Despite some species living for over 200 years and carrying an abundance of blubber for most of their life, whales - the world’s largest mammals – have incredibly low rates of cancer. The same also goes for elephants and porpoises.
But why and could these animals’ resistance help us better understand the disease and how to combat it?
Well, according to a new study by a team of researchers from Northern Arizona University, in Flagstaff; the Arizona State University, in Tempe; and other collaborating institutions, the answer may lie in these aquatic mammals' genes.
Publishing their findings in the journal Molecular Biology and Evolution, the researchers say certain genomic loci had evolved at a faster rate in whales than they had in other mammals. More importantly, these were loci containing genes that regulate the maintenance process of healthy cells.
The team discovered this by analysing samples taken from Salt, a female humpback whale. Salt was the perfect research candidate because she has been being followed since the 1970s and scientists have a wealth of data about her.
Speaking about the findings of the research, Marc Tollis, Ph.D., an assistant professor at Northern Arizona University and leader of the research team, said: “This suggests that whales are unique among mammals, in that in order to evolve their gigantic sizes, these important 'housekeeping' genes, that are evolutionarily conserved and normally prevent cancer, had to keep up in order to maintain the species' fitness.
“We also found that despite these cancer-related parts of whale genomes evolving faster than [in] other mammals, on average, whales have accumulated far fewer DNA mutations in their genomes over time, compared to other mammals, which suggests they have slower mutation rates.”