An international team of scientists has sequenced and analyzed the draft genome of the cane toad (Rhinella marina), a poisonous amphibian native to Central and South America that has spread across many regions of the globe. The findings appear in the journal GigaScience.
A cane toad (Rhinella marina), adult female. Image credit: Bernard Dupont / CC BY-SA 2.0.
Cane toads are known for their rapid adaptation and deleterious impacts on native fauna in invaded regions. However, despite an iconic status, there are major gaps in the understanding of cane toad genetics.
The availability of a genome would help to close these gaps and accelerate cane toad research.
“Despite its iconic status, there are major gaps in our understanding of cane toad genetics, and up until now, no one had put the genome together,” said study senior author Professor Peter White, from the School of Biotechnology and Biomolecular Sciences at the University of New South Wales.
“Sequencing and assembling a genome is a complicated process,” said first author Dr. Rich Edwards, also from the School of Biotechnology and Biomolecular Sciences at the University of New South Wales.
“By using the cutting-edge sequencing technology and expertise, we sequenced 360-odd billion base pairs and assembled one of the best quality amphibian genomes to date.”
“We managed to decipher more than 90% of the cane toad genes using technology that can sequence very long pieces of DNA, which makes the task of putting together the genome jigsaw much easier.”
More toads can now be sequenced at a fraction of the cost, and the genome is freely available — anyone can access it now and conduct further research.
“Future analysis of the genome will provide insights into cane toad evolution and enrich our understanding of their interplay with the ecosystem at large — it will help us understand how the toad spreads, how its toxin works, and provide new avenues to try to control its population,” said co-author Professor Rick Shine, from the University of Sydney.
“Very few amphibian genomes have been sequenced to date, so this is also great news for amphibians. Having a reference genome could provide valuable insights into how invasive species evolve to adapt to new environments.”
Having the genome will also help researchers to find new options for controlling the toad population.
“Current measures like physical removal haven’t been successful, but new methods to teach native species not to eat the toad — called taste aversion — give new hope,” Professor White said.
“However, we need more approaches to control this invasive species.”
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Richard J. Edwards et al. 2018. Draft genome assembly of the invasive cane toad, Rhinella marina. GigaScience 7 (9); doi: 10.1093/gigascience/giy095
