The Biology of Belief - Bruce H. Lipton [21]
What about all those headlines trumpeting the discovery of a gene for everything from depression to schizophrenia? Read those articles closely and you’ll see that behind the breathless headline is a more sober truth. Scientists have linked lots of genes to lots of different diseases and traits, but scientists have rarely found that one gene causes a trait or a disease.
The confusion occurs when the media repeatedly distort the meaning of two words: correlation and causation. It’s one thing to be linked to a disease; it’s quite another to cause a disease, which implies a directing, controlling action. If I show you my keys and say that a particular key “controls” my car, you at first might think that makes sense because you know you need that key to turn on the ignition. But does the key actually “control” the car? If it did, you couldn’t leave the key in the car alone because it might just borrow your car for a joy ride when you are not paying attention. In truth, the key is “correlated” with the control of the car; the person who turns the key actually controls the car. Specific genes are correlated with an organism’s behavior and characteristics. But these genes are not activated until something triggers them.
What activates genes? The answer was elegantly spelled out in 1990 in a paper entitled Metaphors and the Role of Genes and Development by H. F. Nijhout. (Nijhout 1990) Nijhout presents evidence that the notion that genes control biology has been so frequently repeated for such a long period of time that scientists have forgotten it is a hypothesis, not a truth. In reality, the idea that genes control biology is a supposition, which has never been proven and, in fact, has been undermined by the latest scientific research. Genetic control, argues Nijhout, has become a metaphor in our society. We want to believe that genetic engineers are the new medical magicians who can cure diseases and while they’re at it create more Einsteins and Mozarts as well. But metaphor does not equate with scientific truth. Nijhout summarizes the truth: “When a gene product is needed, a signal from its environment, not an emergent property of the gene itself, activates expression of that gene.” In other words, when it comes to genetic control, “It’s the environment, stupid.”
Protein: The Stuff of Life
It is easy to understand how genetic control became a metaphor as scientists with ever-greater excitement zeroed in on the mechanisms of DNA. Organic chemists discovered that cells are made up of four types of very large molecules: polysaccharides (complex sugars), lipids (fats), nucleic acids (DNA/RNA), and proteins. Though the cell requires each of the four molecular types, proteins are the most important single component for living organisms. Our cells are, in the main, an assembly of protein-building blocks. So one way of looking at our trillion-celled bodies is that they are protein machines, although, as you know, I think we are more than machines! It sounds simple, but it isn’t. For one thing, it takes over 100,000 different types of proteins to run our bodies.
Let’s take a closer look at how our cells’ 100,000 plus proteins are assembled. Each protein is a linear string of linked amino acid molecules, comparable to a child’s pop bead necklace, as illustrated below.
Each bead represents one of the twenty amino acid molecules used by cells. Though I like the pop bead analogy because everyone is familiar with it, it is not an exact one because