ruivas

Ruivas, also known as redheads, are individuals with red hair. The red coloration is due to the presence of the MC1R gene, which is responsible for producing melanin, the pigment that gives hair its color. The MC1R gene has a specific mutation that results in the production of pheomelanin, a type of melanin that is red or orange in color, instead of the usual eumelanin, which is brown or black.

Red hair is relatively rare, with only about 2% of the world's population having red hair. It is more common in certain populations, such as those of Northern European descent, and is less common in other populations, such as those of African or Asian descent. The rarity of red hair has led to various cultural and social perceptions, including stereotypes about redheads being fiery, temperamental, or having a higher intelligence quotient.

The red color of hair can fade over time, especially with exposure to the sun, and may turn to a more golden or blonde hue. This is due to the breakdown of pheomelanin by ultraviolet light. Red hair can also be affected by certain medical conditions, such as vitiligo, a condition in which the body's immune system attacks melanocytes, the cells that produce melanin.

In addition to hair, redheads may also have red or pink eyes, a condition known as red-eye syndrome. This is due to the same mutation in the MC1R gene that results in red hair. Red-eye syndrome is relatively rare, with only about 1 in 10,000 people having red eyes.