CNN (CNN) said on the 20th, recently the Swedish National Centre for Molecular Bioscience scientists for the first time from the extinct species - the Tasmanian tiger (also known as the pouch wolf) specimens in the isolation and sequencing of its RNA. although many supporters of the move as a resurrection of the extinct animals a major breakthrough, but the scientific community for the Although many supporters see this as a major breakthrough, there has been much controversy in the scientific community about the need to "resurrect extinct animals".
First RNA isolation from an extinct animal
According to CNN, the last Tasmanian tiger died in a zoo in 1936, and the species has been extinct ever since. But Swedish scientists have successfully isolated and sequenced RNA from a 130-year-old specimen of the Tasmanian tiger, and Emilio Sanchez, the project's lead scientist, said, "RNA gives us the opportunity to look through the cells and tissues to find out the true biology of what was preserved before the extinction of the Tasmanian tiger." The discovery will allow scientists to better understand how the animal's genes function, thus helping efforts to resurrect the animal, the report said.
Tasmanian tiger
Trying to resurrect the Tasmanian tiger requires not only a comprehensive understanding of its DNA, but also a comprehensive understanding of how tissue-specific gene expression dynamics and gene regulation work, which can only be achieved by studying RNA. The researchers were able to identify specific genes by sequencing RNA from skin and skeletal muscle tissue in Tasmanian tiger samples. But trying to do this is not easy; DNA begins to break down after the animal dies and can only be preserved for about 1.5 million years even in the most suitable environment, while RNA is more fragile and breaks down faster than DNA, which scientists had previously believed could not be preserved for a longer period of time. The report highlights that this is the first time biologists have isolated and decoded RNA from a long-extinct creature.
Quite a few ideas to revive extinct animals
The report also mentions that a team of researchers led by Professor Andrew Pask at the University of Melbourne is trying to resurrect the Tasmanian tiger. The project involves several complex steps, incorporating cutting-edge scientific techniques such as gene editing and artificial wombs. According to the report, the team will begin by sequencing the extinct animal's DNA in detail and comparing it to its close extant relative, a mouse-sized carnivorous marsupial, the pangolin, to identify differences. Paschke explains, "We will then take living cells from the pangolin and modify each of the places where their DNA differs from that of the Tasmanian tiger through gene editing. We are essentially modifying the bag marten cells into Tasmanian tiger cells." Once the team has successfully completed gene editing on the cells, they will be "turned back into living animals" through stem cells and assisted reproductive techniques. He said that although marsupials are much smaller than Tasmanian tigers, the small size of the pups born to marsupials means that even mouse-sized marsupials can act as surrogate mothers for much larger marsupials such as Tasmanian tigers. "Our ultimate goal with this technique is to restore these species to the wild, where they play an absolutely vital role in the ecosystem. We hope to see them in the Tasmanian bush again one day."
Cloning is described as one of the most publicly familiar ideas for resurrecting extinct animals. Scientists expect that once the resurrection of the Tasmanian tiger is successful, prehistoric animals such as larger mammoths will be experimented with in the future. However, the report mentions that there is a very critical constraint to this type of technology - it is only applicable to endangered or recently extinct species. Dinosaurs went extinct 65 million years ago, so they cannot be resurrected in this way as they are in the film.
Another method of bringing extinct animals back to life is known as "regression breeding", which involves identifying existing species that share similar characteristics with an extinct species and selectively breeding them to produce offspring that more closely resemble the extinct species. Scientists are currently using selective breeding to produce a species with characteristics very similar to those of the extinct European Protocow by screening modern cattle for genetic similarity from generation to generation.
In addition, there are scientists trying to take advantage of the phenomenon of animal ancestry, through the "reverse genetic engineering" to achieve the effect of restoring the ancestral characteristics of animals. For example, birds are thought to be the descendants of some kind of theropod dinosaurs, scientists are using "reverse genetic engineering" to try to wake up the sleeping dinosaur genes in the body of modern domestic chickens, so that chickens show some dinosaur characteristics. 2015, scientists have been through this kind of genetic technology, so that chickens have grown a beak similar to that of the dinosaurs.
There are many controversies
However, CNN also mentions that all current attempts at resurrecting extinct animals are essentially just creating a hybrid species that is very similar to an extinct animal. Gilbert, director of the Danish National Research Foundation's Centre for Evolutionary Holography, admits that it is unlikely that we will be able to obtain the complete DNA sequences of extinct species, and will never be able to locate those that are lost, and will have to replace them with the DNA of their closest relatives, with unpredictable consequences. "Genetically imperfect hybrid animals may develop health problems and may not be able to survive in nature without significant help from humans."
At the same time, usually the remains of extinct animals are mixed with other organisms in the neighbourhood and there is the problem of contaminated DNA, from which it is a challenge to identify and select broken DNA fragments of extinct animals. In addition, the maturity of contemporary genetic technology itself is also insufficient; in 2003, Spanish and French scientists briefly resurrected an extinct Pyrenean wild goat using sheep cloning technology. However, the lamb died of congenital lung lesions only seven minutes after birth, and the Pyrenean ibex became the first "twice-extinct species" in history.
However, proponents of resurrecting extinct animals argue that the fundamental purpose of this type of research is not just to bring some extinct animals back to life, but rather to attract public attention and support for biotechnology, and to build up technology in the process of research that can be used in the future to improve human health, food species, and other areas.
