Scientists Sequence Genome of Taiwan Pit Viper and Examine Role of Genetic Drift in Venom Evolution

A bite from a pit viper, locally known in Taiwan and Okinawa as habu, can cause permanent disability and even death. Yet, much about its venom remains an enigma. Highly variable in composition, even between littermates, this toxic cocktail keeps changing over generations. A recent study published online on September 27, 2017 in Genome Biology and Evolution sheds light on the evolution of snake venoms. For the first time, researchers have sequenced a habu genome, that of the Taiwan habu (Protobothrops mucrosquamatus), and compared it to that of its sister species, the Sakishima habu (Protobothrops elegans). The article is titled “Population Genomic Analysis of a Pitviper Reveals Microevolutionary Forces Underlying Venom Chemistry.” More than 50 instances of snake bites were recorded in the past year on Okinawa alone, prefectural government figures show. Globally, snake bites cause between 81,000 and 138,000 mortalities per year, according to the World Health Organization. In developing countries and rural areas with high exposure to venomous species and scant medical resources, snake bites can be especially devastating. For such places, creating effective antivenom can be a matter of life or death. "For many years it was known that snake venoms evolve very rapidly, and the most common explanation for this has been natural selection," said Dr. Alexander Mikheyev, senior author on the paper and head of the Ecology and Evolution Unit at the Okinawa Institute of Science and Technology (OIST), "but there are reasons to suspect that this might not be the only evolutionary force at work."
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