Humans have salivary glands, while snakes possess venom glands. But researchers have found that humans might someday possess venomous saliva like snakes.
Researchers from Okinawa Institute of Science and Technology Graduate University and the Australian National University studied the genes that work together and interact with venom in pit viper snakes.
Their findings suggest that the genetic foundation needed for oral venom to evolve can also be found in the genes of reptiles and mammals. This means that humans may be on the evolutionary path of evolving to having venomous saliva.
The study, entitled "An ancient, conserved gene regulatory network led to the rise of oral venom systems" published in the journal Proceedings of the National Academy of Sciences, is the first concrete evidence on the underlying molecular link between the venom glands found in snakes and the salivary glands in mammals.
New Meaning of a Toxic Person
Sky News reported that scientists found the genetic foundation required for oral venom to evolve in both reptiles and mammals.
"It definitely gives a whole new meaning to a toxic person," study author Agneesh Barua jokingly said.
Researchers studied the venom glands found in the Taiwan habu snake, which is a pit viper found in Asia, and looked for genes that work together and cooperate with the venom genes.
They were able to identify about 3,000 of these cooperating genes that play a significant role in protecting the cells from stress brought by the production of lots of proteins.
Also, the researchers investigated genomes from other mammals, such as dogs, chimpanzees, and humans, and found that these mammals have their own version of such genes.
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Venom's Ancient Foundation
The study reveals the ancient foundation of the snake's oral venom. Barua said that venoms are the cocktail of proteins that animals use against prey to immobilize them, and also acts as their self-defense.
But aside from snakes, other animals also possess venom, like jellyfish, spiders, scorpions, and some mammals. Understanding how different genes interact helped the researchers further understand the key in regulating protein modification and folding.
According to MailOnline, the long amino acids must fold in a certain way during gene production because even a single misfolded protein could accumulate and damage the cells.
Barua explained that a robust system in place is needed to manufacture all required proteins for the genes to ensure that it is folded correctly and therefore could function effectively.
When they found that mammals, like humans, have genes in their salivary glands that have similar patterns of activity seen in the venom glands they believed that both glands share an ancient foundation that has remained since the two lineages split hundreds of millions of years ago.
Barua noted that this is the first solid evidence that venom glands evolved from salivary glands. With the apparent ease of salivary glands being repurposed as venom glands, scientists are starting to look at mammals in a different light.
For instance, in the 1980s, researchers have observed that male mice produced toxic compounds when injected into rats. If under certain ecological conditions, mice continue to develop toxic saliva and with reproductive success, they could become venomous mice in a few thousand years.
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