Great white shark’s genome contains secret of success

SCIENTISTS have taken a major step in understanding the biology of the world’s most iconic predators by decoding the entire genome of the great white shark.

It possesses notable characteristics, including its massive size – up to 20 feet and 7,000 pounds – and diving to nearly 4,000ft depths. Great whites are also a big conservation concern, given their relatively low numbers in the world’s oceans.

An international team of scientists have now completed the great white shark genome and compared it to genomes from a variety of other vertebrates, including the giant whale shark and humans.

Decoding the great white’s genome revealed not only its huge size – one-and-a-half times the size of the human genome – but also a plethora of genetic changes that could be behind the evolutionary success of large-bodied and longlived sharks.

The researchers found “striking” occurrences of specific Dna-sequence changes indicating molecular adaptation – also known as positive selection – in numerous genes with important roles in maintaining genome stability, the genetic defence mechanisms that counteract the accumulation of damage to a species’ DNA.

The opposite phenomenon – genome instability – which results from accumulated damage to DNA , is known to predispose humans to cancer and also to age-related diseases.

Contrary to expectations, very large-bodied animals do not get cancer more often than humans, suggesting they have evolved superior cancer-protecting abilities worth studying.

Study co-author Dr Salvador Jorgensen, a senior research scientist at the Monterey Bay Aquarium in the US, said of the investigations: “Decoding the white shark genome is providing science with a new set of keys to unlock lingering mysteries about these feared and misunderstood predators – why sharks have thrived for some 500 million years, longer than almost any vertebrate on earth.”

The team revealed the shark genome had also revealed more new clues about why sharks are known for their impressively rapid wound healing.

The findings were published in the journal Proceedings of the National Academy of Sciences.