The circumpolar bowhead whale can live for more than 200 years, making them the world’s longest-lived mammals. And remarkably, compared to humans, these whales stay relatively free of age-related diseases. Now researchers have sequenced the genome of the Arctic giant and identified the key differences between these bi-centenarians and other mammals. The work, published in Cell Reports this week, is the first time the genome of a large whale was sequenced.
How is it that a large whale with over 1,000 times more cells than humans doesn't seem to have an increased risk of cancer? They must have some natural mechanisms that can suppress cancer more effectively than those of smaller mammals. "Our understanding of species' differences in longevity is very poor, and thus our findings provide novel candidate genes for future studies," João Pedro de Magalhães from the University of Liverpool says in a news release. "My view is that species evolved different 'tricks' to have a longer lifespan, and by discovering the 'tricks' used by the bowhead we may be able to apply those findings to humans in order to fight age-related diseases."
To learn some longevity lessons from the giant baleen whale, Magalhães and a large international team extracted DNA from isolated muscle tissue sampled from a 51-year-old female bowhead (Balaena mysticetus) who was caught in West Greenland’s Disko Bay in 2009. Then they compared the newly sequenced genome to two other whales (minke and killer whales) and 18 other mammals, including a chimp, elephant, human, rat, and platypus.
They found that changes in bowhead genes that are related to cell division, DNA repair, cancer, and aging seem to help increase their longevity and cancer resistance.
Because the bowhead's genome is the first among large whales to be sequenced, the findings may help reveal physiological adaptations related to size. Whale cells have a much lower metabolic rate than those of smaller mammals, for example, and the team found alterations in one specific gene involved in thermoregulation (called UCP1) that may be related to these metabolic differences.
Next, the team will be breeding mice that can express bowhead genes to help determine the importance of different genes for long life spans and resistance to diseases.
Images: Loke Film and Adam Schmedes (top), Kate Stafford (middle) / Cell Reports 2015