Scientists urge caution on gene transfer issue

Friday, 7 February 2003

The authors of a new paper dealing with so-called "hopping genes" say their results are in danger of being misinterpreted.

The latest online issue of the journal Nature contains results of research by the University of Adelaide's Department of Molecular Biosciences and the CSIRO.

The research showed that a marker gene placed within the chloroplast of a tobacco plant had the potential to "hop" to the nucleus of that plant's seedlings. However, the researchers found that the chances of this happening, although surprisingly high for an evolutionary event, were extremely small from the perspective of gene escape.

"We found that one in every 16,000 seedlings showed evidence of this gene transfer," says Associate Professor Jeremy Timmis, co-author of the paper and Head of Genetics at the University of Adelaide.

"That is an extremely low number. It means that our experiments confirm that in the majority of species including tobacco, chloroplast genes are strictly maternally inherited."

Dr Timmis says he is concerned that the anti-GM lobby and the media will misinterpret the results as proving that "hopping genes" are a strong risk in genetically modified plants.

"We have known for nearly 20 years that the DNA remaining in the chloroplast and mitochondria in plants is being constantly transferred to the nucleus. This has occurred over more than a billion years of evolution," he says.

"However, it has not been possible to measure its frequency until now.

"The rate of transfer appears to be extremely low, and we would hope to conduct more tests on the issue before making any claims about the risk or otherwise of gene transfer from GM crops."

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