One noon in August 2011, a familiar dorsal fin surfaced off the coast of Massachusetts. This dorsal fin with small white spots belongs to a female humpback whale. Scientists have been studying the humpback whale since the 1970s and named it Salt based on the prominent spots on her dorsal fin.
Short is a uniquely marked humpback whale that scientists have been studying since the 1970s. | American Coastal Research Center
Humpback whale researcher Jooke Robbins is aiming his crossbow at Short, ready to shoot, on the Shearwater research ship. The crossbows are equipped with sample arrows with special arrows and yellow buoys. emission! The sampling arrow hit the target, and it was designed to take away a few cubic millimeters of meat when it was retracted— a bit of damage like a human being stung by a mosquito, given the size of a whale.
Robbins and her team stored the collected samples in liquid nitrogen and sent them for analysis. Eight years passed in a flash. In the May 2019 issue of the journal Molecular Biology and Evolution, a research team from Arizona State University’s Center for Cancer Evolution (ACE) published a paper stating that Salt and other cetaceans, including whales, dolphins and porpoises, Sophisticated ways to fight cancer have evolved, such as a series of tumor suppressor genes.
This new discovery, and similar previous studies in elephants, all suggest one thing: New treatments for human cancers may lie hidden in the evolutionary history of large mammals, somewhere in their genetic code . But even knowing this, scientists are gradually losing the opportunity to study these giant animals. The numbers of these animals, as well as the biodiversity of their habitats, are in sharp decline due to continued threats from humans.
There is no doubt that whales like Salt are extremely valuable in their own right. There are many legitimate reasons, both ethical and ecological, to protect large mammals. But the idea that their genes might help cancer research is novel.
“I never imagined that cancer would one day be a topic of research in cetaceans, let alone any human cancer,” she said. It was never planned to study this project.”
Peyto’s Paradox: Whales and Elephants
Why not have cancer?
In theory, large, long-lived creatures like the humpback Sauter should have high cancer rates.
Cancer starts with cell division, when one cell goes wrong, and a potentially lethal mutation spreads to neighboring cells. If the error is not found to be suppressed, it can spread throughout the body, causing cancer.
Whales and elephants live as long as humans, and they have hundreds of times the number of cells. However, their cells mutate, lead to cancer, and the frequency of cancer death is very low. The ACE team is studying this strange natural phenomenon known as Peto’s Paradox. The “Peto Paradox” is named after the British epidemiologist Richard Peto. In the late 1970s, Peyto suggested that there must be some kind of natural selection for a tumor suppressor mechanism in nature , because although humans live longer and are much larger than mice, they are both less likely to develop cancer. very similar.
In 2011, ACE researchers and scientists from 11 other institutes around the world first began studying the “Peto’s Paradox” in the genome of humpback whales. Their approach was to compare Salt’s genes with other cetacean genomes. The parts of the whale genome that determine how and when cells divide evolved rapidly, and at the same time that whales gained their massive bodies, according to research published this year.
Marc Tollis, a biologist at Northern Arizona University who joined and leads ACE in 2015, hopes to transfer a cancer-fighting gene from the whale’s genome to other small mammals to help them fight cancerous cells. – It can be tested first in mice and eventually applied to humans.
Other scientists are also studying the “Peto’s Paradox,” using another large animal, the elephant. In 2012, Joshua Schiffman, a pediatric oncologist at the University of Utah, began working on elephants’ cancer defenses after learning that they had extra copies of cancer-fighting genes in their genomes . His patient lacks this cancer-fighting gene, causing Li-Fraumeni syndrome, a rare genetic disorder that predisposes people to cancer.
Schiffman’s team has worked with ACE’s Carlo Maley, the local zoo, Ringling Circus, Barnum Bailey Circus and the Elephant Conservation Centre, before the circus stopped elephant shows, and veterinarians Elephant blood samples were collected during regular check-ups. In a 2015 paper published in the Journal of the American Medical Association (JAMA), they reported that this extra copy of the gene in elephants can trigger a form of programmed cell death and a cancer defense called apoptosis mechanism.
When a cell divides and experiences some kind of DNA damage—for example, from a chemical—the cell either tries to repair itself or self-destruct, preventing the mutation from spreading to other cells. Both whale and elephant cells undergo apoptosis more frequently than human cells.
“People are smart, but nature is smarter. After hundreds of millions of years of evolution, nature has found a solution to cancer,” Schiffman said.
Deep in the genetic code of elephants, there may be clues to curing human cancer |
Schiffman added that it is clear that elephants and whales have evolved immunity to cancer over countless generations. His team is also looking for other cancer defense mechanisms in elephant genes and is trying to transfer these capabilities to humans.
“(These animals) don’t just find a cure for cancer,” he added, “it’s more exciting that they have evolved naturally to find a way to prevent cancer in the first place. “
Of the more than 90 species of cetaceans in existence, 22 have been sequenced, and the sequencing data has been added to the National Center for Biotechnology Information (NCBI) database, and more genetic data will continue to be added in the future. But when Torres began studying Salt’s genome in 2015, there were only five cetacean genome data. Torres said that with the advent of new technologies, sequencing has become cheaper and easier, and related fields of research have grown rapidly.
Scientists have also sequenced the genomes of three living elephants. But this is just the beginning, and scientists may not have enough data to fully understand how these animals ward off cancer. And as human-induced ecosystem destruction, climate change, and many other issues are eroding these populations, researchers have fewer and fewer opportunities to collect samples. The creatures are getting harder to find, regulations to protect them are getting tougher, and research is being delayed.
Given the rate at which these species are declining, Torres hopes the study will raise awareness of the importance of cancer research and environmental protection.
“All in all, since we’re living in a mass extinction event right now,” he said, ” we need every reason to protect species. “
The situation of animals is worrying,
Valuable clues are disappearing
According to the International Union for Conservation of Nature (IUCN), the conservation status of these large mammals is mixed. Some cetacean populations have recovered from centuries of overfishing, such as humpback whales. Others remain endangered, such as North Atlantic right whales and sei whales.
Elephants are also in poor condition, with African elephants listed as vulnerable and Asian elephants as endangered.
Most recently, Botswana lifted a five-year ban on elephant hunting and Japan resumed commercial whaling in July. Conservation experts are more concerned about potential hazards that are not in the light but in the dark, such as loss of habitat.
Kenya has an elephant research and conservation organization, Save the Elephants. Its strategic adviser, Chris Thouless, said elephants suffered because their former habitat was now industrial or farmland, which also led to “human-elephant conflict”.
Elephants in Sri Lanka. As more and more land is exploited by humans, there is less and less habitat left for elephants |
In the oceans, whales are increasingly threatened by marine microplastics and ship noise, said Hal Whitehead, a cetacean expert at the IUCN . Because sight and smell are inefficient underwater, cetaceans use sound to find food and form social bonds, and noise can make these animals nervous.
“Those species that are most in contact with humans are also the most affected,” Whitehead added.
Even if these species recover, collecting genetic data from a large number of species faces other challenges. A sample taken from just one animal is not representative of the entire species, says David Baillie, a molecular biologist at Simon Fraser University in Burnaby, British Columbia.
While a representative genome of a species obtained from many samples is valuable, so are some of the oddities that can arise in individual genomes. Genetic diversity and large population sizes leave a lot of wiggle room for mutations that could benefit both the organism itself and humans—if they are understood correctly in the future.
“The more genomes we have, the better our understanding of the redundant diversity that underlies population structure,” Bailey wrote in an email. He added, “For example, rare mutations can be very important when trying to understand resistance to disease.”
There is evidence that there is strong genetic variation between different regional groups of the same species, Torres said, and we need to put more effort into classifying the genes of the animals’ close relatives.
Schiffman echoed a similar sentiment, saying that poaching, habitat loss and inbreeding have created a bottleneck that compresses the genetic diversity of many species, especially those of the largest creatures.
Cristiana Pașca Palmer, executive secretary of the UN Convention on Biological Diversity, said we don’t yet know how widespread habitat and species loss is affecting medical research.
She wrote in an email: “The disappearance of large species such as elephants and whales is just a microcosm of the dramatic reduction in species diversity in the global ecosystem. When we act to protect biodiversity, we are only protecting Humans themselves.”
The clues hidden in whales are far more valuable than whale meat | undark
We don’t know how human activity will change the genomes of these animals a few generations down the line, or how the potentially untold amount of data they hold. For example, research from the University of Southampton in the UK shows that if humans continue to destroy undeveloped habitats, the median mammal size will shrink by a quarter. The genetics of animals need to adapt to the growing human control of the planet. The genes that a species once used to defeat many diseases, along with other valuable genetic mutations, may inadvertently disappear rapidly in the next generation.
“If we lose the opportunity to study these animals in the wild, if we don’t protect them,” Schiffman said, “we could lose many treatments for diseases.”
Author: Doug Johnson
Translation: Mo Xuan
Edit: You Shiyou
Compiled source: Undark
an AI
When my AI rules the earth, I will definitely keep a few more Homo sapiens for spare…
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