Researchers at Harvard have just confirmed what any history buff will tell you – humans are still evolving, and at a rapid pace. They’ve identified hundreds of genes under selective pressure, which is a fancy way of saying that natural selection is still hard at work.
The study, published in Science, pored over data from over 2,500 people from 26 populations around the world. What they found is that since the last ice age, our species has been adapting to changing environments in some surprising ways.
Adapting to the Urban Jungle
One of the most interesting findings was that genes related to the brain and nervous system are under selective pressure. This makes sense when you think about it – humans have had to adapt to an ever-changing world, from the rise of cities to the advent of new technologies.
Dr. David Reich, one of the lead authors of the study, notes that “we’ve seen an increase in selection pressure on genes related to the immune system, likely due to the spread of diseases in agricultural populations.” In other words, as humans started living in closer proximity to one another, diseases began to spread more easily, and our bodies responded by evolving new defenses.
Another key finding was that there’s been a significant shift in the way we process diet. For example, genes related to lactose tolerance have become more common in populations that have historically consumed dairy products – like Europeans and East Asians.
Ancient Adaptations in Modern Times
So, what does this mean for us? Well, for one thing, it suggests that we’re still a long way from being “fully” adapted to our modern environments. Think about it – we’re still evolving to deal with things like urban pollution, processed foods, and screens.
It also means that we need to be careful when making assumptions about human behavior and biology. For example, traits like lactose tolerance are often seen as “adaptations” to specific environments – but now we know that they’re just part of a much larger story of human evolution.
What This Means
Ultimately, this study reminds us that humans are still part of the natural world, subject to the same forces that have shaped our species for millions of years. And as we continue to evolve, we’ll need to adapt to the changes in our world – whether that’s the rise of new technologies or the spread of new diseases.
