mrz
07-02-03, 02:46
Scientists witness migration of GM cell material
By Steve Connor, Science Editor
06 February 2003
A technique for producing "environmentally friendly" GM crops has been called into question by a study showing how easily alien genes can be transferred around a plant.
Scientists have found that genes can jump from one region of a plant cell to another, making more likely the pros-pect of an introduced gene con-taminating the plant's pollen and escaping into the wild.
The research, led by Jeremy Timmis of Adelaide University in Australia, focused on the DNA of chloroplasts – the photosynthetic structures inside a plant cell – which lie outside a plant's nucleus.
Some researchers have suggested that by modifying the DNA of chloroplasts, GM crops might be created with beneficial traits that cannot be transferred to the plant's pollen and be released into the wild. Pollen is made using DNA from the cell's nucleus.
But Dr Timmis has shown in a study published in the journal Nature that genes introduced into the DNA of a chloroplast can indeed jump into the chromosome of the cell's nucleus. By modifying the genes of chloroplasts, therefore, the theoretical possibility exists to generate GM pollen that could cross-fertilise with related species of plants, producing GM wild flowers or "superweeds" resistant to weedkiller.
Dr Timmis's team used a gene that confers resistance to an antibiotic as a "marker", to see how frequently this alien DNA could move from the chloroplast to the nucleus of a tobacco plant. They found DNA is transferred at a frequency of one in approximately 16,000 tobacco pollen grains.
Peter Riley, of Friends of the Earth, said: "This research suggests that this is a bit of a shock to scientists. They didn't expect the genes to jump from chloroplast to nucleus so readily. It underlines the fact that we must know more about plant genetics before we start manipulating the DNA of crops."
http://www.independent.co.uk/story.jsp?story=375935
By Steve Connor, Science Editor
06 February 2003
A technique for producing "environmentally friendly" GM crops has been called into question by a study showing how easily alien genes can be transferred around a plant.
Scientists have found that genes can jump from one region of a plant cell to another, making more likely the pros-pect of an introduced gene con-taminating the plant's pollen and escaping into the wild.
The research, led by Jeremy Timmis of Adelaide University in Australia, focused on the DNA of chloroplasts – the photosynthetic structures inside a plant cell – which lie outside a plant's nucleus.
Some researchers have suggested that by modifying the DNA of chloroplasts, GM crops might be created with beneficial traits that cannot be transferred to the plant's pollen and be released into the wild. Pollen is made using DNA from the cell's nucleus.
But Dr Timmis has shown in a study published in the journal Nature that genes introduced into the DNA of a chloroplast can indeed jump into the chromosome of the cell's nucleus. By modifying the genes of chloroplasts, therefore, the theoretical possibility exists to generate GM pollen that could cross-fertilise with related species of plants, producing GM wild flowers or "superweeds" resistant to weedkiller.
Dr Timmis's team used a gene that confers resistance to an antibiotic as a "marker", to see how frequently this alien DNA could move from the chloroplast to the nucleus of a tobacco plant. They found DNA is transferred at a frequency of one in approximately 16,000 tobacco pollen grains.
Peter Riley, of Friends of the Earth, said: "This research suggests that this is a bit of a shock to scientists. They didn't expect the genes to jump from chloroplast to nucleus so readily. It underlines the fact that we must know more about plant genetics before we start manipulating the DNA of crops."
http://www.independent.co.uk/story.jsp?story=375935