Beowulf
09-23-2024, 10:06 AM
Why do Greenland sharks live up to 400 years? The answer may be in their DNA
One of the most surprising characteristics of Greenland sharks is their longevity. Recent studies suggest that this species can live up to 400 years and reach sexual maturity around 150 years.
Although the factors behind this long longevity have been addressed by research on their metabolism, their heart or their ecology, a group of researchers decided to study the genes of these sharks to explain how they live for hundreds of years.
“Any research into the mechanisms of how this animal is able to live so long will at some point need the genome sequence,” Steve Hoffmann, a computational biologist at the Leibniz Institute on Aging and Friedrich Schiller University, told The New York Times. from Jena (Germany), who led the research.
This study, published on the scientific portal bioRxiv, provides the most complete mapping to date of the genome composition of these sharks and, in addition, gives some clues about certain biological mechanisms of this species and their relationship with their genes. For example, these sharks were found to have a network of duplicated genes related to DNA repair, which could explain their longevity.
To perform these analyses, the researchers captured several Greenland sharks and took tissue samples from their spinal cords.
With these samples, one of the researchers' first findings was related to the size of the Greenland shark genome, which contains about 6.5 billion “base pairs” of DNA. This is equivalent to twice that of humans and represents the largest genome of a shark recorded to date.
Of these genes, it is estimated that two-thirds are made up of repeated genes known as 'jumping genes'. These genes, according to the researchers, are inserted into other genes and self-replicate through copy and paste mechanisms. In doing so, however, they often alter the functioning of certain genes and cause mutations or duplications that can, in turn, cause diseases or developmental problems.
To explain how this long-lived species has a high level of 'harmful' genes, researchers hypothesize that these sharks developed a way to use them to duplicate genes linked to DNA repair.
“We found that genes duplicated specifically in the Greenland shark form a functionally connected network enriched for DNA repair function, using public shark genomes as a comparison,” the study authors note.
A gene known as TP53 was detected in this network, which has been associated with DNA repair and tumor suppression. In fact, a study published in 2016 found that elephants, which have a high resistance to cancer, carried 20 copies of this gene. In the case of Greenland sharks, this gene is altered, but it is unknown if these differences can explain their longevity.
The researchers indicated that it still needs to be further studied how the genome affects the development of the cells that make up the body of these sharks. For their part, in the future researchers hope to perform more genome sequences of species with shorter lives, but that are similar to Greenland sharks, such as the Pacific sleeper shark, to compare their genetic information.
https://www.elespectador.com/resizer/v2/EASMYOZSVJB3TDQ2VYRS5TJ3T4.jpg?auth=546b3c0a35aaa1 f4f0fcfa66b9d360edb25d9a54bada48f564f5a9b16a8577fa&width=920&height=613&smart=true&quality=60
https://www.elespectador.com/ciencia/por-que-los-tiburones-de-groenlandia-viven-hasta-400-anos-la-respuesta-puede-estar-en-su-adn/
One of the most surprising characteristics of Greenland sharks is their longevity. Recent studies suggest that this species can live up to 400 years and reach sexual maturity around 150 years.
Although the factors behind this long longevity have been addressed by research on their metabolism, their heart or their ecology, a group of researchers decided to study the genes of these sharks to explain how they live for hundreds of years.
“Any research into the mechanisms of how this animal is able to live so long will at some point need the genome sequence,” Steve Hoffmann, a computational biologist at the Leibniz Institute on Aging and Friedrich Schiller University, told The New York Times. from Jena (Germany), who led the research.
This study, published on the scientific portal bioRxiv, provides the most complete mapping to date of the genome composition of these sharks and, in addition, gives some clues about certain biological mechanisms of this species and their relationship with their genes. For example, these sharks were found to have a network of duplicated genes related to DNA repair, which could explain their longevity.
To perform these analyses, the researchers captured several Greenland sharks and took tissue samples from their spinal cords.
With these samples, one of the researchers' first findings was related to the size of the Greenland shark genome, which contains about 6.5 billion “base pairs” of DNA. This is equivalent to twice that of humans and represents the largest genome of a shark recorded to date.
Of these genes, it is estimated that two-thirds are made up of repeated genes known as 'jumping genes'. These genes, according to the researchers, are inserted into other genes and self-replicate through copy and paste mechanisms. In doing so, however, they often alter the functioning of certain genes and cause mutations or duplications that can, in turn, cause diseases or developmental problems.
To explain how this long-lived species has a high level of 'harmful' genes, researchers hypothesize that these sharks developed a way to use them to duplicate genes linked to DNA repair.
“We found that genes duplicated specifically in the Greenland shark form a functionally connected network enriched for DNA repair function, using public shark genomes as a comparison,” the study authors note.
A gene known as TP53 was detected in this network, which has been associated with DNA repair and tumor suppression. In fact, a study published in 2016 found that elephants, which have a high resistance to cancer, carried 20 copies of this gene. In the case of Greenland sharks, this gene is altered, but it is unknown if these differences can explain their longevity.
The researchers indicated that it still needs to be further studied how the genome affects the development of the cells that make up the body of these sharks. For their part, in the future researchers hope to perform more genome sequences of species with shorter lives, but that are similar to Greenland sharks, such as the Pacific sleeper shark, to compare their genetic information.
https://www.elespectador.com/resizer/v2/EASMYOZSVJB3TDQ2VYRS5TJ3T4.jpg?auth=546b3c0a35aaa1 f4f0fcfa66b9d360edb25d9a54bada48f564f5a9b16a8577fa&width=920&height=613&smart=true&quality=60
https://www.elespectador.com/ciencia/por-que-los-tiburones-de-groenlandia-viven-hasta-400-anos-la-respuesta-puede-estar-en-su-adn/