Cucumber. Tomato. Pig. Horse. A veritable cornucopia of crops and livestock. And from it will doubtless emerge fascinating scientific insights.
- “[H]orses have a newly forming part in their genetic make-up which shows the evolutionary process in action in a way that has not been seen before.”
- “[N]ew research applications and innovations at many points in the pork chain.”
- “[F]ar more is going on in the phloem than anybody … had previously expected.”
(The tomato is just an advanced map; no giant claims there, yet.)
This is really important science, no doubt about it. But I’d like to see a moratorium on claims that any of this is going to improve anybody’s food security. It hasn’t, yet. And personally I doubt that it ever will, but maybe that’s just me. I bought into the dream along with everyone else. Back in 1982 I agreed that cereals would fix their own nitrogen, that photosynthesis would be rejigged to become more efficient, that seed storage proteins would be made more completely nutritious.
The thing is, cereals don’t need to be engineered. It might help, but it hasn’t happened yet and in the meantime legumes are there to take up the slack. Changing C3 plants into C4 plants hasn’t happened yet either, and one has to wonder how much it will help poor farmers in the hot environments that make C4 more efficient. Seed storage proteins have been rejigged; Monsanto built a high-lysine maize, but it vanished more or less without trace because conventionally-bred high-lysine maizes are far cheaper and more attractive to the small-scale farmers who really need better nutrition. Nobody back then was too worried about drought or flooding; tolerance to submersion has now been engineered into rice and could be useful.
Overall, though, I wonder how much more progress might have been made had “ordinary” plant breeding been as easy and attractive as messing about with DNA directly. I also wonder how many surprises like this one are in store:
Indirect costs of a nontarget pathogen mitigate the direct benefits of a virus-resistant transgene in wild Cucurbita
Translation: Transgenic squashes — and almost all of them being grown commercially in the US and Mexico are transgenic — are protected from zucchini yellow mosaic virus. Plants that carry the resistance genes suffer considerably more wilt disease as a result. Hey ho, let’s see if we can add wilt resistance to the mix, shall we?
To be fair, the study you cite is talking about wild squashes with the transgene introgressed. In an actually agricultural setting I presume the beetles are controlled with insecticides anyway which should sever the link between virus resistance and cucumber wilt. I tried to document how the findings of that article quickly spun out of control here
But I absolutely agree conventional breeding is as important, if not more, as it ever has been. The improvements are faster, cheaper to get approved, and more fine-tuned than the current fruits of genetic engineering. After all the flood tolerant rice was created using marker assisted breeding after first being proto-typed with a transgenic construct. And for lots of additive traits, everything from yield itself to resistance to lodging, there’s no substitute for plant breeders out in the field making improvements.
James, thanks for your comments. I very carefully weaseled out of saying that the transgenic squash were disadvantaged. “Plants that carry the resistance genes” was deliberately worded that way. The whole question of the survival of introgressed traits — engineered or otherwise — in the absence of selective pressures is, as I am sure you are aware, one of considerable uncertainty. For example, I would expect constitutive traits, where a gene is active all the time, to be much less stable than facultative ones, where the gene is switched on by some signal. But I’m not aware of any studies that demonstrate this.
Anyway, I’m glad you agree with my bigger point, that interesting though the genome studies are, conventional breeding is more important than ever.
I’m not aware of any such studies either. I was excited to read the squash paper because it seemed to be the most detailed research into what would happen to a transgene in the wild up to this point, and was depressed to see it getting spun by others into something else when the actual result is so interesting in of itself. (Sorry for jumping the gun and assuming you’d seen the same spin.)
I would like to point out that whether the viral resistance comes from a transgenic approach or by breeding in endogenous resistance, the issue with the cucumber beetles and bacterial wilt would be the same. (In wild squash, that is) Although you don’t say that these kinds of surprises don’t happen with breeding (which they do), it does seem to be implied by the last part of your post.
So that readers are clear – the paper on transgenic squash did not find that virus-resistance squash in agricultural fields were more susceptible to bacterial wilt – it instead found that in the wild, plants with this resistance were more attractive to cucumber beetles than virus-infected plants. And the beetles spread bacterial wilt. It is a property of the ecology, not of the resistance trait. Definitely read James’ post about the misunderstandings of the paper! (And I agree that Jeremy did not misunderstand it, but there’s the potential that others could from reading this.)
That being said, I would like to suggest that I think that the breeding-vs-engineering dichotomy falls flat on the submergence-tolerant rice developed by Pam Ronald et al example. In that case, simply breeding the trait over failed repeatedly. It wasn’t until they could pinpoint the gene responsible and demonstrate its effectiveness through transgenic approaches that it could be bred over reliably using marker-assisted breeding. And you would think that submergence-tolerance would be simple to select for (submerge it and see!), but what about the more complicated traits? In this example, molecular methods (including genetic engineering) and breeding go hand-in-hand. And that’s sexy.
We need more breeding, but not “ordinary” breeding. We need greater understanding of the genetics of the plants we grow, eat, and wear, which we can then apply to those plants. Association mapping, molecular markers, transgenes, cisgenes, RNAi, comparative genomics, compositional analyses, etc, these and more are going to be increasingly important. Complete genome sequences provide a road map for studying the genetics of those genomes – there are profound practical implications beyond the basic science involved.
Anyway, that’s my stump speech for genetics. Now back to the lab…
Karl, are you sure that the plants containing the transgene are more attractive to cucumber beetles? I’ve a feeling that the reason they suffered more from cucumber beetle attack, and with it great spread of bacterial wilt, was that the virus-susceptible plants had died. The abstract says:
I’ll pull the paper tomorrow once I’m back on the university network (and on the subscription), but that does seem to be the case. Note that in the part you quoted it described the (mostly) transgenic plants as being healthy – which implies that the diseased ones were simply that – diseased and unappetizing rather than dead.