As a domain expert in the field of human genetics and biology, I can provide an in-depth explanation of what determines the color of human hair. The color of hair is a complex trait influenced by multiple genes and environmental factors. However, the primary determinant of hair color is the type and amount of pigment cells called melanin produced by specialized cells in the hair follicle known as melanocytes.

Melanin is a natural pigment that plays a crucial role in determining the color of our hair, skin, and eyes. There are two main types of melanin:


1. Eumelanin: This is the dark pigment that contributes to black and brown hair colors. It has a protective function against the harmful effects of ultraviolet (UV) radiation from the sun.

2. Pheomelanin: This is the light pigment that contributes to yellow and red hair colors. It is less effective at UV protection compared to eumelanin.

The combination and concentration of these two types of melanin are what create the wide spectrum of hair colors we see in human populations. Here's how it works:

- High levels of eumelanin result in black or brown hair. The more eumelanin present, the darker the hair color.
- Low levels of eumelanin combined with higher levels of pheomelanin result in lighter hair colors, such as blonde or red.
- Absence of melanin leads to white or gray hair, which is common as individuals age and their melanocytes decrease in activity.

The genetic control of melanin production is complex and involves several genes. The most well-known gene associated with hair color is the MC1R gene. Variations in this gene can result in a range of hair colors, from black to red. Other genes also contribute, and their interactions can lead to the diverse hair color patterns we observe.

Environmental factors can also influence hair color. For example, exposure to sunlight can lighten hair over time due to the breakdown of melanin. Additionally, certain dietary factors and nutritional deficiencies can affect the production of melanin.

As individuals age, the production of melanin often decreases, leading to the graying of hair. This process, known as canities, is a natural part of aging and is influenced by both genetic and environmental factors.

In summary, the color of human hair is a multifaceted trait resulting from the interplay of genetic factors that control melanin production, the types of melanin produced, and the influence of environmental factors. Understanding this complex system is essential for anyone studying human biology or genetics.

read more >>

It gets its natural color from a type of pigment called melanin. ... Hair has only two types of pigments: dark (eumelanin) and light (phaeomelanin). They blend together to make up the wide range of hair colors. Melanin is made up of specialized pigment cells called melanocytes.read more >>