Evolution: What Will Humans Look Like in 50,000 Years?

Many people hold the view that evolution in modern humans has come to a halt. But while modern medicine and technologies have changed the environment in which evolution operates, many scientists are in agreement that the phenomenon is still occurring.

This evolution may be less about survival and more about reproductive success in our current environment. Changes in gene frequencies because of factors like cultural preferences, geographic migration and even random events continue to shape the human genome.

But what might humans look like in 50,000 years time? Such a question is clearly speculative in nature. Nevertheless, experts that Newsweek spoke to gave their predictions for how evolution might affect the appearance of our species in the future.

“Evolution is part deterministic—there are rules for how systems evolve—and part random—mutations and environmental changes are primarily unpredictable,” Thomas Mailund, an associate professor of bioinformatics at Aarhus University in Denmark, told Newsweek.

“In some rare cases, we can observe evolution in action, but over a time span of tens or hundreds of years, it is mostly guesswork. We can make somewhat qualified guesses, but the predictive power is low, so think of it as thought experiments more than anything else.”

Something we can say with certainty is that 50,000 years is more than enough time for several evolutionary changes to occur, albeit on a relatively minor scale, according to Mailund.

“Truly dramatic changes require a longer time, of course. We are not going to grow wings or gills in less than millions of years, and 50,000 years ago, we were anatomically modern humans.”

Jason Hodgson, an anthropologist and evolutionary geneticist at Anglia Ruskin University in the United Kingdom, told Newsweek that 50,000 years is an “extremely long time” in the course of human evolution, representing more than 1,667 human generations given a 30-year generation time.

“Within the past 50,000 years most of the variation that is seen among human populations evolved,” Hodgson said. “This includes all of the skin color variation seen across the globe, all of the stature variation, all of the hair color and texture variation, etc. In fact, most of the variation we are so familiar with evolved within the past 10,000 years.”

In the more immediate future, Hodgson predicts that global populations will become more homogenous and less structured when it comes to genetics and phenotype—an individual’s observable traits.

“Currently the phenotypes that we associate with geographic regions—for example, dark skin in Africans, light skin in Scandinavians, short stature in African pygmy hunter-gatherers, tall stature in Dutch, etc.—is maintained by assortative mating. People are much more likely to choose mates who are similar to themselves,” he said.

“Part of this is due to the human history of migration and culture which means people tend to live by and be exposed to people who are more similar to themselves with respect to global variation. And some of this is due to preference for similarity within local populations for reasons that we still do not really understand.

“However, admixture—mating between distantly related groups—is increasing, and this will result in less structure and a more homogenous global population. As an analogy, if you stick a bunch of poodles, rottweilers, chihuahuas and St. Bernards on an island and let them breed randomly, within a few generations everything would be a medium sized brown dog.”

When distinct populations mix, so do their traits. Some traits are determined by a few gene variants. But many traits result from a combination of various different genes, and there we will blend together to some degree, according to Mailund.

“So there will be some changes, not caused by selection, but because previously isolated groups are now mixing,” he said.

It is still possible though that despite increasing homogeneity, not everyone would evolve in the same direction, according to Nick Longrich, a paleontologist and evolutionary biologist at the University of Bath in the United Kingdom.

“You could imagine that in distinct subpopulations you could get people evolving in different ways,” he said.

If there are strong, consistent pressures toward certain characteristics, our species could experience “very rapid evolution” in a matter of thousands—or possibly even hundreds—of years, Longrich said.

While we do not know what the selective pressures will be like going forward, Longrich said he expects a number of developments, extrapolating from past trends and current conditions.

For example, we might get taller, because of sexual selection. And we might also become more attractive on average, since sexual selection plays more of a role in modern society than natural selection.

“Attractiveness is relative, so maybe we’d look like movie stars but if everyone looked that way, it wouldn’t be exceptional,” he said.

As time passes and technology evolves, it is also possible that humans will begin to direct our own evolution in a targeted fashion through gene editing tools such as CRISPR—potentially aided by artificial intelligence.

“Applying genetic techniques to humans that alter phenotypes is highly controversial and ethically fraught. Indeed, 20th century eugenicists thought they could improve the human species by only allowing the ‘right’ people to breed,” Hodgson said.

“However, given 50,000 years, it is almost incomprehensible to me that people will not eventually apply this technology to our species. We can only hope that the technology and the ethics are much better understood by then.

“I suspect that things like appearance will largely be up to our own choice by this time. Technologies like CRISPR, or technologies not yet invented, will allow us to choose many things about our appearance. I can even imagine that our appearance might change through the generations in the way that fashions change now.”

We are in the infancy of genetic editing today, but progress in the field is fast and ever evolving.

“Over the next century, I expect that we will perfect the technology,” Mailund said. “We already have gene editing tools, and the main roadblock is a lack of understanding of the consequences of gene editing. As we learn more, we will be more confident in what we can do, and while I expect ethical considerations to hold us back for a while, it won’t be forever.”

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