Nature’s Sleeping Beauties

Nature has an abundance of talents lying dormant. Animals, plants and microorganisms have countless abilities that they mostly don’t need but which ensure their survival when the environment changes. “Dormant innovations are everywhere and are a major driving force of evolution,” says evolutionary biologist and bioinformatician Andreas Wagner. For a good 30 years he’s been researching how organisms develop and adapt, doing experiments in the lab and using calculations to test his theories and ideas. 

“The existence of dormant innovations is clearly demonstrable,” says Wagner, citing the example of an astonishing discovery among the Yanomami, a tribe in the Amazon border region between Venezuela and Brazil. This ethnic group lives in isolation and until a few years ago had had hardly any contact with other people. Around 15 years ago, a group of Brazilian doctors and ethnologists visited the group to find out more about their state of health, taking stool and microbial skin samples in the process. To their great surprise, the researchers found these samples to contain bacteria that were resistant to eight different antibiotics. This was completely unexpected, as none of these indigenous people had ever taken antibiotics.

The finding of millennia-old resistance has now been confirmed multiple times. For example, researchers have discovered antibiotic-resistant bacteria in ancient mammoth bones from the permafrost and in soil samples from deep underground – in other words, from a time when antibiotics didn’t even exist yet. This is astonishing, as resistance normally develops through a competition between the use of antibiotics and new mutations that enable the bacteria to defend themselves against them. This is not so in the cases described, where the resistances had apparently been present for thousands of years. “The bacteria have latent defense mechanisms that protect them from molecules that could eventually destroy them,” explains Andreas Wagner.

Wagner and his colleague Shradda Karve recently conducted a lab experiment showing that bacteria can also be experimentally induced to develop innovative features that are of no immediate benefit to them. To do this, the scientists used an antibiotic to put intestinal bacteria under pressure, rendering them incapable of reproducing properly. With each new generation, the bacteria were better able to fight off the antibiotic; as expected, they developed resistance. The second step in the experiment was to expose the resistant bacteria to over 200 different nutrient solutions with toxic ingredients that were new to the bacteria. And lo and behold, the evolved bacteria also displayed defenses against 20 of these toxins that they had never been exposed to before. These resistances are apparently the by-product of a beneficial defensive response to the original antibiotic. “Evolution finds it easy to come up with innovations,” Wagner sums up. They form a reservoir that comes into play when environmental conditions change. Like the fairytale character Sleeping Beauty, they are awakened from their sleep.

Indeed, “sleeping beauties” is what Wagner calls the phenomenon in his new book. The concept of dormant new talents fascinates him. Once you’ve discovered it, you encounter it at every turn. Take grasses, for example, a family of thousands of species that dominate many ecosystems today and serve as important food plants ensuring our survival. “For millions of years, grasses were sparsely distributed and not very successful,” says Wagner. They emerged 65 million years ago at the time of the dinosaurs. Their triumphant ascendancy began millions of years later when the climate became drier. Then, the green plants were able to exploit properties that had long been dormant, such as the ability to make efficient use of water, and chemical defense mechanisms against pests.

For Wagner, grasses are an important example of the thesis that innovations arise long before they give their carrier a decisive advantage in terms of survival. This also applies to the evolution of humans; more precisely the anatomically modern Homo sapiens, who entered the scene around 200,000 years ago. “These ancestors already had the latent ability to read and write,” says Andreas Wagner. “They would also have been able to drive cars if they had existed back then.” In other words, early humans possessed skills that were only activated tens of thousands of years later. For example, writing and numbers developed around 12,000 years ago in the course of the Neolithic Revolution, when people became sedentary and had to keep records of their supplies. The cultural revolution led people to use the latent abilities in their brains. Again, a changing environment awakened dormant talents.

Thanks to new insights into the genetic mechanisms of cells, it’s becoming increasingly clear how nature creates new things seemingly effortlessly. The process primarily involves promiscuous enzymes and the formation of new genes. We now know that the organization of the genetic apparatus is more redundant and chaotic than was assumed when DNA and associated processes such as enzyme formation were discovered more than 50 years ago. “Cells are not finely tuned machines. In reality, random processes play an important role,” explains Andreas Wagner.

One example is enzymes, which perform all vital functions in cells and are responsible, for instance, for the effectiveness of antibiotics in bacteria. In the case of enzymes, the image of the lock and key has become established, in other words the notion of an enzyme precisely matching a substance and modifying it. We now speak of promiscuous enzymes, as many can adapt their structure and recognize and modify not one, but several substances. This phenomenon also underlies the observation described above of the bacteria that developed defenses against unknown toxins. This is because the enzymes evolved in the experiment are promiscuous and also function with other toxins against which the microorganisms have not developed direct defenses. This versatility is the rule rather than the exception: “Most enzymes are promiscuous,” says Andreas Wagner. The enzymatic, in other words chemical, life processes are amazingly flexible, as is the entire metabolism.

The organization of the genome, the genes in the chromosomes, is also more fluid than expected. Ever since the sequencing of human DNA, we’ve known that only just under three percent of the genes in the genome are active, so-called coding genes. A large part of the genome serves as a testing ground in which DNA is transcribed into a proactive form (RNA) and can randomly reassemble itself and play through new gene forms. New genes can also arise through mutations and duplications of DNA; in a nutshell, new genes are constantly being formed and can become firmly established in the genome. 

“Genetic innovations in nature are not unique and rare, but common and cheap,” says Wagner. Changes in the environment can awaken these dormant innovations and give organisms a decisive survival advantage. Innovations, however, also get lost again. Nature is constantly developing new genetic variations and may discard them if they’re of no use.

All this begs the question of whether these dormant talents will equip nature, and humans in particular, to withstand the rigors of global warming, or more precisely, heat waves and record temperatures. On this question, evolutionary biologist Wagner has to pass: “I have absolutely no answer to that.” There are microorganisms that live in hot springs and it is possible to experimentally evolve a certain heat resistance in bacteria, but this requires hundreds if not thousands of generations. In the case of humans, this would take tens of thousands of years. So, we can’t rely on genetic innovations to save us from global warming by evolutionary means. 

Book tip: Sleeping Beauties, Oneworld Publications, 2023

This article is part of the  UZH Magazin «Kostbare Vielfalt»