Dolphins and Bats… are they really THAT different? February 8, 2010Posted by ecogeeko10 in Behavior, Biology, Evolution, Genetics.
Hey fellow molecular genetics/behavioral ecology students (i.e. Kyle)! Remember when we were discussing how bats and dolphins independently developed similar abilities to use echolocation after diverging from their last common ancestor (which was a looooong time ago)??? Well anyways… Recent (I mean REALLY recent) studies are showing that they might be sharing more than what was once thought!
The evolutionary genetics of hearing
It has been assumed that it was different mutations of different genes that resulted in the “coincidental convergence” of certain traits in different species (I can write sentences like these because this is a blog). However, two studies (here and here) that were published in the January 26th issues of Current Biology suggest that the evolution of echolocation in bats and dolphins were brought about by identical genetic changes.
According to Yang Liu et al, dolphins and bats developed the ability to echolocate because they both experienced similar mutations in their prestin genes. Prestin, which can be thought of as being amplifiers in the inner ear, were mutated in a way so that these species of animals could have a refined sensitivity and selectivity for certain “echolocate-able” frequencies. The evidence shows that these changes in prestin were selected for, so it is likely that they are critical for the evolution of echolocation in animals. The scientists are still working on why this may be.
The researchers were sure to point out, though, that there are still differences in how bats and dolphins echolocate. Dolphins can use echolocation at a range of >100 meters, while bats have a range of only ~3 meters. It is also worth noting that sound travels much faster in water. Therefore, bats and dolphins have had to adapt these differences in order to be successful in their unique environment.