Unmasking the Temple Pitviper

31 March 2017 | Research
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Adult female Temple Pitvipers (pictured) prefer to perch on tree branches, while adult males tend to stay closer to the ground

A proposal by NUS Biological Sciences researchers to sequence the genome of the Temple Pitviper has been selected as one of the five finalists — out of more than 200 entries globally and the only entry from Asia — in the 2017 Plant and Animal SMRT Grant Program. Supporters can vote for their favourite project once a day from now till 5 April.

The team is led by Professor R Manjunatha Kini from NUS Biological Sciences and consists of Dr Mrinalini, Research Fellow at NUS Biological Sciences, and Dr Ryan McCleary, Postdoctoral Fellow at Utah State University.

Prof Kini explained why the study of snakes matters. “One is to make people aware of the importance of snakes and their toxins, and how they improve our lives, in particular, with newer drugs,” he said. He added that it is exciting to improve our knowledge about our surrounding environment as well.

The Temple Pitviper belongs to the viper family. Native to Southeast Asia, this species can be found locally in the Central Catchment Nature Reserve as well as around the MacRitchie, Lower Peirce and Upper Peirce Reservoirs. In Malaysia, many Temple Pitvipers are found in the Temple of the Azure Clouds, popularly known as the Snake Temple. Unlike some of its fearsome relatives, the Temple Pitviper is docile and rarely attacks humans.

...make people aware of the importance of snakes and their toxins, and how they improve our lives, in particular, with newer drugs.

In response to the competition to sequence the world’s most interesting genome, the team proposes to uncover the secrets of the Temple Pitviper given its unique characteristics. The Temple Pitviper produces unusual toxins compared to other snakes. Dr Mrinalini said, “There’s a stark difference between the male and female sexes (in this species) which is very rare in snakes.” Interestingly, the neonates and juveniles of both sexes look the same but the adults are sexually dimorphic. She said, “It is not clear if sex-based differences are also found in their venom and dietary habits.”

The potent venom produced by the Temple Pitviper contains toxins not found in other snake species, an example being a class of novel toxins called Waglerins which impede neuromuscular functions. Physically, the adult male and adult females exhibit distinctive differences in terms of scale pattern, colour and size. Snake genomes typically contain 25,000 to 30,000 genes, which is similar to the number of genes found in other vertebrates including human genome. High levels of gene duplication of toxin genes makes the task of sequencing snake genomes tricky.

Prof Kini highlighted that while it is widely known that people die from snake bites — there are some 100,000 snake-related deaths per year worldwide — a lesser-known fact is that snake venom has contributed to the development of a number of drugs, such as Captopril for hypertension, as well as antiplatelet drugs Eptifibatide and Tirofiban. These, and other drugs which are developed based on snake venom toxins, save millions of human lives every year.

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Prof Kini (left) and Dr Mrinalini propose to conduct genome sequencing on the Temple Pitviper

The Kini Lab at NUS conducts research on protein chemistry, as well as protein design and engineering, among other areas. To date, the laboratory has discovered and characterised more than 30 toxins and eight new toxin families. Prof Kini shared that the laboratory is currently developing several drugs for cardiovascular diseases.

Organised by Pacific Biosciences, the international competition aims to determine the world’s most interesting genome by a public vote. The team with the highest number of votes will be awarded genome sequencing of their chosen plant or animal.

See media coverage.