Humans could become poisonous in the future, according to science

Could humans develop poison? It is highly unlikely that people will join certain types of reptiles and arthropods among the ranks of the most poisonous animals, but research reveals that humans have the necessary tools to produce poison.

For the production of poison, the expression of certain types of genes is needed. This collection of genes associated with human salivary glands explains how venom has evolved independently of nonvenomous ancestors more than 100 times in the animal kingdom. "We essentially have all the building blocks to make venom," said study co-author Agneesh Barua, a doctoral student in evolutionary genetics at the Okinawa Institute of Science and Technology in Japan.

The researchers found a considerable amount of genes that are common in multiple tissues of all amniotes (amniotes are vertebrates where in the embryonic stage they develop four envelopes: chorion, allantois, amnion and yolk sac, and create an aqueous medium in which they can breathe and on which it can feed; include reptiles, birds, and some mammals).
Many of these genes are involved in protein folding, because poisonous animals must manufacture a large number of toxins, whose biochemical nature is protein or peptide. These same types of regulatory genes are found in abundance in human salivary glands; this genetic basis is what allows for the wide range of independently evolved poisons in the animal kingdom.

Oral venom is common throughout the animal kingdom. Biologists have long understood that the oral venom-producing glands are modified salivary glands; now, this research reveals the molecular basis behind the change. "It's going to be a real milestone in this area of ​​knowledge," said University of Queensland biochemist Bryan Fry, who was not involved in the research.

Every mammal or reptile has built in the molecular tools with which an oral venom system is built. In this regard, humans also produce a key protein that is used in many poisonous systems. Kallikreins, secreted in saliva, are proteins that digest other proteins (they are protein structures of the protease type) and are also a key part of many poisons. Therefore, kallikreins are theoretically poisonous from a natural point of view for humans.

In wild species, venom plays an important role in reproduction, development, and feeding. However, within the evolutionary process, humans learned to use other tools for such purposes, leaving aside the fact that poison was a vital aspect in their lives, and because high amounts of energy are required for the manufacture of poison, it is easily lost when not in use. This may account for the fact that humans at some point lost the potential ability to produce venom similar to that of many other species.

Agneesh Barua, doctoral student at this Institute and author of the study, defends that humans have all the basic components in place so that at some point in evolution we produce our own poison, although of course, this is not as powerful as that of certain species, so this research may not raise hopes of seeing humans with poisonous superpowers. Still, understanding the genetics behind the poison could be key to the future of medicine.