www.checkbiotech.org ; www.raupp.info ; www.czu.cz

In the world of genetic engineering one often talks about ?transgenic
organisms?. These are organisms that have been modified by the insertion of
an alien gene into their genome. Now it turns out that there are naturally
occurring transgenic plants. One such instance was found by Dr Lena
Ghatnekar from the research team for evolutionary genetics at Lund
University in Sweden. Her findings have just been published in the
prestigious Proceedings of the Royal Society in London, January 2006.

Sheep?s fescue (Festuca ovina) is a common grass that the research team at
Lund University in Sweden has studied for a long time. One of its genes
codes for an enzyme called PGIC. Lena Ghatnekar discovered that the enzyme
did not look the same in all sheep?s fescue plants. It turned out that
certain plants had extra genes for the production of PGIC and that these
genes existed at a different site in the genome than the normal PGIC genes.
At first the scientists believed that it was a matter of copied genes ? gene
duplications ? but it soon proved to be a question of fugitive genes. Lena
Ghatnekar explains:

?There are always minor differences from one plant to another when it comes
to complex proteins like the enzyme PGIC. Maybe a difference of up to a few
percent. But in this case the difference was six percent, and that is too
much for an ordinary gene duplication.?

The alien has now been identified. The gene that produces the deviant PGIC
comes from another grass, namely a meadow grass (Poa). This is surprising,
since the fescues and the meadow grasses are not particularly closely
related.

?We don?t know how the alien gene got into sheep?s fescue. When we have
located precisely where in the genome the gene is situated, it will be
possible for us to make a guess. But apparently the introgression led to a
variant with high fitness, making the alien gene spread to later
generations. Today, there are populations of sheep?s fescue where ten per
cent of the plants carry the extra gene? says the head of the research team,
Professor Bengt O. Bengtsson, adding:

?This is a truly unique event. Poa and Festuca are so remote from each other
that a plant breeder would never dream of trying to cross them. Perhaps the
gene was inserted into Festuca via a virus that can infect both grass
species. In that case it is a sort of spontaneous genetic transformation;
today?s genetic engineers make use of viruses to transfer genes. Another
possibility is that something very special happened during fertilization. To
be sure, grasses have a ?defence system? that normally prevents foreign
pollen from growing on their pistils, but maybe in some way a fragment of a
Poa pollen hitched a ride with a regular Festuca pollen.?

[www.lu.se]

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