Scientists Uncover the Key Gene Responsible for Echolocation in Dolphins and Bats

Echolocation is used by both bats and dolphins, allowing them to navigate the world with the use of sound. Now, scientists have learned a bit more about this particular ability. They've found that prestin, a key gene responsible for hearing in mammals, independently evolved to play a critical role in the ultrasonic hearing range of animal sonar.

Previous studies have investigated the role of prestin in mammal hearing. This gene creates a protein found in the hair cells of the inner ear that contracts and expands rapidly to transmit signals that help the cochlea amplify sound waves to make hearing more sensitivity. Until now, though, scientists haven't be sure about prestin's role in echolocation.

Both toothed whales and echolocating bats can emit high frequency echolocation calls, which show substantial diversity in terms of their shape, duration and amplitude. These calls bounce off of objects which the animals then receive and analyze in order to navigate murky waters or dark nights. In order to understand this ability a bit better, the scientists finely dissected the function of the prestin protein from two sonar guided bats and the bottlenose dolphin. They then compared its function with non-sonar mammals.

After an evolutionary analyses of the prestin protein sequences, the scientists found that a single amino acid change in protein was the difference between sonar animals and non-sonar animals. More specifically, sonar mammals showed a change from threonine while non-sonar mammals showed a change in asparagine. In addition, the researchers identified four key amino acid differences among sonar mammals, which could contribute to their unique features.

The findings reveal a bit more about echolocation and the role of hearing in mammals. In addition, they offer the first functional evidence supporting the idea that the hearing gene of prestin evolved to play a key role in the sonar system of mammals.

The findings are published in the journal Molecular Biology and Evolution.