Why are gray and green shades so rare?
Secrets of rare eyes. Why are gray and green eye shades in humans are so rare.
Eye color in humans is a unique code encoded in our DNA.
Gray and green eyes are considered among the rarest in the world: only 3% of the population have gray eyes, and green eyes are even rarer, only 2%.
Their unusual distribution is due to geography: these shades are more common in Northern and Central Europe.
Scientific studies point to an evolutionary adaptation to the low levels of solar activity in these regions.
Less melanin also means less protection from excessive light and ultraviolet radiation.
In regions with high levels of sunlight, brown eyes with high melanin are better protected from these factors.
Even in populations with high melanin levels, such as black people, light-colored eyes can occur.
This may be due to rare genetic mutations or combinations of genes that have been passed down through generations.