The predatory similarities shared by great white sharks (as well as other species in the lamnid group of sharks) and tuna include very high metabolisms (which enable them to stay warm), swimming styles and other quick swimming behaviors.
These similarities exist despite a wide divergence in terms of time. The two fish once had a common ancestor but they diverged 400 million years ago. Research carried out at Imperial College, in London, has revealed many shared genes in the two groups and these genes provide the predatory edge.
The identified genes are linked to similar traits and they will have been passed on with each generation in order to give both species a survival advantage. Here the scientists discovered one identical gene in both groups that has an association with metabolism (this helps the creatures to produce energy).
In a research note, one of the leading scientists behind the research, Professor Vincent Savolainen observes: “Lamnid sharks and tuna both have stiff bodies and tails that allow them to swim in bursts.”
The academic adds further: “They can also keep their temperature up in colder waters. Both of these things make them more effective predators, allowing them to snatch prey in usually inhospitable waters”. He also notes that these “are simple traits, and ones that have evolved twice.”
This was based on the testing of muscle tissue from three species of lamnid sharks and six species of tuna.
It is hoped that the research will assist with scientific research that aims to draw a relationship between genetics and physical traits, especially where the same gene works in two different animals. In genetics, different genes give a body code for different proteins, and proteins in turn provide the building blocks of all tissues. The activation of a gene and the subsequent production of proteins is called gene expression. Sometimes this is straightforward to identify, whereas at other times, linking a gene to a complex process like metabolism is difficult to pin down.
The study outcomes have been published in the journal Genome Biology and Evolution. The research paper is titled “Substitutions in the glycogenin-1 gene are associated with the evolution of endothermy in sharks and tunas.”
