Why can't most mammals fly but birds can? Hebrew University helps explain why
The determining characteristic is the genetic coding of the ephrin-B3 molecule that gives birds this ability, according to the study
By GADI ZAIGMount Scopus campus, Hebrew University Jerusalem(photo credit: Wikimedia Commons)
What allows birds the ability to fly in contrast to mammals, which cannot - with the exception of bats - was identified in a study recently published in Science Advances by Prof. Avihu Klar at the Hebrew University of Jerusalem’s Faculty of Medicine and Prof. Claudio Mello from Oregon Health and Science University.The specific features which allow birds to fly, and which does not exist in humans and other animals, was identified. These features, as it turns out, are based in the animals' specific molecular characteristics.Previous studies have shown that certain mammals' capability to walk is due to the genetic make-up of their spinal cord, and while birds' ability to fly is also embedded in their spinal cord as well, the determining characteristic for flying is the genetic coding of the ephrin-B3 molecule that gives birds this ability, according to the study. The team discovered that the genetic coding of the molecule in birds is fundamentally different than those of reptiles and mammals.“The molecule ephrin-B3 is present in mammals but mutated or absent in birds. This simple but profound difference is what allows birds to flap their wings and take flight,” Klar said. “Our study paves the way for future experiments to reveal the evolution of neuronal networks that enable the different modes of movement of legs and hands, a characteristic of bipedal animals, such as birds and human,” he added.The study has also shown that mice with a mutation in the ephrin-B3 molecule "move with a synchronous jumping motion of both left and right sides at the same time, similar to birds." This reinforces the scientists' theory that genetic changes over time have helped birds coordinate a movement pattern, like the simultaneous flapping of wings, which gives them flight capabilities.
