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.
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)