According to bioRxiv.org, an international team of researchers from Colombia, Sweden, and the United States has decoded the DNA sequence of the Capybara, the largest rodent in the world.
During their research, they discovered a unique method that reduces the risk of tumor development in Capybaras.
Capybaras have a special cancer prevention method – (Photo: Carlos Eduardo Livino).
The Capybara (Hydrochoerus hydrochaeris) is widely found in South America. They typically inhabit areas around ponds and lakes, swimming and diving well to escape from terrestrial predators. The ancestors of the Capybara originated in Africa around 80 million years ago and made their way to South America 40 million years later. Capybaras can grow up to 1.35 meters in length, stand 60 cm tall, and weigh over 60 kg.
As a rodent, they are massive, although the subspecies Kerodon rupestris weighs no more than 1 kg. Typically, the small size of rodent species is explained by survival strategies: it is easier to hide when evading enemies, and not all predators prefer to chase after small prey.
However, according to evolutionary biologist V. Louise Roth from Duke University (USA), when the ancestors of the Capybara appeared in South America, there were virtually no predators in the area, which likely allowed this rodent species to increase in body size. But this increase in body size brought about a new challenge for Capybaras. The more cells in the body, the higher the risk that one of them could degenerate into cancer cells and lead to tumor development.
Accordingly, one would expect that the risk of cancer in larger animal species should be higher. However, this is not observed in nature. Both elephants and whales do not have a higher incidence of cancer compared to smaller animal species. Scientists noted this phenomenon in the 1970s, referring to it as the Pet Paradox, named after British physician Richard Peto. It has only been in recent years that scientists have begun to understand exactly why different large animal species achieve this effect. For instance, elephants have a very reliable mechanism for repairing damaged DNA.
In this new study, scientists found that Capybaras also possess a special cancer prevention method. The genes that determine immune system function in Capybaras allow for better detection and destruction of cells that divide too quickly. As a result, immune cells in Capybaras can inhibit the formation of new tumors. According to the study’s authors, this has not been observed in other animal species.