More than just a pigment: What is melanin?

Melanin is a natural pigment found in most living organisms — it colours the eyes, hair, and the skin — and even in squid ink. This natural pigment is produced by specialised cells called melanocytes, which are situated in the skin, hair, or eyes.

Melanin comes in three kinds:

– Eumelanin, which is responsible for brown and black shades of hair, skin, and eyes.

– Pheomelanin, which produces red or yellow hues — more common in people with red hair or lighter skin.

– Neuromelanin, which is found in the brain, and develops from the oxidation of dopamine (a feel good chemical) and noradrenaline (a fight-or-flight hormone)

Melanin also acts as a biological shield, absorbing harmful ultraviolet rays and thereby protecting the skin from potential skin cancers like melanoma, and various carcinomas (cancers that begins in a tissue that lines the inner or outer surfaces of the body).

Melanin is also useful to certain animals. It helps them to blend in with their environment via camouflage. This ability is very crucial for both predator and prey. It also helps in thermoregulation, controlling heat loss and generation through mechanisms like sweating.

Melanin does not work the same for everyone. It gives some people some very rare skin conditions — like vitiligo, which leads to patches on the skin; albinism, a genetic mutation that prevents melanin production, leading to a pale colour in the skin, hair, and eyes; and hyperpigmentation, when excess melanin causes darker spots, often due to sun exposure or hormones.

Your genetics determine how much melanin and what type your body produces. Darker skin tones have much more eumelanin, providing better protection from the sun’s UV rays. Lighter tones, on the other hand, allow vitamin D protection.

But our ancestors did not have all these varying skin tones. How is that? Well, all that is in the hands of the Sun. Around 50,000 years ago or so, our ancestors lived near the equator, the hottest part of the world, and hence where the Sun’s rays are heavy with UV. Sunscreen didn’t exist back then. So, melanin acted as man’s own sunscreen.

With time, some people migrated to places with less sunlight, like Europe and Asia, and eventually lighter skin tones came to be. This allowed their bodies to better absorb vitamin D, thereby strengthening bones, and improving immunity.

As a result of this migration and subsequent adaptability, the world is a colour palette of varying skin tones.

All in all, melanin tells the tale of how our ancestors survived. And while it may indicate your ancestry, it does not indicate a person’s character.