Pufferfish are strange. They have a reduced skeleton, beak-like dentition and “spines” – spiky skin structures – in certain patches around the body.
The how and why of the spines has been something of a mystery, but researchers from the University of Florida, US, think they have the answer after following their development in embryos.
Gareth Fraser and colleagues initially hypothesised that the spines formed from scales: that the pufferfish lost its scale component but retained the spine.
However, they found that the spines are developmentally unique from scales, and that their development 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,” Fraser says.
The researchers also found that by blocking genes that are classic markers of skin appendage development, they could reduce the number of spines and loosen the restriction on where they appear on the fish.
The findings are published in the journal iScience.