Bioengineering animals: attack of the fluoro mouse
By Jason Major
TechNyou
Beasts that glow, grow fast, and lactate drugs. Is it time we questioned the nature and purpose of this research?
This post is in response to a comment and question on our Facebook page, Talking Technology, which was also posted on the TechNyou website News.
The question from Lisa was a response to the Paul Wolpe presentation for Ted Talks where he has a bit of show and tell of genetically modified animals and a brief discussion about the implications of the technology used in this way, though the implication aspect was all too brief and a bit like hearing a series of newspaper headlines rather than any in-depth analysis of the issues.
Anyway, below is Lisa’s question and my extended thoughts to it.
Lisa’s comment and question
Interesting Video. I think the key point is his closing statement on responsibility. Humans have been “genetically altering” their environment since we first domesticated animals and selectively bred food crops. None of these species would survive in the wild, without human intervention/care, though. My question is would these new breeds of transgenic organisms survive in the wild? And what would be the implications if they could? I’m not sure that there is an answer for that question.
My extended answer
You are correct that many, if not all, crops bred for agriculture would struggle to survive outside their well-tended fields (paddocks in Australia). Even canola which is a weedy, out-crossing species will only survive 3-4 generations at most if left to its own devices in the natural environment (see ref. 1 below). We only continue to see it on roadsides, rail lines and near farmland, ports, etc because of the continual spillage of seed from transport or spread from nearby paddocks.
Unnatural selection?
All of our breeding over the thousands of years has resulted in the selection of traits to maximise a crop’s yield, palatability and harvest potential. For example, in relevant species we have eliminated seed pod shatter to prevent the seed bursting from the pod before harvest, we have selected for specific flowering and ripening times, we have reduced the amounts of toxins, allergens and other chemicals that affect the palatability for human consumption, but which are important chemical for a plant to naturally defend itself against pathogens and pest attack in the wild…and so on. Consequently we have also reduced a lot of the natural variability and removed such crops from any selective pressure that would enable them to potentially adapt to any gradual changes in their environment. To some extent we have set up a form of unnatural selection where we control the environment and selective pressures (water, nutrition, weed and pest control) and we choose the traits we want via breeding using any number of modern plant breeding tools such as marker-assisted selection, hybridisation, mutagenesis, embryo rescue, transgenics…etc. You could argue, that we have forced the selection of traits to suit our purposes rather than those of Nature, if you consider humans removed from Nature. In this context, you could ask is agriculture, in any form, is natural? If humans are an integral part of nature, is what we do to feed ourselves via agricultural any different from a wild animal hunting its prey or a hunter gatherer burning the landscape to attract grazing animals? But then we get all deep and philosophical and I need chocolate if I have delve into that obscure part of my brain where “profoundness” hides.
Transgenic escape
There is no doubt we need to be extremely careful in using transgenic technologies to generate new traits in animals or plants because of the risk of letting loose something that might outcompete or displace existing species, or affect the ecosystem in some other way, should it jump the fence (literally or otherwise). For this to happen though the trait (gene) must confer some advantage to the animal or plant in that “natural” environment.
For example, as mentioned in the Talking Technology Facebook post the gene or trait for herbicide tolerance only confers an advantage in the presence of the specific herbicide. In the “natural” environment – ie anywhere outside the paddock – the herbicide tolerant crop is no different to its non-herbicide-tolerant counterpart (that is, it has no competitive advantage), unless someone decides to spray that specific herbicide. I don’t recall ever seeing, nor have I heard of, in Australia at least, seeing agricultural crops becoming invasive weeds outside the paddock. Someone please correct me, if I am wrong on this. Of course, if herbicide-tolerant crops pass on that tolerance trait to related species that are environmental weeds, this might be a problem, though this is unlikely to be an issue in Australia at the moment as I don’t think any of our crop plants a have any relatives that are environmental weeds (see reference 2 below). Again, someone correct me here, if I am wrong.
This is not necessarily a GM herbicide-tolerant issue as we have two conventionally-bred herbicide-tolerant canola varieties to which the same questions and risks apply, especially for one, which, via outcrossing, can transfer the specific gene for herbicide tolerance the same way as the transgenic varieties can.
Another example might be drought-tolerance. This and similar abiotic stress traits such as salt or frost tolerance can all be potentially bred into crops via conventional or transgenic methods. What if we breed such a crop (which we have done via conventional means) that outcrosses with a related wild species and the drought-tolerant trait is transferred? This will potentially allow this wild plant to grow and thrive in environments it doesn’t normally exist. What affect will this have on the ecological systems? These are risks that need to be assessed and managed. The question is, I guess, how acceptable are the proposed ways to manage these risks? This level of acceptability will differ for each person.
The short answer…
I have only provided an overview of some of the implications associated with Lisa’s original question, but in short, yes there is a potential risk of introducing novel traits into animal or plants that might pose a risk to the environment. The risk to the environment and their ability to survive and thrive in it will depend on the trait, the host it is in and the environment in which we raise it. The risk, therefore, will have to be assessed on a case-by-case basis.
References
1. Personal communication Associate Professor Christopher Preston, School of Agriculture, Food & Wine, The University of Adelaide
2. Preston, Reiger, Powles, Risks of gene flow from transgenic herbicide-resistant canola to weedy relative in southern Australian cropping systems, Aust J. Agricultural Research, 50, 115-128 1999
Other relevant stuff
I am happy to email anyone the papers, if required.
Maria Alice Garcia, Miguel A. Altieri, Transgenic Crops: Implications for Biodiversity and Sustainable Agriculture. Bulletin of Science, Technology & Society, Vol. 25, No. 4, August 2005, 335-353
Chris Preston, Mary Riegere, Managing herbicide resistance in weeds from use of herbicide tolerant crops. Plant Protection Quarterly. Vol 15 (2), 2000
Image from – http://shesaidpop.blogspot.com/2011/01/caturday-pretty-shiny-crime-against.html
Jason, In the USA I have seen reports of the gene for herbicide resistance crossing over into “weed” species and giving them that special advantage of surviving herbicide applications. This ends up defeating the initial purpose of the GM crop to begin with. Well not exactly — that goal was to kill the insects that eat the crop, but if we can get more bang for the buck……………. In the end more and more use of pesticides and herbicides are being applied, with not a monumental change in yield (at least by the reports I have seen and read anyway).
Hi again Lisa – yes there are instances of the herbicide tolerant gene crossing over to agricultural weeds. In fact some weeds have picked up multiple genes associated with herbicide tolerance – ie from different GM herbicide-tolerant crops. This was always a risk and requires careful agronomic management to minimise or avoid the risk. Herbicide resistance was (and still is) a problem well before GM crops were around because of the overuse or misuse of herbicides. GM herbicide-tolerant crops can exacerbate the problem because of the greater reliance on specific herbicides. This has always been recognised as a risk and careful agronomic practices are needed to manage that risk. They obviously weren’t followed too well in the US. A lesson learnt perhaps?
But as mentioned, the issue isn’t necessarily a GM one as one of the two types of conventionally-bred herbicide-tolerant canola we have in Australia pose the same risk because of their ability to spread their herbicide-tolerant trait (gene) to related weeds.
And don’t confuse weeds with insect pests. Herbicide-tolerant crops are resistant to herbicides. Herbicides kill particular types of plant, but obviously not the crops with built-in resistance. Insect-resistant crops produce proteins (Bt) that kill specific types of insects that feed on the crop. So far the build up of resistance by insects to the Bt proteins seems to have been managed reasonably well, at least relative to the herbicide tolerance. In Australia the Bt cotton we grow is monitored quite closely for evidence of resistance and managed accordingly – see what CSIRO do at http://www.csiro.au/science/Sustainable-Cotton-Industry.html
As far as yields go, yes it is well known that with Bt crops if you spray enough pesticide to control the insect pest population to an equivalent size as achieved with a GM Bt crop the yields are similar. And yes, if you poorly manage the use of herbicide tolerant crops then weeds will build up of resistance to those herbicides and require different (often more persistent and toxic) herbicides to control them – or greater concentrations of the same herbicide. And therefore your yields won’t be any different, or it will be worse if you weed control is worse than other crops of the same variety. Herbicide-tolerant crops, whether they be GM or conventionally-bred, were developed to manage weeds more effectively. Assuming you been successful in achieving this then theoretically your yield should be higher – assuming all other things are equal, eg nutrients, soil, moisture, other weather factors, etc.
Again, however, build-up of resistance by insects and weeds is always going to happen whether you spray insecticides and herbicides or attempt to achieve the same thing with GM or other breeding methods. The management of each will differ, but management will always be required to minimise the occurrence. And I am sure someone will now comment that this is one reason why we should all be farming biologically or organically, but that is a discussion for another time.
Jason
TechNyou