Dr. Mae-Wan Ho replies to Prof. Alan Schulman

I did not mean to frighten the Finns, only to warn them of the potential hazards of growing GM crops. My arguments were based on scientific findings and official sources that Prof. Schulman ought to be familiar with, but perhaps not.

He says transgenes landing in different position in the genome will have no effect. Many geneticists will disagree, as �insertion mutagenesis' - the generation of mutations from extra DNA inserting into genes � is very well known. The effect will depend on which genes are mutated, and hence where in the genome the transgenes have landed. Such �position effect� is well recognized in risk assessment, particularly as insertion of transgenic DNA tends to scramble the host genome at the site of insertion.

It is misleading, therefore, to say that, �the location of genes in the genome varies between different wild plant species without causing danger.� The genes in the wild species' genomes have co-evolved for hundreds of millions of years, a situation completely different from having transgenic DNA - often carrying aggressive promoters and new gene combinations � effectively forcing its way into the host genome.

Prof. Schulman says transgenic DNA landing in a transposon is very likely to inactivate the transposon. Let's hope so; but as he knows, the inactivated transposon can move with the help of other active transposons in the genome.

He surmises that, as transposon moves by copying itself; that would silence the transgene. Not necessarily so. French government scientists found active transgenes inserted into transposons in commercially grown GM varieties. And silenced transgenes have been known to regain activity in later generations.

Although every plant has transposons, it is not true to say they are �moving throughout the genome, from one location to another, without this altering the properties of plants�. Prof. Schulman should know that most transposons do not move, most of the time. However, they may be mobilised by tissue culture, environmental stress, and by inserting transgenic DNA. The activation of transposons in tissue culture is thought to underlie the profuse �somaclonal' variations found in plant cell culture.

The claim that, �transposons do not automatically or randomly transfer the transgenes�, is only partly true, as many transposons insert at specific sequence motifs in their native genome. However, when transferred to a strange genome, this specificity is lost, and they could insert anywhere.

The assurance that a genetic engineer �opts only for genes that are
proven safe� is false. Twenty-two out of 33 transgene proteins in GM crops were identified as suspected allergens; and newer GM crops contain vaccines, pharmaceuticals and industrial chemicals, many known to be unsafe.

As for Prof. Schulman's claim that the stability of GM varieties is �verified with research�, I cannot find a single publication that backs it up, that provides molecular data documenting that the transgenic insert has remained in the same form in the same position in successive generations.

Prof. Schulman finally tells us transgenic plants have to pass normal plant breeding process, which secures �uniformity and stability of characteristics.�

The meagre evidence available � from findings of French and Belgian government scientists - suggests that commercial GM varieties are neither stable nor uniform.

Prof. Ignacio Chapela at Berkeley University is still fighting for tenure after he and his graduate student published an article in Nature showing that transgenes had contaminated Mexican maize landraces, and that transgenic DNA might be fragmenting and scattering throughout the maize genome.

The stark truth is that GM crops have been created and released in a great hurry without adequate research or due precaution. We cannot continue to allow irresponsible scientists with vested interests to use our planet as a their laboratory, and to victimize and vilify scientists who try to tell the public what they know.