Exploring the Limitations of Resurrecting Extinct Animals

Exploring the Limitations of Resurrecting Extinct Animals ...

De-extinction, a process in which scientists resurrect an organism that is or resembles an extinct species, was once thought of as science fiction. Now, advances in genomic technologies have made it a future reality.

Last month, the University of Melbourne announced that it had received $5 million to construct the Thylacine Integrated Genetic Restoration (TIGRR) laboratory. It is led by Professor Andrew Pask and will develop technologies to resurrect the thylacine (also called the Tasmanian tiger).

Other, smaller creatures are also candidates. Five stages of the de-extinction plan, led by Revive & Restores, suggests reintroduce the passenger pigeon to the Eastern forests of the United States. It suggests that reintroduced the pigeon might stimulate cycle of regeneration, thus increasing the productivity and diversity of the forests.

Professor Tom Gilbert, an evolutionary geneticist at the University of Copenhagen, says he is fascinated with the possibility and technology of de-extinction. Im also somewhat of a nerd when it comes to methods [] and prefer to think about the potential but also limitations.

Gilberts new study, published in Current Biology, where his team utilised the Christmas Island rat (Rattus macleari) as a model to examine these limitations in de-extinction via one particular method.

Genome editing methods for de-extinction

Back-breeding, cloning, and genetic engineering are three avenues for de-extinction. According to Gilbert, genetic engineering is a way to make living cells easier and alter the sequence of the DNA in it, at very specific pre-chosen positions.

If scientists know exactly where an extinct species genome differs from a living relative, they may (in theory) use genome editing to help shape those changes into the organism that is living. Heres a simple analogy. Say you take a text written in US English, and you might just go through and replace all the Z with S. Well, it hasn''t substantially changed the text, but now it''s different at key locations.

Although genetic engineering is dependent on an in-depth understanding of the extinct organisms genome, Gilbert explains that if there are no samples, there is no DNA. Thirdly, I had previously investigated why the Christmas Island rat went extinct (pathogens!) from 1898 to 1908. It has a lot going for it. Thirdly, if you wanted to do so, starting with a rat is easier than say, mammoths, thylacines, etc.

An incomplete picture

Gilbert and colleagues re-sequenced the Christmas Island rat genome and compared it to reference genomes of living members of the Rattus species. Lastly, they examined how evolutionary diversity from the extant reference genome affects the fraction of the Christmas Island rat genome that might be recovered. Despite this, nearly five percent of the genome sequence is unrecoverable, although 1,661 genes were fully absent. Several of the missing genes are implicated in the rats sense of smell, meaning a de-ex

Never say never, however. We have a set assumption that we can never get better DNA from Christmas Island rats. Perhaps this was the case. Or, a Christmas Island rat is discovered deep frozen in an early freezer or preserved in a way that indicates the DNA is of greater quality. That might, however, not alter the picture''s overall picture.

Why not start small?

The researchers are looking to expand beyond computational research and conducting laboratory experiments, whereby they might reintroduce notes into a living relative of the Christmas Island rat and explore the benefits they have. Is it even possible or do you just get a very screwed up hybrid? Gilbert asks.

Gilbert believes that exploring de-extinction in organisms beyond those considered grandeur is problematic not to, but that it depends on the scientists goal. If your goal is to make money, inspire people or something along those lines, then may it be possible to focus on something people will understand. I guess this can be based on modern species, whether it is because you believe that our human eradication has the greatest effect.

A further problematic issue is that, if you are considering de-extinction from an ethical or philosophical perspective, why not stop at the good things? What''s new about the pathogens, according to him, is the right way of life: if the individual is de-extinction philosophically, it becomes problematic.

Certainly, there are a number of ethical and societal concerns about de-extinction. As far as science is concerned, Gilbert and colleagues argue that genome editing should be used as the method of choice. While de-extinction projects continue in various parts of the world, Gilbert is hesitant to make the most appropriate use of scientific effort and resources. I am also interested in the possibility that money may be used in a world of limited resources. Although, I am not sure whether or not to, however

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