Sharks have a certain network of genes that helps them develop and regenerate their teeth throughout their entire lifetime, a new study revealed. Understanding this particular ability may pave the way for humans to someday grow back their lost teeth as well.
Experts said marine creatures such as rays and sharks possess rows of highly-specialized teeth that are capable of lifelong regeneration, but how this happens had remained a mystery until now.
A team of researchers from the University of Sheffield discovered that the network of genes in sharks allows the animals to replace rows of teeth using a conveyor belt-like system -- the mechanism we typically see in airports, but it works within the animal's head.
Led by Dr. Gareth Fraser, the research team identified how a special set of epithelial cells known as dental lamina form, activating the lifelong continuation of tooth regeneration and development among sharks.
Apparently, humans also possess the special set of epithelial cells. These cells facilitate the production of replacement teeth, but we only have two sets: the baby teeth and the adult teeth. Afterwards, the set of specialized cells is lost.
According to Fraser and his colleagues, the tooth-regenerating genes in sharks are conserved through 450 million years of evolution, and had probably resulted to the first vertebrate teeth.
Therefore, the tooth-regenerating genes make up all vertebrate teeth from marine creatures to mammals. In humans, however, the regeneration ability has been highly reduced over time. Thus, it is limited.
Fraser said that as sharks are terrifying predators, one of the primary reasons they are successful at hunting prey is due to their razor-sharp teeth that grow back quickly and are replaced rapidly before decay.
"The Jaws films taught us that it's not always safe to go into the water," said Fraser. But perhaps, to develop therapies to treat tooth loss, humans may need to do so, he added.
Additionally, the Sheffield-led research team suggests that at the start of the evolutionary history of sharks, their teeth continuously regenerated. The process used a core set of genes from members of developmental signal pathways, which were instrumental in the evolution of sharks. This maintained the ability to use the genes they need to replace teeth.
Fraser and his team's findings are featured in the journal Developmental Biology.
Photo : Elias Levy | Flickr