Tibetans, the Tibetan Mastiff, and how sex with strangers made both.
Meet the Tibetan Mastiff.
Holy shit!
No, he's not part rhinoceros. That's all dog, baby!
Tibetan Mastiffs are awesome. No, it's not because they look like a Rottweiler fucked a grizzly bear. And no, it's not just because they're goddamn massive, topping out at 2-and-a-half feet at the shoulder and 160 lbs in weight. It's not even because they live for anywhere between 10 to 14 years, which is incredibly long-lived for such a large-breed dog.
The Tibetan Mastiff is a breed that is native to - you guessed it - Tibet. As a result, it's adapted to cold weather and high altitude, and it's been used for centuries - if not millennia - as a guard dog for herdsmen on the Tibetan Plateau. They're especially good at sleeping all day and then guarding flocks of sheep or goats all night long from wolves, bears, tigers, invading armies - you name it, something's probably scared of it.
A news story came across my desk recently, thanks to my day job, that talked about how the Tibetan Mastiff got its badass nature. A bunch of Chinese evolutionary biologists decided to sequence the dog's genome and compare it to the Tibetan grey wolf - and it turns out that there was some serious interbreeding between wolves and the dog that eventually became the Tibetan Mastiff - and that's the source of its superhuman ability to withstand the cold and the high elevation.
Specifically, there's two particular "genomic hotspots" the researchers found in the dog's DNA where the traits were passed from wolf to proto-Mastiff, and they're at the EPAS1 and HBB loci. Here's where it gets interesting though: the Tibetan Mastiff isn't the only species in the region that inherited its high-altitude hardiness from local inhabitants. The other species:?Tibetans.
I WILL DEVOUR ALL THAT YOU LOVE. Source
Wait, what?
As a subset of the human species, people with Tibetan ancestry are adapted to living at high elevations. That's pretty much common knowledge (and if you didn't know it, now you do). Genetic studies into Tibetan DNA has revealed that they too tend to have high-elevation traits in their genome at the HBB and EPAS1 loci as well. They picked up these traits through interbreeding, just like their dogs.
No, there wasn't one particularly twisted ancient Tibetan that got a little frisky with a grey wolf. There was some cross-species hanky-panky going on back in the day when modern humans migrated into the region, though: there were other people already living there.
Evolution! Like in Pokémon, but with more fucking. Source
People who need people
Okay, they weren't technically "people." They were Denisovans, a breed of archaic humans akin to Neanderthals. Denisovans are thought to be an evolutionary cousin to the Neanderthal that lived roughly at the same time, but just went a different direction when it came to migratory patterns; most Neanderthals stayed in Western Eurasia, while the Denisovans went further East. The ones that settled in the Tibet region adapted to the environment over thousands of years, and when modern humans showed up with their newly-domesticated dogs in tow, both humans and dogs got a nice, warm, wet welcome from the locals.
Like the Neanderthals, the Denisovans eventually died off, probably because they couldn't compete with modern humans for resources. Before they went extinct, though, they passed on enough of their genome to future generations of modern humans to give Tibetans their ability to live in regions comfortably where there's so much less oxygen - and the same genetic interbreeding process gives Tibetan Mastiffs the same ability. And probably the ability to scare the shit out of Tibetan cattle rustlers by blotting out the sun with their massive bulk. Who knew having sex with strangers would be so beneficial?
The funny thing is that Tibetan Mastiffs are incredibly smart, playful, and gentle dogs - especially with children. If I had the space - and the money - I'd totally get one, saddle it up, and send my kid to school on it. Bet you nobody would fuck with her on the playground.
Image taken before they were all eaten. Source
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I'd like to get one too if I had the money.
If I had that kinda money I probably wouldn't spend it on a dog, no matter how awesome it was. Then again, if I had that kinda money I could probably afford the 500 pounds of raw steak a week that the thing probably eats.
Nice post discussing genetics and inheritance. Great job, and looking forward to your future content!
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I bet those three mastiffs weigh more that all those people!
I don't even think those guys are full-grown yet. Dem dogs is big!
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