The simple answer is Yes! Redheads inherit two versions of the MC1R gene that leads to red hair – one from their mum and one from their dad. Red hair is a genetic trait that is caused by a mutation in the MC1R gene. This mutation leads to lower levels of eumelanin and higher levels of pheomelanin, resulting in red or ginger hair. Although almost everyone with red hair has two copies of the red-haired version of MC1R, not everyone carrying two red-haired versions is a redhead.
Red hair is a unique physical trait that has captured the attention and curiosity of people for centuries. Whether you love it or loathe it, there’s no denying that red hair stands out in a crowd. But what causes red hair, and is it a genetic trait? In this blog post, we’ll explore the science behind red hair and investigate the genetic factors that contribute to this distinctive physical trait.
Melanin in the hair shaft
First, let’s review how hair colour is determined. Hair colour is determined by the amount and type of melanin in the hair shaft. Melanin is produced by cells called melanocytes, which are located at the base of the hair follicle. There are two types of melanin: eumelanin, which produces brown or black hair, and pheomelanin, which produces red or ginger hair.
MC1R gene and melanin production
Red hair is caused by a genetic mutation that affects the production of melanin in the hair shaft. Specifically, people with red hair have a mutation in the MC1R gene, which regulates the production of melanin. This mutation leads to lower levels of eumelanin and higher levels of pheomelanin, resulting in red or ginger hair.
Genotype of ginger red hair
Ginger hair colour is determined by a person’s genetics, specifically by the combination of MC1R alleles they carry, which are inherited from their parents. This is referred to as the genetic makeup of an individual. In the case of ginger hair, there are two main alleles that are involved: MC1R-R and MC1R-r. Each person has two copies of the MC1R gene, one inherited from each parent, and they can have either two copies of the MC1R-R allele (homozygous dominant), one copy of MC1R-R and one copy of MC1R-r (heterozygous), or two copies of the MC1R-r allele (homozygous recessive). Hair colour is an autosomal recessive trait expressed by the MC1R gene, which means two copies of this gene must be present in order for the trait to develop
According to https://dermnetnz.org/, most individuals with pure red hair colour (RHC) are homozygous for two variant MC1R alleles. The high penetrance genes (namely, R151C, R160W, D294H and D84E) are denoted as ‘R’ and almost always result in red hair colour when homozygous (RR). People with strawberry blonde or auburn hair colour are heterozygous, carrying only one hypomorphic variant allele (Rr). Not all MC1R variants are associated with red hair. The V60L, R163Q and V92M variants, denoted as “r”, do not produce red hair when in combination with the highly penetrant alleles, due to either a slight functional impairment or normal coupling of cAMP pathway. V60L is common in the general non-RHC population (15%≤), including Asian populations and Caucasians with darker skin, and is considered a silent mutation.
Phenotype of ginger red hair
A phenotype refers to the observable features related to a gene, including but not limited to, thief physical appearance. In the case of the MC1R gene a related phenotype is the hair colour a person exhibits. There are also other features associated with the MC1R gene that are not involved with hair colour, such as pain tolerance and freckles.
The phenotype of ginger red hair is the actual hair colour that is exhibited as a result of those MC1R alleles, along with other factors. If an individual has at least one copy of the MC1R-r allele, they may have red or ginger hair, depending on other genetic factors and environmental factors such as sun exposure. However, having the MC1R-r allele is not a guarantee of having ginger hair, as there are many other factors that can influence hair colour.
Which shades of hair are defined as ginger
It’s also worth noting that the percentage of people with ginger hair may vary depending on how we define “ginger.” Some people may consider auburn or strawberry blonde hair to be “ginger,” while others may only count copper red hair as true ginger. Red hair is more common in certain ethnic and racial groups. For example, red hair is most common in people of Northern or Western European descent, particularly in Scotland and Ireland. However, red hair can be found in many different parts of the world, including Asia, Africa, and the Americas.
Conclusion
Red hair is a genetic trait that is caused by a mutation in the MC1R gene. This mutation leads to lower levels of eumelanin and higher levels of pheomelanin, resulting in red or ginger hair. While red hair is more common in certain ethnic and racial groups, it can be found in many different parts of the world. Regardless of where it comes from, red hair is a unique and distinctive physical trait that has captivated people for centuries.
And don’t forget to check out other articles in our Ginger Red Hair Facts category.