The Tuatara Genome Project

July 10, 2013 • 6:35 am

by Greg Mayer

We’ve had occasion to celebrate the completion of reptile genome projects before here at WEIT (including the first, the Anole Genome, and the recent turtle genomes), so it is especially notable that one of our favorite animals, the Earth’s Only Extant Non-Squamate Lepidosaur*, is now the subject on an ongoing sequencing project being led by Neil Gemmell of Otago University and the Allan Wilson Center for Molecular Ecology and Evolution (whose director is my old chum and fellow MCZ alum, Hamish Spencer). It is of course fitting that the genome project be based in the iconic animal’s native land, New Zealand. David Winter has begun a blog, Sequencing the Tuatara Genome, to document the project’s progress.

Why sequence the tuatara genome (other than just because they’re, you know, great)? This picture from David’s blog, should tell you. (BTW, back when the Anole Genome was completed, a reader asked, “What are the gaping holes in our genomic knowledge?”, and I presciently replied “Among tetrapods, the gaping holes are the tuatara,…”.)

Phylogeny of relationships of the tuatara, from David Winter's Sequencing the Tuatara Genome Project.
Phylogeny of relationships of the tuatara, from David Winter’s Sequencing the Tuatara Genome blog.

If it’s not clear, David spells it out (note that he uses the proper Maori “tuatara are“):

You sometimes hear people mistakenly call tuatara “living dinosaurs”.  In fact, as you can see in the figure above, tuatara are much more interesting than that. If you want to study a living dinosaur you only need to look out the nearest window. Modern birds descend from one branch in the diverse group we call dinosaurs, but each of those ten thousand species are dinosaurs. The tuatara, on the other hand, are the only living members of a lineage that separated from other reptiles more than 200 million years ago.

By placing modern organisms in the context of their evolutionary history, we can work out which traits were present in ancestral species, and reconstruct the changes that gave rise to modern ones. As the tuatara is the only living witness to hundreds of millions of years of evolution, its genome sequence will be immensely valuable in understanding the genetic changes that have allowed reptiles to evolve and diversify.

I urge you all to go take a look at David’s blog now, and check back in there now and again to see how things are progressing.

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* I was going to say the Universe’s Only Extant Non-Squamate Lepidosaur, but I can’t quite rule out that some Vulcan survey craft, while cruising nearby waiting for Zefram Cochrane to release a warp signature, might not have decided to stop by for a bit and then taken some non-squamate lepidosaurs home (I know I would have).

31 thoughts on “The Tuatara Genome Project

  1. One thing I don’t remember from previous discussions…prior to DNA sequencing, how did we figure out that what just looks like a typical lizard is hanging out there on an odd twig on the evolutionary tree?

    b&

  2. Technically, though, there are two species of tuatara: Sphenodon punctatus and Sphenodon guntheri. The latter is endemic to North Brother Island in Cook Straight.

    1. Hi dhillis2,

      As greg says – the two species where sunk back to one in 2010. We are going to have a post about this hopefully next week, but the WEIT post sums up the research nicely.

      Having a draft genome will hopefully let us do some re-sequencing projects and get a good grip on the degree to which the remaining populations have distinct histories.

  3. I want to know how they put dinosaurs where they did, with no DNA to guide them.

    Unless Jurassic Park is real.

      1. Yes, but that’s not genetic analysis, then, is it?

        That’s a problem. I know you can say “well, the anatomy blah blah blah and all that”, but it’s supposed to be a genetic analysis.

        Isn’t. It’s guessing.

        1. What’s supposed to be a genetic analysis? And why should morphological analysis be equated with guessing?

        2. The visual says phylogeny, not genetic analysis.

          Classifying phyla by morphology of fossil remains isn’t guessing. It’s how most of the phylogenetic trees we use today were developed.

        3. Hi Kevin,

          The figure isn’t the result of a particular analysis – it’s a summary of the knowledge that we’ve gathered from many, many studies including those using genetic and morphological data.

          The relationship between birds and dinosaurs is supported by a bit more than a guess 🙂

  4. I love that the Tuatara are getting their genome mapped mostly because tuatara are cute and awesome! The first time I saw one was at Rainbow Springs in New Zealand almost 20 years ago and I’ve loved them ever since! Cute little reptile!

    Loved the Zefram Cochrane reference. 🙂

    1. So did I! First Contact is my favorite Star Trek movie (though I greatly enjoyed Into Darkness this year). I just love when Worf says to Picard: “If you were any other man, I would kill you where you stand.”

    1. Someone has done their mitochondria :

      Podsiadlowski, L.; Braband. A.; Mayer, G. (2008). “The Complete Mitochondrial Genome of the Onychophoran Epiperipatus biolleyi Reveals a Unique Transfer RNA Set and Provides Further Support for the Ecdysozoa Hypothesis”. Molecular Biology and Evolution 25 (1): 42–51. doi:10.1093/molbev/msm223. PMID 17934206.

      http://www.hgsc.bcm.tmc.edu/content/i5k-velvet-worm tells me that another “G Mayer” (or the same one? Probable.) is the “man with a plan” for onchyphore genetics. Most recent data was posted on 21/03/13, so what they’ve been doing for the last 93 years isn’t clear [G].

  5. I’m not Maori, so I’m just going to go ahead and pluralize words in the typical English fashion.

  6. Thanks very much for featuring the blog, Greg. We hope evolution, tuatara and genomics fans all get something out of the posts we publish 🙂

  7. It’s funny. When I was a PhD student in NZ back around 1999-2002 I distinctly recall a PhD student at University of Otago getting in a heck of a lot of trouble with the authorities for doing tuatara sequencing work (“Maori sensitivities”). It blew up in the media, her own institution behaved like cowards and refused to support her, and all of her material was confiscated and destroyed. All records of this happening seem to have been removed from the interwebs, but some vestiges remain. http://web.kuicr.kyoto-u.ac.jp/supp/hiranuka/pub/EGENES/animals/Sphenodon_punctatus/report I guess that scientists are assisted with iwi consultation these days and the project can go ahead with the blessing of Maori. I was stunned at the time both by the attitude of Otago University towards their student, but also because there was nothing in the world to stop researchers from outside of New Zealand sequencing the Tuatara genome and getting all the glory!

    1. and that’s why academic freedom is important and more importantly an example of why the institution itself is usually the greatest threat to that freedom.

  8. Non squamate lepidosaurs don’t need aliens to survive. Some could develop advanced technology and fly to space when the Triassic-Jurassic extinction hit the Earth. In the other scenario, they might still be living. Maybe somewhere deep in the unexplored parts of New Guinea. I believe, as New Guinea is near Australia that had preserved many ancient forms, that somewhere in the deep forests or mountains of the country there might be living fossils waiting discovery. Other non squamate lepidosaurs, land crocodiles, meiolaniid turtles, or even premammalian synapsids.

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