Blue whale’s giant secret down to four key genes

WITH a heart the size of a car and a body twice the length of a bus, the blue whale is the biggest animal on the planet.

The ability to reach such vast proportions and still remain healthy has previously proved a mystery, but now scientists believe four newly identified genes hold the key to the secret. Logically, the larger an animal is and the more cells it has, the more likely that individual is to develop cancers.

However, in the case of whales and other giant creatures, previous studies have found they have a remarkably low risk of cancer, leading to Peto’s paradox where big beasts rarely develop tumours.

Scientists from the State University of Campinas (Unicamp) in Brazil studied the genetics of 19 cetaceans, including the sperm, blue and humpback whale. “We found molecular signs of selection in the GHSR, IGFBP7, PLAG1, and NCAPG genes,” the scientists write in their study, published in the journal Scientific Reports.

The GHSR gene is involved with releasing growth hormones to boost appetite and energy metabolism; IGFBP7 is involved with another form of growth factors which promote cell growth and division; while PLAG1 and NCAPG have been linked to bigger bodies in cattle.

“Our results indicate four genes likely to be involved in increasing body size in giant cetaceans,” the scientists write. “Some of these genes may also be responsible for mitigating the possible consequences of extreme size.

“Hypothetically, being a giant has severe consequences, such as increased chances of developing cancer.”