WE ARE ALL DESIGNIST NOW:

Welcome to the world of Hox genes, a roughly 600-million-year-old "toolkit" that controls how body plans--the head-to-tail layout of our symmetrical, physical selves--develop. Once thought to exist only in flies, Hox genes rocked biology in the mid-'80s when it was discovered that they were in every single animal on Earth. And while the number of Hox genes tends to vary according to how complex you are (insects have 8; humans have 39), the genes themselves have changed so little in millions of years that they're what's called "highly conserved" across species.

In labs, that means flies function surprisingly well when one of their Hox genes is swapped for the corresponding chicken Hox gene. From an evolutionary perspective, it means earthworms, humpback whales, butterflies, and humans are all just variations on a theme. "Despite the fact that we don't think of ourselves as looking anything like a fly," says Patel, "our development basically uses the same genes."

Hox genes are "master instructors"--each oversees development in a different region of the body (head, thorax, abdomen), turning other genes on and off to ensure you grow the right form for your species. "In the field in general," says Patel, "I think we've increasingly convinced people that single genes can have big roles in evolution," but his team hunts proof, examples of how small tweaks to the Hox toolkit may have given rise to Earth's massive species diversity.

Follow @brothersjudd