5th January 2015
Whale genome may provide clues to 200-year lifespan
Scientists have mapped the bowhead whale genome and identified genes responsible for its 200-year lifespan, the longest of any mammal.
The bowhead whale is a 20 metre (65 ft) species of whale found in the waters of the Arctic and subarctic. It is believed to be the longest-lived mammal, with a recent study estimating they can live to at least 211 years of age, equivalent to a human born today reaching the year 2226. In a paper due for publication tomorrow in Cell Reports, a team from the Liverpool Centre for Genomics Research, UK – in collaboration with scientists in Alaska, Denmark, Ireland, Spain and South Korea – present the first complete bowhead whale genome and identify key differences compared to other mammals.
The researchers compared the bowhead's genes with those of a minke whale. The latter typically lives for only 30-50 years. As a result of their sequencing effort, they found that bowhead whales have unique mutations in two genes. These are the ERCC1 gene – which is believed to repair DNA, increase cancer resistance and slow aging – and the PCNA gene, which is also linked to DNA repair.
"Our understanding of species' differences in longevity is very poor – and thus our findings provide novel candidate genes for future studies," says the senior author, Dr. João Pedro de Magalhães, of the University of Liverpool, UK. "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."
The fact that large whales, with over 1,000 times more cells than humans, do not seem to have an increased risk of cancer suggests the existence of natural mechanisms that can suppress cancer more effectively than those of other animals. Dr. Magalhães now hopes to begin a project that will insert bowhead whales' genes into mice to observe the effects on health. If successful, human trials could follow, using drugs to activate the genes already inside the body, or by inserting the bowhead's genes into human cells before inserting them back into people.
The researchers also note that because the bowhead's genome is the first among large whales to be sequenced, the new information may help reveal physiological adaptations related to size. For example, whale cells have a much lower metabolic rate than those of smaller mammals, and the researchers found changes in one specific gene involved in thermoregulation (UCP1) that may be related to metabolic differences in whale cells.