Tooth Enamel May Have its Origin in Fish Scales

Scientists discovered that tooth enamel, the hardest substance in the human body, could have its origin in prehistoric fish scales.

The research project was conducted by the Institute of Vertebrate Plaeontology and Palaeonthropology in Beijing, China, and the Uppsala University in Sweden, and it was published in the journal Nature. The two institutions arrived to the conclusion after combining lots of data from the fields of genomics and palaeontology. The findings suggested that a material very close enamel was found in ancient fish scales.

Enamel is the strongest tissue produced by the human body, as well as by many other species of vertebrates from our planet. The research concluded that on the evolutionary scale, this type of tissue started forming in fish scales. The scientists were fascinated because until now they have though enamel was produced only in teeth, not in scales. To think that its origin is not in teeth is pretty amazing.

The research concluded that some fish species that lived on our planet about 400 million years ago, had enamel in their scales. Psarolepis and Andreolepis are two of them.

Over time, enamel became a fundamental part of teeth tissue. The study found that only a couple of species produced enamel though. This was not the first research that asked whether enamel was produced in any other types of tissue than vertebrate teeth, some older studies also hinted that prehistoric fishes had some form of enamel in their scales. However, they only found substances similar to enamel, which mostly consisted of calcium phosphates, but at the core were different.

In addition, the scientists who conducted the new study found a freshwater fish from southern United States that is covered with a luminous substance which is very similar to tooth enamel. The fish is called the spotter gar, and is believed not to have changed much since the prehistoric age.

Per Erik Ahlberg, paleontologist and professor at the University of Uppsala in Sweden, said that the new findings are as important as they are unexpected, because in the human body the substance can only be found in teeth. He, along with many other experts never thought that the substance evolved from something else than denture, considering that it is a key component of our teeth.

The team noted that although he prehistoric fishes both have enamel on their scales, it was only a thin layer of tissue. The Swedish Andreolepis and the Chinese Psarolepis may be the earliest animals found that have enamel on them, but the scientists believe that the substance that is found in our teeth has possibly appeared in other species.
Photo credits: Wikimedia