Insect-eating bats navigate effortlessly in the dark and dolphins and killer whales gobble up prey in murky waters thanks in part to specific changes in a set of 18 genes involved in the development of the cochlear ganglion — a group of nerves that transmit sound from the ear to the brain, according to a study by researchers at Stanford University.

Surprisingly, these very different species evolved their unique ability to use sound waves to navigate and identify obstacles and tasty morsels, be they mosquito or minnow, in part by acquiring identical mutations in their genomes — mutations not shared by other, more closely related species like humpback whales, which patiently sieve the ocean for krill, or fruit bats, which seek stationary, yummy-smelling snacks.

The discovery solves a long-standing biological debate as to whether echolocating bats and whales have independently undergone many similar genomic changes “under the hood” to accomplish the same goal. It also opens the door to understanding more about the molecular basis for human disorders as varied as deafness, skin lesions caused by high cholesterol and altitude sickness, the researchers said.

“Not only is it breathtaking to see how these very different species carved their own evolutionary niches for themselves through independently acquiring similar genetic changes, it’s beneficial to our understanding of our own physiology and development,” said Gill Bejerano, PhD, associate professor of developmental biology, of computer science, of pediatrics and of biomedical data science at Stanford. “Developmental biologists have long wondered whether, at the most basic level, something that’s the same on the outside — like species that use echolocation — are the same on the inside. That is, do they acquire these traits through similar molecular changes? Now we know that not only is this true at least some of the times, but also that many of these changes occur in the coding region of the genome. It’s fascinating.”

Bejerano is the senior author of the study, which was published Sept. 30 online in the Proceedings of the National Academy of Sciences. Postdoctoral scholar Amir Marcovitz, PhD, and graduate students Yatish Turakhia and Heidi Chen share lead authorship.

Although the cochlear ganglion has been previously implicated in the sound-as-GPS technique known as echolocation, past studies have relied primarily on researchers’ intuition to identify possible genetic players based on prior knowledge of their function — a kind of looking-for-your-lost-keys-under-a-lamppost approach. These studies suggested only a few responsible mutations in just four genes involved in hearing.