A study on how red hair is inherited

People with red hair make up about one to two percent of the world's population. It's fascinating how people inherit red hair. While it used to be assumed that the inheritance of a single recessive gene determines whether people inherit red hair or not, a new study has uncovered several previously unidentified genes that are also involved. In the study, described as the "largest genetic study of human hair color", a team of scientists from the university ran an analysis using data from the UK Biobank study.

inheriting red hair

Inheriting Red Hair - The DNA

The scientists assessed the DNA of nearly 350,000 people and compared the DNA of people with red hair to that of people with blonde, brown and black hair. It used to be understood that the MC1R gene determined whether a person would have red hair or not. When comparing redheads with people with brown or black hair, however, the scientists were able to identify eight genetic differences associated with red hair that they had not discovered before. The study, published in the journal, assessed only people of European ancestry because of the greater variability in hair color among them.

 

Inheriting Red Hair - The MC1R Gene

Earlier studies have shown that people with red hair inherit two versions of the MC1R gene, one from each of their biological parents. However, not everyone who carries two versions of the MC1R gene will automatically inherit red hair. Against this background, the scientists were aware that there must be other genes too, but until now they didn't know exactly which ones they were.

Taking a closer look at the functions of the newly discovered genetic variants, the researchers concluded that some of them can determine when the MC1R gene is switched on or off. Melanie Welham, executive chair of the Biotechnology and Biological Sciences Research Council, which helped fund the research, spoke about the study's fascinating results, saying that only collaborative research would help find answers to the question of exactly how you can inherit red hair.

Besides discovering the eight genetic differences linked to red hair, the scientists also found nearly 200 genes associated with blonde and brown hair. One of their unexpected discoveries was the fact that many of these genetic differences affect hair texture rather than color. Most people with red hair have a gene mutation in the melanocortin 1 receptor (MC1R). When MC1R is inactivated, the body produces more pheomelanin, which is responsible for reddish skin and hair tones, than eumelanin, which is responsible for brown and black tones. In people with an activated MC1R, eumelanin can balance out pheomelanin, while in redheads the gene variant prevents this.

 

Inheriting Red Hair - Redheads Have Health Benefits

Inheriting red hair can also have some advantages, even though redheads sometimes don't like their pale complexion. Scientists have found that fair skin has an important anti-disease property. It absorbs more vitamin D, which is essential for bone health and preventing osteoporosis. Some researchers believe it also boosts immunity and helps prevent cancer and autoimmune diseases.

 

Health benefits:

  • increased vitamin D absorption
  • increased immunity
  • possibly lower risk of cancer or autoimmune diseases