'Jaws' may help humans grow new teeth, shark study suggests

A new insight into how sharks regenerate their teeth, which may pave the way for the development of therapies to help humans with tooth loss, has been discovered by scientists at the University of Sheffield.

The study has identified a network of genes that enables sharks to develop and regenerate their teeth throughout their lifetime. The genes also allow sharks to replace rows of their teeth using a conveyer belt-like system.

Scientists have known for some time that some fish, such as sharks and rays, develop rows of highly specialised teeth with the capacity for lifelong regeneration. However the genetic mechanisms which enable this to happen were poorly understood.

Now the research team, led by Dr Gareth Fraser from the University of Sheffield's Department of Animal and Plant Sciences, has identified how a special set of epithelial cells form, called the dental lamina, which are responsible for the lifelong continuation of tooth development and regeneration in sharks.

Humans also possess this set of cells, which facilitate the production of replacement teeth, but only two sets are formed - baby and adult teeth - before this set of specialised cells is lost.

The Sheffield-led team show that these tooth-making genes found in sharks are conserved through 450 million years of evolution, and probably made the first vertebrate teeth. These 'tooth' genes, therefore make all vertebrate teeth from sharks to mammals, however in mammals like humans, the tooth regeneration ability, that utilises these genes, has been highly reduced over time.