Vole teeth reveal how a simple change can create complex new features over time

At a time when biodiversity is under severe pressure from human activity, understanding how evolution works is more important than ever. New research on vole teeth. published V PNASshows that evolution does not always require complex genetic changes to create complex new functions.

“When we tried to understand the origins of voles' strange molars, we discovered that a simple change in tooth growth, occurring over millions of years, was responsible for the success of these small rodents. Over the past six million years, their molars have developed more and more cusps—pointed tips that help grind food—eventually resembling the grinding teeth of much larger herbivores such as horses or elephants,” said lead author Fabien Lafuma, a doctoral student at the University of Helsinki.

These adaptation made voles excellent herbivores, allowing them to thrive during ice ages. But what's striking is that the evolution of voles' teeth mirrors how they develop in the womb.

A surprisingly simple change in tooth growth gave voles head start compared to other rodents: the formation of tubercles is accelerated, so as the tooth grows, more of them can develop.

“By showing how development drives species adaptation, studying teeth can help us understand how life responds to environmental change. Such knowledge is needed to guide conservation efforts as species today face unprecedented climate change and habitat loss” explains Lafuma.