How Pufferfish Developed Its Unusual Spines

Pufferfish are known for their strange and extreme skin ornaments, but how they came to possess the spiky skin structures known as spines has largely remained a mystery. Now, researchers have identified the genes responsible for the evolution and development of pufferfish spines in a study published online on July 25, 2019 in iScience. The open-access article is titled “Evolution and Developmental Diversity of Skin Spines in Pufferfishes.” It turns out that the process is pretty similar to how other vertebrates get their hair or feathers--and might have allowed the pufferfish to fill unique ecological niches. "Pufferfish are some of the strangest fish in the ocean, particularly because they have a reduced skeleton, beak-like dentition and they form spines instead of scales--not everywhere, but just in certain patches around the body," says corresponding author Gareth Fraser (@garethjfraser), PhD, an Assistant Professor at the University of Florida. Dr. Fraser and his team followed the development of pufferfish spines in embryos. While the scientists had initially hypothesized that the spines formed from scales--that the pufferfish lost its scale component but retained the spine--they found that the spines are developmentally unique from scales. They also found that the development of pufferfish spines relies on the same network of genes that are commonly expressed within feathers and hairs of other vertebrate animals. "It just blows me away that regardless of how evolutionarily-different skin structures in animals are, they still use the same collection of genes during development," Dr. Fraser says.