Sir, - I would like to respond to the criticism (October 15th) of my letter (October 8th) by Quentin Gargan, spokesperson for Genetic Concern! I am accused of trivialising the arguments against genetic engineering. I find this difficult to understand, as my letter was a criticism of the Green Party's misuse of scientific argument in support of its political ends. I was not supporting, or otherwise, genetic engineering, and indeed stressed the importance of vigilance with regard to this new technology.
However, Mr Gargan's letter provides another example of misuse of scientific argument. Mr Gargan cites as precedent the production of L-tryptophan (not tryptophane) by biothechnological techniques using genetically engineered bacteria. L-tryptophan is an essential amino-acid, and not a food additive, although it is sometimes added to fortify foods. He correctly relates the disastrous consequence of the presence of a toxic impurity in a number of batches of L-tryptophan. However he fails to mention that this toxin was produced by the chemical coupling of two molecules of Ltryptophan in a reaction known as dimerisation. As such, the production of this toxin is particular to L-tryptophan and could not happen with sugar, which has a different molecular structure and therefore a different chemistry. Mr Gargan's thesis that this toxin could occur in sugar is therefore incorrect.
Mr Gargan should also be aware that if a molecular material such as sugar is synthesised either in a plant such as beet or indeed synthetically in a laboratory, the molecules of sugar do not have a "memory" of whence they came. They will have an identical chemistry.
Mr Gargan classifies many scientists, including myself, as having a "blind faith in this new technology" i.e. genetic engineering. The scientific method requires that all opinions and theories, including his, should be subjected to reasoned and informed criticism. - Yours etc.,
From Conor Long
Dean of Research, Dublin City University, Dublin 9.