Villain of the ocean could help to save humankind

Great white sharks have an extraordinary genome that could help to save the lives of human beings, scientists claim.

The first ‘‘map’’ of the creature’s DNA has uncovered a multitude of mutations that protect against cancer and other agerelated diseases. They also have enhanced wound-healing properties. Experts believe that understanding more about the way the great white has evolved to keep its genome stable and resist disease could lead to new human treatments.

‘‘Genome instability is a very important issue in many serious human diseases. Now we find that nature has developed clever strategies to maintain the stability of genomes in these largebodied, long-lived sharks,’’ Mahmood Shivji, the study’s coleader and director of the Save Our Seas Foundation Shark Research Centre at Nova Southeastern University in Florida, said. ‘‘There is still much to be learnt from these evolutionary marvels, including information that will potentially be useful to fight cancer and age-related diseases, and improve woundhealing treatments in humans, as we uncover how these animals do it.’’

The great white shark’s genome contains an estimated 4.63 billion ‘‘base pairs’’, the chemical units of DNA, making it one and a half times bigger than its human counterpart.

In the predator’s DNA there are about 24,500 protein-encoding genes, compared with 19,000 to 20,000 in the average human.

Great white sharks, which can be 6 metres long and weigh three tonnes, have been on Earth for at least 16 million years.

Over time they have evolved numerous molecular changes in genes linked to DNA repair and damage tolerance, the scientists found. Together these adaptations have acted to keep the shark’s genome stable.

In contrast, humans suffer from high rates of genome instability caused by accumulated DNA damage, which accounts for our vulnerability to age-related diseases such as cancer.

‘‘Not only were there a surprisingly high number of genome stability genes that contained these adaptive changes, but there was also an enrichment of several of these genes, highlighting the importance of this genetic fine-tuning in the white shark,’’ Dr Shivji said.

The findings are published in the journal Proceedings of the National Academy of Sciences .– The Times

The DNA of great white sharks have a multitude of mutations that protect against cancer and other age-related diseases. They also have enhanced wound-healing properties.