You have genes that code for proteins. These are then put together to make you. Understanding these genes and how they've changed is obviously very important for understanding human evolution. However, they only make up ~2% of your DNA. A significant chunk of the rest (perhaps upwards of 10%) is regulatory DNA. As the name suggests, these genes regulate those protein-making ones; telling them how much to make, when to make it, where to put it and all that other important stuff.
So studying this regulatory DNA is maybe even more important to understanding human evolution. However, it's a lot harder to research than the stuff that makes proteins. After all, there's an extra step in how it influences the body (if it influences it at all). Fortunately new research is shedding some light on this crucial component of human evolution.
Back in the mid-2000s a team of researchers had a brainwave: look for regulatory DNA that was the same across different animals. This would be strong evidence that this was DNA important to survival. After all, if important DNA did mutate there's a good chance it would break and the animal would die. So there would be a strong pressure for that DNA to remain unchanged across many different species.
However, DNA conserved like this isn't necessarily doing anything. Which is where the latest research comes in. They used the results of the recent ENCODE project - which identified DNA that was active - and cross-referenced them with this conserved regulatory DNA. The result was that they could identify regulatory DNA that was both important and actually doing something.
So it seems geneticists can finally start researching this crucial part of our genome. However, that isn't the most important implication of this study.
No, the most important finding is that more than 500 of these important bits of regulatory DNA have mutated in humans. What's more almost 70% of these mutations appear to have been influenced by positive selection. In other words they are beneficial mutations that are likely a key part of building a human.
Genes influenced by this regulatory DNA include which may be involved in language, and , which control the layout of the body. Clearly these are some pretty important things. It looks like we're now tantalisingly close to shining a light on this key component of human evolution.
Reference
Gittelman, R. M., Hun, E., Ay, F., Madeoy, J., Pennacchio, L., Noble, W. S., ... & Akey, J. M. (2015). Comprehensive identification and analysis of human accelerated regulatory DNA. Genome research, gr-192591.
