Delicious, Cross-Bred Corn -- Now With Lasers!
Mapping desirable genes in a crop like corn used to require farming and, therefore, time. You'd plant a big field with seeds, wait for them to germinate, collect samples, and escort them back to the lab for further analysis. Then scientists started probing seeds before planting. Using dog toenail clippers and eventually larger, metal-blade "chippers," they slice off a chunk of seed, using one little portion for DNA analysis and saving the rest for potential planting. The idea is that if you can decipher up front which seeds contain the most desirable genes, then you can plant only those to see which sprouts lives up to their genetic expectations. From there, you move forward with cross-breeding the best specimens to try manufacturing that perfect, "golden seed."
Neat and pretty efficient, but nothing compared to the next phase: lasers!
When DuPont/Pioneer's "Laser-Assisted Seed Selection" rigs were unveiled last summer, I got fairly obsessed. Featuring basic 120-watt carbon-dioxide lasers (like the ones used for cosmetic surgery), the fully-automated rigs are said to score up to 96 seeds all in one pass, within a matter of minutes. When I spoke with folks from Pioneer a while back they made some pretty big claims: 1) using lasers instead of force-exerting blade chippers reduces the risk of sample contamination (fair enough); 2) ramping up the throughput and applying the results to conventional breeding techniques could increase corn yields by 40% within the next decade (whoa momma!).
Whether you find such figures hyperbolic or not is somewhat besides the point. The take-away here is that sometimes the most elegant solution to a problem is a combination of high and low -- in this case, lasers... and spray paint?
Before getting zapped, corn cobs are literally coated in a magnetically-active, iron-based paint (not unlike Krylon's magnetic spray paint). Individual seeds are then inserted into metal plates with magnetized walls.
When each seed enters its appropriate slot, it's held in place, precisely-aligned so the laser can shave off a clean, 10mg portion. Done and done.
There are other aspects of this process that are smart: the rigs can run 24 hours a day (meaning millions of seeds can be scored and analyzed per year); since the rigs weigh about 250-lbs, they can be easily transported. The amount of potential acreage saved alone is nifty.
But using magnetic spray paint along with the type of laser wielded by dermatologists? That's just awesome.
On a related note, here's an assortment of projects you can do around the house with magnetic spray paint. If you've got a particularly fun one to add, please let us know.
the latest
latest episodes
Oooh, up next automated eugenics engine!
DO NOT WANT!!!
Are they even testing the resulting modified corn on people?
The key thing here is that this is NOT genetic engineering of corn. It's genetic analysis. They are finding corn that already has desirable traits in its genome, in order to propagate it. It's exactly what farmers have been doing for centuries, just done faster and on a larger scale.
I like this a whole lot more than mixing, say, fish DNA into a tomato or a strawberry.
Actually, it looks like they're just shaving off a bit of the seed to screen for only the seeds containing the genes of interest that they have introduced to the corn, not genes present naturally. This is mainly a time saving tool for managing field trials I would assume. When you're running field trials the size that they are, sampling, prepping, and running gels on many thousands of samples by hand on a really tight schedule is no fun at all. And seriously, there's nothing to fear from genetically modified corn, unless you really like the idea of the farmers spraying lots of pesticide on the field instead.
To quote from the piece above: "applying the results to conventional breeding techniques could increase corn yields by 40%". The big problem with conventional breeding is finding out if the natural disease resistance/hardiness/whatever genes have been bred into the plant without the tedious business of growing it - which can take a long time for some important plants. High throughput screens like this can really speed things up.
Generally, if you're doing GM you're doing less/different screening for gene incorporation.