Rasmus Nielsen

The paper on the Denisovan origin of one of the key altitude-adaptation genes (EPAS1) in Tibetans is now out (lead author Emilia Huerta-Sanchez,  senior author Rasmus Nielsen).

It’s on a Denisovan haplotype.   Likely Denisovans occupied a lot of East Asia, and quite a bit of that area is fairly high altitude, not just Tibet.  We have evidence that East Asians have a bit of Denisovan ancestry,  and a small amount of admixture is all it takes to pick up a highly advantageous variant.

Denisovans were probably in Asia for at least a couple of hundred thousand years, much longer than anatomically modern humans.  Homo erectus and descendants were there a good deal earlier, and this variant might have originated that far back, although it may not be divergent enough for that to be plausible.

Here’s what Rasmus Nielsen said about this discovery:

“It was a complete surprise,” says Nielsen. “It took years after the Denisovan genome was published for us to even try this, because we thought it was so far-fetched.

Which is strange, because it was quite obvious. Not just in the sense that I told y’all about it over and over, wrote an article with Hawks on it in 2006, and mentioned it in our book – clearly I should have gone ahead with the fiery-letters-in-the-sky approach.  Let me tell you about a conversation I once had with Jim Crow, maybe ten years ago.  I was saying that adaptive introgession from Neanderthals was likely, and he mentioned once hearing someone say that although there might have been a bit of admixture with Neanderthals, it would have been biologically insignificant.  He heard that and thought “No!”; he knew that even a few copies of an adaptive variant would likely rise to high frequency.  He never wrote it up for the Neanderthal case, but he knew.

Of course it was also likely because the Tibetan adaptations are too damn good – different from the Andean ones, more like those seen in mammalian species that have lived at high altitude for a long time. Which Nielsen should have noted. Which is why the Ethiopian adaptations, some of them anyhow, surely have pre-modern-human origins – unless anatomically modern humans originated up on that plateau.  Which I doubt.

This may sound as if I think Nielsen is dumb, but I don’t.  He was wrong, but not dumb: I don’t pretend to know what screwed up his thinking on this issue. One could always blame Ernst Mayr.

On the other hand, I can think of a couple of fairly well-known players in this business who really don’t seem to understand much of anything.  I’ll  let you guess who they are.

 

 

 

 

 

Advertisements
This entry was posted in Altitude adaptations, Denisovans, Genetics. Bookmark the permalink.

22 Responses to Rasmus Nielsen

  1. Fun to see Nature limping years behind West Hunter. “a small amount of admixture is all it takes to pick up a highly advantageous variant.” Perhaps that, rather than archaic human influences, is the finding some people find hardest to stomach. It would explain why some groups are very different from others.

  2. Here is a pretty good account in the Daily Mail about the research. Yes, they don’t nail the less good Andean adaptation, but I think they have done a good job for a general audience, and the “super athlete” gene is a useful shorthand.

    http://www.dailymail.co.uk/sciencetech/article-2678547/The-fastest-mutation-history-Super-athlete-gene-lets-Tibetans-live-high-altitude-evolved-just-3-000-years.html

    • Patrick Boyle: many thanks for great story. Once met a musician who had been assessed by von Karajan. A line of violinists queued to stand onstage before the Master. He would randomly give a composer’s name and number of the piece and listen attentively for a minute, then say Next. The musician said the experience was worth the plane fare.

  3. I want to know who the “couple of fairly well-known players in this business who really don’t seem to understand much of anything” are. Can anyone hazard a guess?

  4. craigferling@gmail.com says:

    I’ve read that there are some similarities between the Tibetan and Andean altitude adaption. Is this dues to shared Denisovan ancestry? Are the Andean populations just not as far along the same path of adaption as the Tibetans?

    I think the settled area of the Ethiopian Highlands are slightly lower, so the adaption may not be as strong, but the population has been there longer..

    I’m very curious if there has ever been offspring from the result of mixed Tibetan / Andean / Ethiopian relationships.. Would the effectiveness of the adaptions be enhanced, or not?

    • gcochran9 says:

      Not that similar, and the Tibetan strategy is more effective.

      mixed Tibetan / Andean / Ethiopian relationships? probably never happened. I’m sure that a number of interesting possible mixes have never occurred.

      • Kate says:

        “a number of interesting possible mixes”

        mm I love those.

        I worked with a man who had South Asian-East Asian parents, he was about 6′ 4″ and broad.

        I watched Coast Australia last night, apparently there are 50 ethnic mixes in Darwin – Aboriginal – European and a host of ethnicities from the Makassan sea-cucumber trade with islands to the north.
        [13 days left to watch (in the UK). http://www.bbc.co.uk/programmes/b0444s5m%5D

        The History of Makassan Trepang Fishing and Trade
        http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0011346

        And I once met a woman with a Malaysian mother and Ghanaian father. So I said hello to her in Twi because it was on my interview sheet and she was very surprised because she had no idea what Twi was.

        Not much help!

      • The fourth doorman of the apocalypse says:

        I watched Coast Australia last night, apparently there are 50 ethnic mixes in Darwin – Aboriginal – European and a host of ethnicities from the Makassan sea-cucumber trade with islands to the north.

        I wonder how they count them? When I lived there there were Greeks, Italians, Chinese, white Australians, Aboriginals, some Malay/Indonesian and mixes of all those, but fifty sounds too many, unless you count every different Aboriginal tribe …

    • Kate says:

      Sure, how long’s a piece of string. What struck me as interesting is that the chap they spoke to was most interested in his Aboriginal ancestry – that’s the one he ‘felt’. Being somewhat cynical about ‘ethnic pride’ I put that down to Aboriginals having some of the most interesting cultural ideas, like sand-painting and dreamtime. I have a book of Aboriginal art given to me as a child and I think I ‘feel’ a bit Aboriginal too.

  5. Greying Wanderer says:

    neat prediction

  6. I think that the advantages of mixing Andeans with Tibetans have already been proposed by our far seeing host.

  7. Unladen Swallow says:

    This post just reminded me of something I thought of when the Denisovans were first announced: Do we know that the Denisovans were not Homo Erectus or Homo Heidelbergensis or some regional variant thereof, In other words are they a hominid species we are already aware of?

  8. David Benson says:

    In other words are they a hominid species we are already aware of?

    Very likely. If they were a different species of archaic hominids, where are the tools? You generally find a lot more tools than bones, and yet we have turned up nothing which has not already been assigned to Homo Erectus or Neanderthals.

    • The fourth doorman of the apocalypse says:

      It seems quite possible that they had the same mental toolkit and yet were reproductively isolated.

      • harpend says:

        Time for another hard look at Movius’ line?

      • The fourth doorman of the apocalypse says:

        Clearly, reproductive isolation was not achieved, since we seem to have picked up useful genes from them …

        On reflection, and after looking at the suggestion of the Movius Line that there might have been genetically modulated differences in mental toolkits … and in different regions they could have developed local adaptations to their environments.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s