Alaimo: What changes and works better stays more
My lady and I were arguing about genetically modified food this week. She is against them and I am (mostly) in favor of their continued development. I wrote about this in June and if you think this is an odd topic to continue to argue, let me tell you, arguing about genetically modified food beats arguing about visual impact regulations or (worse yet) who was supposed to put the garbage out and didn’t. But the funny thing about discussing genetically modified foods (GMFs) is that even though 34 percent of Americans polled (in 2010) were concerned about the development of GMFs, most of those polled as concerned did not have a clear understanding about what genetically modified organisms actually are or what their use as food is. So this week (just so we can all argue better) I will take some time to write about the basics of natural genetics. Then next week, I will visit some more about the pros and cons of GMFs.
But I need to paint some background. When speaking of my lady, know that she snores. So does her dog. At night they make a very complicated syncopated symphony. They also both have beautiful eyes.
I imagine that the lady’s ancestor’s spouse and the dog’s ancestor’s owners both really liked pretty eyes better than they liked sleep—and by breeding with the one (and letting the other one breed) they essentially selected for this particular characteristic.
People who make up names call this selection pressure. By necessity, the more important one feels pretty eyes are (more selection pressure in favor of that trait) the more lax one must be regarding other characteristics like quiet breathing.
In the natural world there are selection pressures too. There are selection pressures from drought, disease, predators, etc. Worse yet, there is competition from other species and even other members of one’s same species —like my family at Christmas dinner—for limited resources. In nature these pressures happen all at once—so in order to survive (and hopefully breed) one needs to respond to all of the pressures successfully. If one survives then one gets to transfer the information of one’s success to one’s offspring. If one develops a way to survive which is better, that one gets to put more offspring into the world than those which survive less “better.”
By the way, if the last paragraph made sense to you then you understand pretty much all you need to know about evolution by natural selection. From cell phones to spouses to the kinds of rocks in your driveway—evolution by natural selection could be said to apply to everything you have ever seen or heard or done. What works stays, what changes and works better stays more.
So, let’s get back to GMF. When we say genetically modified, what exactly are these “genes” which are getting modified? Well, you and I are made of cells and I think of cells as little factories with each factory having a primary task, such as movement or fighting germs. In addition, cells perform self maintenance—such as getting supplies in, getting waste out and possibly making new cells.
Inside each cell there is a library, called the nucleus, and in the library there are a bunch of books (DNA) that have the instructions on how to build all the machines (usually proteins) that the ‘factory’ needs—primary task proteins, getting supplies in and waste out proteins, and even new little cell protein making proteins. These instructions are copied out onto something called RNA, which (like little slips of paper) are brought out onto the factory floor where they are read. Just about all the proteins that make up the characteristics of a cell or individual come from this reading—such as proteins to make eyes brown or hair curly. The smallest amount of instruction in DNA that can make a discreet characteristic of a cell can be referred to as a gene.
Now, when it is time for a cell to make a new cell, a copy is made of the library, a new factory is built and the two cells split. Living things may differ in detail (i.e., using functional RNA instead of proteins) but the basic plan is the same. Inherited instructions = genes. Now sometimes a gene changes or a whole gene can even be lost or added and this can be good, bad or neutral in regard to the particular pressures on the cell. For instance—changing the number of tires on a car might be good or bad for driving, but changing the color might not matter.
I apologize for the boring sermon this week but I wanted us all on the same “page” for next week—which may include how GMFs are related to Ouray County Visual Impact Regulations—so stay tuned.
Dr. Joe Alaimo is the owner of Ouray Vet and partner of Trail Town Still. The savior of small animals, thirsty people everywhere and a fairly dangerous man with a garlic press.