Molecular characterization of Bt brinjal "inadequate", results "unpredictable" - genetic engineer Dr David Williams
PROFESSOR OF OPHTHALMOLOGY &
JULES STEIN EYE INSTITUTE
200 STEIN PLAZA
DAVID GEFFEN SCHOOL OF MEDICINE AT UCLA
LOS ANGELES, CA 90095-7008
To: The Hon. Jairam Ramesh,
Minister of State (Independent Charge)
Ministry of Environment & Forests
Government of India
Paryavaran Bhawan, CGO Complex
New Delhi 110 003
January 10, 2010
Dear Minister Ramesh,
I am writing to you as an independent scientist on the subject of Bt-brinjal. In my research laboratory, we have been generating and using transgenic organisms over the past 15 years. Hence, I have considerable first-hand experience on the “behavior of transgenes and the advantages and disadvantages of transgenic organisms. I have also followed the development of genetically-engineered organisms for use in agriculture and medicine. Four years ago, I participated in a workshop on the safety of genetic engineering in agriculture at the FAO in Rome (ftp://ftp.fao.org/es/esn/food/meetings/2005/gm_workshop_info.pdf).
I have read the report of the Expert Committee (EC-II) on Bt brinjal, and have some concerns on the observations and conclusions of the EC-II. My general concern is that the molecular characterization of Bt brinjal is clearly inadequate so far, and that the need for future monitoring of molecular characteristics seems to be grossly under appreciated.
First, the arrangement of a transgene is not predictable. For the procedures used in the generation of transgenic plants, the site of insertion varies, as does the precise makeup of the DNA included in the transgene. Second, transgenes often change from one generation to another. For example, more often than not, transgenes begin as tandem arrays. Breeding tandem arrays to homozygosity results in uneven crossover, and the consequential gain or loss of a copy in following generations, resulting in major changes in transgene expression levels.
For these reasons, no evaluation of the safety of a transgenic crop can be made without adequate molecular characterization at the outset as well as continued characterization as subsequent generations are bred. In this respect, let me make three comments with regard to Bt brinjal.
1. Argument against proper molecular characterization by EC-II.
The concluding remark of the EC-II on Dr Bhargava’s recommendations on DNA fingerprinting and proteomic analysis (D.1) is as follows:
“The EC II noted that the technologies such as transcriptomics (transcript profiling), proteomics (protein profiling) and metabolomics (metabolite profiling) involve long drawn expensive procedures with little value, and therefore not recommended for safety assessment of GM crops. These technologies are research tools and have not been validated for use in evaluation of GM crops.”
Yet, these procedures can now be performed efficiently and relatively inexpensively. Especially when one considers the risks to human and environmental safety, with the proposal of Bt-brinjal being used as a food crop in a nation as large as India, the costs are barely significant. If a company cannot justify this expenditure on the basis of advantages of the GE crop, then one has to question claims of the crop’s advantages.
2. Inadequacies of molecular data so far presented on Bt brinjal.
The Southern blot data presented to characterize the transgene are of such poor quality that no reliable conclusion can be made from them. Mahyco claims that there is only a single insertion site of the transgene, but I am not convinced by their data. Moreover, I could not find where the issue of whether or not the transgene is a tandem array of more than one copy of the transgene has even been addressed. Agrobacterium-mediated transformation typically generates a tandem array of two copies of the transgene.
3. Proposal for continued molecular characterization.
I could not find any plan for continued molecular characterization. Of course, this seems likely to be unpracticable, if local farmers breed their own subsequent generations. Yet, it is well documented that transgenes can and do change with time. They can become rearranged. And, as noted above, if they are present in a tandem array, uneven crossover will eventually result in one line gaining a transgene(s) and another line losing a transgene(s). In this case, the line that loses a transgene will likely suffer a drop in the expression level of Cry1Ac protein, to the point that it may become ineffective. The line that gains a transgene will likely express much more of the protein, making many of the previous safety tests on the original line irrelevant.
Minister, I am only a scientist, and I leave public policy up to people like yourself. However, knowing what I know about transgenic organisms, and from what I have read in the EC-II Report on Bt-brinjal, I shudder at the thought of this food crop, with its current lack of molecular characterization, being grown and consumed by humans, especially on such a large scale as that proposed.
David S. Williams PhD
RPB Jules and Doris Stein Professor