But multinational agricultural companies aren’t just hoping for some nerd in a university laboratory to get lucky. Instead, they’re spending huge sums hunting for genes that might fulfill pressing agricultural needs. This usually involves turning off or enhancing genes and observing the consequences. Does the change create pesticide tolerance? Does the fruit ripen more quickly? Those are indications that the gene could be promising.
Genes that enhance resistance to drought and heat are on the top of agribusiness wish lists, although researchers haven’t yet found anything particularly effective. That’s not surprising, considering that discovering useful genes is quite a bit harder than finding a needle in a haystack. Genetic code doesn’t have to come from another plant; it can come from just about anywhere: bacteria, fungi or even animals.
“Fundamentally, a strand of DNA is the same in animals and plants,” says Peter Pauls, a plant scientist at the University of Guelph in Ontario. “There are regulation systems around genes that make them work better in the organism they evolved in, but they code for the same protein in any organism.”
In other words, researchers are combing through the genome of the entire tree of life for a few promising base pairs. So looking for a drought-resistance gene is kind of like searching for a single needle that could be hidden in any haystack, anywhere on Earth.
When they find a candidate gene, researchers place it in a test tube with an enzyme that “amplifies” the sample, meaning they make millions of copies of it. Then comes the complicated part: inserting the gene into the target crop’s genome.
For the sake of illustration, let’s assume we’re working with corn. Companies focus almost exclusively on high-value crops such as corn, soybeans and wheat because this research is expensive. There’s not a lot of money in genetically modified fava beans.
There are a couple of ways to modify a corn genome. The slightly crude method is to place a bunch of the sample genes onto small particles of tungsten or gold, then shoot them into a corn cell. Suddenly flooded with genetic information, the plant cell can’t help but integrate some of it into its own genome.
More often, however, scientists use microbes called agrobacteria, which Pauls calls “natural genetic engineers” because of their behavior in the wild.