersome to use and difficult to operate in practice – unlike the Crispr technique.

Click HERE to see a video of how the Crispr system derived from bacteria works on human cells to correct genetic defects

Video by Janet Iwasa

Start your day with The Independent, sign up for daily news emails
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

Sheridan Maine: Accounts Assistant

£25,000 - £30,000: Sheridan Maine: Are you looking for a fantastic opportunity...

Neil Pavier: Commercial Analyst

£50,000 - £55,000: Neil Pavier: Are you a professionally qualified commercial ...

Loren Hughes: Financial Accountant

£45,000 - £55,000: Loren Hughes: Are you looking for a new opportunity that wi...

Sheridan Maine: Finance Analyst

Circa £45,000-£50,000 + benefits: Sheridan Maine: Are you a newly qualified ac...

Day In a Page

No postcode? No vote

Floating voters

How living on a houseboat meant I didn't officially 'exist'
Louis Theroux's affable Englishman routine begins to wear thin

By Reason of Insanity

Louis Theroux's affable Englishman routine begins to wear thin
Power dressing is back – but no shoulderpads!

Power dressing is back

But banish all thoughts of Eighties shoulderpads
Spanish stone-age cave paintings 'under threat' after being re-opened to the public

Spanish stone-age cave paintings in Altamira 'under threat'

Caves were re-opened to the public
'I was the bookies’ favourite to be first to leave the Cabinet'

Vince Cable interview

'I was the bookies’ favourite to be first to leave the Cabinet'
Election 2015: How many of the Government's coalition agreement promises have been kept?

Promises, promises

But how many coalition agreement pledges have been kept?
The Gaza fisherman who built his own reef - and was shot dead there by an Israeli gunboat

The death of a Gaza fisherman

He built his own reef, and was fatally shot there by an Israeli gunboat
Saudi Arabia's airstrikes in Yemen are fuelling the Gulf's fire

Saudi airstrikes are fuelling the Gulf's fire

Arab intervention in Yemen risks entrenching Sunni-Shia divide and handing a victory to Isis, says Patrick Cockburn
Zayn Malik's departure from One Direction shows the perils of fame in the age of social media

The only direction Zayn could go

We wince at the anguish of One Direction's fans, but Malik's departure shows the perils of fame in the age of social media
Young Magician of the Year 2015: Meet the schoolgirl from Newcastle who has her heart set on being the competition's first female winner

Spells like teen spirit

A 16-year-old from Newcastle has set her heart on being the first female to win Young Magician of the Year. Jonathan Owen meets her
Jonathan Anderson: If fashion is a cycle, this young man knows just how to ride it

If fashion is a cycle, this young man knows just how to ride it

British designer Jonathan Anderson is putting his stamp on venerable house Loewe
Number plates scheme could provide a licence to offend in the land of the free

Licence to offend in the land of the free

Cash-strapped states have hit on a way of making money out of drivers that may be in collision with the First Amendment, says Rupert Cornwell
From farm to fork: Meet the Cornish fishermen, vegetable-growers and butchers causing a stir in London's top restaurants

From farm to fork in Cornwall

One man is bringing together Cornwall's most accomplished growers, fishermen and butchers with London's best chefs to put the finest, freshest produce on the plates of some of the country’s best restaurants
Robert Parker interview: The world's top wine critic on tasting 10,000 bottles a year, absurd drinking notes and New World wannabes

Robert Parker interview

The world's top wine critic on tasting 10,000 bottles a year, absurd drinking notes and New World wannabes
Don't believe the stereotype - or should you?

Don't believe the stereotype - or should you?

We exaggerate regional traits and turn them into jokes - and those on the receiving end are in on it too, says DJ Taylor