The drug was created by combining genes from three different organisms, namely bacteria, a type of plant and yeast.

The end result was artemisinin. This drug already exists and is extremely effective against strains of malaria which are resistant to most other frontline treatments. However, it is very expensive.

This discovery could now pave the way for much cheaper versions of the drug to be made available, particularly in developing countries where it is most needed.

Plant extract

Artemisinin was originally developed in the 1970s in China. It is a derivative of the sweet wormwood plant.

Turning it into a drug is generally an expensive and laborious process because it involves extracting the chemical from the plant.

This, in turn, means it is often priced out of the reach of many of those who need it most.

But Professor Jay Keasling and colleagues at University of California Berkeley may have found a viable alternative.

They took a total of 10 genes from the E. coli bacteria, yeast and wormwood, and successfully made them work together. This produced the chemical needed to develop the drug.

The decision to include E. coli genes was based on the fact that bacteria grow quickly. This means that artemisinin can also be produced quickly and cheaply.

"By inserting these genes into bacteria, we've given them the ability to make artemisinin quickly, efficiently and cheaply," Professor Keasling said.

He believes the technique can be used to produce similar chemicals which are also derived from plants, so-called isoprenoids. These include the key ingredient of the powerful anti-cancer drug taxol.

Scientists estimate that there are as many as 30,000 different plant compounds that could be used to develop new drugs to fight disease.

Many of these have not been properly examined because of the high costs associated with turning their key ingredients into drugs.

"This process could be of interest to everybody - drug companies making cancer agents, the government producing antibiotics against bioterror agents or industries making flavours and fragrances," Professor Keasling said.

"A company could tweak the bacteria a bit, adding any number of plant genes involved in making the chemical of interest to get pretty much any isoprenoid. It would be easy to do now."

The study is published on the Nature Biotechnology website, ahead of the release of the journal in July.