 Show Some parents worry that their children will be born with a rare disease or a hidden genetic disorder. Other parents, however, wonder if their children will possess something more obvious: red hair. A British ancestry company, BritainsDNA, is now offering parents the chance to see if their children might inherit the so-called "ginger gene," the Telegraph reports. The test will scan each parent's DNA for signs of the so-called MC1R gene that causes redheadedness. "Through a simple saliva test to determine deep ancestry, we can … identify whether an individual is a carrier of any of the three common redhead variants in the gene MC1R," said Dr. Jim Wilson, chief scientist at BritainsDNA, as quoted in the Huffington Post. The gene for red hair is recessive, so a person needs two copies of that gene for it to show up or be expressed. That means even if both parents carry the gene, just one in four of their children are likely to turn out to be a redhead. As a result, families that have no redheads for decades can suddenly discover a carrottop in their midst. "Families can carry a variant for generations, and when one carrier has children with another carrier, a redheaded baby can appear seemingly out of nowhere." Wilson said, as quoted in the Daily Mail. Though there's no scientific evidence that redheads deserve their reputation for having fiery temperaments, some recent reports suggest having red hair is associated with a number of health issues. A study from the journal Nature found that the pigment pheomelanin, which is responsible for red hair, may also make redheads even more susceptible to melanoma than fair-skinned blondes, according to the Los Angeles Times. And a widely reported study from the Journal of the American Dentistry Association found that redheads are more sensitive to pain and require extra anesthesia during surgery, according to ABC News. But there may be some advantages to having red hair, too, EverydayHealth.com reports. The pale skin that redheads usually have is more efficient at soaking up sunlight — and sunlight is required for the body to manufacture vitamin D, an essential nutrient. Worldwide, red hair is quite rare, and just over 0.5 percent, or one in 200 people, are redheads — this amounts to almost 40 million people, the Daily Mail reports. In Ireland, an estimated 10 percent of the population has red hair, though about 40 percent of the Irish carry the recessive gene. In Scotland and England, 13 percent and 6 percent, respectively, are redheaded, according to the Daily Mail. The DNA test will be offered by BritainsDNA at a genealogy and ancestry exhibition named Who Do You Think You Are, associated with the popular NBC television show and scheduled to be held in London next month. Follow LiveScience on Twitter @livescience. We're also on Facebook & Google+. Marc Lallanilla has been a science writer and health editor at About.com and a producer with ABCNews.com. His freelance writing has appeared in the Los Angeles Times and TheWeek.com. Marc has a Master's degree in environmental planning from the University of California, Berkeley, and an undergraduate degree from the University of Texas at Austin. Worldwide, red hair is quite rare. And a lot of people wonder about the chances that their children will be in that group! We do know quite a lot about how red hair is inherited – but some of the details still need to be figured out! We will start with a mostly-true answer first, and then we can get into more complex details. Redhead basicsAs you might have heard, you inherit genetic information from each of your parents. And then you will pass your genetic information to your children. Your genetic information, or DNA, is organized into small pieces called genes. Genes have the instructions to make you who you are, including your hair color! Genes come in different versions, called alleles. So let’s imagine that there’s one gene that controls hair color. The different alleles of this gene could be “brown hair”, “blonde hair” and “red hair”. If you have the brown allele of the gene, you have brown hair. If you have the blond allele, you have blonde hair. And if you have the red allele, you have red hair. But it’s not so simple - you don’t only have ONE allele for each gene. You actually have two: one from your mom and one from your dad. They could both be for the same hair color… or they might be for two different colors. It may seem obvious that if you have two brown hair alleles you will have brown hair. But what if you have “brown DNA” plus “blonde DNA”? Or brown plus red, or blonde plus red? It turns out that brown hair DNA is stronger than the other colors. You only need one brown allele to have brown hair. It is a dominant trait. The DNA for blonde or red hair is not as strong as brown. In order to have blonde hair, both of your alleles need to be blonde. The same is true for red hair. These are recessive traits. The DNA for blonde hair and red hair are about equally strong. People who have DNA for both often have strawberry blonde hair. Putting it all together you get:
So what does that all mean for your chances of having a red-headed child? Since you need two pieces of “red hair” DNA to have red hair, your child will only have red hair if they receive “red hair” DNA from both parents. Even if you don’t have red hair, you can still pass on a red hair allele to your child! Since red hair is recessive, you could carry instructions for making red hair hidden in your DNA. Someone like that is called a carrier for red hair. Since carriers don’t actually have red hair, it’s hard to know if you are one. But if you know you have redheads in your family, it’s quite possible you have hidden redhead DNA! Following this pattern of inheritance, you can have a redheaded child given 3 different scenarios: 1. Both you and your partner have red hair = 100% chance of having a redheaded child 2. One parent has red hair and the other one doesn’t, but secretly carries the red hair allele = 50% chance of having a redheaded child 3. You and your partner don’t have red hair, but you both carry the red hair allele = 25% chance of having a redheaded child It’s complicated!For the most part, the way hair colors are passed down matches my explanation above. However, the story isn’t quite so simple. As with pretty much everything in genetics, the “rules” are often broken! It turns out there isn’t just one gene that controls hair color. Your hair gets its color from a type of pigment, called melanin. You have two types of melanin in your hair: eumelanin and pheomelanin. Eumelanin is a brown pigment. It colors hair and skin shades of brown and is responsible for skin tanning. On the other hand, pheomelanin has a reddish color and is present in the lips, nipples and genitals. All humans have small amounts of pheomelanin in their hair. But if there’s a lot of eumelanin, the brown pigment drowns out any red color. However, if someone has very little to no eumelanin, their hair appears red. The lack of eumelanin also causes fair skin. As you might have noticed, there are different shades of red hair. It all depends on the combination of eumelanin and pheomelanin that each redheaded person has! And what controls how much of each type of melanin your body makes? Multiple different genes are in charge of working together to give you your specific hair and skin color. In fact, skin and hair color depend on a bunch of different genes working together. There are dozens of genes that are known to affect hair color, and hundreds of genes for skin color. And we surely even have more to discover! If that wasn’t enough, there are some external factors that can change the way genes work. For example, hormones can cause blonde hair to get darker as children get older. Some other factors can lead the hair color to fade, including stress, sunlight, smoking, a poor diet… All of that means that even if two people have the exact same combination of multiple genes … they might still have different color hair. In conclusion…Hair color genetics is surprisingly complicated! There are a lot of different genes that impact hair color, plus a lot of non-genetic factors. Scientists are still looking into the genetics of hair color, so I am sure we will have more definite answers in the near future! How do you know if you have a redhead gene?The test will scan each parent's DNA for signs of the so-called MC1R gene that causes redheadedness. "Through a simple saliva test to determine deep ancestry, we can … identify whether an individual is a carrier of any of the three common redhead variants in the gene MC1R," said Dr.
Which parent determines red hair?In order to be a redhead, a baby needs two copies of the red hair gene (a mutation of the MC1R gene) because it is recessive. This means if neither parent is ginger, they both need to carry the gene and pass it on — and even then they will have just a 25% chance of the child turning out to be a redhead.
Does everyone carry the red hair gene?Previous studies had shown that redheads inherit two versions of the MC1R gene that leads to red hair – one from their mum and one from their dad. 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.
Can I test for red hair gene?23andMe's Health + Ancestry Service can tell you more about the genetic roots of your hair color. Get the kit, spit, and see what your genes have to say about red hair.
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How to know if you carry the red hair gene
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