Sometimes years go by without seeing a single one. In the icy waters of the northern Atlantic and the Arctic, the Greenland shark hides. It must be said that he has time to play cat and mouse with the researchers. This species is the longest-lived among vertebrates. A study published in 2016 estimated that a single one of these sharks could live 400 years.
Other scientists decided to go further. To understand what allows the Greenland shark to live so long, German biologists sequenced 92% of its DNA, reports CNN. “Only with genome assembly can we understand what mutations accumulated in the shark for it to have this enormous longevity, for example,” explains Dr. Steve Hoffman, biologist and lead author of the study, awaiting peer validation.
The Greenland shark genome is very astonishing on all levels
The Greenland shark is impressive in many ways. It only grows one centimeter per year but still ends up reaching 6 meters in length, and would only reach puberty after a full century of life. By analyzing its genome, scientists realized that it was also very long. Larger than all other shark genomes already known. And this could be due to an ability of the Greenland shark to repair its DNA.
In addition to its length, the genome of this species is also surprising by its composition. 70% of genes are jumping genes, capable of transposing themselves to different places in the DNA sequence by duplicating themselves, which sometimes creates mutations. In general, these jumping genes are feared because they can create genetic diseases or cancers. But the Greenland shark got around the problem. According to biologists who analyzed its sequence, its jumping genes appear to be those that repair DNA, which “negates the negative effects of jumping genes and perhaps even allows for better genome integrity,” it Dr. Arne Sahm, one of the authors of the study.
How can these discoveries be applied to human genes?
This discovery could ultimately help humans live longer, or at least live better. The Greenland shark genome is perhaps not similar enough to that of humans to transpose the same principles without question, but the analysis of long-lived species provides new avenues for reflection.
Dr. Vera Gorbunova, professor of medicine and biology interviewed by CNN and unrelated to the study explains: “Perhaps we could imagine a drug that targets a human gene and makes it work a little more like a Greenland shark gene. And that would improve DNA repair in humans.” This won't allow us to live for centuries, but it could help us delay cell aging and the diseases that accompany it. A way to live longer in good health.
