When the going gets tough, some animals take to the air: a squirrel might leap from tree to tree, a flying fish will launch itself out of the water, even some snakes can glide through the air for surprisingly long distances. Now, researchers at the University of Adelaide have discovered how marsupials have repeatedly evolved the ability to glide through the treetops – all thanks to a single gene.
The gene in question, EDAR, plays a vital role in hair development. But researchers discovered that genetic changes to EDAR in several marsupial species are associated with their ability to glide.
"Toothed gliders were previously shown to carry mutations in this gene, suggesting an association between these EDAR mutations and the evolution of gliding in this group of marsupials, but whether this genetic link extends to other gliding species beyond the toothed gliders was unknown," says Dr Vera Weisbecker, who led the research.
"What we've now discovered is that the same EDAR mutations we see in toothed gliders are also present in all six lineages of gliding marsupials and, interestingly, they're only found in gliding species of marsupial."
These genetic changes cause structural alterations in the hair shaft, modifying the geometry and aerodynamics of the fur in such a way that enables these marsupials to glide.
It's still not exactly known why or how EDAR-related hair structure adaptations led to the evolution of gliding.
Dr Weisbecker believes these structural changes are likely linked to a reduction in weight-bearing capacity which, combined with an ability to climb, are both key pre-requisites for the evolution of gliding.
Understanding why and how this link between these gene and gliding has come about will help us understand more generally how animals, over generations, can overcome environmental challenges in a changing world.
