Edit: David
【New Zhiyuan Introduction】How to resurrect extinct animals? Spell one with DNA! For example, an ancient mammoth.
Is it really possible to bring extinct animals back to life?
For researchers studying the problem of "eliminating extinction," they're doing exactly that. A paper published in Contemporary Biology in March confirmed this.
Thomas Gilbert, a genomics researcher and professor at the University of Copenhagen, led a team of researchers to test the feasibility of "eliminating extinction" by sequencing the genomes of Christmas Island rats, which became extinct in the late 19th and early 20th centuries.
Of course, people cannot be resurrected from the dead, and the same is true for animals.
This research, which sounds a bit infiltratory, is simply to restore the genomes of extinct animals as completely as possible, and to recreate ancient animals that are to be "resurrected" at the DNA level.
Gilbert says his research now reflects the ideal state of extinction. The Christmas Island rats in the text went extinct not long ago, and DNA samples are relatively new and well preserved.
In addition, extinct mice are very closely related to the extant brown Norwegian rat, which has rich DNA reference data.
In terms of research difficulty, the "resurrection" of this mouse is much simpler than the "resurrection" of the jungle cat that has been extinct for a longer period of time, let alone the dinosaurs.
However, while this is theoretically the case, scientists have done their best to recover nearly 5 percent of the genome of Christmas island rats. Many of the missing genes are associated with immunity and smell, which are two very important functions.
Gilbert said: "It's not just the irrelevant things, a lot of things can't be found, so what you end up with may be completely different from what is extinct."
While the Gilbert team's findings have new perspectives, they are still consistent in many ways with what many scientists have long understood.
Beth Shapiro, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, said: "The biggest misconception about eliminating extinction is that this goal can be achieved."
Ben Novak, chief scientist at Revival and Restoration, one of the forefront of extinction-free nonprofits, readily agrees with Shapiro.
"You'll never be able to bring extinct creatures back to life."
But for Novak and most of the researchers who eliminated extinction, creating a functional "replacement" with extinct animals is not a problem, which is the main goal of the extinction elimination organization.
In fact, most researchers don't want to revive an attractive ancient animal and put it in a zoo for people to see.
Rather, the main purpose of these studies is to educate or protect the ecology, creating "alternatives" to these ancient animals, such as filling the gaps left in the ecosystem by the extinction of these animals, or saving endangered species and increasing the population of endangered animals.
"Spelling" out a genome
"Eliminating extinction" is a daunting challenge that starts with DNA.
In Jurassic Park novels and movies, dinosaur DNA from more than 65 million years ago can be extracted from mosquitoes preserved in amber. But in real life, DNA is too fragile to survive that long. Its half-life is only about 521 years.
Even in well-preserved tissues left behind by recently extinct species, the DNA contained is often fragmented.
"Because these DNA fragments are so small, it's impossible to reassemble them like a puzzle to put them together as they were," Says Novak.
In particular, on reconstructed chromosomes, the order of genes is not always clear. These details are important because studies of living species have shown that a slight change in the order of genes can have a significant impact on animal behavior and other traits.
Researchers typically use the genome of a species closely related to extinct animals as a guide, but this approach has limitations.
"Even if we could get 100 percent of its genetic code, we would still create an organism with the same genetic order and number of chromosomes as its living relatives," Novak said. As Gilbert's new work suggests, approaching all of the genetic code may often be impossible.
Many extinct species have intrigued biologists, but not all extinct species are suited to efforts to eliminate extinction. The image above (from the top left, clockwise) shows the now extinct Terraca, Kwaga, Christmas Island Rat and Dodo.
Resurrecting the ancient mammoth is on its way
Gilbert's research suggests that genetic engineering is the difficulty of "eliminating extinction," an approach favored by researchers such as Harvard's genetics professor George Church, who is currently leading a research project aimed at reviving mammoths from prehistoric times.
The project, driven by Colossal, a company co-founded by Church, aims to use CRISPR to edit the genomes of existing Asian elephants to recreate them.
In this sense, this creature is very similar to mammoths, but it is actually more like a mixture of elephants and mammoths.
In fact, Church's lab has been advancing the project for years. And the company has managed to convince investors that this crazy project to revive mammoths can really come true.
In September 2021, Colossal's "Resurrected Mammoth" project received a $15 million seed round led by former CEO of Legendary Entertainment, Thomas Tull.
The round included investments from institutions and individuals such as Breyer Capital, Global Space Ventures, Climate Capital, Winklevoss Capital, Liquid2 Ventures, Capital Factory, Tony Robbins and First Light Capital.
"This project could completely change our understanding of modern genetics while developing innovative technologies that not only have the potential to bring back species that have disappeared, but will also drive the industry as a whole," said Tony Robbins, who participated. "I am proud to be part of this investment."
Bigger goal: To save endangered species, about 1 million plant and animal species are currently threatened with extinction.
If the Colossal project is successful, it means that it has been developed to resurrect the recently extinct creatures, and even to implement "genetic rescue" to prevent extinction.
The so-called "gene rescue" is the process of increasing genetic diversity in endangered populations through gene editing. In some cases, it is even possible to create a broader gene pool by cloning new individuals.
There is already some evidence that this is possible. In February 2021, a black-footed ferret named Elizabeth Ann became the first cloned endangered species native to North America. She successfully cloned DNA from frozen tissue samples collected in 1988.
3D rendering of a mammoth in the mountains
Resurrecting extinct animals may help address the consequences of climate change, but it won't solve the underlying problem. As long as the human drivers of climate change remain, there is little hope that new organisms that previously went extinct as a result of climate change will have much hope of surviving; in fact, climate fluctuations are one of the reasons why megafauna went extinct in the first place.
Moreover, resurrecting extinct species can have serious adverse consequences for ecosystems, such as spreading new diseases, crowding out existing species, and changing the actual situation of ecosystems (after all, elephants are called "ecosystem engineers").
From the perspective of another Colossal co-founder, Ram, this sprawling project resembles a moonshot.
To achieve their ultimate goal, they must develop specialized other intermediate technologies that can be licensed or sold to potential buyers.
"This project is very similar to the real moon landing program, the Apollo program. When the Apollo program was in progress, a series of new technologies were born during the period. Such as GPS, Internet and semiconductor technology. All of these technologies are very easy to monetize." He said.
In short, this Mammoth Resurrection project is more like an incubator for developing a lot of intellectual property. Ram pointed out that this may include artificial uterus, as well as other APPLICATIONS based on CRISPR.
Many of these projects will still face significant scientific hurdles — existing artificial uterus projects haven't even entered the human trial phase — but overcoming these hurdles may be easier to achieve than the big goal of reviving mammoths.
For the ambitious "resurrection of mammoths" project, Gilbert said, "Even if an elephant is resurrected in the end, it is certainly not a mammoth." What you get is probably a "hairy elephant" that can live in the cold.
Another researcher, Shapiro, said, "The reason I'm excited about this type of research is not because I think we're going to get a mammoth, I think it's a goal that can't be achieved, but in the process of our efforts, it can really play a major role in protecting existing living species and promoting ecological diversity."
Resources:
https://techcrunch.com/2021/09/13/how-colossal-sold-investors-on-a-quest-to-resurrect-a-woolly-mammoth/
https://www.cnbc.com/2021/09/13/geneticist-george-church-gets-funding-for-lab-grown-woolly-mammoths.html
https://www.quantamagazine.org/why-de-extinction-is-impossible-but-could-work-anyway-20220509/