Not Just Your Ordinary Lizard: The Unique Genome of the Tuatara

Dinosaurs rose and fell, but one foot-long scaly creature persisted. The tuatara is the last remaining species of an ancient group of reptiles that diverged from lizards and snakes 250 million years ago. Once a common global species, the tuatara now only survives on 32 offshore island reserves in New Zealand (Aotearoa). Recently, the first tuatara genome was sequenced, unlocking insights into the evolution of other reptiles, birds, dinosaurs, and even our own mammalian lineage.

Although tuataras may resemble an ordinary lizard, they can live over a century and tolerate colder temperatures. Researchers found that the tuatara genome is composed of 36 chromosomes and is approximately 5 billion base pairs in length, making it one of the largest vertebrate genomes ever sequenced. Through phylogenetic analyses, an approach that compares similarities between genomes, geneticists found the tuatara genome has highly repetitive sequences that are usually only found in mammals. Moreover, scientists identified changes in genes, as compared to those of other reptiles, that are implicated in the maintenance of body temperature. These findings further cement that the tuatara is unlike any other living animal on this planet.

Saving the last species of this once abundant reptilian family is important for continuing to unlock the secrets of this living fossil. Habitat loss, predation by invasive species, and climate change have led to the tuatara to become endangered. But now, with the tuatara genome in hand, conservation biologists hope to determine best practices to avoid in-breeding and identify changes in different island populations. Moreover, the tuatara is a taonga, a cultural treasure, to the indigenous Māori people.  As a result, the Ngātiwai tribe, the kaitiaki (guardians) of the tuatara, were intimately involved in the decision-making process regarding how the genetic data would be used. This partnership, bridging conservation, research, and indigenous knowledge, is one of the first of its kind and serves as a blueprint for future genetic studies rooted in respect.

Managing Correspondent: Olivia Foster Rhoades

Press Article: How tuatara live so long and can withstand cool weather

Original Scientific Article: The tuatara genome reveals ancient features of amniote evolution

Image Credit: Wikimedia Commons