Standard Pages (they don't change often)

Wednesday, August 7, 2013

A quick lesson in evolution

Fennel gone wild.
Two topics that I track for the purposes of science-based cuisine are the issue of genetically modified crops (notably, the use of glyphosphate resistance genes) and the use of antibiotics in farm animals. In both cases, farmers use a reagent chemical to eliminate undesirable organisms (weeds or infectious bacteria) from the population of desired plants or animals. Whenever these technologies are described, the specter of resistance is also aptly invoked, which limits the useful lifetimes of these methods. The choice of words that the popular media uses, however, can be infuriatingly misleading in its oversimplification.

The most common mistake is to say that "bacteria become resistant". So, here is a quick lesson in evolutionary biology. The vernacular language tends to treat bacteria as an individual, but really, it's a population going through changes. And the basic thing to remember is: the resistance mechanism is already in the population. The treatment with antibiotics did not create resistant organisms - it simply selected for them to increase in population frequency.

But perhaps more exasperating is the frequent populist writing about "creating superweeds". Coined by antiGMO activists, superweed is a poorly defined term meant to bring up the specter of unkillable weeds. By definition, a weed is simply an undesired plant growing in an agricultural set up competing against a desired crop. The technique of engineering crops to be herbicide resistant opens up the method for using herbicides to kill off weeds - but, eventually, the resistance mechanisms will increase in frequency among surviving plants going on to the next generation. It's simply evolution in action. There's nothing super about it.

No comments:

Post a Comment