The Ginger Gene
Only slightly more than 0.5% of the general human population is known to have the ginger gene, the gene responsible for the traits of red hair and freckles. Two to six percent of the population in Northern and Western Europe has red hair, where the highest number of redheads is found in Ireland, with Scotland and England taking up second and third place respectively.
The particular gene that causes one to have red hair is a recessive one, meaning that it’s ‘weaker’ in the presence of another gene that affects pigmentation, and will be looked over when traits are being manifested. The only time the trait is manifested is if both parents have red hair, and they pass on this trait to their child.
People could also be carriers of this gene. This means that the recessive gene that causes red hair is present, but has no effect. In such a situation, the individuals will not have the red hair, but they may have freckles. If both parents are carriers of the ginger gene, each of their children will have a 25% chance of turning out as redheads. This is why sometimes the trait of red hair seems to skip a couple of generations. The recessive gene is only manifested physically when it occurs in twos, and it may take a while for that to happen when the parents are carriers. If none or only one of the parents is a carrier of the ginger gene, then none of their children are going to be redheads.
Hair color is usually determined by two types of pigments- eumelanin and pheomelanin. Eumelanin in the hair is what causes hair color to range from blonde to brown to black, with each color being an indication of the pigment’s intensity. When pheomelanin occurs in larger amounts than eumelanin in the hair, then the hair color will vary between different shades of red, ranging from burgundy to bright copper. Red hair is the rarest naturally occurring hair color there is. This is because the product of the variant gene responsible for this hair color causes any pheomelanin to be converted to eumelanin, and thus the red hair trait is overlooked.
The ginger gene is usually linked to other traits like fair complexion and lighter eyes. This is because the low levels of eumelanin in their hair also affects the pigmentation in their skin. The low melanin in their skin makes them unable to tan, and they’re therefore more susceptible to melanoma. However, their fair skin also works to their advantage in areas with low levels of sunlight as their bodies are able to manufacture their own Vitamin D.
Due to their rarity, redheads have been the victim of a couple of myths. The most common is that they are on the verge of extinction. This is however not true. The recessive nature of the ginger gene and intermarriages across between different people makes the traits manifest themselves only once in a while, but the number of gene carriers does not diminish.