7 Fascinating Genetic Traits, And Where They Originate From In The World

If you've ever wondered why you have red hair, or why everyone in your family is lactose intolerant, then you might find it interesting to trace your family's history with a genetic testing kit such as 23andMe. These types of tests can help you uncover the genetic secrets of your past. Or, at the very least, tell you a bit more about the genetic traits associated with your ancestry.

"Essentially what happens is you receive a kit, and it is a 'spit kit,' so you just provide a saliva sample. You mail that off to our labs and the lab will analyze the DNA that’s found in your saliva," Alisa Lehman, Senior Product Scientist at 23andMe, tells Bustle. And that's when the fun begins.

"When we get that DNA information back, what we can do is analyze it and see how that might link and predispose you to certain traits," Lehman says. "What we have currently in the product is mostly the physical traits, maybe some that might be considered behavioral. So, for example, we have trigger points that tell you whether you’re more likely to have either blue eyes versus brown eyes, a cleft chin versus not having a cleft chin. We also have ... a sweet versus salty report. That report tells you basically whether you’re predisposed to prefer sweet snacks versus salty snacks."

It's important to remember, though, that just because your ancestors were from a certain part of the world doesn't mean you're guaranteed to have the traits common to that region. "We cover a lot of those [genetic] variants, but we can never capture everything," Lehman says. "Just because you’re more likely to have something doesn’t necessarily mean that it’ll be true for you. So just because you’re more likely to have a cleft chin or more likely to be lactose intolerant doesn’t necessarily mean that’s the way it’s going to work out." Here are a few behavioral and physical traits associated with certain parts of the world, according to 23andMe.

1Lactose Intolerance

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If you can trace your roots to Northern Europe, there's a good chance you have an easy time digesting dairy products. "It’s not a physical trait, but we have a lactose intolerance report and that draws a similar line where the genetics that make you less likely to be lactose intolerant — that you can digest dairy — [are] much more commonly found in Northern Europeans," Lehman says. "So people who are of more Northern European descent tend to be able to indulge in ice cream and cheese and dairy. That one [has a] genetic and geographic connection."

23andMe also found a trend that suggests folks from East Asia, on the other hand, might not have as easy a time. "East Asia and China tend to have much, much lower rates of being able to digest dairy, so higher rates of intolerance to lactose," Lehman says. Pretty interesting, right?

2Preference For Sweet Foods

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Another trait that 23andMe is looking into is peoples' preference for salty and sweet foods. And, as with their other data, the team figures this out by interviewing research participants.

As Lehman says, "We have an internal research program in the company that customers can consent to participate in research, and they will answer questions like 'Do you prefer sweet snacks? Do you prefer salty snacks?' ... And with that information we can then link up genetic variants that we might see in peoples’ DNA that are more commonly found with people who prefer sweet or prefer salty."

If any ethnicity prefers sugary snacks, it tends to be Europeans. But, of course, that's not true for everyone. As Lehman says, "as far as sweet preferences ... people of European decent [are] pretty split between preferring sweet and preferring salty."

3Preference For Salty Foods

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On the other side of the world, salty foods tend to reign supreme. "For reasons we don’t totally understand, people of East Asian descent tend to have a stronger preference towards preferring salty," Lehman says. "So we do see a little bit of that in their DNA."

4Red Hair

Hannah Burton/Bustle

If red hair runs in your family, there's a good chance you have a family history linking back to Europe, where red hair variants are most commonly found. "The red hair variants that we look at tend to be ... found in more European populations," Lehman says. But what's even more interesting, is that 23andMe has been able to trace these variants back to when they first showed up in humans.

"They seem to have showed up right around the time when people were leaving Africa," she says. "So they appeared in humans when humans had already made it to Europe."

5Freckles

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Along with red hair, 23andMe has been able to trace the history of freckly skin to see where this trait is most commonly from. "[We have seen freckles] more commonly in people of Northern European descent," Lehman says.

And here's why: "Some of the genetic variants we've found that are associated with having freckles are near genes that we know play a role in skin color, eye color, and hair color," she says. "So it's possible that genetic variants that make people of European descent more likely to have lighter skin also make them more likely to have freckles. It is also possible that freckles are just more prominent in people with lighter skin tones." Of course, you don't have to be Northern European to have freckles, but it is a trend 23andMe has noticed.

6Dark Eyes

Ashley Batz/Bustle

You might think eye color is pretty intuitive, depending on where your family is from. But the science behind it is actually pretty interesting. "Eye color is an interesting report that we have," Lehman says. While it can't be broken down to specific countries just yet, the test can predict eye color based on region. And, as Lehman says, they see a trend of darker colored eyes being more prevalent or more common in people of African or East Asian descent. "So for that, we are able to look at generally … large regions, so East Asian versus African, not subregions within that," Lehman says. "We are able to see the prevalence of ... how often certain genetic variants are found in certain populations."

Of course, dark eyes aren't exclusive to these regions, but this is just something 23andMe has found in their research.

7Light Eyes

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On the flip side, light eyes are more commonly found in people of European descent, Lehman tells Bustle, though they can be seen in other places too. But information about traits like these are really just the tip of the proverbial iceberg.

As research continues, 23andMe hopes to gather information about other, less obvious traits. "Something we’re interested in is moving towards some of those traits that you can’t see, so getting more towards things like sweet and salty, things that you might know about yourself but you might not know about other people," Lehman says. "Anything that falls in that realm that’s not visible. I think it’s really interesting to see how the genetics might push you one way the other."

While certain genetic predispositions like eye color may seem obvious, there is still so much to uncover about the types of traits we have in our DNA.