• Proteins, Genes and You
    Awake!—1981 | August 22

    • Plans and Blueprints​—DNA and RNA

      But how do your pancreas cells know which amino acids to hook together to make insulin? And what keeps the cells in your big toe from making insulin too? The answer lies in a unique and very large molecule called DNA (deoxyribonucleic acid), which is mostly contained in the nucleus of each of your trillions of cells. How does it work?

      Have you ever been on a construction site? Perhaps you noticed groups of workers​—carpenters, bricklayers, electricians—​frequently consulting blueprints that tell them what to do. Where do the blueprints come from? In the main construction office there are many architectural drawings that are copied on special machines to make the blueprints. Various job foremen take the blueprints out to their crews on the site.

      Your cells are like that construction job. In the nucleus (the “construction office”) are the “original drawings” for all the proteins your body will ever need. These “drawings” are the DNA molecules. When you need insulin, the appropriate section of DNA, called a gene, is activated in the nucleus of special cells in your pancreas.

      The DNA does not go outside the nucleus, just as original architectural drawings are not generally used on a job site. It is too valuable. Instead, a “blueprint” is made of the DNA gene by a special molecule called messenger RNA (ribonucleic acid). This “messenger” takes the blueprint out of the nucleus to the “job site,” where a crew is waiting to build an insulin molecule.

      This crew consists mainly of a ribosome, a sort of master carpenter molecule, and helpers called transfer RNA. The little helper molecules of transfer RNA round up amino acids and bring them to the ribosome. The ribosome “reads” the messenger RNA “blueprint” and makes the insulin chain.

      In the “construction office” of each of your cells there are far more “drawings” than any given cell needs to function. The cells of your big toe, for example, have the genes for making insulin, but the genes cannot be activated. These drawings are “under lock and key” in your big-toe cells. Each cell uses only part of the DNA in its nucleus to make the things it needs. We can be glad this is the case, because cells that “break into” a set of drawings they should not use and start making proteins they should not may harm themselves, or other cells, or even become cancerous.

      Changing the Plans

      Most professional architects would strongly disagree if you suggested that the complex set of drawings used to control the construction of a giant skyscraper came into existence just by accident. Those drawings required a highly skilled, well-trained architect. The DNA in the cells of all living creatures contains instructions far more complex and detailed than a set of architectural drawings. Is it not reasonable that DNA​—which controls the precise “construction” of bacteria, maple trees and people—​should be the product of a Master Architect? That Master Architect is Jehovah God.​—Gen. 1:11-28.

      Ask any good architect how he feels about it when unauthorized, unqualified people make changes in drawings that have been painstakingly prepared for a specific building. He does not like it, because he knows that the person altering the drawing has probably not considered the overall consequences of his change. True, a rest room might be enlarged, but what will happen when valuable space is lost from the entryway? What will happen when the plumbing has to be redesigned?

      Scientists are now able to change the DNA content of living creatures​—altering the “architectural drawings” provided by the Creator. In some cases these changes, such as inserting genes for human insulin into bacteria, are said to be for humanitarian, medical purposes. Other changes, such as inserting viral genes into embryonic mice, are more for scientific curiosity about what makes cells work.

      Although scientists are now able to alter genes, they are far from fully understanding how genes operate. In 1979 the New York Times reported: “The structure of animal genes, including those of humans, is far different from what had been believed for at least 20 years, new discoveries have revealed.” What happened? It was learned that animal genes do not usually work the same way as bacterial genes, as scientists had thought. Animal genes are more complicated and contain long sequences of information that are not understood. In effect, scientists have learned that reading bacterial “master drawings” will not teach a person how to read human “master drawings,” as they had expected it would.

      Scientists also have learned recently that the genetic code of DNA molecules is not constant, as had always been thought. It turns out that the code is slightly different when the DNA is not in the nucleus, but in different parts of the cell called the mitochondria. “The dogma that the genetic code is universal has been shaken,” admitted New Scientist magazine. Why does the code change? They do not know. “Some questions raised by the revelations of genetic analysis may never be answered,” comments New Scientist.

      No wonder, therefore, that people are concerned about possible dangers in genetic research! Most biologists now claim the research poses few risks, but do they really understand genetics well enough to know? Scientists claimed that atomic testing in the American West posed no dangers to the public back in the 50’s, but the cancer rates of people living downwind of those tests now indicate that the scientists were mistaken.

      Is it possible that, as they tinker with forces and biological processes they do not fully comprehend, scientists will accidentally unleash on mankind some terrible new disease? Some people think this possibility exists.

      Just what are scientists doing to those genes anyway?