Back in high school, I remember visiting the house of a friend whose parents were the proud owners of two bulldogs. They were cute and slobbery (the dogs, not the parents), but what I most vividly recall about them are how the sound of their snuffles and wheezes would fill the whole house. The upside of this is that my friend’s family was never in danger of misplacing their dogs, but their constant labored breathing always made me feel a little concerned. I learned later that those wheezes are but one outward symptom of a host of chronic health issues that bulldogs are prone to. Their heads, while adorable, are so disproportionately huge that oftentimes a bulldog can’t successfully give birth to its large-headed babies without human intervention.
Left to their own devices in the wild, bulldogs wouldn’t survive for long. And it’s human intervention that has made them the way they are—breeders choosing dogs with larger heads, shorter snouts, and stubbier legs to breed generation after generation, purposefully emphasizing these traits until we’ve ended up with our present day bulldogs.
What humans have been doing for thousands of years—to crops, livestock, and now domesticated pets—nature has been doing since the first blobby bit of life pulled itself together in the primeval sea. In the wild, it would be the bulldogs with the sharpest teeth, strongest legs, and sharpest eyes that would survive, reproduce, and then populate the world with similarly fierce offspring, in a process called natural selection.
But what gives rise to these variations in the first place? It’s evolution, my dears! Random mutations and changes in our genetic code are the cause of changes in our outward appearance, which natural selection then acts upon. Some mutations don’t cause any outward effects, while others cause bad ones (cancer is a great example of this), but when a mutation occurs that helps an organism to better survive it can eventually spread to that individual’s descendants.
Evolution occurs slowly, especially among species like us which live relatively long lives and reproduce slowly. Bacteria, which can produce a new generation of cute baby bacteria in a day or less, evolve relatively quickly. Our culture and knowledge might have changed drastically over past 10,000 years, but our species is still essentially the same as our hunter-gatherer ancestors, genetically speaking. We are slaves to our genomes, like it or not, and the the glacial pace of evolutionary change has not kept pace with our lifestyle changes—hence the current epidemic of chronic, largely preventable diseases such as diabetes, heart disease, and obesity. We would do better, scientists say, to alter our lifestyles to fit those of our hunter-gatherer ancestors. This recommendation—more exercise, less fatty/high carbohydrate foods—is a bitter pill to swallow when we are biologically programmed to shove all the sugars and fats we can find down our gaping maws.
But wait. Must we accept self-control and moderation as our fate?
In the past few decades, we’ve increased our understanding of evolutionary processes by leaps and bounds, to the point where people are suggesting that the heyday of direct genome manipulation is not so far off. We’ve already meddled with the genomes of crops to make them pest-resistant and created fluorescent fish for no greater reason than our viewing pleasure. Could we directly change our own genetic makeup to increase how efficiently we process fat, for example? Or make it so we never experienced diabetes, arthritis, or even old age?
This an extreme idea with many detractors, and for good reason. There are still a lot of things we don’t understand about the way our genomes function, and genetic modifications would be disproportionately beneficial to the very rich. But now that we are beginning to have the tools to meddle with what makes us tick, I think their eventual use is an inevitability. Genetic manipulation—whether through artificial selection or gene therapy—is a tool, neither inherently good or ill. It is how we use our newfound knowledge, and the boundaries we set for ourselves, that will determine how this new technology plays out. We may shape the world the way we’ve shaped the bulldog, adapted for all the wrong things and worse off for it, but we don’t have to. Genetics has the power to improve life on Earth, if we can have the wisdom to let it.
Inspiration for this article from: http://www.nsf.gov/news/news_summ.jsp?cntn_id=132674&org=NSF&from=news