Do you know how whales grow into gigantic sizes? 

Nature never fails to amaze us, especially when it comes to the animal world. In fact, the variant sizes of different animals are what fascinates us the most. For instance, whales, one of the largest animal species on earth are mammoth in size, so much so, that the blue whale surpasses even the largest of dinosaurs that ever lived. Have you ever wondered how they got so big? Well, a brand-new study has revealed that there are four genes with respect to gigantism that are found in whales and justify their gigantic sizes.  

However, these genetic underpinnings not only fostered huge sizes, lower chances of being preyed upon and greater chance of acquiring food, but also offered them with disadvantages such as high risk of cancer and lower reproductive output. The latest study titled “Our results are among the first to study gigantism in cetaceans from a molecular perspective” has been published in the journal Scientific Reports also revealed how whales alongside other cetaceans like dolphins and porpoises evolved more than 50 million years ago from a wolf-like, terrestrial animal that belonged to a mammal group called artiodactyls, that today includes cows, sheep, and pigs among others.  

Okay, but how on earth did the cetaceans then grow up to be so huge if their ancestors were normal sized? Turns out, it’s because their physical characteristics underwent many changes, especially genetic and ecological ones. This was found out by Brazil-based marine biology research institute called UNICAMP.  

Sources cite that the team of researchers focused on seven whale species that are more than 33 feet long, including the blue whale, sperm whale, baleen whale, humpback whale, bowhead whale, right and gray whale. After rounds of assessments on their genes, they discovered that four specific ones namely GHSR, IGFBP7, NCAPG and PLAG1 together led to the gigantic body evolution of these species.  

GHSR is a gene involved in releasing growth hormone through the pituitary gland, body weight, energy metabolism, appetite and fat accumulation. It also is linked with controlling cell proliferation and programmed cell death. In contrast, IGFBP7 is a gene that promotes cell growth and division. There is evidence it acts as a cancer suppressor in prostate, breast, lung and colorectal tumours. Similarly, NCAPG is a gene associated with growth in humans and other farm animals and leads to increased body size, weight gain, cell proliferation and cell life cycles. Finally, PLAG1 leads to overall body growth, including embryo growth and cell survival. Now, although the cetaceans emerged 50 million years ago, it was only 5 million years ago that they got their gigantic sizes. Prior to that, they were just normally big such as 10 metres in length.  

The recent study thus throws light on the broader evolutionary study of marine species and is a step forward in the field.