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If you use the internet, you may have read about a nutritional study about the deadliness of fried potatoes. It's a little more complex than that, though. Even if you haven't heard of that one, we're pretty sure you've heard of the internet's favorite subject: cats.

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If you’re a cat owner, or even just a lover of cat videos, you might have wondered how these cuddly creatures came to be.

Like, why’s little Fluffy happy to sit on your lap, and not tearing you to shreds with its claws? Most of what we know about cat domestication has come from one-off studies.

But this week, scientists reported the first large-scale paleogenetic study of cats in the journal Nature Ecology and Evolution. By analyzing the ancient DNA in hundreds of cat mummies and other archaeological finds like bones and teeth, researchers now have a better sense of how these animals evolved and spread around the globe. The modern domesticated cat isn’t all that different from a wildcat, especially the subspecies Felis silvestris lybica.

In fact, the two still breed, complicating things for researchers. The study found that our pet cats, though, can trace their history back 9,000 years and to 5 lineages of silvestris lybica. But the two big players are from the Near East and Egypt.

Domesticated cats first got started in the Fertile Crescent, the area of the Middle East where plants could actually grow and farming began. Here, cats kept rodents in check and out of grain stores. By at least 4400 B.

C., these mice-killers made it to Europe, probably because the word spread about their helpfulness. But when you think cat and ancient civilization, you might think Egypt. And these scientists suspect that the Egyptian cat had evolved to be more cozy with humans, making it another favorite.

Most of the cats the researchers sampled from western Turkey in the first millennium were from the Egyptian lineage. By the 700s, Egyptian kitties had even made it to a Viking port on the Baltic Sea. As time passed, other lineages got into the mix.

Cats from Asia popped up in Turkey, possibly through the Silk Road. And the Near East cats landed in East Africa, likely as first century seafarers. This study also suggests that, for most of cat history, people didn’t care about the appearance of their animals so long as they caught mice and didn’t bite.

It revealed that tabby markings—the blotches on some house cats—didn’t come along until the Middle Ages. Before then, all domesticated cats likely looked like wildcats and had more defined stripes. Looks aside, our kitty companions flourished and ended up on every continent except Antarctica.

And of course, they own about half of the internet. That other half—at least this week—was about killer fried potatoes. You may have seen the headlines warning you to put down the french fries, because of a paper in the American Journal of Clinical Nutrition earlier this month.

The study found that people who eat fried potatoes, like french fries or potato chips, two or more times a week were twice as likely to die as those indulging just once a month. Which is … a bold claim. Fried potatoes aren’t the healthiest foods.

But, to set the record straight, the study’s not saying that fried potatoes are going to kill you. To dig up this dirt on potatoes, the researchers actually piggybacked on another, totally unrelated study about knee osteoarthritis called the Osteoarthritis Initiative. Participants had reported the types of food they usually eat as part of the data collection.

And the study has been running for eight years, during which some people died. That meant these nutritionists could mine the data for interesting correlations between food and death. They didn’t find any effect on mortality by all potatoes, but when the statisticians looked at fried potatoes as a sub-category … wham!

That’s where the ‘twice as likely to die’ comes from. Before you panic, there are a couple of things to keep in mind here—and they’re true for a lot of nutritional studies. For one, the amount of potatoes people ate was self-reported, just once over the 8 years.

And do you have any idea how many potatoes you ate last November? Memories aren’t always accurate … or people might not admit to eating a whole bag of potato chips every week. All of these folks also had, or were at-risk for, arthritis in their knees.

So it’s not a given that these findings would translate to everyone. And because this is just a correlation, something besides fried potatoes could be at fault. Someone who eats lots of fries, for instance, might also eat lots of burgers.

Or they might not make it to the gym that often. The scientists tried to control for as many factors like these as they could, but you can never account for everything. So, are fried potatoes stone-cold killers?

The idea is plausible … They’re usually loaded with fat and salt, which could put you at higher risk for obesity, diabetes, and cardiovascular disease. But the reality is that this study can’t tell us for sure, which is pretty typical of nutrition studies. Usually, they just end up finding possible links, and then it’s up to researchers to follow up and see which ones might be real.

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