Reporter 450, 3 April 2000

GM crops need not be resistant to antibiotics

Plant geneticist Professor Peter Meyer and colleagues in the School of Biology have developed a revolutionary technique for removing antibiotic resistance genes from genetically modified crops, reported today (April 3) in Nature Biotechnology.

The discovery enables the breeding of modified plants which inherit the desired genetic changes, such as pest-resistance or herbicide tolerance, without also carrying the antibiotic resistance genes introduced as markers to distinguish them from the unmodified crop.

Professor Meyer and colleagues, working with GM tobacco plants, have developed a way of splicing into the plant’s DNA a gene resistant to the antibiotic kanamycin. After a few generations, the marker gene is bred out of almost half the plants.

The research team believes there is no general reason why this technique shouldn’t work with all plant types. Professor Meyer said: "When a genetic modification is introduced, only a few cells will integrate the imported DNA. The mechanism we studied is called homologous recombination, where two DNA sequences join together.

"Once the selected gene is present in the plant, there is no longer a need for the marker. This could be a valuable tool to make genetic modification safer, especially for slow-growing plants such as trees."

For more information, Professor Meyer has a web page:
or the Nature web site:

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