Monday, September 13, 2021

Is Behavior Genetically Hardwired?

 In our last post we used the expressions “It’s in my genes” and “It’s in my DNA.” These popular conversational utterances indicate there is a cause and effect relationship between molecular genetics and morphological, functional, and behavioral traits in all organisms.

Living things exist with the DNA molecule inherent in their body cells. Therefore, the effects of DNA are hardwired in the bodies of all living things—the effects of DNA are ever present. DNA is a complex, information rich chemical entity. Bioscientists agree that form or morphology (physical characteristics), body function, and behavioral traits are hardwired in living things to varying degrees, thanks to DNA. Hardwiring is a descriptive term for a permanent physical feature, as in the example of electrical circuits in a home or factory meant to be functionally long lasting and intrinsic. In living things, hardwired DNA control is intrinsic. 

With respect to human life, bioscientists agree that physical characteristics (morphological traits) are genetically hardwired. We do not have control over the shape of our nose or our hair color. In similar fashion, most body functions such as metabolism rate, physical growth rate, and heart rate, are essentially separate from our conscious control. But with behavior, humans have far more conscious control than lower animals. Behavior in living things is often not easy to explain.

Molecular structure affects variations in morphology, function, and behavior. This is the reason for the question “Is Behavior Genetically Hardwired?” in our post title. Molecular geneticists study how differences in the structure and/or expression of genetic molecules result in variation among living organisms. This specialized study surely ranks among the most fascinating in all of science. It may be one of the ultimate topics in the study of scientific cause and effect.

Bioscientists have established that genetic molecules such as DNA drive the production of the physical form of living organisms as well as their functional processes such as body metabolism and growth. Before dealing specifically with the genetic basis for behavior, consider the challenges involved, for example, in determining how DNA and RNA are responsible for producing thousands of proteins, the “building blocks” of our body’s physical form. The process inspires a deep sense of wonder.

Consider the incredible challenge our body’s protein building mechanism faces after following the DNA code for protein synthesis. The body first produces a series of protein polymers—long ribbons of amino acids. Those protein polymers must then be folded. We quote Mark Zimmer, a computational chemist writing in The Conversation, December 2020: Protein folding is…..“a process of twisting and bending that transforms the original form of protein—long chains of amino acids linked together like beads on a string—to a three-dimensional structure that can interact with its target in the cell.” Artists’ conceptions of folded proteins challenge our imagination. Proteins fold into many thousands of different 3-D shapes. The correct shape (form) of a folded protein molecule is crucial for human health. (Recall the scientific principle “Form fits function.”) Errors or defects in protein folding result in Alzheimer’s disease, cystic fibrosis, and a host of other human diseases.

Mark Zimmer, already quoted above, refers to the “protein folding problem.” The process of protein folding is easily described, but virtually impossible to explain. Similarly, another mystery of life, dubbed the “problem of consciousness is nearly impossible to explain. Scientists continue to probe problems in science, not hopelessly, but hopefully! 

Is behavior genetically hardwired? My qualified answer is, “Yes.” We may describe the phenomenon of behavior very well, but we may be unable to explain behavior with the same degree of certainty. Behavior is both intrinsic and learned to varying degrees. Complex behaviors for simple animals is clearly hardwired, but genetic factors create a framework within which environmental factors may also act to shape behavior. Complex human behaviors are mostly the result of learning and conscious decision-making, but genetics is most important in explaining human morphology and function. The study of epigenetics in the last several decades extends our knowledge of gene expression and the behavioral outcomes of environmental factors beyond the protein coding of the DNA molecule.

In terms of distinguishing between genetic and environmental causes and effects, we tread on some of the mysteries of life itself. Our understanding of life, our understanding of deeper explanations of morphology, function, and behavior in terms of what actually happens as living things manifest the characteristics of life, leads us on a fascinating investigative adventure.

Our Creator is the Author of life itself. He is the Source and Sustainer of life. The study of life is not merely an academic, scientific pursuit. Beyond that, life is a source of wonder, devotion, and worship of the Creator of All Things. We link a past post from 2013: “What is Life?”…..