AsianScientist (Aug. 10, 2018) – In a study published in Scientific Reports, scientists in Japan have mapped the entire genome of an Okinawan snake known as the habu, shedding light on how it produces its venom.
Nearly 50 people—most often farm workers tending crops in fields and orchards—are reportedly bitten by the Okinawan habu (Protobothrops flavoviridis) every year. The venom of the Okinawan habu is hemotoxic, destroying blood cells and tissues. Though antidotes are now available, habu bites can still cause severe pain and permanent tissue damage in humans. Hence, scientists continue to seek out antidotes and treatments for habu bites.
In the present study, a collaborative team of scientists from research institutes and universities across Japan sequenced the entire genome of the Okinawan habu, including the genes involved in venom production. The researchers first caught Okinawan habus in the wild using a long metal pole with a hook at one end. They then collected venom, blood and tissue samples from the snakes.
“Though the Okinawan habu is not as venomous as cobras or taipans, it can produce a large amount of venom—up to one milliliter,” said Professor Hiroki Shibata, a collaborator on the study from the University of Kyushu, Japan.
Next, using the DNA sequencing facilities at the Okinawa Institute of Science and Technology, the researchers identified nearly 60 genes from 18 different gene families that contribute to the habu’s venom. Mapping venom genes of the habu not only allows scientists to explore their potential in drug development, but also gives scientists the tools to study how venom toxins have evolved.
The researchers subsequently delved into the evolutionary history of habu venom, constructing a phylogenetic tree of venom genes. Venomous snakes across the world belong to one of two families: Viperidae or Elapidae. Members of the family Viperidae, including the habu, have venom that is hemotoxic, whereas members of the family Elapidae, such as cobras, have venom that is toxic to the nervous system, or neurotoxic. The researchers found many common components among the venom genes of both families of snakes.
The article can be found at: Shibata et al. (2018) The Habu Genome Reveals Accelerated Evolution of Venom Protein Genes.
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Source: Okinawa Institute of Science and Technology Graduate University; Photo: Hiroki Shibata.
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