Hair has long been a topic of interest to people throughout the world. The color, texture, style, and length come up often in conversation. There is one particular coloration of hair that is almost universally associated with one region of the world despite it actually being a part of many. The naturally red-haired human being is a rare creature. They are often referred to as “titian” or “gingers”. While science has a very specific reason for this physical trait there have been many other reasons cited for its existence for hundred of generations. Most of these folklore explanations have been negative and often incredibly insulting.
Scientifically speaking red-haired has been determined to be caused by a single gene on the sixteenth chromosomal strand of human DNA. This recessive gene affects the MC1R protein which determines color based on two chemicals pheomelanin and eumelanin.
These two types of melanin intermix to create protein strands which eventually becomes hair color. Pheomelanin generates lighter colors such as red and blonde hair. Eumelanin generates darker colors such as black and brown.
When these two melanin types appear they determine the coloration of the hair. With a very low Eumelanin amount and a higher Pheomelanin production hair will become red. There are several differing thoughts among the scientific community as to the origin of these gene that range from the largely discounted acquisition of it from intermixing of homo sapiens sapiens with homo neanderthalensis to negative selection. The red-haired gene evidenced in that cousin species to modern cro-magnon humanity has been determined to be a different type of mutation that the one that exists within homo sapiens sapiens. Negative selection is a concept that dictates that the red haired mutation survived in northern Caucasians because the environment didn’t select against it. Red hair and fair skin would have caused incredible hardship in an area like Africa but in the far north it didn’t cause as many issues and the fair skin simply aided in the acquisition of vitamin D.
While non-pathological genetics are considered the general reason why this rare hair coloring exists it is not the only reason. There are actually several types of genetic disorder, disease, and injury that can cause hair to turn red.
A disease known as Kwashiorkor and similar protein deficiencies can cause hair to turn red. Severe malnutrition will cause the hair to change from a darker color to red or possibly blond due to lack of protein and chemical shifts within the body as it tries to stave off starvation.
There is a type of albinism known as “Rufous” albinism that afflicts individuals of African Decent as well as some from New guinea that also causes red hair and red skin to occur. It is also generally found in individuals with a deficiency in pro-opiomelanocortin. This is a precursor polypeptide that controls several factors of physicality. Mutations in this gene have been cited as being causes for obesity and adrenal insufficiency as well as pigmentation it can cause.