Tibetan mastiff

tibetan-mastiff

The Tibetan Mastiff can take high altitude better than generic dogs, or so breedists would like you to think. Some of the genetics changes are similar to those seen in human Tibetans – regulatory changes in EPAS1, for example. Domesticated dogs haven’t lived in Tibet all that long – but wolves have. The Tibetan Mastiff picked up some of those useful variants from local wolves, even though the amount of admixture wasn’t large. Adaptive introgression, just as Tibetans seem to have acquired their high-altitude version of EPAS1 from Denisovans.

Andean Indians didn’t have any archaic humans around to steal adaptations from. They have had to develop their own altitude adaptations (in a relatively short time), and they aren’t as effective as the Tibetan adaptations.

Naturally you are now worrying about sad Inca puppies – did they suffer from hypoxia? There are canids in South America, like the maned wolf and the bush dog, but they are probably too divergent to be able to hybridize with dogs. The chromosomes are different, so pre-Columbian dogs probably couldn’t acquire their alleles. Moreover, the dogs of the Amerindians seem to have done poorly in competition with Eurasian dogs: I know of only a few breeds [the Carolina Dog, for example] that are known to have significant pre-Columbian ancestry. Perhaps Amerindian dogs were also scythed down by Eurasian diseases.

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30 Responses to Tibetan mastiff

  1. MawBTS says:

    Perhaps Amerindian dogs were also scythed down by Eurasian diseases.

    I’ve always wondered: what happened to plants and animals in the Columbian exchange, epidemiologically speaking?

    The Native American population shrank by half in a short period of time, and disease is usually blamed. Is there evidence of similar pandemics ravaging North America’s flora and fauna? Any mass die-offs of bison and white-tailed deer? Any problems trying to grow indigenous crops like potatoes (bearing in mind that potato blight is a New World disease)?

    • ursiform says:

      There is some evidence bison populations rose as the Plains Indians died. (Although they were later decimated, but by guns, not germs.)

      You’d only expect pandemics to occur where similar species were brought into the Western Hemisphere, and there weren’t a lot. Native horses were already gone before Columbus. European bovine didn’t seem to do much, at least not compared to bullets. Deer weren’t imported.

      “We” did eventually export phylloxera, which trashed vineyards in Europe.

    • Humans went through bottleneck to populate Americas, and they brought only one domestic animal, the dog. Everything else they domesticated in-place did not suffer from low genetic diversity.

      • ohwilleke says:

        Good point on low genetic diversity. Incidentally, the success of some Mayan/Aztec ritual and medical practices, IIRC, is attributed to low genetic diversity and high frequency of blood type O.

      • Matt says:

        I still wonder if the Americans had problems from their genome having low diversity, or more that they’d lost a lot of diseases and didn’t have a reservoir to pick them up from.

        That relaxes the selection pressure a lot and leaves them prey for Eurasian diseases when reintroduced.

        I’m a skeptic on genetic bottlenecks causing genetic f***edupness though, generally.

        As for the Bison, yes, Ice Age Bison populations ranged through the Americas to the Eurasian steppe. Should be a competitive species.

        • Reziac says:

          “Low genetic diversity means trouble” sounds like a great theory on paper, but there have been a number of studies of isolated, bottlenecked populations that showed zero deterioration. One case I recall offhand involved wolves on an island, all known to be descended from a single female. Further, DNA analysis of a broad spectrum of wild species found average coefficient of inbreeding was 0.25 (which was to be expected; do you really think that bull elk cares that he’s breeding his own daughters?) — basically the same effect as a bottleneck. — This is a much higher degree of inbreeding than in any domesticated species; the difference is that in wild animals, natural selection does its job.

    • ohwilleke says:

      One of the biggest ecological impacts allegedly came from the introduction of the Old World Earthworm. In its absence leaf litter accumulated into mass piles in New World forests and once the earthworm was introduced, this was rapidly eaten away.

      There weren’t all that many Old World fauna species introduced early, with dogs and cats probably among the most ecologically significant. Nobody brought Old World bison or deer, and the deaths of the Native Americans, as noted, reduced predation and allowed them to see a population surge.

      Domestic cats were a huge source of species destruction most places they were first introduced, but wild cats seem to have been one of the most successful forms of New World fauna in the face of an otherwise general megafauna extinction at first contact with Native Americans (perhaps because they thrived in jungles to which humans are not very well suited).

      As a result some of the effects of Old World fauna introduction are still in the process of being told. The recent introduction of Old World pythons to the Everglades has had a major ecological impact there.

    • Farmer Brown says:

      Franklinia alatamaha, maybe. It’s believed this species is vulnerable to a disease of cotton, which may be responsible for its extirpation in the wild. All remaining trees seem to be descendants of a collection made in the late 1700s.

      The slow decline of the Black (American) mulberry and its replacement by the White may be tied to diseases to which the White is resistant. This process probably didn’t get started until the 1800s.

      Somewhat afterwards, you’ve got Chestnut blight, which has nearly exterminated the American chestnut.

  2. st says:

    There are claims that atmosferic oxigen levels in the megapolises and cities of the western world are currently lower than oxigen levels in Tibet – as low as 12% in some cases (versus 21% which H.S. is supposedly adaptet to, except Tibetian people and tibetian dogs) – https://www.theguardian.com/commentisfree/2008/aug/13/carbonemissions.climatechange
    Do you think this (cerebral hypoxia), if true might account for what you often reffer to in this blog as “crazy” and “nuttines” in part of the western population?

    • gkai says:

      I have to read the link, but this claim (oxygen level decreasing from 21 to 12% since the industrial revolution) is completely nuts (that being in inner cities, cities, or anywhere considered an habitable place). For one, there is no way one have released enough carbon to achieve that. And then, no way this would have be unnoticed by the fauna, human and other animals….people will not stay in a place with 12% oxygen, not even for 1h.

      • amac78 says:

        I followed the link. Peter Tatchell found some fools to interview, and added fuel to his Oxygen Crisis with out-of-context quotes of non-nuts scientists. I don’t know if innumeracy and ignorance are prerequisites for employment at the Guardian, but Mr. Tatchell makes a strong case for that proposition.

        • Jim says:

          It is mind boggling that someone who presumably has a college education could believe that the oxygen level in some cities is 50% below the general level.

    • et.cetera says:

      gkai already pointed it out, but it bares repeating: Ervin Laszlo is bonkers. Really bonkers.
      That claim comes from one of his esoteric-environmentalist books “Macroshift”. His other masterpieces include “Science and the Akashic Field: An Integral Theory of Everything”, and “The Self-Actualising Cosmos: The Akasha Revolution in Science and Human Consciousness”.

      The titles give away exactly what you would expect.

      • st says:

        No need to panic, you are probably right – oxygen has been decreasing but at a much slower rate than Guardian wants us to believe (http://scrippso2.ucsd.edu/), so the Tibetans won’t inherit the Earth from us due to their superior adaptation to hypoxia, as I have been suspecting after reading D-r’s Cochran’s peace on Tibetian Mastiffs, so, back to Tibet:
        -D-r Cochran, do you think that the changes in EPAS1 in Tibetans has anything to do with their excessive abilities to meditate for prolonged periods of time or to go into states of semiletargy for weeks or months, or to put it another way – their genetic adaptations have made possible their religious practices which include self forced oxygen depletion during deep buddhist meditation that would otherwise damage the physiology of a human being, which lacks the changes in EPAS1 that Tibetans have, uniquely relating Tibetan religion and Tibetan genetics? I mean, if a non Tibetan human being /or a dog lacking the adaptations that have made their religion possible tries to follow it, would not he/she end up half brain dead?

    • Todd says:

      If there are fires and Fire Departments in those cities, they are not at 12% O2.

  3. FlemurFlemur says:

    We’re in “Indian [Navajo] Country” – There are a lot of dogs around that look like the google image search results for “Carolina Dog”, but they’re mostly owned by white people. The Navajos tend to have (mixed) European herding dogs, tho a very common dog in both places looks like the supposed “Carolina dog” about half-way down here, which everyone calls a “heeler” (they like to nip feet and legs … and “herd” cars). There’s one on our back porch right now.

  4. dearieme says:

    Have any dogs evolved around the Dead Sea that are particularly suited to low altitude? Or indeed, to particularly salty water?

  5. TWS says:

    Native dogs have done poorly for the part. Except for husky dogs.

  6. TWS says:

    It struck me that I am missing something. Wouldn’t the first Americans have the same genes as other Asians? Either they were missing some genes Tibetans have or Tibetans have a different admixture or additional admixture events.

    Other than altitude adaption is there other evidence of archaic admixture in Tibetans?

    • Yudi says:

      Few if any other Asian groups aside from the Tibetans have the altitude adaptation allele even now, let alone ~20,000 years ago. Greg has suggested elsewhere that it carries some penalty outside of the mountains, which sounds reasonable (if it allowed for better breathing without any strings attached, why wouldn’t most people have it by now?).

  7. Jamesjw says:

    There are a number of references to little dogs belonging to the Aztecs in the chronicle by the Spanish conquistador Bernal Diaz del Castillo. He says they bred them to eat them.

  8. Reziac says:

    DNA analysis of coyotes found that 26% have some domestic dog DNA — from 2000 years ago. Further, coyotes are not native to most of North America, but rather, followed man across the continent. My own opinion, based on both this data and their often-semi-domesticated behavior, is that coyotes ARE [pre-Columbian] Indian dogs, albeit heavily mixed with native wolves. Carolina dogs are probably a relict population that was sufficiently isolated that they didn’t crossbreed with wolves. (The so-called “endangered red wolf” is just a wolf/coyote hybrid.)

    Incidentally, the black coat gene in wolves came from crossing with domestic dogs, and is associated with a stronger immune system.

    • TWS says:

      Coyotes make awful pets normally and hybrids are worse. They are clearly closely related to dogs and wolves but they just don’t have the submissive juvenile type behavior seen in a domestic.

      Coyotes followed humans north but I don’t think south. They were probably jackal type desert/plains scavengers that were opportunistic and adaptable when it came to humans. They are harder to trap out than wolves cannier around traps and baits. My guess is they just fill the jackal niche and because they are less frightening and dangerous to humans they have learned to surf the space at the edges of human habitation that wolves because of their size and pack behavior cannot.

  9. deuce says:

    The Chihuahua breed has been quite successful (on a purely “pet”/non-working level):
    https://en.wikipedia.org/wiki/Chihuahua_(dog)

    There are two breeds of Amerindian hairless dogs:

    https://en.wikipedia.org/wiki/Mexican_Hairless_Dog
    https://en.wikipedia.org/wiki/Peruvian_Hairless_Dog

    The Peruvian breed, especially, can have a pleasing “Doberman” look to it.

  10. jhurangu says:

    The Mahidant Mastiff/Gaddi Dog are similar to the Tibetan Mastiff and are the most popular dogs in the Indian Mountain regions. Every shepherd and village household has one. Here’s my blog about the same: https://jhurangu.wordpress.com/2017/02/11/the-quintessential-companion-mountain-dog/

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