E-mail this article to
yourself or a friend.
Enter address:


Jumping genes seen in plant experiment

(Friday, Feb. 7, 2003 -- CropChoice news) -- The Australian via Agnet: Genes in the chloroplast of a genetically-modified plant cell have been observed jumping into the cell's nucleus for the first time, Australian scientists have announced.

But the researchers, from the University of Adelaide, said that their study of tobacco plants did not indicate genetically-modified (GM) crops are less safe. The work is described in today's issue of the journal Nature.

Led by Associate Professor Jeremy Timmis, the group bred a marker gene into the plant's chloroplasts, semi-autonomous organelles inside each plant cell that are chiefly responsible for photosynthesis.

They then looked for signs of the marker gene in 250,000 of the seeds the plant produced. In about one in every 16,000 seedlings, the marker gene had done the unexpected - it had moved into the nucleus of the cell, where DNA is stored and replication controlled.

This means it not only migrated through the cytoplasm of the cell, but passed through the double membrane wall protecting the nucleus.

Timmis downplayed the implications for GM plants, saying the marker gene used was specifically chosen for the purpose. And while movement of genes from chloroplast to nucleus does not occur naturally, there are many more processes before a complete and functional gene could make the migration.

"We put a new gene in - but made it absolutely ready to be expressed in nucleus," he told ABC Science Online. "The gene was not expressed at all in the chloroplast, only if it ended up in the nucleus."

It is possible to differentiate between the two regions as chloroplast genes are controlled in a completely different way, he said.