200-Year-Old Whale May Hold Clues to Long Life
Whales that live for two centuries are providing researchers with clues on how to extend the average human lifespan.
Bowhead whales, which can live over 200 years with almost no evidence of age-related disease, could help humans to live longer, healthier lives, suggests a new study that presents the complete bowhead whale genome.
The genome, published in the latest issue of Cell Reports, represents the first time that any big whale's complete set of genes has been sequenced. The minke whale's genome was previously sequenced, but the minke is a much smaller, shorter-lived whale.
Researchers are studying the information on bowheads to determine how these whales, which can grow to about 60 feet long and weigh 60 tons, live so long. One male might even be around 250 years old. The species is now believed to be the longest-lived mammal.
"We discovered changes in bowhead genes related to cell cycle, DNA repair, cancer and aging that suggest alterations that may be biologically-relevant," senior author João Pedro de Magalhães of the University of Liverpool told Discovery News.
"So my own view," he added, "is that this points toward improved DNA repair and cell cycle regulation mechanisms to prevent DNA damage accumulation during the life course, which in turn promote longevity and resistance to age-related diseases."
De Magalhães suspects that other large whales, such as the blue and fin whales, are also very long lived. He explained that these whales have few natural predators. This allows them to evolve a life of slow growth and delayed reproduction. Cellular, molecular and genetic mechanisms then help to suppress age-related diseases and degeneration.
Remarkably, there's only one known case of a bowhead whale dying due to natural causes. Humans kill them and they can suffer from predation by orcas, but even orcas rarely mess with such enormous whales.
Humans are clearly not the shortest-lived mammals. Dogs and cats, for example, have much shorter average lifespans. But our average longevity is just a drop in the bucket compared to that of bowhead whales.
Humans, for example, reach physical sexual maturity at around 12 or 13 years old, and sometimes even younger. Bowhead whales do not reach sexual maturity until about the age of 20, and may then enjoy intercourse for literally hundreds of years.
Even bowhead whales have their problems, though.
"Bowheads can carry parasites and harmful microbes, and without the benefits of medicine, this might result in discomfort and pain," de Magalhães explained.
"So even though bowheads can live longer than humans and appear to be protected from age-related diseases, I wouldn't assume they have a better quality of life."
Nevertheless, scientists are always looking for ways to extend human longevity. In the future, the researchers hope to identify specific genes in the whales that allow for this to happen. They have already identified gene ERCC1 as playing an important role in DNA repair.
De Magalhães and his team think it could be possible to manipulate the same, or similar, genes in humans to prevent aging and certain diseases.
Steven Austad, chair of the Biology of Aging and the Evolution of Life Histories Department at the University of Alabama at Birmingham, told Discovery News that it's reasonable to conclude that changes in certain of the bowhead whale's genes associated with DNA repair may play a role in its exceptional longevity and ability to ward off cancer.
"This paper is an exciting and necessary start in trying to understand the exceptional longevity and cancer resistance of this very unusual species," Austad said.
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