Walk into any crowded place, be it a mall, a train station, a college cafeteria. You immediately start seeing differences. Heights, skin tones, eye colors, the way someone carries themselves. We look wildly different from each other. And yet, if you pulled out a copy of literally anyone’s genome and placed it next to yours, you would find that more than 99.9% of it is identical. That sliver, one base change per thousand, explains almost everything that makes you look, age, an