Freckles are what kind of trait

In response to UV light, cells in the skin begin to release signals that are detected by the MC1R protein in melanocytes and prompts increased coloration of the skin 1,2. You might recognize the MC1R gene for its role in producing red or blonde hair.

This happens when someone inherits at least one variant in the MC1R gene that causes it to be less effective. As a result, cells contributing to hair coloration are prompted to produce pheomelanin instead of eumelanin, which results in red pigmentation.

In the skin, MC1R variants are associated with fair complexion as a result of reduced brown pigment production. Curiously, variants in MC1R are also associated with increased likelihood of freckling 1,2. Characteristically, ephelides get darker in the summer months, likely as a result of increased sun exposure.

Research into the biology of freckling has shown that the concentrated color change is a result of increased melanocytes and an elevated production of eumelanin relative to the surrounding skin. Scientists have identified and analyzed more than 80 variants in the MC1R gene, some of which are strongly associated with freckle formation in people from various ethnicities. There are also many other genes that could contribute to freckle formation 1. Decades of research have shown that ephelides are a heritable trait and that genes like MC1R have a big role to play in this—however, the amount of color in those freckles may be influenced by a combination of genetics and environment.

Helix Newsletter. If both don't work well, they get red hair and freckles. Now the red hair makes sense. If MC1R doesn't work, you'll get a build up of pheomelanin and end up with red hair.

But why does having half your MC1R work sometimes cause freckles? Scientists don't know. What they know is that having one or two non-working copies of MC1R can sometimes cause freckles.

Note the sometimes. Not everyone who is a carrier for red hair has freckles. So there must be more to freckles than the MC1R gene itself. We haven't yet found what that other thing is. Some recent work also shows that there are other ways to get freckles besides the MC1R gene. Recently a group of scientists in China found another freckle gene. This one was on chromosome 4 in a Chinese family with freckles. So as you can see, we have part of the story on freckles but don't know everything yet.

Having broken copies of the MC1R gene isn't always enough. And there are other ways to get freckles besides MC1R. Most likely we are missing some other genes needed for freckling. Certain versions of these genes might need to be there along with certain versions of MC1R to end up with freckles.

Scientists will keep looking. MC1R is a very interesting gene. It leads to the confusing result that freckles are dominant and red hair is recessive. Even though they are the same gene! The MC1R gene is actually responsible for hair color in many animals.

Blond or ginger colored mice were found to have the same gene variations. Scientists have also recently found that woolly mammoths that were light colored also had the same MC1R changes. Hair, skin, and particularly eye color can all get pretty complex. Most often, these traits aren't as simple as being dominant or recessive, like having red hair or freckles. But even if you have freckly genes from birth you are not born with freckles — they arise during childhood and tend to crop up on sun-exposed regions of the body.

They are more pronounced in summer, generally stop spreading around adolescence and may not be as noticeable with age. Freckles are harmless, but the fair skin they tend to be linked with can sunburn easily, and anyone who notices a change in any area of pigmented skin should get it checkedout.

Please update your payment details to keep enjoying your Irish Times subscription. Why do some people get freckles? Tue, Mar 2, , The number of freckles you have is down to a combination of genes and environment. More from The Irish Times Health. Home energy upgrades are now more important than ever. The Dublin start-up making the future better with an appreciation for innovation. Covid Lives Lost The rich, full and cherished lives of the people behind the numbers.

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