The Big White Shark is one of the most famous marine creatures on Earth, generating widespread public charm and media attention, including the reproduction of one of the most successful Hollywood films. This shark has remarkable features including its massive dimensions (up to 20 feet and 7,000 pounds) and scuba diving up to almost 4,000 feet deep. Large whites are also a great concern for conservation, given their relatively small number in the world's oceans.
In a great scientific step to understand the biology of this iconic predator and shark in general, the entire genus of the white shark is now deciphered in detail.
A team led by scientists from the New Western Reserve Research Foundation (NSU) and the GHRI Research Institute, Cornell University College of Veterinary Medicine and the Monterey Bay Aquarium have completed a shark genome and compares it to genomes from various other vertebrate animals, including the giant shark and humans.
The findings are reported in the journal's "Recent Articles" section .
The decoding of the white shark genome revealed not only its vast size ̵
The researchers found astounding cases of specific changes in the DNA sequence showing molecular adaptation (also known as positive selection) in a number of genes with an important role in maintaining genomic stability. ¬- mechanisms of genetic protection that counteract the accumulation of DNA damage to a species, thereby preserving the integrity of the genome
These changes in the adaptive sequence are found in genes intimately linked to DNA repair, damage response DNA damage and DNA damage. tolerance, among other genes. The opposite phenomenon, the genomic instability resulting from accumulated DNA damage, is well known to predispose people to multiple cancers and age-related illnesses. "Not only was there a surprisingly large number of genome stability genes that contained these adaptive changes, but there was enrichment of several of these genes, highlighting the importance of this genetic fine tuning in the white shark," said Mahmud Shivigji, PhD, Director of the Shark Survey Center, and GRI of the Rescue of our Seas Foundation Shivji has jointly led the study with Michael Stanhope, PhD, of Cornell University College of Veterinary Medicine
It is also noted that the white shark genome content but a very large number of "skipping genes" or transposons, and in this specific type known as LINE, in fact, this is one of the highest proportions of LINEs (nearly 30%) found in vertebrates so far
. LINEs are known to cause genome instability by creating double-strand breaks in DNA, "Stanhope said." It is likely that LINE proliferation in the white shark genome is a strong selective agent for the evolution of effective DNA repair mechanisms, and is reflected in the positive selection and enriches not of so many genomic stable genes. "
A research team including scientists from the California State University, Monterey Bay, Clemson University, University of Porto, Portugal and Theodosius Dobanski Center for Genomic Bioinformatics, Russia, also found that many genes for white genus shark genome were also under positive selection and enriched with the enormous whale whale
The discovery that whale shark also has these key adaptations for genome stability is significant because the theorem ichno risk of cancer should be increased by two. of the cells (the large bodies) and the life of the organism – there is statistical support for a positive relationship between the size of the body and the risk of cancer within a given species. Interestingly, it is not inclined to behave differently.
Contrary to expectations, very rich animals do not get cancer more often than humans, suggesting that better protective ability for cancer has developed. Genetic innovations found in genes for genome stability in white and whale sharks may be adaptations that facilitate the evolution of their large bodies and long life.
"The decoding of the white shark genome provides science with a new set of keys to unlock retained mysteries for these cowardly and misunderstood predators – why sharks have flourished for about 500 million years, more than almost every vertebrate on the ground , says Dr. Salvador Jorgensen, senior researcher at Monterey Bay Aquarium who co-authored the study.
But the innovations do not end here
Shark genomes reveal other intriguing evolutionary adaptations in genes linked to roads "We have found a positive selection and enrichment of the content of genes involving several genes associated with some of the most fundamental pathways for wound healing, including in terms of wound healing. the key blood clotting gene, "said Stanhope," These adaptations, including wound healing genes, may be at the heart of the shark's boasting ability to effectively cure even large wounds. "
Researchers say that just- what they are exploring and "tip of the iceberg" in terms of the white shark genome. "Unsustainability of the genome is a very important issue in many serious human illnesses; we now find that nature has developed clever strategies to maintain the stability of genomes in these long-lived live sharks, "says Shivi. "Of these evolutionary wonders, we still need to learn tons, including information potentially useful for combating cancer and age-related illnesses, as well as improving wound healing in humans as we reveal how these do animals. "
the white shark genome will also help preserve this and related sharks, many of which quickly reduce populations due to overfishing, "said Stephen O'Brien, a genetic conservation specialist at the NFU, who jointly develop this study. Data will be a great asset to understanding the dynamics of white shark populations to better preserve this amazing species that has captured the imagination of so many people. "
This study is funded by the Save the Seas Foundation of the NMS, the Guy Harvey Ocean Foundation, the Stiftung / Shark Foundation, the Monterey Bay Aquarium, and Ilumina, Inc., and the genomics of the lasura. 19659020]