I know. That title is a pretty bad joke. One could even say it was a poultry attempt. Okay, I’m done now, promise. Now, to science!
In a new study published in the online version of the journal Biology Letters, a group of chickens show us just how quickly evolution can take place. A team of scientists led by Oxford’s Dr. Greger Larson looked at fifty years worth of data in order to trace how mitochondrial DNA was passed from mother to daughter. Now fifty years may seem like a long time to us mere mortal humans, but on the evolutionary time scale it’s a drop in the Darwinian bucket. That’s why what the scientists found was so surprising. In just fifty years, this dynasty of chickens had not one but two mutations in their mitochondrial genomes. This means that the rate of evolution for these chickens was fifteen times faster than thought possible, since according to estimates based on fossil studies, scientists had previously thought the rate of change for mitochondrial genomes to be at most a measly two percent per million years.
But the surprising findings don’t stop there. As anyone who has ever marathonned CSI may be able to tell you, mitochondrial DNA is supposed to be passed strictly as is from mother to offspring. But our fine feathered friends were having none of that, as the scientists discovered when they noted an instance of mitochondrial DNA being passed from father to child. Combined with the much higher than expected rate of mutation, this “paternal leakage” shows just how busy evolution can be, even over relatively short time periods. As the study’s lead author Dr. Michelle Alexander said, “Both of these findings demonstrate the speed and dynamism of evolution when observed over short time periods.”
So what does this mean for our understanding of evolution? For one, it underlines the fact that evolution is happening all around us, all the time. And if we don’t see it, it may just be because we aren’t looking closely enough.