Online Conference on GMO for Management of Animal Populations

We need to build safety mechanisms into disseminating GMOs used to manage wild animals to confine their effects to the target species and the target country. We need to minimise the following risks:
1. That the GMO will spread to another country;
2. That the GMO will affect species other than the target species; and
3. That the transgenes will be transferred to another microorganism, thereby possibly giving rise to unintended effects, or widening the host range.

A major difficulty with safety mechanisms is knowing that they will work under all (or at least most) circumstances. Another is that some of the problems with wildlife are urgent, but if we agreed that the GMOs should only be released if they had inbuilt safety mechanisms that result in their working only where we wanted them to, we would probably have to wait decades before these devices were ready.

So the sooner we start developing them, the better. What kinds of safety mechanisms might there be? Four possibilities come to mind:
1. The GMO will only work in the presence of a chemical in the environment. For example, this could be something in the target species’ diet which is specific to the country of release.

2. The GMO has a complex life history. For example, it requires the presence of another organism in order to propagate. Thus the GMO could not spread to another country on its own, but the transfer of two organisms would be required. It is probably this requirement that has kept myxomatosis out of New Zealand: vectors for the virus are absent.

3. Genetic mechanisms. What we need here is some genetic mechanism that allows us to "recall" the GMO, or prevent it establishing in another country. Any suggestions?

4. Genetic transfer. How might we reduce the risk that the transgenes will be transferred to another microorganism?

Robert Henzell
Animal and Plant Control Commission
South Australia

Robert, has raised critical issues which need comments such as "tracking" of GMOs across boundaries or establishing in another country. How do we follow up on accidental movements of GMO animals?  These are issues for discussion and will help enrich our discussions.  Participants can give suggestions to these questions and the issue of risks involved with movement of transgenes to other microorganisms.

There will be no way of tracking the effects of GMOs.
What can be tracked is its effects to animals,humans and
biodiversity loss.By that time it will be to late.
The contaminations will continue like wildfire and cannot be stopped.
Consider its effects as like those of Invasive
which has caused tremendous effects.
Thus the Catagena Biosafety Protocol and the Precautionary Principle.

Perhaps the issue is larger than the tracking of GMOs across boundaries?
After all GMOs are just one of many methods by which novel genetic
material is introduced to new areas. If we take the example of the
concerns raised by the possible introduction of GH Atlantic salmon on
the western seaboard of the US. Most of the public debate that I have
seen has been related to the potential threat of these GMO salmon. I
would suggest that the real problem is that Atlantic salmon themselves
(GMO or not) are being farmed in an ecosystem that they are not part of,
and experience has told us repeatedly that these farming practices will
in escapes of tens of thousands of individuals.

While it is convenient to target the potential dread threat of
introduced GMOs escaping, I believe that this distracts us from looking
at the more pervasive and (arguably) more important threat of introduced
whole orgamisms escaping into and establishing in new systems.

The threat of GMOs is a component of a much larger issue and could
potentially profit from being treated in that manner.

Nic

Dear friends,

I know we are discussing a very important issue, we in the
less-developed countries (LDCs)  face a more critical situation
regarding the GMO and biotechnology.

There seems to be no rules and regulations in place, people are using
different bits and pieces of information according to their choice for
their own interest.

A very confusing situation indeed; I am afraid we may have  GMOs in some
labs unofficially introduced for reasearch like Bt, some products in
shop floors and undisclosed trials. There is no lists, no notification,
labeling and we are entering the 'Open Market'. Cross boundary movement
of GMO is a real threat.

I think many of the LDCs are facing same situation; this will made the
use of modern technology more difficult, control and monitoring
impossible and risks more real.

We should take this aspect into account while discussing issues at more
advanced levels.

M.I.Zuberi, a geneticist and university teacher, Bangladesh

I agree with accessing effects of the modified product or material on animals, humans and biodiversity.  But the assumptions made seem to be speculative.. What methodologies do we use now even in conventional breeding and other animal management technologies?  How do we track them?  Science based assessments are critical in addressing these issues.  Precautionary issues must be based on scientific responses as required by the protocol.

At the risk of appearing somewhat self serving, it has been my focus for
that last several years to address the issue of how to assess GMO risk using
science based methods.  Following are some publications in which
methodologies, and concerns, have been put forth. These methods are based on
sound population genetics principles, first introduced by Darwin over a
century ago.  These papers point out both potential risks and methods to
assess those risks before release.


Muir, W.M. and R.D. Howard.  1999.  Possible ecological risks of transgenic
organism release when transgenes affect mating success: sexual selection and
the Trojan gene hypothesis.  Proceeds of National Academy of Science
24:13853-13856.

Muir, W.M. and R.D. Howard.  2002.  Methods to Assess Ecological Risks of
Transgenic Fish Releases. In Genetically Engineered Organisms: Assessing
Environmental and Human Health Effects Eds.  D.K. Letourneau and B. E.
Burrows.  CRC Press, pp. 355-383.

Muir, W.M. and R.D. Howard.  2001.  Fitness Components and Ecological Risk
of Transgenic Release: A Model Using Japanese Medaka (Oryzias latipes)
American Naturalist. 158: 1-16.

Muir, WM and R.D. Howard.  2002. Environmental Risk Assessment of Transgenic
Fish with Implications for Other Diploid Organisms.  Transgenic Research
11:101-114.

Muir, W.M.  2002.  Potential Environmental Risks and Hazards of
Biotechnology.  Part I: Risks and Hazards.
http://www.isb.vt.edu/news/2001/news01.nov.html#nov0105.  Information
Systems For Biotechnology (online version)

Muir, W.M.  2002.  Potential Environmental Risks And Hazards Of
Biotechnology.  Part II: Methods to Estimate Risks and Hazards.
http://www.isb.vt.edu/news/2002/news02.feb.html#feb0201. Information Systems
For Biotechnology (online version).

NRC (National Research Council).  2002.  Animal Biotechnology: Science Based
Concerns. Washington, DC: National Academy Press.

Howard, R.D., J.A. DeWoody, and W.M. Muir.  2004.  Mating advantage of
transgenic males provides opportunity for Trojan gene effect in a fish.
Proceeds of National Academy of Science 101:2934-2938.

Muir, W.M.  2004.  The threats and benefits of GM fish.  European Molecular
Biology Organization EMBO 5:2-7.

____________________________________________

Bill Muir, Ph.D.                          
Professor of Genetics                  
Department of Animal Sciences 
Lilly Hall
915 W. State Street
Purdue University
W. Lafayette IN 47907-2054

I think the issue of tracking transboundary movements of GMOs especially
in animals may pose some challenges.  Accidental movements of GMO
animals appears even more problematic.  However, I think a detailed
risk assessment and risks management plan will assist in dealing with
potential risks associated with such accidental movements across gene
boundaries so as to avoid gene erosion or gene pollution.

John Ugolo, Esq.
Legal Drafting Department,
Federal Ministry of Justice
Federal Secretariat (10th Floor)
Abuja. Nigeria.

Robert Henzell kicked off this thread to discuss on the possible mechanism to minimize risks of GMO, risks that could be due to spread to other countries, spread to other species, or transfer of trasgenes to other organisms.

If we focus on the GM microorganism, nematodes or insect for biological control or for the management of other species, we should think on a ‘ideal release’ that is made where the non-GM species is distributed. The issue raised by Nic Bax about introductions is interesting when caused by the escape of GMO from farming establishments or when the GMO is designed without a mechanism that limit their spread.

Thus, I think we should focus this tread on the discussion about these mechanisms that would limit their spread accross countries and species.

Alex Owosu-Biney raised the issue of how to track GMOs accross boundaries. Even considering an ‘ideal release’ in which the GMO has mechanisms to reduce the spread to non-focused countries or species, this issue remains interesting. A safe release should considerate that we can assess what happend to the released GMO. I think there is some national regulations that obligate researchers to put some genes on the GMO to have the possibility of tracking it after their release. But, are these ‘tracker’ genes stable in the long term? Would there be transfer of these genes? And thus, would it be possible to track GMOs at the long term after release? We can though about GM fishes as Bill Muir mentioned but what about GM viruses?

Thanks Bill for sharing the results of your research. If I have well understood, you propose models based on the competition between GM and not-modified individuals (based on their fitness: survival, fertility, etc.) to assess the risk of spread of transgenes in native populations. This is valid for organisms with two-sex mating systems (as fishes). But would it be possible to use the same models for GM viruses? How we could assess fitness of different strains, even when we are not sure of how many strains there could be? I am sure someone has already think on this...

Elena Angulo
Université Paris XI
Lab. Ecologie Systematique et Evolution, Bat 362                         
F-91405  Orsay, FRANCE

How can we make disseminating GMOs safer?
Dear colleagues
I think that we need more scientific findings in field trial performance, and a strong legislation on Biosafety issues.

We don't permit field trials without risk management and emergency
plans.  Risk assessment, risk management and emergency plans must be included in biosafety authorization for field trials before any release to the environment.

What happens with field trials with GM animals is based on the fact
that every body says it is very expensive. But it is the gist of the
problem.

I suggest that we should take account all the risk assessment, risk
management and emergency plans in the field trials before they are
performed and assess the local conditions and the environment.


Miguel

Dr.Bill
I agree with assessing GMO risk using science-based methods. We need these methods and knowledge on the environment before release of GMOs. I think that Biosafety legislation is important in ensuring the use of risk analysis at each step, and that field trials are very important (key) before the release.
Miguel

We can make dissemination of GMOs safer through
training of the users GM animals. When the breeding
objective of the GMO is clearly known, the management
system mastered and the consequences of mismanagement
known to the producer/user, safe dissemination may be achieved. At the level of the consumer of the GMO, information similar to the one for each drug should be given. Legislation covering all levels,
production, use and handling is very important and should precede involvement in GMO activities.
David A. Mbah

In response to the message from John Ugolo:
The issue of tracking transboundary movements of GMOs in animals may pose some challenges and real risks, but these can be minimized if you have Biosafety legislation, if you do a scientific risk analysis, if you take into account the precautionary principle, if you have emergency plans, if you have good specialists and advisers, and in general if you have a Biosafety policy. I also think that a detailed risk assessment and risks management plan will assist in dealing with potential risks associated with such accidental movements across gene boundaries so as to avoid gene
erosion or gene pollution.

Miguel Lorenzo
Cuban Biosafety specialist

In the case of recombinant bacteria, a number of biosafety systems have been designed and tested. These are of 2 main types:

1) those that make the bacteria dependent, for their survival, upon a chemical substance (signal) not normally found in the environment. Thus, these bacteria die in the absence of the environmental signal.

2) those that kill recipient bacteria in the event they receive recombinant genes by horizontal gene transfer.

In the first case, the suicide bacteria are engineered so that they contain a lethal function whose transcription is repressed in the presence of the environmental signal. This environmental signal has typically been an environmental pollutant such as methylbenzoate, phenol or biphenyl.  The lethal function may be a ribonuclease, or an endonuclease, or a protein that disrupts membrane function. In the absence of the environmental signal, the suicide function is expressed and the bacteria die. For increased killing efficiency, combinations of different suicide genes may be used and the efficiency of suicide is of the order of 10-9 to 10-10.
In the second case, a suicide function (poison) is also present in the bacterial cell, but its lethal effect is counteracted by an antidote function (examples include (i) the colicin E3 gene, coding for a cellular toxin, and the imm gene coding for immunity to the toxin (ii) the gene coding for the EcoRI restriction endonuclease and it corresponding DNA methylase). In this case, the genes are placed at different genomic locations (e.g. with the antidote gene on the chromosome and the toxin gene on a plasmid), so that, in the event of conjugal transfer of the plasmid to another bacterium, the poison and antidote genes become separated and the recipient bacterium will be killed. Various permutations and combinations permit further reductions in lateral transfer.
While initially designed for bioremediation systems, these containment systems may find applications for recombinant bacteria useful for biocontrol purposes. Recent reviews include:
Torres B, Garcia J, Diaz E (2003)
Plasmids as Tools for Containment. In Plasmid Biology, B Funnell, G Phillips (eds), : ASM Press, Washington,  pp 589-601
Davison J (2002)
Genetic tools for Pseudomonads, Rhizobia, and other gram-negative bacteria. Biotechniques 32:386-401
Davison J (2002)
Towards safer vectors for field release of recombinant bacteria. Environ Biosafety Res 1:9-18


John Davison
Unit of Cellular Biology
INRA, Versailles, France

Hi,

The technology's description [in post #206] is fascinating.  I have a quick
question and maybe it has already been indirectly answered in previous
correspondence: despite this very specific gene manipulation, are there
'any' remote chances for the gene suicide to be transmitted to any wild
population? (i.e. any insignificant case or even low percentage). In
your message you said: "different suicide genes may be used and
the efficiency of suicide is of the order of 10-9 to 10-10" - what
happen to the one left from the 10-9 or is it 9 out of 10?  I did not
understand this part of your explanation. 

Or are the explanations from Miguel Lorenzo's (#184), Elena Angulo
(#123), John Ugolo (#161), Bill Muir (#154), and also considering
questions from Robert Henzell (#123) part of the answers?

Sincerely,

Janick Lorion
Environmental Analyst
Agriculture and Agri-Food Canada

The work John Davison describes in post #206 on safety devices in recombinant bacteria looks very promising. Is it known whether whatever it is that allows the one in a billion or so bacteria to survive genetically programmed suicide is heritable? If the heritability is zero, it is difficult to imagine any organism surviving generational mortality levels like that. If the heritability is close to 1, there might still be a very small residual risk of persistence, even with the dual containment systems John describes (where presumably the survival rate would be about one in a billion billion).

Some of the GMOs under development for controlling vertebrate pests (or protecting vertebrates from disease) are GM viruses. Does anyone know of any work on viruses comparable to that John describes on bacteria?

Robert Henzell, Animal and Plant Control Commission, South Australia

Thank you for your answer. 

The only GM virus biocontrol that I am aware of at the moment is the
Baculovirus research conducted by the Canadian Forest Service.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=421645

http://www.nrcan-rncan.gc.ca/biotechnology/english/d_unexplor.html

http://www.nrcan-rncan.gc.ca/cfs-scf/science/biotechfacts/baculovirus/cf
sdo_e.html

Hello All,
The recombinant Baculovirus program for insect control is an interesting
one.  The array of genes used in research on that application  included 
various insect venomous, bacterial toxins, even the human cancer gene
myc  which were effective in controlling insect pests. Wild
baculoviruses persist for years in soil  and tend to be relatively mild
to prevent killing all their food. The genetically "enhanced"
Baculoviruses  need to be handled with care  to avoid overkill and
beneficial  bystander insect killing.
Furthermore,  the Baculovirus  do cause "non-pathogenic" infections of
human liver and there is a huge and growing literature on Baculovirus 
as vectors for human and animal gene therapy. They work very well and
avoid the immune toxicity of adenovirus vectors.
However,  the insect control Baculovirus promoters  tend to ignore the
fact that  the insect killing toxins  may also effect the human liver
throug Baculovirus infection. It is unwise to undertake Baculovirus 
experiments from the stand point of two solitude's, insect researchers
ignoring gene therapy research!
Sincerely, Prof. Joe Cummins, Professor Emeritus of Genetics, university
of Western  Ontario,Canada

Dear friends
Are there GM virus biocontrol under development other than the Baculovirus research conducted by the Canadian Forest Service? What might happen if they escaped from containment? Are there regulations or guideline specific to Biocontrol?

Also, I want to know WHO has practical experience in biosafety on biocontrol

Regards
Miguel Lorenzo
Cuban biosafety regulator

In addition to the work on using GM viruses to control insects mentioned by Janick Lorion (post #213), GM viruses are being developed in Australia to control house mice, rabbits and foxes (all pests in Australia), and in Spain to immunise wild rabbits against myxomatosis and rabbit haemorrhagic disease. This work (together with work on a GM nematode to control possums in New Zealand), and the safety concerns associated with it, are summarised in:
Cooke, B., R. Henzell, and E. Murphy. 2004. International issues in the use of GMOs for the management of mammal populations. Biocontrol News and Information 25(2): 37N-41N.
which is available from the online conference website as a background paper.

I am not aware of any work to build safety into these GM viruses comparable to that described by John Davison for recombinant bacteria, and the purpose of my original question (post #210) was to see if anyone else was aware of any. Also, does anyone have any ideas on how we might make these GM viruses safer? I am talking here about building safety into the GM viruses themselves to reduce the risk that the GMO (or the transgenes it contains) will affect:
1. non-target populations of the target species (in the country of release or elsewhere)
2. non-target species.

The use of international agreements/consultation/regulation/risk analysis to manage risk is being dealt with elsewhere in this conference.

Robert Henzell, Animal and Plant Control Commission, South Australia

The comments from Janick Lorion and Robert Henzell are completely valid and represent the weakness of the containment system. A mutation or deletion of the suicide gene results in the suvival of the mutant bacterium. Survivors are obtained even in bacteria containing double-suicide systems and this proportion is usually higher than simple probability theory would predict.
Thus I agree with the comments, that zero-escape is not easily obtainable. It should also be borne in mind that for the field releases (in this case bioremediation, but it would also apply to biocontrol) the numbers of  bacteria to be released may be very very large.
I hope that this answers the questions.

John Davison
Unit of Cellular Biology
INRA, Versailles, France

Dear colleagues
Before release, what biosafety conditions will be in place for field trials? Of course zero-escapee is not simple but there must be prevention of escapes and mitigation planning.
Miguel

In response to Miguel Lorenzo's question (#238), at present is appears the biosafety conditions for field trials of GMOs will depend very much on the country in which they are conducted.

The only field trial of a GMO designed to manage wild animals that I am aware of is that conducted on Isla del Aire (one of the Balearic Islands) of a modified myxoma virus designed to protect rabbits in Spain against myxomatosis and rabbit haemorrhagic disease. The biosafety aspects of the trial are discussed in Torres et al. (2001) Vaccine vol 19, pp 4536-43. However, apparently the regulatory authorities imposed no requirement to eliminate the rabbits or the GMO at the end of the trial, so it is possible that the GMO is still present at the trial site (there is good circumstantial evidence for the existence of a carrier state (latency) for myxoma virus in rabbits). Unauthorised access to the trial site was prevented during the trial, but not afterwards.

Robert Henzell, Animal and Plant Control Commission, South Australia

In relation with Guillermo Castillo comment (#165) which proposed to start with the big picture more than from isolate cases, I think it would be useful to make a quick list of the GMOs for the management of animal species that are currently under research or in use. Some have appeared in previous post comments:

- GM myxoma virus for the vaccination of rabbits in Spain (#219Robert Henzell)
- GM myxoma virus for the sterility of rabbits in Australia (#219Robert Henzell)
- GM virus for esterility of mice in Australia (#219Robert Henzell)
- GM virus for esterility of foxes in Australia (#219Robert Henzell)
- GM virus for the esterility of stoats in New Zealand (#121 Elaine Murphy)
- GM attenuated virus used as vaccines in Australia (#175 Ben Gilna)
- GM possum nematode Parstrongyloides trichosuri to cause sterility in possum (#205 Elaine Murphy)
- GM baculovirus for insect control (#213 Janick Lorion, #214 Joe Cummins)
- Daughterless technology in the common carp (# 253 Tony Peacock)

What about GM insects against diseases?
(for example, GM Anopheles unable to transmit malaria? Scott TW, Takken W, Knols BG, Boete C. 2002 The ecology of genetically modified mosquitoes. Science. 298:117-9)

Others?

Elena Angulo
Université Paris XI
Lab. Ecologie Systematique et Evolution, Bat 362                         
F-91405  Orsay, France
elena.angulo@ese.u-psud.fr

The following can be added to Elena's list (thread: How can we make disseminating GMOs safer?, post #258):

GM bacteria for trypanosome control:
Aksoy, S. 2003. Control of tsetse flies and trypanosomes using molecular genetics. Veterinary Parasitology, Volume 115, pp. 125-145.
This case involves the use of GM bacteria living symbiotically in the gut of the fly to reduce transmission of the parasite.

GM bacteria to prevent stock poisoning:
http://wwwscience.murdoch.edu.au/centres/rumen/biosafety.html
Involves the use of GM rumen bacteria to break down toxic fluoroacetate inside the sheep's stomach to offer protection against poisoning. Fluoroacetate occurs naturally in some plants in Australia.

Robert Henzell, Animal and Plant Control Commission, South Australia