Month: Feb 2019

The Race to Save Pando

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First Published in UCD College Tribune

Pando is the largest living thing on earth. Weighing 6,000,000 kilograms, it is about as heavy as a thousand African elephants or forty blue whales. When you enter Pando, you may hear a soothing sound like the beating of tiny wings. Pando is a grove of 47,000 quaking aspen trees, named for the distinct sound their leaves make in the wind. Every tree in the forest is genetically identical. This is because they are all parts of a single being, connected underground by a huge root system. We cannot be sure of Pando’s age, but based on its rate of expansion, coupled with a knowledge of historic climatic conditions, it could be up to 80,000 years old. If Pando is this old, it is not only the largest known organism on earth but also the oldest. In a painfully familiar twist, humans pose a serious threat to this gentle giant.

Pando’s name derives from the Latin for ‘I spread’ as Pando started life as one seed, then gradually spread itself out over an incredible 106 acres of Utah, an area equivalent to 1,700 tennis courts. Aspen spread through a process called vegetative reproduction. They send out roots underground which travel horizontally for as much as a hundred feet before sprouting into new trees. The roots then carry water and nutrients to the new sprout as needed. One reason why aspen clones like Pando can get so big is that aspen are remarkably quick to repopulate an area following a major destructive event like a forest fire. Aspen compete with conifers for light and nutrients, a competition they may well lose without the help of forest fires. Unfortunately for aspen, humans tend to put out fires wherever we can, leaving conifers to creep into the aspen’s territory. This is just one of the ways in which we are harming Pando.

For the last hundred years or so, humans have been hunting predators like wolves, bears and mountain lions in Utah and the surrounding area, leading to an increase in ungulate (hoofed mammal) populations. The main culprits are a species known as mule-deer, who eat young aspen trees before they have time to grow a thick bark with which to protect themselves. Not only does a decline in predator populations mean that fewer mule deer are being eaten, but it also means that they have become more likely to stick around and enjoy the good eating. With no predators to chase them away, the deer see no reason to move on and find a new feeding spot.

It does not help that the US forest service allows ranchers to graze their cattle on Pando for two weeks every year. Aerial photographs taken over the last fifty years show that Pando is in serious trouble. Given such data, it is extremely irresponsible for the forest service to allow any grazing at all. You may well be wondering at this point why I’m telling you all this. Pando is not like other organisms. While it is a single being, Pando is also a vast ecosystem which is home to a huge variety of animals from black bears to wild turkeys. By saving Pando, we are saving not only a biological marvel but also a forest and everything that lives within it.

A healthy aspen grove should have trees of all ages growing within it. As in a human community, it is far from ideal for the individual trees to all be the same age. If everyone in a town is over 80, there will be no youngsters to replace them when they’re gone, and the town will die with them. This is exactly what is happening to Pando’s trees. The director of the Western Aspen Alliance and Pando expert Paul Rogers has said that in many areas there are “no young or middle-aged trees at all” and that the trees that remain are “very elderly senior citizens”. Aspen trees can live anywhere from around 75-150 years old. Worryingly, the average age of trees in Pando is 130 years; if we are to save it, we are going to have to move very fast indeed.

So what can be done to save Pando? Paul Rogers recently conducted an experiment in which parts of Pando were fenced off to stop ungulates from getting in. The experiment showed very promising results, although, despite the fences being 8 feet tall, the deer were somehow able to jump over them in some places and damage the new shoots. Some have suggested that to save Pando, wolves need to be reintroduced into the ecosystem to kill the deer. The proximity of Pando to campsites and cottages makes this idea hard to sell. The evidence suggests that taller fences around larger sections of the grove and a ban on all grazing should allow new trees to flourish. Once a new generation of trees come up and live to maturity, Pando will be in a strong position to live on for years to come. However, it will also face the very real threat of global warming if we do not significantly reduce our emissions soon.

Pando’s downfall is emblematic of the large scale ecological and climatic devastation that humans have wrought on this planet. By altering certain variables, we may have sealed Pando’s fate without even knowing it was there. It is important that knock-on effects like these are understood so that we may avoid repeating the same mistakes. Pando is also a symbol of how, with a bit of elbow grease and a bit less greed, we can at least partially right many of the wrongs that we have done to the natural world. When you are responsible for a problem, it is your responsibility to fix it. We can save Pando. Maybe by joining together to preserve this one beautiful colossus, we can create a success story that can serve as a poster-child for conservation efforts around the globe.

Gene Genie: The Scientist who Jumped the Gun on Gene Editing

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First published in the UCD College Tribune

In November of 2018, Chinese scientist He Jiankui made an announcement that astonished the scientific community. He claims to have helped to make the first ever gene-edited babies with the use of a revolutionary technology called CRISPR. The babies, twins by the names of Lulu and Nana, were born to a father infected with HIV, the virus which causes AIDS. If Dr He’s experiment is successful, the twins will have an immunity to the virus. While this may seem at face value to be a noble goal, many believe that the risks involved outweigh the benefits.

Dr He’s experiments used a type of editing called ‘germline’ editing, meaning that any children that Lulu and Nana may have in the future will also carry this immunity. Germline editing involves making changes to reproductive cells. This means that any changes made to the individual’s genome will be passed on from generation to generation. This can be distinguished from somatic editing, in which the only person affected by the edit is the person who undergoes the procedure.

One reason why somatic editing is seen as more acceptable than germline is that people who undergo somatic editing have given informed consent prior to the procedure. While the parents of Lulu and Nana have given consent, the children themselves and any future children the twins may conceive have not consented to the potentially high risks. While HIV immunity could potentially be inherited by the descendants of these CRISPR babies, so could a myriad of unwanted and possibly even deadly side-effects.

Another concern that has been raised is that it is not clear whether Dr He’s treatment fulfilled an ‘unmet medical need’. With modern HIV treatments, someone who is carrying the virus can have the same expected lifespan as someone who is not and their chance of transmitting the virus to their children can be brought down to just 5%. Hence, geneticists worldwide have called for a moratorium on human germline trials. Critics say that gene editing technology has not yet been developed or tested sufficiently for use on human embryos. We simply do not yet know the long-term effects of genetic modification using CRISPR.

Despite a myriad of imaginable ethical hazards, CRISPR has the potential to revolutionize the biomedical sciences. CRISPR allows biologists to edit genetic information by using an enzyme called Cas9, which has the ability to cut strands of DNA. The process was pioneered in bacteria as a defence mechanism against viruses. Geneticists use CRISPR to target specific areas of genetic code and cut it in a specified region. Cutting a strand of DNA in the right place can cause a certain gene to be disabled, activated or replaced by one introduced by scientists. The possible applications of CRISPR range from curing cancer to eliminating malaria from mosquitos. One team at Harvard led by Prof. George Church even famously claimed that they will be able to ostensibly resurrect the woolly mammoth in the next year or two using the technology.

Some scientists, including mammoth-man George Church, have come out in defence of He. While Church had reservations regarding He’s level of transparency, he suggested that enough studies had been carried out that maybe it was the right time to end the moratorium anyway. While he accepted the risk of off-target mutations, he said that the risk ‘may never be zero’ and that Dr He had done enough to minimise it. This contradicts the views of most scientists and institutions, including a statement released by Francis Collins, the director of the National Institutes of Health. Collins denounced He’s work, saying, among other things, that ‘the possibility of damaging off-target effects has not been satisfactorily explored’.

Genes are extremely complex things. Locating a single gene and modifying it requires an extraordinary level of precision and even when it is successfully targeted it is impossible to fully predict the consequences. Though we have been studying certain genes for a very long time, we still do not know what the indirect effects of certain edits may be as no long-term studies of how edits affect the human body have been carried out as of yet. Such unintended effects are known as ‘off-target mutations’.

The final concern is perhaps the most serious. While CRISPR may in the future be used to treat some forms of cancer, it is possible that premature germline editing like the kind He carried out may actually increase the risk of cancer in people like Lulu, Nana and their descendants. Two recent studies have raised concerns about an off-target effect that CRISPR may have on a gene for a protein known as the ‘guardian of the genome’: p53. This protein is responsible for repairing or destroying damaged DNA. A mutated or ineffective p53 gene has been shown to be responsible for nearly half of all ovarian cancers and a significant portion of many other types of cancer too. CRISPR interventions activate p53, since DNA has been cut and must be either repaired or destroyed and p53 undoes the work CRISPR has done. The worry is that this could result in a kind of artificial selection on the cellular level, as CRISPR is more successful in cells with ineffective copies of the p53 gene, which are more at risk of becoming cancer cells. So far, only certain forms of cells have shown evidence of raising the risk of cancer when modified using CRISPR and no company is attempting clinical trials using CRISPR on these cells. Some scientists have called the recent studies concerning p53 a ‘cautionary tale’ since they may affect future CRISPR trials that are yet to begin.

CRISPR is an incredible technology that will surely be responsible for many breakthroughs in biological and medical science. It may someday give us powers that we cannot even conceive of today. However, that time has not yet come. It is imperative that we do not jump the gun. Dangerous, premature experiments like Dr He’s harm the public perception of gene editing and, in turn, harm the funding available for important research. While we should not give up on gene editing, we should also not use it to play with human lives until we know more about the benefits and the risks.