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Nematodes, Climate Change, and Extinction Level Events

microscopic image of nematode

Human-driven global warming is having devastating impacts around the world. The Earth is warmer now than it has been since records began. Indeed, according to a report by the Intergovernmental Panel on Climate Change, the planet is hotter now than it has been in 125,000 years. This has led to record temperatures across the globe, with doctors in some places, like Arizona, having to treat people for third-degree burns after simply touching the pavement. Combine this with the deadly Mediterranean wildfires, the rapid rise in sea temperatures, and the shifting ocean currents, and we are on course for a bleak future.

However, while scientists have been predicting many of these impacts for decades, some more unusual happenings have come a little out of left field: case in point, the survival of ancient nematodes, a type of roundworm.

Now, I know that worms do not seem exciting compared to entire islands being ablaze or the seas getting so warm that there is a mass die-off of ocean life. Yet, these worms are fascinating as they are old, very old.

In an article in PloS Genetics, scientists recount how they discovered the frozen worms while excavating a fossilized squirrel burrow in northeastern Serbia. After bringing them back to their lab, the scientists thawed the worms, which are less than a millimeter long, and immersed them in a nutrition-rich environment. A couple of weeks later, the worms began wriggling and eating. Sadly, they died after only a few months, but not before reproducing, and now scientists and researchers are studying their descendants.

What makes this interesting is how long the worms had been in suspended animation. Similar species to the one excavated tend to live a total of 20-60 days. Yet, the worms recovered from Siberia were over 46,000 years old. This means that before they had gone into suspended animation, they were sharing the planet with Neanderthals, mammoths, and saber-toothed tigers. In itself, this is incredible. Those worms excavated from the permafrost could have been the oldest living multicellular organism to have existed. At the very least, they are contenders for the crown of the oldest reanimated multicellular creature.

While these worms will not help humanity’s quest for functional cryopreservation, their discovery does have immediate implications for the study of biological evolution; as Professor Teymuras Kurzchalia notes, “Our findings are important for the understanding of evolutionary processes because generations times could be stretched from days to millenia, and long-term survival of individuals of species can lead to the refoundation of otherwise extinct lineages.” In other words, the scale at which some species play out their lives has been extended dramatically.

The reason these worms were accessible to those scientists is because the Siberian permafrost is melting, and it is melting because the planet is heating up. As the frost recedes, scientists and explorers will gain access to more natural time capsules like stumps, crevices, and maybe even small caves. This means that more and more discoveries of this nature might be possible, and even more worms and other invertebrates species could be revived. In turn, this could provide even more insight into the natural mechanisms that underpin life on this planet. After all, if it has happened once, that is some reason to believe it could happen again.

This possibility, however, is not all sunshine and rainbows. While learning about how life came to be is an inherent good, not every organism that emerges from the newly revealed earth might be as harmless as a worm. Some could be actively dangerous. That is not to say that dinosaurs could be exhumed from the ice, brought back to life, and immediately go on a rampage (despite what films like Dinosaurus! tell us). Instead, it is far more likely that global warming could release ancient viruses and other pathogens from their icy slumber. If this happened, it could have devastating consequences.

The prospect is not as far-fetched as it might seem. Jean-Michel Claverie, emeritus professor of medicine and genomics at the Aix-Marseille University School of Medicine in France, has been testing samples taken from the Siberian permafrost to see what viruses are contained within and whether any could still be infectious. He’s managed to revive viruses from samples over 48,500 years old. Fortunately, these viruses are harmless to humans, targeting only amoebas. This, however, is a result of his deliberate choosing, as he wishes to avoid reviving anything which might infect humans. Indeed, pathogens we are susceptible to could be buried just below the surface, simply waiting for global temperature to rise enough to release them.

This is not simply scaremongering either. In 1997, a body discovered in Alaska contained the genomic material from the virus responsible for the 1918 Spanish flu pandemic (which killed roughly 500 million people). In 2012, The New England Journal of Medicine reported that mummified remains could be reservoirs of DNA fragments from ancient pathogens, including smallpox (which has killed more than 300 million people since 1900 alone). Finally, scientists traced an anthrax outbreak in Siberia directly back to the burial grounds of long-dead animals that had, until recently, been covered in permafrost (Anthrax being 100% fatal without treatment and only 55% survival with it).

In addition to the horrors we know about, the permafrost could harbor viruses and pathogens about which we have no idea, and more importantly, which our immune systems have no way of combating. As temperatures rise and increasing amounts of previously isolated ground are revealed, the danger grows that a disease that has not seen the light of day for hundreds of thousands of years, and to which we have no natural defense, could be released.

What does this mean for us? Well, in one sense, it should motivate us to up our efforts to reduce our carbon emissions, slowing and eventually reducing the global warming for which we are all responsible. On the other hand, however, we have already got a plethora of reasons to stop climate change, from ecological collapse to increasing the likelihood of war and famine. Is another potential danger going to tip us over the edge into more drastic action? Probably not.

Unfortunately, it seems that we may have to live with the ever-possible danger that the price for our modern way of life is the release of an ancient pathogen; one which could be as innocuous as the common cold, as deadly as smallpox, or potentially something far worse.

Should Scientists De-Extinct the Woolly Mammoth?

photograph of woolly mammoth sculpture

The startup Colossal Laboratories & Biosciences made headlines recently when they announced that they had received $15 million in funding for their project that is looking to “de-extinct” the woolly mammoth. The idea is to edit the DNA of an Asian elephant, resulting in the creation of an embryo that would be a hybrid of woolly mammoth and Asian elephant. While the project is in its early phases, CEO Ben Lamm has stated that the group’s eventual goal is to restore a sustainable population of mammoths to their once native tundra lands.

The project has raised more than a few eyebrows. There are, of course, many questions surrounding the science of the project, as it’s not clear what the chances of success really are. Then there have been the ethical questions. Many have drawn connections to Jurassic Park, although it seems unlikely that the woolly mammoth, should it be successfully reintroduced to the wild, would eat many theme park tourists. Instead, there have been concerns about whether the animals that could result from the project would, in fact, be able to live quality lives, whether they would have a negative impact on the environment and climate, and whether we should really be messing around with bringing animals back to life at all. The project leaders have pointed to potential benefits of the project in the form of developing gene technology that could result in new ways of helping existing animals, although this has prompted some to ask why developing this technology couldn’t be pursued without involving woolly mammoths.

Indeed, one of the biggest complaints lodged against the project is that there are plenty of endangered animals that could benefit from these kinds of efforts from the scientific community. For instance, in an interview with NPR, paleontologist and director of the Weis Earth Science Museum Joseph Frederickson notes that, “If you can create a mammoth or at least an elephant that looks like a good copy of a mammoth that could survive in Siberia, you could do quite a bit for the white rhino or the giant panda.” He also emphasized that there are endangered species with “dwindling genetic diversity” that could potentially benefit from the kind of gene technology being developed by Lamm and his team.

Here, though, is a question: why should we have greater obligations to animals that exist, but are endangered, than to animals that are extinct? Let’s say that there is value in trying to ensure the continued existence of the giant panda and white rhino. Didn’t woolly mammoths also have value? Is there more value to preserving the life of an animal species that exists, but is dwindling, as opposed to bringing an extinct species back to life?

We have, of course, seen some reasons to be concerned about resurrecting the woolly mammoth already, namely that doing so could have detrimental environmental consequences. While they happily roamed the earth thousands of years ago, a lot has changed since then, and so reintroducing them could very well go poorly for the environment and the animals themselves.

But let’s put that to the side. Say the woolly mammoth could be reintroduced successfully, the environment wouldn’t be any worse off for it, and there would be no JurassicPark-esque disastrous consequences. Would bringing back the woolly mammoth be worthwhile?

Some of those working on “de-extinction” projects think that it would be. For instance, the Revive & Restore group looks to “enhance biodiversity through the genetic rescue of endangered and extinct species,” and has interests in reviving not only the woolly mammoth, but the heath hen and passenger pigeon, as well. Some of the reasons that these animals in particular have been chosen is because of the viability of bringing them back at all (for example, they have close living ancestors), but also because they may be able to occupy certain ecological niches. One reason why we might want to bring such species back to life, then, is that doing so could repair the environmental damage done when they went extinct.

Again, it’s a matter of scientific debate as to whether such animals really are needed to fill ecological voids they may have left when they disappeared, or whether other animals have been able to fill those roles in the meantime. We might wonder, though, whether it would be a better idea to try to preserve the animals that currently exist and are in danger of becoming extinct, since we know for sure that they have a role to play in the environment.

There is perhaps an additional reason why we might want to bring certain species back from extinction: guilt. The going theory for many years was that woolly mammoths went extinct because of overhunting by humans (although that theory is also up for debate), and it is well-documented that the carrier pigeon was hunted to extinction, as was the heath hen. There is no doubt that humans are directly or indirectly responsible for the endangerment and extinction of a tremendous number of animal species, and so we might think that we have a special responsibility to those species that we had a hand in eliminating.

The issue of whether animals like the woolly mammoth should be brought back to life is certainly worth further discussion. However, given the uncertainty surrounding whether such an animal could, in fact, be successfully made un-extinct, and given that there is certainty surrounding the endangerment of animals like the giant panda and white rhino, one might suspect that more good could be done trying to preserve the animals that still exist rather than those that are long gone.

Is It Ethical to Extinguish a Species?

photograph of mosquito swarm, blurry from motion

Diseases like malaria, dengue fever, Zika fever, and chikungunya virus are responsible for hundreds of thousands of deaths each year. What is common to all of these illnesses? They are largely spread by mosquitoes who, while not being that harmful in themselves, are considered to be one of the deadliest creatures on the planet because of their ability to transmit disease. For example, one species of mosquito known as Aedes aegypti are mostly responsible for the transmission of dengue fever which kills 10-20,000 people every year. If this species of mosquito is deadly, why don’t we simply eradicate the species? A more important question, however, might be whether it is ethical to do so.

The idea of eradicating several species of mosquito has been proposed multiple times. Bringing about the extinction of Anopheles gambiae, which are prominent in the spread of malaria, could save millions of lives. Biologist Olivia Judson advocates for the use of genetic modification to cause “specicide.” She argues that “It is hard to argue that a targeted, genetic attempt to remove an insect that is clearly harmful to us is worse than the haphazard, expensive, destructive and largely unsuccessful approach we’re using now.” E.O. Wilson, a champion of biodiversity, has also advocated for the extinction of Anopheles gambiae noting, “Anopheles gambiae […] is specialized to live in human settlements and lives on human blood. As a result, it’s a principle conveyer of malaria. That’s one I wouldn’t mind seeing go.”

Many have wondered how the extinction of various species of mosquito might affect ecosystems. While Aedes aegypti is an important source of food for amphibians, bats, birds, fish, insects, and reptiles, it has been suggested that species could adjust to the loss of this food source while other mosquito species could fill the ecological niche. According to entomologist Joe Conlon, “if we eradicated them tomorrow, the ecosystems where they are active will hiccup and then get on with life. Something better or worse would take over.” Because of this, advocates of eliminating certain species of mosquitoes see little downside for the environment if they were driven to extinction. In the meantime, using genetic modification to eliminate the species may be preferred. The use of pesticides can be harmful to human health, and the elimination of mosquito breeding grounds pose greater risks of disrupting ecosystems.

One very prominent attempt to put this thinking into practice takes the form of Oxitec’s OX513A mosquito. Through genetic modification, the males of the species will not be able to produce viable offspring unless they are exposed to the antibiotic tetracycline. In other words, when released into the wild they will still be able to mate with female mosquitoes, but the resultant eggs will not be viable. Field trials of this genetically modified mosquito have been conducted in Brazil, the Cayman Islands, and Malaysia. As a result, the population of mosquitoes in the trial area have fallen by 80-95% and with a reduction of dengue fever cases by 91%. Since the modified mosquitoes are all male they must be replaced over time. However, since males do not bite humans, the immediate risk of a modified mosquito biting humans is minimal.

The prospect of eliminating an entire species carries some significant ethical considerations. One of these concerns is whether these edited genes are controllable. One of the reassurances of using a genetically modified mosquito is that the edited genes should disappear with their death; their offspring will not be viable, so there should be no chance of such organisms spreading. However, according to a study at Yale, mosquitoes captured up to two-and-a-half years after the release of OX513A carried genetic modifications signifying that some of their offspring did manage to survive. In other words, genes from the released OX513A mosquitoes did make it into the general population.

There are other important concerns. First, it is difficult to predict how changes to evolutionary pressures on viruses like dengue fever will affect their virulence. According to David B. Resnick at the National Institute of Health such modifications “might promote malaria resistance but increase yellow fever susceptibility.” In addition, there are concerns that Oxitec has not engaged as much public consultation as they should before releasing their mosquitoes in trial areas. There is also the more general concern about genetic modification. Various groups have opposed genetic modification as “they feel deeply that it is wrong to tamper with the DNA of wild things.”

But there is perhaps a more significant moral issue. Use of genetically modified organisms aside, there is still the question about eliminating a species. The most emphatic proponents of efforts to eradicate these mosquitoes seem to be those who focus on global health ethics. Eliminating certain species that cause great harm to humans will alleviate suffering and potentially save millions of lives, while at the same time their elimination is not likely to seriously harm ecosystems. From a global health perspective, the argument is clear.

Alternatively, from an environmental ethics standpoint there is concern about the unknown environmental effects. Even if the risk is minimal however, there is a more important question to consider: Does a species have inherent value such that it would be morally wrong to eliminate it even if their extinction served our interests? According to philosopher Paul W. Taylor a species is merely a class and only individual organisms within a class have inherent worth. Thus, there is nothing more immoral about eliminating a species like Anopheles gambiae than there is eliminating the individual insects.

Alternatively, JP Sterba emphasizes that species can evolve, become endangered, and go extinct. In effect, a species can be harmed or benefited, and therefore a species has a good of its own. If all species possess this kind of inherent value then eliminating Anopheles gambiae is immoral. This view asks us to look beyond whether we value Anopheles gambiae, or whether Anopheles gambiae is valuable for things we care about (like ecosystems), and consider the question of the value of the species from another vantage.

However, even if we accepted that a species has inherent value, that would not mean that it is more valuable than other considerations. So, perhaps, this very specific case is poignant because as the human species continues to practice ever more control over nature, we need to become better at understanding how and why things should be valued; these answers will be instructive in determining what we should (and should not) do with that control.

Modifying the Mosquito

Never in recent memory have the bounds of human impact on the world felt so wide. At a time when researchers are finding cans of soda at the bottom of the Marianas Trench, and scientists are grappling with the possibility of creating human-animal “chimera” tissues for study,  our ability to influence the world around us seems practically unparalleled. And when it comes to dealing with a public health crisis brought on by one of nature’s most annoying pests, it would seem that these limits may soon expand once again.

Continue reading “Modifying the Mosquito”