How Genetics Determine the Color of Your Skin

Key Takeaways

• Other factors like sun also affect skin color - Jump to Section
• Skin color comes from both parents - Jump to Section
• UV radiation influences skin color variation - Jump to Section

A complex series of genes and the many pigments and proteins in our bodies are what produce the whole range of human skin colors.

There are several pigments in your skin that are responsible for its color. Melanin is the most important of these. It is produced in skin cells called melanocytes and comes in two types. 

• Eumelanin is most abundant in people with darker skin
• Pheomelanin is more common in lighter-skinned people

Different amounts of each pigment are responsible for creating different hair colors, eye colors, and human skin tones.¹

Human skin pigmentation is not just for appearance’s sake. They can have major impacts on your overall health.

Keep reading to learn more about your skin color, including the genetics behind it, the other factors that influence it, and what it could mean for your health. 

Is Skin Color Solely Determined by Genetics?

No, genetics are not the only thing that can affect human skin color, although it does play the most important role.

Some non-genetic factors can result in light and dark pigmentation. That being said, your DNA is still the biggest factor that controls human skin color.²

For example, age can affect skin pigmentation. The amount of melanin in your skin decreases as you get older. This makes your skin lighter and more translucent as you age.³

Sun exposure and UV radiation also affect the color of your skin.

UV radiation from sunlight can damage your skin and potentially cause skin cancer over time, but melanin helps prevent this damage. The more UV radiation your skin is exposed to, the darker it will get. This is why your skin tans when you’re under the sun for a long time.⁴

How Do Different Genes Contribute to Skin Pigmentation?

Genetics is the most important factor in determining human skin color. There is not only one gene that decides what color your skin is. In fact, scientists are still not sure how many genes can affect skin pigmentation, but some estimates show that over 150 could be involved. 

There is a whole range of genes that can affect human skin color, but a few common genes are known to be particularly impactful. These include:²

• TYR – This gene contains the code for an enzyme called tyrosinase, which helps initiate the process of melanin creation in your cells
• OCA2 – This gene contains the code for P protein, which helps transport tyrosinase
• MC1R – This gene is more commonly associated with hair color, but certain forms are known to result in red hair, pale skin, and freckles

Does Skin Color Come From More from One Parent?

Yes, your skin color is affected by the skin color of both of your parents.

You have two sets of alleles for each of your genes. One set is inherited from your mother, and one is inherited from your father. This means that across all the genes that can affect your skin color, some will be from your mother, and some will be from your father.

Usually, this means that your skin color is somewhere in between your mother’s and your father’s.

There may be some cases when a person’s skin color is closer to one parent than the other. Even when this happens, that person will still have inherited skin color genes from either parent.⁷

Can Two Dark-Skinned Parents Have a Light-Skinned Child (and Vice Versa)?

Yes, dark-skinned parents can have a light-skinned child, and light-skinned parents can have a dark-skinned child. 

Because the genes that you receive from each of your parents are essentially random, it is possible to receive a combination that would result in your skin being much lighter or darker than either of your parents’.

While these cases are rare, there are several known instances of this happening.⁷

Dark-skinned parents could also have a light-skinned baby due to conditions like albinism. This is a condition caused by mutations in genes related to skin color. If you inherit two mutated copies of certain genes, your ability to produce melanin can be reduced. 

There are several forms of albinism. Some result in only slightly lighter skin, but some rare forms can result in a complete inability to produce melanin. A person with albinism born to two dark-skinned parents can have significantly lighter skin.²

Why Do Different Populations Have Varying Skin Colors?

Populations in different parts of the world generally have different skin colors. More than any other factor, skin tone changes with latitude. Populations closer to the equator tend to have darker skin, while populations further away from it usually have lighter skin.

This is related to how much UV radiation is present in different areas. Sunlight is more intense closer to the equator, which means people in these areas are affected by more UV radiation. 

Because of this, these people have dark skin with more melanin to provide better protection against UV radiation, which can cause skin cancer. This makes dark skin pigmentation more advantageous near the equator.

On the other hand, melanin is thought to impair vitamin D synthesis. Your body can create its own supply of vitamin D, but sunlight is required for this process.

The melanin in dark skin is thought to interfere with this process. This is why lighter skin is advantageous away from the equator. With light skin, people can produce more vitamin D with less sunlight exposure.⁵

While sunlight helps us create vitamin D, it also breaks down another vitamin called folate. 

According to one theory called the vitamin D-folate hypothesis, the primary reason we evolved different skin colors was to help us maintain a proper balance of vitamin D and folate.⁶

How Has Migration Impacted Skin Color Over Time?

Modern humans evolved in Africa and migrated all over the world from there roughly 100,000 years ago. Today, there is a whole range of human skin colors all over the world, from dark skin to light.

We also know that darker skin is more common in people close to the equator, and lighter skin is more common in people further away from the equator.

The question of how skin color variation evolved as humans migrated to different parts of the world is one scientists have been trying to answer for a long time.

Human skin color is affected by a large number of genes. Different variations of these human pigmentation genes are called alleles, and different alleles can make your skin darker or lighter.

By looking at how common different alleles are in different parts of the world, we can start to put together how skin color variation evolved over the years.

However, this is not as simple as it seems. For example, both Europeans and East Asians tend to have light skin pigmentation. Despite this, light skin in Europeans is created by a different set of alleles than light skin in East Asians. 

Because many studies looking at skin color genetics are done in Europeans, it is difficult to figure out exactly how different human skin colors and skin color variations emerged as humans migrated to different countries.⁵

Common Questions About Skin Color

What affects the skin color of a newborn baby?

Genetics is the most important factor in determining the skin color of any person. However, newborn babies can have smaller variations in their skin color.

When a baby is first born, their skin will usually be purple or dark red, which will fade as the baby starts to breathe. Over their first day of life, a baby will also have reddish skin.

In some cases, a baby’s skin color can be bluish. This is normal if it is limited to the baby’s hands and feet, as their circulatory system is still not fully developed.

If the blue color spreads beyond the hands and feet, it indicates a problem. If you notice this, you should consult a doctor.

A baby can also have jaundice, where the skin turns slightly yellow. This can be normal and can resolve over time. In some cases, it could be a sign of a health issue. If your baby has jaundice, consult a doctor, especially if it worsens.⁸

Does Skin Color Affect How Much Vitamin D You Have?

Vitamin D production and skin color are closely related.

Your body can produce vitamin D when your skin gets direct sunlight. However, the UV radiation that comes with sunlight can cause skin damage or skin cancer. It can also degrade another vitamin called folate.⁶

Folate is essential for the production of red blood cells. Not having enough folate can result in anemia, weakness, or fatigue.⁹

According to the vitamin D-folate hypothesis, light pigmentation and dark pigmentation evolved so that different populations could maintain a balance of both vitamins in different parts of the world.

Darker skin could have evolved to help preserve folate in areas with intense sunlight. On the other hand, light skin could have evolved to help increase vitamin D in areas with less sunlight.  

The vitamin D-folate hypothesis is only one of many theories that could explain why variations in skin pigmentation evolved in humans. Other theories state that dark skin could have been more important to protect against skin cancer. 

Another explanation could be that lighter skin developed so that the human body could spend fewer resources producing the melanin needed for dark skin. These resources could be used to help deal with colder climates.⁶

Can a Dominant Gene Decide Your Skin Color?

Some alleles of genes involved in skin color are dominant, but overall, there is no genetically dominant skin color.²

For each of our genes, we have two alleles. Sometimes, both alleles are expressed, and in others, only one is expressed. When only one allele is expressed, it is called a dominant allele. The other allele is called a recessive allele.¹⁰