Controlling how evolution happens might sound like science fiction, but examples in the past illustrate this endeavor. Think of the process of artificial selection, where humans selected and bred organisms with desirable traits thousands of years ago. This gave us agriculture, one of the most transformative human inventions. Later, artificial selection in animals and plants led to an understanding of genetics and gene evolution in populations. Yet, artificial selection is still generally restricted. One noticeable difference from natural selection is that the latter drives adaptive evolution on Earth, and it occurs without any conscious agent doing the selecting. In natural selection, nature itself chooses the variants with the highest “fitness” — those most likely to survive. And when nature decides, the outcomes are often challenging to predict.
As we move forward, scientists are aiming to influence how evolution proceeds at the molecular level and exert direct control over the reproductive process. Is it possible to steer evolution mutation by mutation, creating preferred outcomes? The outstanding achievement in 2018 was the development of a method called directed evolution, which allows scientists to engineer new biomolecules. For example, Nobel laureate Frances Arnold pioneered a technique to mutate proteins in the laboratory and measure their effectiveness, leading to the modification of proteins with improved functions, like an enzyme that metabolizes sugar highly efficiently. This approach, where chemists act like dog breeders, but without relying on sexual reproduction, can result in a diverse protein population whose properties can be measured in hours, ultimately allowing control over how evolution unfolds.
Biologists have realized that steering evolution towards specific outcomes necessitates the right mix of prediction and engineering. Recent studies have proposed directing evolution away from creating antibiotic-resistant pathogens by using different antibiotics in a certain order, and suggested leveraging molecular insights into cancer to guide cancer cells toward susceptibility to certain drugs. Meanwhile, multidisciplinary teams have employed ideas from quantum physics to adjust populations toward predetermined goals in various systems, like using directed evolution to control microbial communities such as those that live on our skin and in our gut.
These breakthroughs highlight that a certain degree of evolutionary control exists today. But most successful examples to date have occurred only in limited settings, such as the manipulation of microbes, microbial communities, and proteins. Further, existing efforts target control over short time periods, rather than molecular evolution acting over longer periods of time. The technical and ethical challenges of evolutionary control are significant — the ethical dilemmas overlap with those surrounding genetically modified organisms. Overzealous implementation of such technologies might lead to genetic determinism, which holds that humans and other organisms can be steered, and falls short given the intricate forces that shape biological evolution, for which current knowledge and tools are insufficient.
Ultimate control over the evolutionary process remains restricted by our current capabilities. Over the long term, attempts to steer biological evolution might be premature and could lead to unforeseen consequences. Artificial intelligence is not a universal remedy for these uncertainties; it is most beneficial in situations where the systems being modeled and predicted are well-understood, which is not the case for evolutionary biology.
In summary, while modern biology’s aspirations to gain control over evolution are captivating, we must also recognize our limitations. For example, the eugenics movement, modeled after methods used in developing domesticated animals and crops, has been discredited. It is a stern reminder that thoughtless attempts to control complex forces like evolution are likely to fail. Quanta is currently conducting a series of surveys to better serve our readers. Take our biology reader survey and you may win free Quanta merchandise.
