Europe South Asia Asia Pacific Americas Middle East Africa BBC Homepage World Service Education

Front Page



UK Politics







Talking Point

In Depth

On Air

Low Graphics

Monday, March 29, 1999 Published at 17:21 GMT 18:21 UK


Lift off for rival DNA technology

PCR has become the standard for amplifying bits of DNA

The Anglo-Swedish company Amersham Pharmacia Biotech has signed an exclusive deal to develop a rival technology to PCR (Polymerase Chain Reaction), which has become one of the fundamental tools of molecular biology.

Tony Smith: RCA has advantages over PCR
PCR was invented by Californian scientist Kary Mullis, and won him a share of the Nobel Prize for Chemistry in 1993.

PCR will target and duplicate a specific stretch of DNA, producing millions of copies in just a few hours. It works by exploiting processes that occur naturally in living cells, using an enzyme to copy a DNA template over and over again.

The amplification process makes it much easier for researchers to study the genetic code and has made PCR a standard technique for scientists investigating the human genome. It is used in the mapping of genes, can help diagnose disease and is a crucial tool in the "fingerprinting" techniques used to track down criminals.


An alternative technology, called Rolling Circle Amplification (RCA), was discovered in 1995 by Paul Lizardi at Yale University School of Medicine. It borrows some of the same molecular "machinery" used by viruses to rapidly churn out copies of their DNA in infected cells.

In RCA, the enzyme reads around a circle of DNA - literally "rolling out" long, repeated sequences of DNA.

Amersham Pharmacia Biotech has joined forces with Molecular Staging Inc, to bring the Yale technology to the marketplace. They believe RCA has a number of advantages that will help it challenge the older technology's pre-eminence in the laboratory.

Tony Smith, Vice President for Research and Development in UK for AP Biotech, says RCA does not require the processing temperature to be changed up and down as is required with PCR.

"Ten-billion-fold amplification can be achieved in as little as one to two hours. It can give you that without having to cycle the temperature and can allow you to get very good quantitation."

He also believes RCA is much more effective in amplifying much larger stretches of DNA, including gene-sized fragments.

Amersham Pharmacia Biotech expect to have products ready for use within the next couple of years.

Advanced options | Search tips

Back to top | BBC News Home | BBC Homepage | ©

Sci/Tech Contents

Relevant Stories

25 Mar 99 | Sci/Tech
Better test for GM foods

19 Feb 99 | Sci/Tech
Zoo elephants in danger

29 Jan 99 | Health
Gene screens pass blood test

06 Nov 98 | Health
From mummy to modern medicine

Internet Links

Amersham Pharmacia Biotech

Paul Lizardi

1993 Nobel Prize in Chemistry

The BBC is not responsible for the content of external internet sites.

In this section

World's smallest transistor

Scientists join forces to study Arctic ozone

Mathematicians crack big puzzle

From Business
The growing threat of internet fraud

Who watches the pilots?

From Health
Cold 'cure' comes one step closer