A discovery made by a group of researchers has offered new insight regarding the origin of the enamel that covers human teeth.
By studying the evolution of prehistoric fish, the researchers concluded that enamel originated from the scales before developing on teeth and bones, LA Times reported.
As explained by the researchers, enamel is a protective layer that covers teeth and bones. It is also considered as the hardest part of the human body.
In the study of prehistoric animals, the researchers already know that this material first manifested on the scales of fish. They previously believed that it moved to the bones and teeth after the process of evolution drastically rearranged the location of the scales. The new discover, however, provided a different scenario.
For the study, the researchers analyzed the genetic make-up of the Psarolepis romeri, an ancient fish that thrived in an area that is now known as China 410 to 415 million years ago. According to the researchers, this animal had enamel coating on its scales and facial bones.
They also studied the fish known as Andreolepis, which lived in Sweden 425 million years ago. Unlike the Psarolepsis romeri, the Andreolepis only had enamel on its scales. Both animals, however, did not have the protective material on their teeth, according to Science Mag.
The researchers then compared the two animals and noted their distinct differences. The Andreolepis is older and only featured enamel on one part of its body. The Psarolepsis romeri, on the other hand, is younger but had a more spread-out development of enamel.
These details led researchers to conclude that instead of relocating the scales to different parts of the body, evolution may have caused the pattern of enamel production to shift. In other words, the proteins that make up enamel may have extended to cover the bones of the fish.
This then could have led to enamel production spreading to other parts of the body such as the teeth. However, the researchers noted that more studies are needed in order to prove this theory.
According to Per Erik Ahlberg, a paleontology professor from Sweden's University of Uppsala and member of the research team, this discovery can shed light on the origin of enamel in humans. It can also provide a better understanding regarding the evolution of ancient animals.
"This is important because it is unexpected," he said according to ABC.net. "In us, enamel is only found on teeth, and it is very important for their function, so it is natural to assume that it evolved there."
The study conducted by Ahlberg and his team were published in the scientific journal Nature on September 23.