London (19
January 2006) – One of the objections to agricultural biotechnology,
endlessly reiterated by campaigners and their commercial allies, is that GM
crops are not “natural”.
That begs two questions: what does “natural” mean and does gene
transfer between plants take place without human intervention?
As regards the first point, the Shorter Oxford English Dictionary (1955 printing)
has a number of rather woolly definitions of “natural” along the
lines of “not altered or improved in any way” (altered by what
is not stated), “taking place or operating in accordance with the ordinary
course of nature” (that encompasses everything, including human activities)
and “existing in, or formed by, nature; not artificial” (elsewhere
defining “artificial” as “not natural”).
Since human beings are the products of “natural” evolutionary
processes, they themselves and all that they do must ipso facto also
be “natural”. What they do includes inventing gene splicing technology
which is accordingly “natural”. If it is not, then one must explain
how a dam made by a badger by chewing down trees, or birds' nests made with
twigs and leaves, differ in naturalness from dams made by people using concrete
or houses built with bricks. If badgers and birds are natural while humans
are not, when did people become “unnatural” – or should
it be “supernatural”?
The second matter has recently been illuminated in Sweden. Although it is
not difficult for molecular biologists to imagine how genes might be moved
between organisms via the agency of bacteria and viruses, it is much more
difficult to provide good examples of such events. Not only are they likely
to be relatively rare, and biology is a very large place in which to look
for needles in haystacks, there is a large question of how a gene might be
recognised as originating transgenically from another source.
Results just published by Dr Lena Ghatnekar from the research team for evolutionary
genetics at the University of Lund give such an example. One of the genes
in the common grass sheep’s fescue codes for an enzyme called PGIC.
Dr. Ghatnekar found that the enzyme differed between various sheep’s
fescue plants. She discovered that certain plants had extra genes for the
production of PGIC, present at a different site in the genome from the normal
PGIC genes.
At first it was thought to be a matter of gene duplication – but it
turned out that the extra genes were sufficiently different from the main
ones to make duplication most unlikely.
It turned out the deviant PGIC came from meadow grass, a plant not closely
related to sheep’s fescue and so unlikely to have transferred the additional
gene by cross pollination. Dr Ghatnekar commented that they “are so
remote from each other that a plant breeder would never dream of trying to
cross them”.
Finding the foreign gene did not immediately disclose how it had moved. It
might have been transferred by a virus which infects both grasses, just one
of the things that human genetic engineers do. Or perhaps a fragment of meadow
grass pollen became attached by chance to sheep's grass pollen and so introduced
foreign DNA in the pollination event. That is rather like shooting it in using
a biolistics gun.
It all makes human genetic engineers less like the wicked monsters portrayed
by those who campaign against improving agriculture and closer to being the
inheritors of a long and venerable biological tradition of genes moving about
in the most unexpected ways.
Sources:
1. Fugitive gene. Lund University, Sweden (18.1.06) (http://www.checkbiotech.org/root/index.cfm?fuseaction=news&doc_id=12053&start=1&control=166&page_start=1&page_nr=101&pg=1
2. Lena Ghatnekar, Maarit Jaarola and Bengt O. Bengtsson. The introgression
of a functional nuclear gene from Poa to Festuca ovina. Prceedings of
the Royal Society (Biological Sciences) (http://www.journals.royalsoc.ac.uk/(idu1cp45b2fgw345c42c0oy4)/app/home/contribution.asp?referrer=parent&backto=issue,56,91;journal,1,214;linkingpublicationresults,1:102024,1)
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