We humans like to think of ourselves as the final act in a long process of genetic trial-and-error whose sole raison d'être was to produce us: Earth's alpha species. But the story of evolution is far from over. Even today we can see our species being tweaked and reshaped by a multitude of forces.
While the story of evolution is written in the language of nucleotides, current research reveals how genetics are not the be-all-end-all of speciation (shhh don't tell your high school biology teacher). As researchers dive further down into the rabbit hole of life sciences, we are learning how fluctuations in culture, the food supply, and technology have had a hand in creating that big bag o' human you see in the mirror.
As we move into the future, our evolutionary story only promises to become more complex. We are seeing the mixing of once-disparate communities in a new swingin' global community. New chemicals and materials are rapidly making their effects known on millennial-old genomes (there was no need for peanut-free classrooms a generation ago). And most importantly, new technologies that can alter our DNA at its most fundamental level will add wild new dimensions into the evolutionary process.
Recently, I had a chance to speak with author, bio-medical entrepreneur, and TED Talk "all-star" Juan Enriquez (seriously, check out his past talks—they're amazing) as part of our interview series, The Convo (download the episode in podcast version here). We talked about some of these strange contributors—both natural and otherwise—that paved the way to us (and will lead the way to what we'll be next).
Consider obesity. We often brand the spike in obesity as a kind of disease of the modern developed world. But when you think about it, it's also a form of evolution—we are getting fatter through the generations.
Most people think they know all the reasons for this global embiggening, namely a bountiful food supply rich with empty calories (thanks science!) and an increasingly sedentary lifestyle (thanks technology). While both of those factors are surely contributors, there's more to the obesity story. Not only are humans getting bigger, but so are our pets and even wild animals. There just seems to be some kind of invisible fat magic floating in the air. So, what's going on?
"I can see how having fast food every day would lead to human obesity, but why lab rats, why wild birds?" asks Enriquez. "Part of what is happening is that on farms we feed all animals a very small dosage of antibiotics. And it's not to make them well because they've been sick. We feed it to them as growth promoters. Because what it does is kill some of microbes in their stomach, so that the nutrients get absorbed by the animal, not by the microbes. And when that leaches out into the environment that may be promoting obesity elsewhere."
While the introduction of foreign unnatural substances into the environment can cause changes over time (certain cancers, for example), changes in culture and society can also have an effect on future generations. For example, in the United States, blue eyes are slowly dropping off in frequency. This is because blue eyes are a recessive trait, so their occurrence is bound to fall off in a population with a lot of brown-eyed people. In the past century, the melting pot of the nation has lowered the social barrier of dating outside one's ethnic group. Another way to put that: Everybody's doin' it.
"Suddenly, you're getting a lot of people who [in a previous era] would have never met each other, who would never intermix," Enriquez explains. "So, because blue eyes are a recessive trait, they may go away."
About That Spike in Autism...
There has been a sharp rise in the occurrence in various forms of autism in recent decades. There is still a lot of debate as to why (which is a global phenomenon, not just in the US); Enriquez believes it is due to various factors: Perhaps it might be due to the fact that we are looking more for the disease and we've expanded the spectrum of conditions that we label autism; it also appears correlated to older parents and obesity (both of which have been introduced to society's mix in recent years); and it seems to be clustered in areas around certain chemical plants.
However, there is another way to think about autism—as an adaptation. One "reinforcing" element to consider is how the traits associated with functional autism—namely the ability to obsessively concentrate on a single task—are quite practical at this point in technological and economic history.
Individuals who are proficient at focusing their attention on tasks that require abstract thinking may prosper in disciplines like science, mathematics, and computer programming (even if they lack previously well-rewarded attributes like athleticism and social grace). Today's "nerds" tend to be well-compensated and well-regarded by society. This sort of inversion is unprecedented in human history.
"Suddenly all these nerds who were very shy and didn't have a social standing are now the cool kids on campus. That—in a strange way—may be reinforcing autism and may be reinforcing Asperger's," Enriquez explains. "So, this sort of mating theory—where you have these clusters of people who are obsessively focused on something. They might have otherwise never met because they were very shy, but suddenly they're intermingling and working at the same companies and universities."
The Weirdness
However the future of human evolution might actually have nothing to do with natural or cultural forces influencing the occurrence of specific attributes over a matter of centuries. New technologies and cutting-edge research is allowing scientists to alter our genetic code at its most fundamental level. One of the most promising (and slightly frightening) of these technologies is CRISPR.
The science is a little complicated, but—in a very simplified way—it allows researchers to write genetic code and swap it into a living organism's DNA. "In the same way you can write a sentence on your tablet—either 'I love you' or 'I hate you'—we can now do the same thing with genetic code," he explained. So, if we change a few code in a tangerine, we can turn it into a lemon or a grapefruit (or some hybrid of them all). If you combine this technology this with our increased ability to sequence whole genomes, we gain the ability to evolve species in near real-time.
This means that we may—in the not-crazy-distant future—swap out the genes that allow certain cancers to thrive, cause male pattern baldness, or are the reason we age. This also means that new human traits may not take shape over numerous generations, but over a visit to the doctor's office.
Our grandkids may have the ability to program their genetic code like line of computer code. Once you "hack" into this source code enough, it inevitably results in something completely new. That means there's a chance your kids might eventually be a whole new species.
The future is certifiably nuts.
The Convo is PCMag's interview series hosted by features editor Evan Dashevsky (@haldash). Each episode is initially broadcast live on PCMag's Facebook page, where live viewers are invited to ask guests questions in the comments. Each episode is then made available on our YouTube page and available for free as an audio podcast, which you can subscribe to on iTunes or on whatever podcast platform you prefer.