Humans could evolve to be venomous, study finds

Ever wondered if you could have the potential to produce venom? Turns out humans do have the toolkit to evolve and produce venom just like snakes, and so do all other mammals and reptiles. Astonishing right?

Human salivary glands have the required genes to produce venom. (Image credit: Miles Coles)

Biologists knew that oral venom glands are modified salivary glands. But in a recent study by scientists from the Okinawa Institute of Science and Technology Graduate University (OIST) and the Australian National University it was found that both - salivary glands of mammals and venom glands of reptiles had a similar pattern of activity. Scientists therefore assume that salivary glands in mammals and venom glands in snakes share an ancient functional core that has been maintained since the two lineages split hundreds of millions of years ago, EurekaAlert! stated.

“Venoms are a cocktail of proteins that animals have weaponized to immobilize and kill prey, as well as for self-defence,” said study co-author Agneesh Barua.

In this research scientists looked for genes that work and strongly interact with venom genes by using venom glands of the Taiwan habu, an Asian pit viper.

They detected a constellation of genes that are common in multiple body tissues across all amniotes, the report said. Amniotes are animals that fertilize their eggs internally or lay eggs on land (these include reptiles, birds and some mammals).

Scientists studied the genome of Taiwan habu, a venomous Asian pit viper. (Image credit: Alexander Mikheyev)

Many of these genes are involved in folding proteins, said Barua. This makes sense as venomous animals must produce a large quantity of toxins, which are made of proteins.

Moreover, the same sort of genes are found abundantly in the human salivary gland, which produces an important range of proteins that are found in saliva in large quantities. This genetic foundation is what enables the wide array of independently evolved venoms across the animal kingdom from jellyfish to spiders and snakes.

Also, humans already produce a key protein of many venom systems - kallikreins. These are proteins that digest other proteins and are secreted in the saliva. Kallikreins are very stable and beneficial mutations will only make the venom more painful and deadly. They might be a start for theoretically ‘venomous humans’.

Although it is highly unlikely for humans to evolve to be venomous, this could be possible if the right ecological conditions ever existed. “It definitely gives a whole new meaning to a toxic person”, joked Barua.