Scientists investigating the extinction problem of Australian rat species

Mice on Australia’s extinct Christmas Island are the subject of scientists’ research into the potential for extinction and the ethics behind it.

Tom Gilbert, an evolutionary geneticist at the University of Copenhagen (UCPH) in Denmark, is trying to rebuild an extinct Christmas Island rat, also known as McClear’s rat.

Mice on Christmas Island have been extinct since 1903. Australian marsupials were wiped out by a deadly disease brought home by a European black rat brought to the island by a British explorer in 1886.

UCPH Gilbert Media release On March 9, Maclear’s rats were extinct only 119 years ago, and their genome did not diverge significantly from modern rat species, making them suitable candidates for extinction.

“To get something back by genome editing, you find the closest living relative, and it’s an animal that lives today with a genome that most resembles an extinct one. This is a minimal edit. “I need it,” Gilbert said in an email to the Epoch Times. “The more they diverge from each other, the more they will have evolved.”

So far, extinction scientists have focused primarily on animals that died earlier than Mammoths and other McClear rats.

Early animal reconstructions are less accurate than the original animals because most of the genomes of extinct animals cannot be identified. The modern genome of the closest living relatives of an extinct animal is used to interpret the old genome, and if it evolves significantly from an extinct creature, a large chunk of the genome remains indistinguishable.

“As we try to use the genomes of increasingly distant species to regain the genome sequences of extinct species, we miss more and more information,” Gilbert said.

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A model of the Woolly Mammoth at the Royal BC Museum. (CC BY 2.0 / Wikimedia)

He says that a completely intact book is like the genome of a modern organism, and even if the book is shredded, it can be deciphered by reading all the books in sufficient time, so much about it. Said that it can be deciphered.

“But say this book is written in 15th century English, and say you’re not a 15th century English scholar,” he said. “Sure, you can look at every piece and guess what some are, but others aren’t very clear.”

“One of the things you can do is take all the pieces out and compare them to the understandable 20th century edition of the book,” Gilbert said. “Many fragments match, but some haven’t changed because some of the languages ​​have changed so much in 500 years.”

“This is essentially our point. DNA changes are fast in some parts of the genome and slow in other parts,” he said.

“Comparing a crappy sequence of fragmented Christmas rats to a modern sequence, about 95% of the sequences are still similar to modern rats and can be identified. However, 5% have too many changes, I can’t identify it. “

Although 5% of the Christmas Island rat genome cannot be identified, 95% have been determined by sequencing the DNA of extinct rats and comparing them to the Norwegian rat genome.

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Rattus norvegicus. (Pete Beard / Flickr CC BY 2.0)

Theoretically, a partially identified genome could be used to produce a hybrid of extinct rats. Scientists can use CRISPR technology to edit the DNA of living species and match it with the DNA of extinct organisms. This is an important scientific development.

CRISPR technology consists of two molecules: an enzyme called Cas9 and an RNA called a guide RNA or gRNA. RNA delivers a message from DNA to the cell’s protein manufacturing plant.

The enzyme acts like scissors, cutting two strands of the DNA helix at specific locations in the genome, allowing DNA to be removed or added. The RNA sequence acts as a map of the enzyme, dictating where to cut.

When the enzyme makes a cut, the cell recognizes that it is damaged and tries to repair the cut. This allows scientists to use the cellular DNA repair mechanism to introduce mutations into that region of the genome.

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This study conveys large-scale scientific development, but it also reinforces ethical debate about the process of extinction. This study proves that animals produced by this process cannot be extinct animals as they should be.

According to Gilbert, unrecognizable genomic sequencers are probably concentrated in important genomic regions, such as the regions that cause the body’s sense of smell.

“And given that the Evolutionary Hologenomics Center believes that the genome shapes the microflora and that the microbiota shapes the way things live, how does this missing genetic information affect the animal’s microflora? I’m wondering if it’s possible, “Gilbert said. UCPH Media release..

In an email to the Epoch Times, Gilbert investigates whether the purpose of his work is not to reestablish the population of McClear rats on Christmas Island, but to reconstruct extinct rats by genetic editing. I said that.

“Given that when released, it doesn’t exactly match the lost form, I think it will die as soon as it’s biologically ruined. And certainly, the right microbes that are key to survival. I don’t have a flora, “he said.

Gilbert said the choice between spending money to get back an extinct animal or spending money to save an endangered animal is “not a headache.” He focuses on saving animals that are currently endangered, as the process of extinction cannot make 100% replicas of extinct creatures, and therefore replicas cannot function as lost. Said that guessing is a better choice.

“Of course, money doesn’t work that way in reality,” Gilbert said. “Some wealthy philanthropists only want to help disappear … that’s great. I’m all for those who are trying. But our message is … exactly what you want. You won’t get it. “

On the other hand, Australia’s marsupials, which are currently on the verge of extinction, are not the only marsupials in McClear.

In Melbourne, Australia, scientists are trying to regain the Tasmania Tiger population and are building a $ 5 million gene repair lab.

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Tasmania Tiger (Thylacine) exhibited at the Australian Museum in Sydney in 2002. (TorstenBlackwood / AFP / Getty Images)

Professor Andrew Pask of the University of Melbourne’s Department of Life Sciences states that Tyramine is one of the most compelling cases of all proposed extinction species.

Pask argued that this was because Tasmania’s habitat had changed little and provided an optimal environment for reintroducing Tyramine.

Lily Kelly


Lily Kelly is a reporter for The Epoch Times, based in Australia, dealing with social issues, renewable energy, the environment, health and science.