It’s common knowledge that those who have been kissed by fire also have pale skin and freckles, increasing their chance of developing skin cancers, but why exactly this is the case has remained a little hazy. Now researchers think that they have found a potential contributing factor, and also revealed that far more of us could also have an increased risk of developing melanoma.

People who have red hair carry two copies of a particular gene known as MC1R. This gene is related to the production of melanin, the dark protein in your skin that helps to protect against UV radiation from the Sun. Yet it turns out that far more of the population, around one in four, carry a single copy of MC1R. While they may not show any external indications of being ginger, they may still carry the risk of melanoma.

The researchers have found that those who have the genetic variant for red hair actually have more mutations in their skin cancer. It was already known that the genes associated with ginger hair increased the risk of the melanoma, but this new study is able to show that this increase of risk is at least in part down to an increase in mutations found within the cancers. It has also been able to show that many people within the population, while not having red hair themselves, still carry a copy of this gene and subsequently also have an elevated risk of skin cancer.

“All people, not just pale redheads, should be careful in the Sun,” Dr David Adams, who led the research published in Nature Communications, told BBC News. “It has been known for a while that a person with red hair has an increased likelihood of developing skin cancer, but this is the first time that the gene has been proven to be associated with skin cancers with more mutations. Unexpectedly, we also showed that people with only a single copy of the gene variant still have a much higher number of tumour mutations than the rest of the population.”

They found that while there was a marked difference in the number of mutations found within the tumors of those who have MC1R and those who don’t, there was little difference in the number of mutations in the cancer between people who were not ginger but had one copy of MC1R and those who were red haired with two copies of MC1R. This implies that even if those who don’t have ginger hair but still carry the gene may be at the same risk of developing cancer as full red heads, but that they are probably unaware of this.