Evolution faster when it’s warmer
Climate could have a direct effect on the speed of “molecular evolution” in mammals, according to a study.
Researchers have found that, among pairs of mammals of the same species, the DNA of those living in warmer climates changes at a faster rate.
These mutations – where one letter of the DNA code is substituted for another – are a first step in evolution.
The study, reported in Proceedings of the Royal Society B, could help explain why the tropics are so species-rich.
DNA can mutate and change imperceptibly every time a cell divides and makes a copy of itself.
But when one of these mutations causes a change that is advantageous for the animal – for example, rendering it resistant to a particular disease – it is often “selected for”, or passed down to the next few generations of that same species.
Such changes, which create differences within a population but do not give rise to new species, are known as “microevolution”.
The idea that microevolution happens faster in warmer environments is not new. But this is the first time the effect has been shown in mammals, which regulate their own body temperature.