Introduction
I recently wrote a post entitled “The Power of the Gene and Biology.” By exploring biological anthropology, I have furthered my appreciation for the fascinating abilities of genes and evolution. Not only do they cultivate diversity but also improve our health and influence social phenomena. However, as you know, our blog is devoted to providing a balanced take on anthropological issues. Alyna often brings cultural factors to my attention that do not undermine the power of biological ones but make me realize the interplay between the two branches of anthropology. In my own research for “The Power of the Gene and Biology,” I discovered criticism of the concepts and studies I describe that I would like to briefly detail below. Nevertheless, I would recommend reading the previous post first to gain beneficial context as well as a more balanced understanding.
Gene Determinism
Gene determinism is the popular tendency to exaggerate the power of the gene and claim that it determines health and behavior. The media enthusiastically discusses genetic counseling, gene therapy, and cloning. We often rely too heavily on genetics when trying to explain or solve medical and behavioral experiences. For instance, numerous articles claim there is a gene for shyness. While shyness is linked to genetics, a single gene does not make me reticent around new people and others eager to socialize. The process of gene expression is often not as simple as a single gene crafting a single protein to express a specific trait. In fact, a single gene can produce multiple proteins, and a single protein can be produced by multiple genes. As we continually emphasize, not only are many traits polygenic but also the result of genes interacting with your environment.
Although many understand that behavioral traits are affected by environmental factors, we often overlook the role of nurture in physical traits. Eye color, for instance, is purely genetic, but other traits viewed as biological are merely influenced, not determined, by genes. For example, being tall is partially genetic, but for the height genes to be expressed, environmental conditions must be ideal. Quality nutrition and medical care are just two requirements.
Pet Cloning
Many who exaggerate the power of the gene point to pet cloning as a seemingly magical process the almighty gene can carry out. Yet, there appear to be significant physical differences between donors and clones.
In December 2001, an adult domestic cat named Rainbow (on the left in the photo below) was cloned to produce the kitten CC (right). However, their fur differed in both color and pattern; Rainbow exhibited a calico coat with white patches while CC was a white tabby cat with gray streaks. If their genomes were identical, why were these two cats so different? To find out, we must discuss the interesting workings of the X and Y chromosomes, for coat color is a sex-linked trait.
X-Chromosome Inactivation
As you likely know, an animal is female if it contains two X chromosomes and male if it possesses a Y chromosome. However, the Y chromosome is significantly smaller than the X chromosome and contains fewer genes. That females carry two copies of a gene-rich chromosome while males carry only one causes a genetic imbalance. Dosage compensation combats genetic imbalance by achieving equal gene expression across both sexes. In mammals, such as cats, this process is called X-inactivation, which silences the genes on one of females’ X chromosomes. Thus, both sexes are left with just one active X chromosome. Rainbow was heterozygous for coat color, a codominant trait, and thus had calico and black fur. DNA was taken from only one of Rainbow’s cells to produce a clone, and in this cell, the X chromosome had been inactivated, so the orange allele was silenced.
While genes are generally understood to not control personality or temperament to the extent they control appearance, the cats’ distinctions suggest that genes are not fully responsible for merely physical traits, such as coat color, either.
Additional Concerns
The Humane Society of the United States (HSUS) further details issues with pet cloning. First of all, medical problems can result from this process, for clones may be weak and thus struggle to live long or successfully reproduce. Additionally, due to the overpopulation of cats and dogs, pet cloning is counterproductive in a sense. Although those who have lost their beloved pets may seek exact replicas, pet cloning is not guaranteed to fulfill these desires, so they may as well purchase pets from a shelter.
Genetic Counseling
Tay-Sachs disease (an often fatal genetic disorder that affects children’s central nervous systems) occurs when patients lack an enzyme for which a gene on Chromosome 15 codes. Since Tay-Sachs is clearly linked to a specific defective gene, gene therapy may aid patients. Likewise, through genetic counseling, prospective parents may be able to discover if they are carriers of the recessive gene. Thus, they could determine the likelihood of their children experiencing Tay-Sachs. However, most diseases cannot be traced back to a single gene. Conditions like heart disease and diabetes in addition to mood disorders, such as depression, have complex origins rooted in biological and social factors as well as their interplay. Your diet, the genetic and social aspects of your family, and your stress level are just a few contributors to heart disease and depression.
Criticism of Darwinian Medicine and Evolutionary Psychology
My previous post is correct in stating that evolution has resulted in beneficial syndromes and contributed to physiological processes. However, skeptical biological anthropologists worry that Darwinian medicine and evolutionary psychology are approaching biological determinism. They believe that we could come to think of being sick as natural. Likewise, if we view male sexual jealousy as natural, don’t we risk justifying inexcusable actions, such as domestic violence?
Additionally, Darwinian medicine and evolutionary psychology involve the Environment of Evolutionary Adaptedness (EEA): the environment to which our ancestors adapted and thus to which modern humans are adapted. Critics argue that we still have much to learn about the EEA’s social characteristics, which could act as additional selective pressures, and that the EEA varied based on where our hominid ancestors resided.
We should also research cross-cultural differences revolving around morning sickness and other medical conditions. For instance, females’ experiences with menopause differ from culture to culture, so it is a biocultural, not purely biological, syndrome. American women report more unpleasant symptoms, such as hot flashes, than Japanese women, for example. Although the reasons behind this distinction are unclear, a hypothesis has been suggested: Japanese society reveres older women and places them in a more active role while American society focuses on youth. This treatment of older Japanese women may allow them to experience menopause more comfortably, with less severe symptoms.
Potential Flaws in the Study on Brain Activity
My previous post pointed to brain studies to support evolutionary psychology. However, the study that Dr. Barbara J. King described (on the activation of the amygdala) included a small sample size of 28 volunteers. Likewise, Rebecca Todd’s study featured only 39 participants, all of whom were white. As sample size decreases, the variance of results increases, so more participants would be required to derive a better supported conclusion. Also, the first study was limited to testing brain activity and thus disregarded the behavioral and emotional changes frightening stimuli can cause. Such responses are influenced by your environment in addition to your genes.
Conclusion
We may be able to resolve medical issues and more due to our sequencing of the human genome and ability to determine genes’ effects on diseases such as Tay-Sachs. Nevertheless, approaching issues from a purely genetic lens is insufficient. Biological anthropology can improve your health and overall life only if it analyzes social and cultural factors alongside biological ones.
Sources
- The Great Courses – Biological Anthropology: An Evolutionary Perspective
- https://www.nottingham.ac.uk/biosciences/documents/burn/2011/why-are-cloned-cats-not-identical–emma-stubbs.pdf
- https://www.mun.ca/biology/scarr/Cloned_Cat.html
- Feature image: https://socialistworker.co.uk/features/how-genes-failed-hilary-rose-and-steven-rose-on-the-limitations-of-biological-determinism/
Leave a Reply