Researchers recently discovered why certain cats have stripes and others spots— and it all has to do with mutations. In particular, tabby house cats and king cheetahs share a gene responsible for the cats’ stripes and the cheetahs’ spots. But when a mutation in the single gene (called Taqpep) occurs, the tabby will develop patches, not stripes, and the cheetah’s spots become wide stripes. The biggest question remains: What is the biological and evolutionary significance of this mutation?

Scientists are currently trying to determine if a small mutation of a gene known as EDAR helped to shape human evolution. About 30,000 years ago, this small change may have helped humans in Asia survive excessive heat and humidity by endowing them with extra sweat glands. But the researchers believe this was not the only change from mutations—and point to mutation of genes involved in bone density, skin color, hair changes, and immune system function—all necessary for humans to spread to new environments around the world. But the interpretations are not easy—after all, “reading” how mutations have been passed down and tweaked over thousands of years of human evolution still remains difficult.