Transgenic
technology- the good, bad and the ugly
Transgenic technology
has emerged as one of the major bio-technological innovations of our time.
Diverse clients of transgenic technology include fields of medicine to
environmental management and crop science. Notwithstanding the fact that this
technology has remained in eye of fierce policy and public debate, particularly
with respect to its application in agriculture, there is no denial that transgenic
innovations have opened new horizons of possibilities that never existed
before. The various things that it can help us achieve almost seem science
fictional and if not bizarre at times-, but they are not. For the first time in
the whole evolutionary history of life on this earth transgenic technology has
given one its millions of species- man-, the power to create new life forms.
This appears like browbeating the process of evolution itself. What is it all
about? Are the products of this technology all good to cheer about or are there
reasons for worries too? But before we take a close look into that, perhaps we
should try to understand the basic biology of the Gene and how it works.
The
Gene and the Central dogma:
Cells of an organism’s
body are like the bricks in a building. Inside the nucleus of a cell are the
chromosomes- the thread like structures that pass on to the offspring from both
parents. These chromosomes are again made of double helical threads called the
DNA (Deoxy ribose nucleic acid). Genes are the short sections of DNA. DNA is a
complex molecule and is made up of four types of biological bases- Adenine,
Guanine, Thymine and Cytosine. Combinations of pairs of these bases constitute
a gene. Genes are called the ‘functional unit because each combination of the
base pairs contain information for producing a particular ‘amino acid’. Amino
acids are the building units of any protein and as we all know- proteins are
vital ingredients of an organisms physiology and responsible for large number
of fundamental traits of an organism. Quite naturally then since genes regulate
what kind of proteins would be produced they are called the functional unit of
life too.
But we should also know
perhaps a little bit about the mechanism of production of amino acids from
genes. This mechanism of production of amino acids from gene is not a reversible
process (i.e. it is not possible to make a gene from an amino acid) and follows
a fixed pattern that regulates the flow of information from a gene to amino
acid. This mechanism is known as the central dogma in molecular biology.
The
classic view of central dogma states that the coded genetic information
hard-wired into DNA is transcribed into messenger RNA (m RNA). This process is
called transcription. The DNA can replicate via a process called replication.
Each m RNA contains the information for the synthesis of a particular protein
(or a small number of proteins) which is carried out through a process called
translation. The diagram below shows an illustration of the central dogma in
molecular biology.
Fig: The central dogma
in molecular biology
Transgenesis:
Transgenesis
is the process of transfer of genetic material (foreign) into an animal or
plant genome. Thus, a transgene is a genetic material that has been transferred
either naturally or by genetic engineering techniques. This transfer process is
called transfection. The introduction of a transgene has the potential of
changing the phenotype of an organism.
Various
vectors like plasmids are used in transfection. The plasmid is a small DNA
molecule that is physically separated from and can replicate independently of
the chromosomal DNA within a cell. These plasmids used in transfection commonly
include p RSV for fishes, p BR322 (used as shuttle plasmid vectors). Other than
plasmids various other vectors which are used include BPV vectors, Retrovirus
vectors, Polyoma virus vectors, Vaccinia virus vectors, P element vectors
(transposable element in Drosophila) and Bacculovirus vectors.
Transgenic
Products- the Good:
Genes
have been transferred into animals with an objective to obtain a large scale
production of the proteins encoded by these genes in the milk, urine or blood
of such animals. Such animals are called bioreactors
and the approach is referred to as molecular
farming or gene faming. For
example, cattle, goat, sheep and swine are used for large scale production of
proteins from human genes (such as alpha 1 antitrypsin, tissue plasminogen
activator, blood clotting factor IX, and protein C) expressed in the mammary
tissues of these animals.
A
special case of gene transfer aims at alleviating or even eliminating the
symptoms and consequent problems of genetic diseases. In this approach, normal
and functional copies of the defective gene (that produced the genetic disease)
are introduced into the patient. This is called gene therapy. The most logical step that scientists have taken is
trying to introduce genes directly into human cells, focusing on diseases
caused by single gene defects such as cystic fibrosis, haemophilia, thallasemia
and sickle cell anemia. However,
this has proven more difficult than genetically modifying bacteria, primarily because of the problems involved in
carrying large sections of DNA and delivering them to the correct site on the
gene. Today, most gene therapy studies are aimed at cancer and hereditary
diseases linked to a genetic defect.
Specific transgenic animal strains or lines are created
to fulfill specialized experimental and/or biomedical needs. Often used is the
“knock out” mice strain in which specific genes have been replaced or knocked
out by their disrupted counterparts through a process of homologous
recombination.
It is now believed, that in the next two decades 300 000 lines of
transgenic mice will be generated. Of particular interest is the application of
such transgeny in the medical field. The study of the function of the human genome is
now carried out using transgenes -- adapting animal organs for transplantation into humans, and the production of pharmaceutical products such as insulin, growth hormone, and blood anti-clotting
factors from the milk of transgenic cows. One of the most promising avenues of
transgenesis is the possibility of the treatment of genetic diseases to which
many succumb. In this regard, gene therapy will hold particular value in the
years to come. Even though it is not a widely accepted remedy, the lives of the
people who fall prey to genetic diseases like haemophlia and thallasemia lie in
the hope of this promise.
Transgenic products: the Bizarre:
A recent transgenic plant project, known as the “glowing
plant project,” incorporated a gene from a firefly into a houseplant, creating
plants that display a soft illumination in the darkness. One of the proposed
goals is to create trees that could illuminate streets and pathways, thereby
saving energy and reducing our dependence upon limited energy resources.
However, the public release of such plants has sparked a heated debate centered
around potential environmental impacts of introducing highly genetically
engineered plants into natural ecosystems.
BioSteel® is a high strength, resilient silk product
created by inserting the genes from a silk-spinning spider into the genome of a
goat’s egg prior to fertilization. When the transgenic female goats mature,
they produce milk containing the protein from which spider silk is made. The
fiber artificially created from this silk protein has several potentially
valuable uses, such as making lightweight, strong, yet supple bulletproof
vests. Other industrial and medical applications include stronger automotive
and aerospace components, stronger and more biodegradable sutures, and bio-shields,
which can protect military personnel and first responders from chemical threats
such as sarin gas.
Transgenic
Products: the Bad and the Ugly:
Alongside the
applications of transgenic in medicine and bizarre attempts to produce light
with glowing plants attempts are on to apply this technology in crop science.
One would see a novel initiative in this as answer to existing and growing
demand for food. But there are perhaps more than that meet our eyes in this
initiative. In our country itself market approval has already been given to
transgenic cotton (Bt Cotton). There was an attempt to market Bt Brinjal too
but a moratorium was slapped on its commercial release after large sections of
the society including scientists and farmers raised serious objections.
Through rest of the
sections we shall have a close look at the transgenic crops or Genetically
Modified (GM) crops and why are there so much of debate on this. There is a
major view within the progressive movement that the GM crop technology should
not be opposed as such since there is nothing wrong with the technology and
opposing it would be anti-science & technology. This view suggests that
progressive movement should press for freeing this technology from the hands of
monopoly trans-national agencies like Monsanto and DuPont and should fight for
increased indigenous engagement in GM crop research. It is hence all the more
important to analyse what might not be all that right with GM crop technology
after all and we shall try to argue the
position people’s science movement should adopt with regards to the issue of GM
crops.
Transgenic plant was
first produced in 1982 was a herbicide resistant tobacco and the field trial of
this plant was carried out in France and
the USA in 1986. In 1987, a Belgian company named Plant Genetic Systems first
developed genetically engineered pest resistant tobacco plants that bore toxin
producing genes from a soil bacteria (Bacillus thuringensis) by expressing
genes encoding for insecticidal proteins. The People’s Republic of China was
the first country to allow commercialized transgenic plants, introducing a
virus-resistant tobacco in 1992, but this was withdrawn from the market in in
1997. Subsequently, in 1994 a genetically modified tomato (FlavrSavr) with longer shelf life was approved for sale in USA. Approval
for transgenic crop in European Union first came in 1994 for herbicide
resistant Tobacoo that was the first transgenic developed in 1982. In 1995, Bt
Potato was approved for marketing in USA. Subsequently marketing approval in
USA also came for a rape plant variety canola
with modified oil composition (Calgene), (Bt) corn/maize (Ciba-Geigy), herbicide
resistant cotton (Calgene), Bt cotton (Monsanto), soybeans resistant to the
herbicide glyphosate (Monsanto), virus-resistant squash (Asgrow), and
additional delayed ripening tomatoes (DNAP, Zeneca/Peto, and Monsanto). As
of mid-1996, a total of 35 were marketing approvals were given for 8 transgenic
crops and one flower crop of carnations, with 8 different traits in 6 countries
plus the EU. In 2000, a variety of rice that can synthesise Vitamin A- the prevention
for blindness was developed. This was termed the ‘Golden Rice’!
Genetically modified
plants and evidence of scientific uncertainties
The main limitation of
this technology is the availability of preliminary knowledge about the role of
gene in determining a given trait and is, at present, only applicable for
traits that are ‘determined’ by one or a relatively small number of genes. To
date, most applications that have reached the field involve the use of
heterologous genes (i.e. genes from other organisms) to engineer various
adaptive traits as herbicide and insecticide resistance where the window of
opportunity has been limited by the operation of biology / nature prevailing
over the resources of farmer in practice sooner than the state of art in
genetic engineering expects the problems to hit back.
Further, it is
necessary to recognise that delivery methods like the “gene gun”, or more or
less scattered shot technologies, are still being used in genetic modification
technology. The place of insertion of new genes into the plants’ genome is not
the result of a finely targeted process yet and hence the probability that the
target gene would carry along extra genetic load when it gets inserted.
Furthermore, the biological activity of newly inserted gene sequences has to be
enforced artificially. The plants’ own gene regulation has to be knocked out
(partially) to avoid silencing the additional gene constructs. As a result, it
has been observed that unintended biological interferences can also have
various effects at the level of the genome, cell metabolism and or the whole
organism[1].
Toxicological and
health impacts can be serious. One has to take into account unintended
components caused by occasional interference of the plants’ metabolism.
Environmental impacts cannot be taken lightly. The relevant risks are not of a
steadily fixed nature, they involve dynamic processes involving factors like
the growth of the plants and various environmental influences. Exposed to
external stress factors, genetically engineered plants can also exhibit
unexpected effects not noticed before (Matthews et al, 2005). There is also the
problem of unintended gene transfer; special cause for concern is the fact that
the spread of the artificial gene constructs via and other escape routes cannot
be prevented. All in all one has to deal
with a complex matter of ecological, biological and health related issues which
is dependent on a broad range of additional external factors which are not
fully understood in all details.
In a much talked about
piece in Science,
Dominigo
(2000) showed that while there are many opinions on the GM crop issue, data on
the potential health risks of GM food crops are rare; even though these should
have been tested for and eliminated before their introduction. Our present data
base is woefully inadequate. As this article pointed out then, there are hardly
any scientific literature on the the GM related health risks published by the
scientists working in the Biotech companies. If they have tested for the
toxicity and allergenicity of GM crops, then why haven’t they been publishing
it? Since Dominigo’s article is a decade older, we looked for the current
status of the same using the same search procedure as Dominigo’s and found the
same pattern in more contemporary published literature. Quoting Dominigo-, “Moreover,
the scientific quality of what has been published is, in most instances not up
to expected standards. If, as claimed, our future is dependent on the success
of the promise of genetic modification delivering wholesome, plentiful, more
nutritious and safe GM foods, the inescapable conclusion of this review is that
the present crude method of genetic modification has so far not delivered these
benefits and the promise of a superior second generation is still in the
future.” Obviously then quoting Dominigo again, “We need more science, not less”.
The underlying
principle of GM crop risk assessment has been a so-called “comparative
approach”, which tries to draw a comparison between the genetically engineered
organisms and their counterparts produced in conventional plant breeding. In
this approach, conventional protocols use the concept of “familiarity” for the
risk assessment of the cultivation of transgenic plants and “substantial
equivalence” for the risk assessment of food and feed. The problem with such an
approach is that if-due to insufficient scientific methods-no substantial
differences can be found between the transgenic plant and its comparator, the
product is likely to be categorised as being safe. It is important here to know
that methods especially relevant in the analysis of the proteom and the
metabolom have not yet been developed sufficiently to be used as standard
procedures in risk assessment (EFSA, 2007 a), despite these methods having been
seen as decisive tools.
‘Substantial
equivalence’ (SE) between the transgenic crops and conventional crops (meaning,
two varieties are so similar to one another that they can be taken to be same)
are often argued by the proponents of universal value of GM crop technology.
The objections to this SE argument are the following:
- There is no specific,
statistical basis for the standard (Brunner and Mayer 1999). Substantial”
is an adjective rather than a statistical parameter like an F value or a p value, which begs the obvious
question: How different is acceptably different versus unacceptability
different?
- GM and conventional crops
cannot be compared for the possible consequences to food quality and
composition due to unintended effects, either predictable or unpredictable
ones. How can one investigate unintended effects using directed testing
methods?
It can hence be argued
that, instead of making the GM varieties the only subject of analysis, we
require a deeper understanding of naturally occurring variations that would
also represent the range of consumer acceptable variation.
A completely different
concept of risk assessment would apply if the underlying hypothesis took into
account the fact that transgenic plants are derived from a technical process
that cannot be compared to methods used in conventional breeding. The basic
difference between conventional breeding and genetic engineering is becoming
more and more evident because it can be shown that the mechanism for regulation
of the genome is far more complex than was estimated some years ago. Today the
organization of the genome is much more defined by networks and (quantitative)
synergies of gene clusters than by the function of single genes. Wentzell et
al. (2007) for example indicate this development including its consequences in
the case of plants when they state “Most phenotypic variation present in
natural populations is under polygenic control, largely determined by genetic
variation at quantitative trait loci (QTLs). These genetic loci frequently
interact with the environment, development, and each other, yet the importance
of these interactions on the underlying genetic architecture of quantitative
traits is not well characterized”. In the light of such advances in scientific
understanding, we understand that this uncertainty would be better reflected in
the development of hypotheses on the risk assessment of the transfer of
isolated genes in the precautionary approach.
This new insight
matters also because in the case of GM crops the new genetic information and
its expression in the cells is forced into the plants by such technical means
that knock-out partially the normal mechanisms of gene regulation. Invasive
methods like this are not used in conventional crossings or mutation
technologies. New genetic information obtained in conventional breeding gets
used if it fits with the existing genetic background of the plants. But for the
risk assessment of genetically engineered plants it is crucial not to deny the
basic distinction between methods for breeding and technical construction of
genetically engineered plants. While conventional breeding uses existing
biodiversity and its potentials developed by evolution over a long period of
time, genetic manipulation tries to enforce a technical program without obeying
the rules of normal gene regulation. The changes associated with genetically
engineered plants are not restricted to specific regions in the genome. The
findings of Batista et al (2008) show that the assumptions that changes in
genetically engineered plants to be restricted only to the specific trait
inserted, are not based on scientific facts.
Horizontal gene
transfer (HGT) problem looms large
The
transgenic technology is essentially a technology wherein genes are transferred
across non mating species. This transfer is essentially horizontal as against
vertical transfer of genes from parents to progeny through sexual reproduction
within the same species. The issue is not whether such horizontal transfer is
unnatural as some voices against GM crops that Purkayastha and Rath mentions,
but the point precisely is that-, it is not. The point is different; HGT is
known to have affected the evolutionary process in the past (Syvanen 1985,
Doolittle et al. 2003, Rivera and Lake 2004, Bapteste et al. 2005, Koonin 2007,
Richardson and Palmer 2007, Keese 2008). Therefore, HGT can significantly
impact genetic diversity at least among phylogenetically close species and can
promote novel adaptations among organisms, thereby also tinker with the natural
evolutionary process. It has also been said that in the short term HGT has been
a major contributory factor behind rapid spread of antibiotic resistance
amongst pathogenic bacteria in the last 50 years (Mazel and Davies, 1999).
There is a growing body of literature that attributes incidences of increased
virulence to HGT (Derbise et al., 2007; Friesen et al., 2006; Mild et al.,
2007). Following table illustrates some short term and predictable adverse
impacts of HGT from GMO (after Keese 2008):
Table
1.
|
Impact category
|
Impacts
|
References
|
|
Adverse Environmental
Effects
|
Enhanced pathogenicity
or virulence in
people or animals
|
Kleter et al 2005
|
|
Unpredictable &
unintended effects
|
Introduced genes from a GMO to
multitude of other species, some of which are potential pests or pathogens,
and many organisms are yet to be identified and characterized. Introduced
gene might escape to indigenous bacteria and can alter its ecological niche
characteristics. Difficult to predict the outcome but is a strong
possibility.
|
Prescott et al, 2005, Heuer and
Smalla, 2007
|
|
Genomic disruption
|
More complex genomes,
e.g. that of higher organisms are more intolerant of change and may lead to
genomic instability. Possible to measure.
|
Ho et al 2000, Woese
2004
|
|
Uncontrollable
management
|
HGT from GMO would
create new GMO. This new GMO might lead to adverse effects that are not
controllable through management measures permitted in the license while
releasing the original GMO
|
Keese 2008
|
HGT and Centre of Crop
Genetic Origin
HGT assumes added
importance when it comes to genetic modification on crops at the site of its
origin. Crops at the centre of their origin are likely to have more number of
phylogenetically related species. HGT has been seen to be increasing with
decreasing genetic distances and vice versa (Beiko et al 2005, Majewski 2001,
Fraser et al 2007, Bonnet et al 2005) meaning crops at the centre of its origin
will have more chance of transferring novel genes into its related species and
landraces. The most noteworthy case in support of this apprehension is that of
GM maize in Mexico, where fragments of CaMV 35s promoter from genetically
modified maize, commonly used as a construct to boost up gene expression of
inserted gene in plant genetic modification, was found to be contaminating
Maize landraces. This discovery by Quist and Chapela, two University of
California, Brakeley scientists was reported in Nature (Quist and Chapela
2001). An independent study by Mexican government later corroborated this
finding.
HGT and Public Health
concerns
There is a growing body
of evidence to suggest that the genetic material from CaMV virus (Cauliflower
mosaic virus) mentioned in the Mexican incident, as a transgenic construct for
plant genetic modification is potentially hazardous due to a number of reasons
and has serious public health bearing. The CaMV 35s promoter is found across
the living world and is even found in humans. In 1999 it was discovered that
this promoter has ‘recombination hotspots’ where it tends to break and join up
with other DNA (Hull et al. 2000, Ho et al. 2000). It is now understood that
CaMV 35S promoter will be extra prone to spread by horizontal gene transfer and
recombination and can even interact with human genome. Hence, so far the
present state of technology goes; search for a safer gene expression promoter
is definitely in order even if genetic modification technology in plants is to
be pursued. The health risks associated with this are the following:
- Antibiotic
resistance genes spreading to pathogenic bacteria.
- Disease-associated
genes spreading and recombining to create new viruses and bacteria that
cause diseases.
- Transgenic
DNA inserting into human cells, triggering cancer or hitherto unforeseen
and uncertain other expressions.
Genetic stability
Evidences from a number of studies indicate that
transgenes are inherently unstable compared to natural DNA and are more likely
to break up and rejoin. Transgenic DNAs are also designed to break species
barrier through flanking them with recombination sequences which enable them to
jump into genome and is hence potentially more prone to horizontal transfer.
Worse, since they come from a wide variety of sources, e.g., pathogens,
allergens etc., in case of these fragments sitting pretty in the host get into
any homologous arrangement with the donor genome due to similarity in base
sequence, the probability of HGT increases many fold, since homology enhances
HGT (Primrose & Twyman 2006). The recent discovery of ‘recombination
hotspots’ both in plant as well as in human genome is indicative of the risk of
inserted DNA fragment around these hotspots and hence would be further prone to
expressions that were not intended primarily.
Towards
a Precautionary Assessment Principle:
We have a choice to
make from the four different approaches to assessment; each approach being
designed to gather the information necessary for making adequate and prudent
governance decisions in different contexts.
- If a significant harm is
expected with almost certainty, then, subject only to consideration of any
over-riding justification, they are assigned directly to preventive
measures.
- If the threats in question are
minor and quantitative data about probabilities and magnitudes is either
available or is to be produced, then they should be assigned directly to
the approach of risk-based assessment.
- But if we are unable to
allocate threats to straightforward preventive measures or to risk-based
assessment, then more comprehensive assessment procedures are recommended.
If any scientific uncertainty has been identified, then the
subsequent approach to assessment is precautionary assessment.
- If socio-political ambiguity
has been identified, where the problem lies not with probabilities, but in
agreeing on the appropriate values, priorities, assumptions, or boundaries
that apply in defining the possible outcomes, then a process of concern
assessment is adopted in subsequent assessment.
Both conditions (uncertainty
and ambiguity) can apply at the same time and for the same assessment
candidate. We argue that in the case of Bt crops, both approaches, i.e. the
precautionary assessment approach and the concern assessment approach need to
be combined.
The technocratic way of
framing the assessment protocol of risks involved in the case of GM crops
(wherein “objective science” is seen to directly inform policymaking), is quite
inadequate and ethically inappropriate. The introduction of GM food crops
cannot be handled in terms of merely the conventional risk assessment approach
that refers to a situation where it is possible to confidently quantify both
the magnitudes of and the probabilities for a defined range of outcomes (such
as forms or degrees of harm). If the intractable circumstances include also
conditions of ‘uncertainty’ (where possible outcomes are clear but difficult to
quantify probabilities), ambiguity (where the problem lies not with
probabilities but in agreeing on the values assumptions and boundaries that
apply in defining the possible outcomes), and ignorance (where neither
probabilities nor outcomes are fully or confidently characterized); then the
precautionary principle based technology regulation is a must in our view.
Conventional risk assessment would leave residual uncertainties unaddressed. A
more comprehensive approach to assessment is preferable to unconstrained
reliance on conventional risk assessment methods.
Since the precautionary
assessment approach can address a set of more intractable circumstances under
which various forms of incertitude render such quantification incomplete or
problematic, it is far more appropriate to adopt this approach for the
regulation of technology of GM crops in India. Argument that familiar safety
testing protocols are sufficient to serve societal needs well because GM crops
carries non-catastrophic consequences, is certainly not an appropriate
objection. As far as the demand for the implementation of precautionary
assessment approach based regulation is concerned, it is not pertinent that the
technology of GM crops carries non-catastrophic consequences. What is important
is that there are areas of uncertainties, ambiguity and elements of ignorance
in the case of GM food technologies.
Although the basket of
technologies to be championed by the progressive movements deserves to include
certainly the technology of agro-biotech and genetic engineering (which might
also involve genetic modification for the development of transgenic
technology); the progressive movements should not reject or overlook the
precautionary approach to commercial introduction of the GM crops. The people’s
science movement need to struggle for a comphrensive framework for the
assessment, management and communication of technological risks to mobilise
their own basic classes in a sustainable way. This framework is essential
because we are going through a neo-liberal phase when system of public-private
partnerships (PPPs), the new trend in the division of the innovative labour
between public and private entities is becoming all pervasive in agricultural
research; and the public sector in science and technology (S&T) is being
made to come under the greater influence of big business and global corporations.
The precautionary
assessment approach requires to be pressed for as other choices do exist for
immediate purposes and can be selected suitably from the basket of technologies
being developed with the efforts of modern science and technology. Efforts
going on in the field of ecological approaches to agriculture are equally
modern and can even serve the basic classes better whom the people’s science
movements hope to mobilize for a better future for the agriculture sector in
India. It is time now for the
Further, the
implementation of precautionary assessment approach based regulation means more
directed research, improvement in quality of risk assessment and participation
of the people in assessment, evaluation and management. There is nothing to be
feared from the use of a wide variety of broad based approaches at the earliest
stages in innovation or policy making process, extending beyond conventional
quantitative, expert-based techniques of risk assessment. The precautionary
assessment does not bar introduction of technology of GM crops per se forever.
We are not asking the Government of India to stop scientific and technological
research on the development of technology of GM crops. Decisions regarding the
introduction of GM crops are required to be undertaken case-by-case, which is
fully permitted by the precautionary assessment approach to regulation. Given
the basket of technologies that are becoming available in respect of habitat
management, systemic application of cultivar mixtures in integrated farm
systems, agro-forestry and biological control that can potentially address even
the issue of productivity; there is no reason to rush into genetically modified
crops without a going through a case by case precautionary assessment protocol.
Advancement of
molecular biology has allowed us to delve into a great many mysteries of life
on earth and everyone sees the potential of this science breaking new frontiers
in solving problems that has plagued humanity for centuries. But obviously the
objective approach would be to weigh options that are less hazardous, more
certain and at the same time are potential technologies that can solve problems
at hand including the present crises in agriculture. We need to compare any new
technology with the best available technology or practice at hand before we
clutch on to it. A good example would be marker assisted plant breeding; a
technology option that also makes the best use of our progressing knowledge of
molecular biology but is essentially devoid of the hazards associated with GM.
Marker aided breeding
and other approaches
Traditional plant
breeding has essentially involved incorporation of desirable traits in a plant
through phenotype based selection. Genotype based selection would involve
zeroing on the gene of interest and incorporating the gene in the desired plant
race through hybridization. However, this potential could not be realized due
to lack of marker genes. Discovery of a wide range of genetic markers since the
late 1970s has made this possible since it is now possible to detect genes of
interest with the aid of their associated markers (Ruane and Sonnino 2007).
Pioneering work by Peterson and his colleagues (Paterson et al 1988) in tomato
led the way. For example a plant having a gene that provide resistance to a
particular disease can be selected with the help of the particular disease
resistant gene’s markers and can then be hybridized to bring about disease
resistance in the desired plant variety. An excellent overview of this
technology and its potential can be found in the FAO publication on Marker
assisted selection (FAO 2007).
Learning from the
experience of other countries
We can also learn from
the practice of the member countries of European Union which have been made to
deal with the genetically engineered maize (MON810). More than eleven countries
have chosen to withdraw the permission for the commercial introduction of
MON810 on the basis of the new doubts about safety that have now surfaced after
allowing the cultivation of Bt toxin producing maize for a period of about ten
years. It is however to be noted that so far this Bt toxin producing maize has
been the only genetically engineered crop allowed to be commercially cultivated
within the EU. MON810 was granted market authorization for the EU in 1998. The
German government prohibited the cultivation of MON810 in April 2009. It was
done on the basis of the new publications that showed negative effects on
organisms such as ladybird larvae and water fleas.
An overview of recent
publications shows that the effects observed on these and other non-target
mechanisms in the case of MON810 indicate a general problem. Until now it was
supposed that the toxins as produced in the plants can only fulfill their
deadly mission under conditions as met in the gut of the larvae of certain
insects (Lepidoptera). Specific receptors, described as ‘target organisms’,
occurring in the gut of these pest insects (and in the case of MON810 the corn
borer especially), are needed to activate the toxin. In contrast, so called
‘non target organisms’ are supposed not to be endangered because those
receptors cannot be found. Recent publications show that the toxin produced in
the plants is different in its structure from the natural occurring Bt toxin
and thereby also changed its biological activity. Several publications show
that a coherent theory for the mode of action of Bt toxin (and the role of
receptors) is missing. Recent research shows that the selectivity and the
efficacy of the Bt toxins can be quite substantially influenced by external
factors.
It
is but to be noted that although Chinese Agriculture ministry has certificated
two strains of GM rice, it would still take a considerable time before the Bt
rice grains are found on the shelves (Shan Juan and Wu Jiao, 2010). As has been
announced by Chen Xiwen, a member of the Chinese People's Political
Consultative Conference (CPPCC) and deputy director of the Central Rural Work
Leading Group of CPC, the products would need to be certified by government
agencies from the health and quality inspection sector, any of which might stop
the entry of the food grains into the market. As has been asserted out by Xiwen,
“the certificates, based on fair safety evaluation, won't mean GM rice would be
commercially planted immediately. It will require production trials and
registration.” Wei revealed that the applications for the two rice
strains were filed 11 and 6 years ago respectively.
Are we saying no to GM
then?
The
controversy over Bt brinjal brought to the fore the issue about the choice and
selection of a technology in tackling serious concerns in Indian agriculture.
Bt technology was pushed to tackle a biotic stress namely the pest problem.
This technology was pushed at a time when the nation was also taking notice of
the phenomenal success of non pesticidal management (NPM) in Andhra Pradesh.
Through NPM, a package of ecological techniques of tackling pests, about 420
villages in A.P. successfully managed pest in about 23000 acres covering 10
districts. This experiment has shown that a range of biotic stresses can be
overcome through ecological management of natural biological resources. But
there are issues involving abiotic stresses like drought, water logging etc for
which answer may still be sought within GM technology. For example, instilling
the vigour of the drought tolerant C4 plants like sorghum in C3 cereal crops
like paddy or wheat through genetic modification will definitely be a welcome
intervention.
Keeping
these in view, risk assessment of genetically engineered plants should be
conducted without preconditions such as assumptions of similarity (familiarity,
substantial equivalence) between transgenic plants and plants derived from
conventional plant breeding. Transgenic plants have to be seen as technically
derived products with specific risks and have to be subjected to comprehensive
risk assessment per se.
A
mandatory step-by step procedure, as it is now being evolved in EU, with
screening process introduced for the purpose of framing of criteria and threshold
of evidence required, should be introduced. To avoid unnecessary feeding and
field trials, testing in contained systems should be given enhanced weight.
Tests need to be recommended where considered necessary, for stress exposures
of transgenic plants under defined conditions (crash tests), for metabolic
compounds profiling under different stages of plant growth and environmental
conditions, simulations of different ecological systems and interactions with
different external factors. Needless to say, case by case method has to remain
in vogue for the risk investigations required to be undertaken each time.
Finally,
let the mastery of technical construction program based on scientific advances
that we have referred to be allowed to mature. Precautionary approach based
risk assessment is consistent with the development challenge that the
progressive movement faces today in India.
Risk governance includes matters of institutional design, technical
methodology, administrative consultation, legislative procedure, and political
accountability on the part of public bodies, and corporate responsibility. It
also includes more general provision on the part of government, business and
civil society groups for building and using scientific knowledge, for fostering
relevant technical competences, and for promoting social and organizational
learning. It is quite clear to us that the demand is growing in the country
among very different kind of publics for a more effective, efficient and, at
the same time, a balanced and fair regulatory process which is also
characterized by more transparent and participatory decision making procedures.
Let the people’s science movements champion the democratic agenda and not fall
into the trap of productivist and technocratic approaches to assessment.
In
conclusion, we understand that the ideological debate is not just limited to
the anti- and pro-transgenic camps. It is also a debate around how the decision
regarding the introduction of genetically modified (GM) transgenic food crops
needs to be approached by the people’s science movements.
Notwithstanding
the fact that areas under GM crops is on the rise, the scientific concerns that
were raised way back at Asilomar conference on Recombinant DNA technology in
1975 are still alive and valid. As long as these concerns, categorized broadly
into environment and public health, are not addressed and a consensus is not
arrived at within the progressive scientific community, these issues would
definitely deserve to be revisited over and again and would have to be reviewed
against fresh scientific literature.
[1]
The changes associated with genetically engineered plants are not restricted to
specific regions in the genome. This process impacts the genome and cell
regulation on several levels. See for details Batista et al., 2008, Clark et
al., 2007, Wilson et al. 2006, Wentzell et al., 2008.
