There is a long-standing debate about the role of nature and nurture in shaping human beings. Initially, it was believed that genes determined our bodies and even our personalities, but as research has progressed, epigenetics has come to the forefront, suggesting that environmental influences can alter gene expression. As a result, the idea that genes and the environment interact to shape human traits and behaviors is gaining importance.
The question of how humans are made has been around since ancient times. Advances in science and technology are gradually unraveling these questions. Starting with Watson and Crick’s discovery of the double helix structure of DNA, DNA is slowly being sequenced and genes are being studied. Initially, it was thought that genes only determined physical features, but over time, the view that genes are also involved in the formation of human personality began to emerge. The debate between scientists about the formation of human character intensified when Francis Golton first used the phrase “nature and nurture”.
Those who believe that nature is more important in the formation of human character argue that innate genes cannot be changed. They believe that genes control not only a person’s physical features, but also their emotions and behaviors. They have developed a theory called genetic determinism. Genetic determinism is the view that an organism’s behavior is determined by a combination of genes, and it argues that human social behavior is also determined by genes. According to this theory, genetic studies can be used to predict how an organism will behave, what diseases it will get, and what it will look like. As DNA research advanced, so did the number of proponents of genetic determinism, who believed that by unlocking the secrets of genes, they could unlock the secrets of human formation. This led proponents of genetic determinism to launch the Human Genome Project. The Human Genome Project was a project to find and catalog all the genes in the human body, which proponents of genetic determinism hoped would prove that a large number of genes regulate human formation. This mindset stems from reductionism. Reductionism is the idea of analyzing complex phenomena by reducing them to simpler ones, and modern biology was built on this idea. As science progressed, scientists tended to analyze things in smaller and smaller units, which led to the discovery of cells and DNA. This was great as a research method, but not as a way to interpret it. According to the reductionist approach, gene expression is a unidirectional process that builds from smaller to larger units. This is called the “central dogma,” and it asserts that DNA is the primary determinant of the properties of proteins in a one-way information transfer from DNA to proteins.
However, the results of the Human Genome Project have shown otherwise. According to genetic determinism, there should be at least 120,000 genes on a human chromosome, including the genes that regulate the activity of the genes that encode these proteins. However, research has shown that there are only 25,000 genes in humans. This means that genes don’t control everything in humans. Even the most primitive organism, the nematode, has 24,000 genes, and the fruit fly has about 15,000 genes. This suggests that one gene does not correspond to one trait, which means that genes do not determine everything about us. This leads to the conclusion that other factors play a more important role in human formation than genes, namely nature.
In opposition to genetic determinism, a new theory emerged: epigenetics. When the Human Genome Project, which started with a reductionist approach, failed to prove genetic determinism, scientists tried a new direction: they found that environmental influences can change DNA, or genes. This means that trait formation is not unilaterally initiated by DNA, but can be modulated by environmental cues. The activity of genes is regulated by regulatory proteins, and environmental signals control these regulatory proteins. The finding that environmental signals can generate more than 2,000 protein variants from the same gene through regulatory proteins also supports the involvement of environmental influences in human formation. Genes don’t directly control their own activity. Gene expression is achieved through the action of effector proteins that are regulated by environmental signals picked up by cell membrane receptors. In other words, the expression of a gene’s trait is regulated by environmental factors, not the gene itself. Experiments with mice carrying the agouti gene support this claim. Mice with the agouti gene are characterized by yellow fur and obesity. When mice with this gene were fed a diet that blocked gene activity, their mothers gave birth to offspring with chestnut-colored fur and slimmer bodies. This shows that the environmental changes experienced by the mothers were passed on to their offspring. Gene expression was regulated by an environmental factor, food. This means that genetic determinism is wrong.
Genetic determinism can also be seen in historical events. During the Nazi rise to power, the Nazi Holocaust was the result of eugenics based on genetic determinism. Eugenics is the study of artificial selection to preserve the best genes, based on the premise that there is a dominance between genes. In the past, those who believed that genes determined everything also thought that human talents and traits were inherited, which gradually led to the categorization of those with superior genes and those with inferior genes. In the 19th century, eugenics spread in many countries, and it evolved to categorize racial excellence. Differences in genes across races were used to categorize superior and inferior races. Eventually, in Germany, the effects of eugenics led to the Holocaust, or the genocide of the Jews. After these events, the falsity of eugenics was exposed and it began to decline. It proved that there is no dominance between genes, and that human differences are not related to genetic differences. In other words, nature (genes) does not play a significant role in the formation of human beings.
Now let’s look at the nurture aspect. The view that nurture is more important than nature is based on environmental determinism. Environmental determinism argues that the environment plays a more important role than genes in shaping human beings. According to this theory, living beings are not governed by their genes, but actively change in response to their environment. This means that the flow of information is not one-way, but rather a web of interactions. In other words, the factors involved in human development are interrelated and interact with each other. Recent studies have shown that proteins in cells interact with the external environment. Environmental determinists support epigenetics by emphasizing that human development is shaped by the environment. Epigenetics argues that environmental factors regulate gene expression, which manifests as changes in gene expression rather than changes in genes. Environmental determinism also emphasizes plasticity, or the ability of organisms to adapt to their environment.
Genes are an important factor in determining human physical characteristics and behavior. However, genes are not fixed, but have the potential to change in response to environmental cues. This suggests that genetic determinism is wrong. Genetic determinism, which is based on the assumption that genes are unchanging, is no longer supported by the emergence of epigenetics, which shows that gene expression can change under the influence of the environment. The fact that gene expression can be regulated by environmental factors emphasizes the importance of environment (nurture) over nature (genes) in human formation. Human formation is the result of the interaction between nature and nurture. Genes provide the framework for human formation, but environmental factors shape and express that framework. In human development, genes and environment interact with each other to shape the human being.
Identical twins are a great example of this interaction. Identical twins have the same genes and look alike, but if they are raised in different environments, they can have very different personalities. This shows that even if you have the same genes, environmental factors can shape you differently. Another example is Tiger Woods. He’s considered one of the greatest golfers of all time. What makes him the best golfer he is is not only his natural physical talent, but also the environment he grew up in. His father taught him to play golf from a young age and worked hard to nurture his talent. These environmental factors helped him to become the best player he could be. In other words, his natural talent was not the only factor in his success, but the environment that nurtured it was even more important.
In conclusion, the question of whether nature or nurture is more important in human formation is not easily answered. It’s true that genes and environment interact to shape us. Recent research suggests that environmental factors play a more important role. Genes provide the framework for human formation, but it’s the environment that fills and shapes that framework. Therefore, the most important factor in human formation is not genes, but the environment in which a person lives.
