What Determines Your Skin Color? It’s No Big Deal

I previously wrestled with the confusing terminology of the times in my article about the meaning of Latinx. Now I got another one for you. I’m referring to the person of color terminology. Some seem to love it. Others wonder why there’s no such thing as a person of pallor. And then there are the proponents for just person. Which got me thinking—what determines your skin color anyway? And have we yet again allowed people without much knowledge of science to kidnap our vocabulary?

 

A Quick Primer on Skin

Skin, considered an organ, has the critical function of protecting the human body from all sorts of potential insults. One such insult is ultraviolet (UV) radiation emitted by the sun.

The human skin is divided into three layers. The epidermis—the outermost layer—overlies the dermis, which in turn overlies the hypodermis.

Two major cell types in the epidermis are the keratinocytes and the melanocytes. Using the amino acid tyrosine, the latter produce a pigment called melanin (much of which is transferred to the keratinocytes) that absorbs UV radiation and thus protects the DNA of the cells from the potentially harmful effects of the radiation. This process is important as damage to the DNA can increase the risk of skin cancer.

 

So What Determines Your Skin Color?

Skin color is actually determined by many substances, but melanin is the most important. While the quantity of melanocytes is similar in most individuals, variables include the amount of melanin produced and the exact type of melanin produced.

Individuals who produce more melanin and/or a darker type of melanin typically have darker skin.

Individuals who produce less melanin and/or a lighter type of melanin typically have lighter skin. In such individuals, the perceived skin color is often determined by the color of connective tissue and blood vessels in the dermis.

(Of course, increased exposure to UV radiation—via the sun or a tanning salon—can stimulate an increase in melanin production, better known as a tan.)

How did such differences come to arise? A non-nuanced answer is that the skin color of historical human populations adapted to their surroundings. Populations exposed to higher amounts of UV radiation (generally closer to the equator) have been defined by darker skin (which is protective). Similarly, those exposed to less UV radiation have been defined by lighter skin—this adaptation may have optimized a desired effect of UV radiation on the skin, namely that of producing vitamin D, important for calcium absorption.

Given the large range of skin color on the planet, it follows that skin color is a polygenic trait. In other words, a large number of genes are responsible for someone’s skin color. Stated yet another way, the basic processes outlined above are governed by many different genes working in concert and not just one gene.

As a last point, it should be mentioned that humans have at times gone to extreme measures to change their skin color. Obviously, human behavior doesn’t always make sense.

 

New Terminology

Taking this knowledge into account, I think it’s only fair that we change our current terminology to something that’s more scientifically sound.

I am a person will be I am a collection of cells that human beings have termed to be a human being.

I am a person of color will be I am a collection of cells that human beings have termed to be a human being with an outer layer that excels in melanin production.

I am not a person of color will be I am a collection of cells that human beings have termed to be a human being with an outer layer that prefers not to engage in excess melanin production.

 

Anyway, what’s the take-home message? Skin color is mostly determined by melanin, a pigment whose granules measure less than one-thousandth of a millimeter in diameter. As such, there are bigger things to worry about.