We briefly nibbled SciDev.Net’s take on a press release from the International Atomic Energy Authority, advocating “Nuclear Science for Food Security”. It’s an old story; bombard seeds with radioactivity to induce more mutations, from which breeders can select wonderful new varieties. But as a correspondent reminds us:
There’s really nothing inherently wrong with it. Because it’s a totally random, “shotgun†approach to generating new variations, it lacks the benefits of natural selection to sort out not only what’s viable, but also what’s somehow well-adapted to growing in the environment and have other desirable traits.
Radio-induced mutagenesis was a popular technique decades ago, and some improved varieties were produced as a result. But I think that a much more logical approach would be to more fully assess and exploit the vast amount of extant diversity currently languishing unstudied in genebanks and farmers’ field, material that has already passed through the filter of many centuries, if not millennia, of natural and human selection. Radio-induced mutation is really just a shot in the dark. Better to focus more attention on the existing crop diversity that has yet to be exhaustively collected, characterized or evaluated, before resorting to such an aleatory approach.
Do you agree? Is inducing extra mutations — by chemistry, radioactivity, whatever — a good way to generate more diversity for breeders (and farmers?) to select from. Or should we focus on understanding the diversity we already have? It isn’t binary, of course, but I wonder where the balance should be?
This is sooo 1960s!
I wonder, does what we know now about evolution plus biotechnology still justify these techniques?
What about TILLING then?
http://www.ars.usda.gov/is/AR/archive/jul05/genes0705.htm
They have a long list of success stories in that press release. But there is no counter-factual: would we have been better off by investing the resources in more conventional techniques? Who knows, but most of these varieties could also have been developed without induced mutations (including the rice variety growing in water). I would find it interesting to know if there is evidence for induced mutations creating traits (degrees of stress tolerance) that were not available (or accessible) in the genepool of a crop. That could be the basis for a justification of this type of work. But what are the odds?
What I think / guess:
– induced mutations create diversity but have not proven to raise yields above levels also attained by conventional breeding and/or biotech
– that’s because induced mutations will seldom create “new” functional genes
– screening lots of genotypes is expensive
– other, better methods of creating variation in functional traits exist with a higher probability of success
– do we expect anything impartial from the FAO/IAEA Joint Division of Nuclear Techniques in Food and Agriculture?
Let’s close them down, then. Now there is a low hanging fruit for the FAO reform. (Any news on that? Has it stalled in debates about process and procedure?)
I could open Luigi’s link now. TILLING is really about gene function discovery. They do mutagenesis with chemicals. Inducing mutations is the least difficult bit of the equation and I think doing it with chemicals is simpler than doing it with radio-activity.
Perhaps the press release is news about the inner workings of the reform process. I would guess we are not the only ones who can spot low-hanging fruits.