ASU biologist launches crowdfunding campaign to fund 1st genome sequencing project for this unique reptile
It was her very first encounter with a strangely beautiful orange and black beaded Arizona native, the Gila monster — one of only two venomous lizards in the world — that convinced Melissa Wilson Sayres to divert from her 11-year path of studying mammal genomes.
One of Wilson Sayres’ main interests is in studying sex chromosomes. So when she found out that a Gila monster’s sex determination system is the opposite of humans — whereas human males have X and Y sex chromosomes, it is the female Gila monster that has two different-shaped chromosomes — that piqued her interest in the venomous lizard.
The more she learned about the Gila monster — “They store fat in their tails, they’re underground for 11 months a year, they’re venomous, but they don’t use their venom like snakes do,” she said — the more Wilson Sayres, an assistant professor in the School of Life SciencesThe School of Life Sciences is an academic unit of the College of Liberal Arts and Sciences. and researcher in the Biodesign Institute’s Center for Evolution and Medicine, was intrigued.
There is much not yet known about this shy creature, even though human-health uses have been found for its venom. Wilson Sayres and her collaborators have launched a crowdfunding campaign on experiment.com hoping to raise just under $9,000 to develop the very first reference genome for the Gila monster.
Snakes attack and use their venom to subdue their prey, but Gila monsters don’t need to do that, because they raid nests for their food, Wilson Sayres explained.
“We don’t understand why they’re venomous, and yet their venom is unique, and special in the animal kingdom,” she said.
One unexpected application is to advance human health. Gila monster venom contains a protein, the synthetic form of which has been used to successfully treat type 2 diabetes by helping regulate blood sugar and increase insulin response.
“Moreover what’s fascinating is that we don’t know anything about the Gila monster genome,” Wilson Sayres said. “There are more than 3,000 more species of reptiles than there are mammals, but we have 20 times as many mammalian genome sequences than we do reptile sequences. This means that if you are interested in studying reptile biology ... trying to find a closely related species for comparison is extremely difficult.”
Imagine setting out to study humans, because they are interesting, but the closest related species to humans that you have with a genome is a kangaroo, Wilson Sayres said.
“That's about as close of a reference as we have for the Gila monster right now. So if we really want to understand their biology, get the venom protein evolution, develop resources for conservation — we need this first stage to develop a good reference genome for the Gila monster.”
The crowdfunding effort runs through the end of April.
“If we are successful with this crowdfunding campaign, it will be the first attempt at scaffolding for generating a reference for the Gila monster genome,” Wilson Sayres said. “A large-scale genome project takes about $30,000 — it’s quite expensive. In this project we’re just getting the first stage of it.”
If they receive the funds they need, Wilson Sayres and her team will first sequence a reference genome from one individual that they can use to compare Gila monsters with other reptiles, and then they will sequence the DNA of six other Gila monsters to look at genetic variation within the species.
Collecting DNA samples presents a unique challenge — Gila monsters are venomous and shy, which means that they are difficult to locate in the desert, and although it takes a lot to get one to bite you, their bite has been described as lava pouring through your veins, or being hit repeatedly with a thousand hammers.
Luckily for Wilson Sayres, she works next to Dale DeNardo, a physiologist in the School of Life Sciences who has, in the course of studying reptilian adaptations, adopted 18 Gila monsters. He will be contributing his years of Gila monster knowledge to the project, along with the needed blood samples.