‘The tuatara is a bizarre animal,” says University of Otago biology professor Neil Gemmell. The only living representative of an ancient order of reptiles, Sphenodon punctatus can function happily with a body temperature as low as 5°C. The gender of hatchlings depends on the temperature at which the eggs are incubated. And although tuatara look like lizards, they share some aspects of their physiology with turtles and crocodiles. But it’s more than a biological curiosity. “The tuatara is a linchpin in vertebrate evolution,” says Gemmell. “It seems to have remained relatively unchanged, based on the fossil record, for close to 200 million years.” This means the tuatara was around while early dinosaurs walked the Earth and millions of years before the earliest mammals emerged. This evolutionary importance, combined with its cultural significance to New Zealanders, means the tuatara is one of 100 pilot species – along with the giant panda, great white shark and bald eagle – chosen to have its genome sequenced as part of an ambitious international project.
The aim of Genome 10K is to create a “genomic zoo” – a collection of DNA sequences representing the genomes of 10,000 vertebrates, the group of animals that includes fish, mammals, birds, reptiles and amphibians. New genome-sequencing technology is making it possible. Gemmell thinks they could get all 10,000 genomes sequenced within five years, then start on the rest of the 66,000 known species of vertebrates. The tuatara genome is being sequenced in collaboration with Ngatiwai Iwi, at the Otago node of New Zealand Genomics, with funding from the Allan Wilson Centre for Molecular Ecology and Evolution and Illumina. Sequencing the tuatara genome will help us understand the origin of modern vertebrates – humans included. “By sequencing tuatara, we are effectively putting a stake in the ground on what the genome of the ancestor of modern lizards, birds and mammals may have been like,” says Gemmell. It will also help biologists understand some of the weirder things about tuatara physiology. Why do they live so long? Why is their gender temperature-dependent? There are questions about immunity, too. Tuatara appear to be resistant to various microbes, suggesting they have some form of intrinsic immunity. What we know about the tuatara genome so far is contained on two large hard disks in Gemmell’s office. By the end of next year, he and his team hope to have the first answers to the pressing questions about this bizarre animal. ¬
Snails’ Love Lives and Other Stories
A blog post by Dunedin-based Sciblogger and evolutionary biologist David Winter (below) is one of more than 50 pieces featured in The Best Science Writing Online 2012, published this month. Winter rarely writes about his own research area – in his blog, the Atavism, he is more likely to be applying his sceptical mind to the likes of Ken Ring’s earthquake predictions – but the selected writing was about Pacific land snails, the subject of Winter’s PhD research. As an evolutionary geneticist, Winter started his research thinking of snails as “little bags of genes that help me answer questions”. But three years of examining them changed his view. “I’m a complete snail fan-boy and I frequently find myself preaching on the wonders of life as a terrestrial mollusc to people whose only mistake was to ask me what I do for a living.” The blog is not just informative about snails – they stab each other with love darts! – and genetics and evolution, it’s a delightful piece of writing. If you can’t wait for the book, you can read Winter’s original blog at goo.gl/M0Rvd.
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