species. Genes for the colour red placed into petunia flowers not only
changed the colour of the petals but also decreased fertility and
altered the growth of the roots and leaves. Salmon genetically
engineered with a growth hormone gene not only grew too big too fast
but also turned green. These are unpredictable side effects,
scientifically termed pleiotropic effects.
We also know very little about what a gene, or for that matter any of
its DNA sequence, might trigger or interrupt depending on where it got
inserted into the new host. These are open questions around positional
effects. And what about gene silencing and gene instability? How do we
know that a genetically engineered food plant will not produce new
toxins and allergenic substances or increase the level of dormant
toxins and allergens? How about the nutritional value? And what are the
effects on the environment and on wild life? All these questions are
important questions yet they remain unanswered. Until we have an answer
to all of these, genetic engineering should be kept to the test tubes.