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.