Rice with a human touch

Resistant to 13 herbicides

Published: Wednesday 15 June 2005

in the first case of its kind, Japanese scientists have incorporated a human gene into the rice genome to evolve a variety resistant to several herbicides. The move, however, has kicked up a controversy with many people opposing the use of a human gene in food.

Usually, genetically modified (gm) crops use genes derived from bacteria to make them tolerate herbicides, so that they are not harmed when fields are sprayed to kill weeds. But most of them are only able to deal with a single herbicide, which means the same herbicide has to be used over and over again. This allows weeds to build up resistance to the herbicide used.

The researchers at the National Institute of Agrobiological Sciences in Tsukuba, north of Tokyo, took the gene from the human liver. It codes for an enzyme called cpy2b6, which is particularly good at breaking down harmful chemicals in the body. The scientists found that adding the human gene gave the rice immunity to as many as 13 different herbicides. This would mean that weeds could be kept down by constantly changing the chemicals used.

Some scientists say the gene could also help to beat pollution. Richard Meilan of Purdue University in Indiana, who has worked with a similar gene from rabbits, says that plants modified with it could "clean up toxins" from contaminated land. They might even destroy the toxins so effectively that crops grown on the polluted soil would be fit to eat.

But he and other scientists caution that if the gene were to escape to wild relatives of the rice, it could create particularly vicious superweeds resistant to a wide range of herbicides.

Meanwhile, the use of human gene has become a big issue with those opposed to gm food. They say no one will want to eat the partially human-derived food because it would be suggestive of cannibalism.

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