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,…”.)
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.
* 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).