Look around you. Brunettes, blondes, redheads, there are visible differences in appearance no matter where you are. But what makes these differences possible? It can all be explained through gene inheritance. Different traits are passed on through one gene or through many genes. This is what allows for distinct looks.
Some traits require multiple genes in order to appear, otherwise known as polygenic traits. A polygenic trait, like skin, needs matching conditions in order to reveal a certain color. It’s easy to see that not everyone has identical or even similar genes for skin tone. For example, if you held your arm up to your friend’s, you’d likely see at least a few shades of difference. This is due to the fact that skin color is determined by dozens of genes, but there are a few distinct ones. When thinking about tone, the most prominent gene is SLC24A5. This gene handles the majority of tonal variation globally because it influences the amount of melanin that is produced in the body. Melanin is what makes skin lighter or darker. Another gene that is incredibly important to melanin production is OCA2, which helps to mature the melanosomes, allowing melanin to be used in the body. The culmination of the work of these cells helps to create the various colors you see when you look in the mirror.
Some traits require only one gene in order to appear. The most common example of a monogenic trait is whether a person’s earlobes are attached or detached. It’s easy to tell what you have. All you have to do is reach up and feel if your earlobe is fused to the side of your head, or if it dangles. Monogenic traits are also known as Mendelian traits because they work off of a simple dominant and recessive pattern. The dominant trait passes down more often because it only needs one of the two alleles in a chromosome to have it. In the case of earlobes, attached is the dominant trait. If the attached allele appears once, then a person will have attached earlobes. In contrast, both alleles for detached earlobes have to be present in order for a person to have detached earlobes.
Due to traits being defined as polygenic or monogenic, some traits are considered to be more rare than others. For example, you are more likely to see ten brunettes on the street before you see a real blonde. As a result, traits that are considered ‘rare’ are often more sought after. Hair colors like red or blonde are often re-created using bleach and hair dye. Freckles can be drawn onto the face. Facial features can be altered using surgery. At the end of the day, everyone wants what they don’t have. It’s important to take pride in your own unique features instead of constantly chasing after others.
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