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Is the world ready for GM (Genetically Modified) animals?

By Paul Rincon Science editor, BBC News
Март 2015
Опубликовано 2015-03-02 15:00

The use of genetically engineered animals could revolutionise whole areas of public health and agriculture, according to advocates. But is the world ready for modified mosquitoes and GM salmon?

The Aedes aegypti mosquito is a principal vector for diseases such as dengue

Back in the 1950s, two American scientists came up with a revolutionary idea to eliminate a longstanding scourge of livestock farming.

A parasite known as screwworm was devastating herds in the American south, disrupting food supplies and costing hundreds of millions of dollars in annual losses.


Hadyn ParryChief executive, Oxitec Screwworms are the larval stage of the blowfly, and are able to bore through live flesh - killing farm animals within 10 days of infection.

Raymond Bushland and Edward Knipling broke the screwworm's life cycle without using toxic insecticides. They bred large numbers of blowflies, sterilised them with X-rays and released them into the wild. Here, the sterile males mated with native females to produce sterile offspring.

Repeated releases caused populations to crash, and over two subsequent decades, the US brought the problem under control.

A British biotech company called Oxitec is now pioneering a novel twist on this idea, known as the sterile insect technique (SIT). But the firm has swapped irradiation for the more precise and cost-effective toolkit of genetic modification.

Oxitec has developed a transgenic strain of the Aedes aegypti mosquito which transmits the virus responsible for dengue fever in its bite. There is currently no vaccine for dengue, which causes severe flu-like illness that can result in lethal complications. Estimates put annual cases atbetween 50 and 100 million worldwide, and the incidence is rising.

The company's patented technique involves the insertion of a lethal gene into insect embryos. The scientists rear the modified mosquitoes in a laboratory, keeping them alive by supplementing their diet with the antibiotic tetracycline.

Modified males - which don't bite people - are then released to mate with wild female mosquitoes. The males impart the lethal gene to their offspring which, lacking the dietary supplement to keep them alive, die before adulthood. Continued releases of engineered mosquitoes should cause wild populations to crash.

 

Full Story: BBC Science "Is the world ready for Genetically Modified  animals?"

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