BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Crispr (Page 3 of 6)

Can We Genetically Modify Humans to Live on Mars?

CRISPR is a gene-editing technique that modifies the genomes of living organisms. They do this by searching for a strand of DNA and “when the target DNA is found, Cas9 – one of the enzymes produced by the CRISPR system – binds to the DNA and cuts it, shutting the targeted gene off.” CRISPR has been used to cure people of genetic diseases. Crispr

Humans have always dreamed of being able to live freely on another planet other than earth. It has been the topic of many pop culture movies throughout history. However with the use of gene editing theoretically this is possible. In a research paper written in 2016, they state that the main problems of living in other worlds would be radiation. With the use of gene-editing they’ve found that the protein named “Dsup prevented the animal’s DNA from breaking under the stress of radiation and desiccation“. It was also able to block X-ray damage by almost 40%. Lisa Nip a scientist at MIT state that “using genetic editing tools like CRISPR to actually transform our own DNA and make ourselves more able to survive in space.” This relates to our AP Bio class as we learned about genes as well as how the genes shape our traits as human. The idea of changing our genes is incredible as we always believed that it’s just how we were born and our parent’s chromosomes determined how we are, but now with CRISPR gene-editing, they can alter our DNA structure. Then through Mitosis, we are able to multiply our DNA, and eventually, all our genes are the edited version.DNA replication cy

CRISPR is rapidly advancing our research of gene-editing as it is the easiest and most reliable way to review gene-editing meaning that people are able to study it easily. This also means that scientist have easy access to it and are able to run many trials on DNA editing. Finally, there is a moral question to ask. Is it ethical to edit a person’s genes even if it helps them? Should we tamper with our human genetics? These questions aren’t very pressing as of now because we are still in the primary stages of gene-editing, however, some day these are going to be upon us. Thank You For reading let me know what you think about gene-editing down below.

CRISPR Tomatoes Help You De-Stress

Tomato jeFor the first time, genome-edited food is being sold on the open market. A recent article published on December 14th, 2021 outlines how CRISPR-Cas9 technology has been used to create genome-edited food. Consumers in Japan have been able to purchase genetically edited Sicilian Rouge tomatoes through the Tokyo-based company, Sanatech Seed. These genetically edited tomatoes have been altered to have high amounts of y-aminobutyric, aka GABA. 

In Japan, consuming GABA is very popular. It is supposed to lower blood pressure and promote relaxation. It does so through reducing the excitement of neurons in the nervous system. GABA is an inhibition neurotransmitter in the nervous system.

To test its audience, in May 2021 Sanatech first sent seedlings for genome-edited tomatoes to 4,200 home gardeners in Japan. Because of the positive feedback and high demand, Sanatech started selling tomatoes to the general public.

The tomatoes are altered through CRISPR-Cas9 genome editing. CRISPR has successfully been used to alter foods, such as making mushrooms that don’t brown, or soybeans that are tolerant to drought. Although many foods have been regulated, these tomatoes by Sanatech are the first to be commercialized.

CRISPR Cas9 technologyCRISPR is a technology that can be used to edit the genes of prokaryotic organisms like archea and bacteria. CRISPR is a way of finding a specific sequence of DNA in a cell, and then altering that DNA. CRISPR-Cas9 (pictured to the right) is the enzyme which finds and binds with specific DNA strands complementary to the CRISPR sequence.

DNA simple2DNA is a polymer which carries the genetic instructions for an organism. It is made up of two strands of bases (two polynucleotide chains) which compliment each other. Each base in a strand of bases can be one of four nucleotides, adenine, thymine, guanine, and cytosine. One nucleotide, or base, on one side of the DNA double helix matches with the corresponding base on the other side of the DNA to form a base pair. Adenine nucleotides must match with thymine, and guanine must match with cytosine.

GRNA-Cas9Sanatech increased GABA in the tomatoes by altering GABA’s metabolic pathway, aka the GABA shunt. They first inserted a strand of guide RNA along with the enzyme CRISPR-Cas9. This guide RNA is a strand that compliments the part of the DNA strand Sanatech wishes to disable: the gene that encodes CaMBD (calmodulin binding dominant). The RNA strand attaches, and the enzyme CRISPR-Cas9 cuts the DNA sequence Sanatech wishes to remove out. Disabling the gene that encodes CaMBD increases the enzyme glutamic acid decarboxylase’s activity. This enzyme catalyzes the decarboxylation of glutamate to GABA, raising GABA levels.

Increasing GABA levels is said to be a healthy way to decrease stress and lower blood pressure, and people around the world love being able to do so through eating everyday foods, such as tomatoes. People are also more accepting of these genome altered tomatoes because they have been edited specifically by CRISPR, which is a pretty trusted and well known form of gene editing technology. CRISPR technology has, and will, change the world by giving humans the power to alter and change DNA.

CRISPR Mini | New Territory Unlocked

For over a million years, DNA has centered itself as the building block of life. On one hand, DNA (and the genes DNA makes up) shapes organisms with regard to physical appearance or ways one perceives the world through such senses as vision. However, DNA may also prove problematic, causing sickness/disease either through inherited traits or mutations. For many years, scientists have focused on remedies that indirectly target these harmful mutations. For example, a mutation that causes cancer may be treated through chemotherapy or radiation, where both good and bad cells are killed to stop unchecked cell replication. However, a new area of research, CRISPR, approaches such problems with a new perspective.

The treatment CRISPR arose to answer the question: what if scientists could edit DNA? This technology involves two key components – a guide RNA and a CAS9 protein. Scientists design a guide RNA that locates a specific target area on a strand of DNA. This guide RNA is attached to a CAS9 protein, a molecular scissor that removes the desired DNA nucleotides upon locating them. Thus, this method unlocks the door to edit and replace sequences in DNA and, subsequently, the ways such coding physically manifests itself. Moreover, researchers at Stanford University believe they have further broadened CRISPR’s horizon with their discovery of a way to engineer a smaller and more accessible CRISPR technology.

This study aimed to fix one of CRISPR’s major flaws – it is too large to function in smaller cells, tissues, and organisms. Specifically, the focus of the study was finding a smaller Cas protein that was still effective in mammalian cells. The CRISPR system generally uses a Cas9 protein, which is made of 1000-1500 amino acids. However, researchers experimented with a Cas12f protein which contained only 400-700 amino acids. Here, the new CasMINI only had 529 amino acids. Still, the researchers needed to figure out if this simple protein, which had only existed in Archaea, could be effective in mammals that had more complicated DNA.

To determine whether Cas12f could function in mammals, researchers located mutations in the protein that seemed promising for CRISPR. The goal was for a variant to activate a protein in a cell, turning it green, as this signaled a working variant. After heavy bioengineering, almost all the cells turned green under a microscope. Thus, put together with a guide RNA, CasMINI has been found to work in lab experiments with editing human cells. Indeed, the system was effective throughout the vast majority of tests. While there are still pushes to shrink the mini CRISPR further through a focus on creating a smaller guide RNA, this new technology has already opened the door to a variety of opportunities. I am hopeful that this new system will better the general well-being as a widespread cure to sickness and disease. Though CRISPR, and especially its mini version, are new tools in need of much experimentation, their early findings hint at a future where humans can pave a new path forward in science.

What do you think? Does this small CRISPR technology unlock a new realm of possibility or does it merely shed light on scientists’ lack of control over the world around us?

Unnatural Selection: The Future of The Future?

Imagine it’s Saturday night, you are snowed in until the morning and you need a way to pass the time. Like many people, you resort to Netflix. Upon browsing through the vast selection of horror, comedy, and romantic films, you decide you are in the mood for a documentary. Scrolling through the options, you stop at a title that grabs your attention: Unnatural Selection.

Since you are an AP Biology student, you immediately connect the words “Natural Selection” to the work of Charles Darwin, the study of genetics, and most importantly: evolution. In brief, natural selection is the survival and reproduction of the fittest, the idea that organisms with traits better suited to living in a specific environment will survive to reproduce offspring with similar traits. Those with unfavorable traits may not be able to reproduce, and therefore those traits are no longer passed down through that species. Natural selection is a mechanism for genetic diversity in evolution, and it is how species adapt to certain environments over many generations.

If genetic diversity enables natural selection, then what enables unnatural selection? Well, If natural selection eradicates unfavorable traits naturally, then unnatural selection essentially eradicates unfavorable traits or promotes favorable traits artificially.

The Netflix docuseries “Unnatural Selection” focuses on the emergence of a new gene-editing technology named CRISPR (an acronym for “Clustered regularly interspaced short palindromic repeats”). CRISPR is a revolutionary new method of DNA editing, which could help cure both patients with genetic diseases and patients who are at risk of inheriting unwanted genetic diseases. The two pioneers of this technology, Emmanuelle Charpentier and Jennifer Doudna, recently won Nobel Prizes in Chemistry for their work on CRISPR.

CRISPR illustration gif animation 1

Animation of CRISPR using guide RNA to identify where to cut the DNA, and cutting the DNA using the Cas9 enzyme

CRISPR works with the Cas9 enzyme to locate and cut a specific segment of DNA. Scientists first identify the sequence of the human genome, and locates a specific region that needs to be altered. Using that sequence, they design a guide RNA strand that will help the Cas9 enzyme, otherwise known as the “molecular scissors” to locate the specific gene, and then make precision cuts. With the affected region removed, scientists can now insert a correct sequence in its place.

Using the bacterial quirk that is CRISPR, scientists have essentially given anyone with a micropipette and an internet connection the power to manipulate the genetic code of any living thing.

Megan Molteni / WIRED

CRISPR is just the beginning of gene editing, introducing a new field of potential gene editing research and applications. But with great power comes great responsibility — and great controversy. Aside from the obvious concerns, people speculating the safety, research, and trials of this new treatment, CRISPR headlines are dominated by a hefty ethical dilemma. On one hand, treating a patient for sickle cell anemia will rid them of pain and suffering, and allows their offspring to enjoy a normal life as well. However, by eliminating the passing down of this trait, sickle cell anemia is slowly eliminated from the human gene pool. Rather than natural selection choosing the path of human evolution — we are. We are selecting which traits we deem “abnormal” and are removing them scientifically. Although CRISPR treatment is intended to help people enjoy normal lives and have equally as happy children, putting evolution into the hands of those evolving can result in more drastic effects in the future.

For our generation, CRISPR seems like a magical cure for genetic diseases. But for future generations, CRISPR could very well be seen as the source of many problems such as overpopulation, low genetic diversity, and future alterations such as “designer babies.” Humans have reached the point where we are capable of our future. Is CRISPR going to solve all of our problems, or put an end to the diverse human race as we know it? Comment how you feel down in the comments.

 

CRISP[ie]R Corn Kernels?

Corn is unique in the way that its genome is highly complex, thus causing it to be very difficult to edit those genes with technology such as CRISPR. CRISPR is an advanced technology that is used to find a specific portion of DNA in a cell and then it alters that piece of DNA. To learn more about CRISPR, click here.

CRISPR CAS9 technology

In a recent study at Cold Spring Harbor Laboratory, researchers attempted to modify the growth of stem cells and promotor regions in corn using CRISPR. Thousands of years ago, corn was just a plant covered in weeds that formed very few kernels on its surface. Through gene editing technologies, scientists were able to transform the hopeless plant into a delicious vegetable with juicer kernels bursting from all surfaces. To increase the number of corn kernels 0n the surface of the plant, Professor David Jackson along with Lei Liu worked in collaboration with Professor Madelaine Bartlett from the University of Massachusetts Amherst. They were one of the first groups to tackle the editing of corn’s complex set of DNA.

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We are currently learning in AP Biology how DNA is replicated and can be altered. In replication, DNA is first untwisted by a helicase enzyme. Similarly, CRISPR uses an enzyme called Cas9 that unzips the DNA. This allows for the newly created strand of RNA to be matched to the target DNA. The Cas9 then cuts the DNA strand which causes the cell to attempt and put the strand back together and this results in new genes being formed because the DNA sequence is altered. This is just like how in replication, the DNA polymerase adds nucleotides to an existing strand of DNA. This video also provides a great visual description of how CRISPR can edit existing genes.

Since corn is a plant, it consists of plant cells that have a much stronger cell wall than animal cells do. This makes it harder for the CRISPR to access the cell’s DNA and make edits. CRISPR can be used to disrupt genes and eliminate them, as well as help the promoter regions which activate the genes instead. Corn kernel development depends on the genes supporting stem cell growth. They experimented by targeting random areas of the promoter to see which part will change the number of kernels on the cob.

Ontario-Corn-field 03

As a veggie-lover myself, I am so glad that these new gene-editing procedures allow for fuller, juicier corn kernels. Not only is this beneficial to those who eat corn on the cob or choose to enjoy a moist slice of cornbread, but also to those who love to sit down with a big bowl of popcorn to watch a movie. If a vegetable with such complex genes as corn is able to be improved, imagine what the future holds for other plants yielding yummy additions to our diets!

CRISPR Injections: The Fix for Genetic Mutations?

A recent study shows the first success of CRISPR being directly injected into the bloodstream, reducing the effects of a toxic protein, caused by a genetic mutation, for up to 1 year. CRISPR-Cas9 is a fairly new genetic technology that allows scientists to edit and manipulate specific DNA sequences; it can remove, add, or alter specific sections of DNA. There are two key components that are involved in the CRISPR-Cas9 technology. Cas-9, an enzyme, works to untwist and unzip the DNA at a specific location. This Cas-9 enzyme is very similar to the helicase enzyme. As we learned in AP Biology, helicase untwists and unzips the DNA. However, unlike the Cas-9 enzyme, helicase unzips the whole DNA strand as the DNA is preparing to replicate. The second key component to CRISPR is guide RNA or gRNA. Guide RNA works to guide the Cas-9 enzyme to make sure it cuts the right part of the DNA. 

CRISPR-Cas9 mode of action

A condition called transthyretin (TTR) amyloidosis, inherited from a gene mutation, causes numbness, nerve pain, and heart failure in adults. These symptoms are caused by a buildup of nerves and organs of misfolded TTR proteins, which are made by the liver. Intellia Therapeutics and Regeneron Pharmaceuticals funded research in which scientists figured out a way to fix the genetic mutation. They created a fat particle that contained messenger RNA that codes for Cas-9, CRISPR’s cutting enzyme. This fat particle was then injected into the subjects. Once injected, the gRNA guides the Cas-9 enzyme to cut out the mutated TTR genetic code from the DNA in liver cells. Once this code is cut out, the cells repair the DNA code to a non mutated form; this stops the production of the TTR protein. 

One month after six patients received this injection, these companies reported that the levels of TTR in the patients blood fell drastically. While the symptoms of these patients have not improved, the blood levels gave enough evidence to prove that the injections of CRISPR-Cas9 were successful. In addition, this form of treatment has led to no safety issues. These companies and many others are continuing to test this technology with TTR patients as well as patients with other genetic mutations. 

 

Is CRISPR the COVID-19 Cure?

New Developments In CRISPR Gene Editing Technology Show Promising Advances In Possible COVID-19 Antiviral Pill

CRISPR Gene Editing. If you have never heard of it, don’t worry, I hadn’t either. When google searching CRISPR Gene editing, I went straight to Wikipedia for the simple answer that it is a procedure done in molecular biology, in which the genomes of a living organism can be modified with extremely high precision. One of its many applications is the treating and prevention of disease, enabling researchers to edit DNA and use the natural defense system of bacteria to target and destroy the genetic material of viruses. In a new study from this summer, Dr. Sharon Lewin and her team of researchers at the Peter Doherty Institute for Infection and Immunity at the University of Melbourne believe they may have harnessed CRISPR’s gene editing abilities to block the replication of COVID-19. 

Very similar to the replication of DNA, RNA replication begins with a single strand of “Template” RNA. In DNA, because it can only be replicated in one direction (5’-3′), and the strands run antiparallel, each strand is built in opposite directions creating one leading strand and one lagging strand. However, RNA only needs one strand made because it is single-stranded instead of a double. In SARS-CoV-2, an enzyme called RNA-Dependent RNA Polymerase adds nucleotides in the 5’-3′ direction, replicating the template RNA. Because humans have DNA, we don’t copy RNA; instead, we transcribe it to make proteins. Therefore this RNA replication process does not occur in humans and only in viruses.

Lewins’ team designed the gene editing to target single strands of RNA, like those found in COVID-19. CRISPR is most commonly associated with Cas9, an RNA-guided enzyme that cleaves foreign nucleic acids. However, Lewin and her team used a different enzyme, Cas13b, which could cleave RNA instead. Targeting specific sites on the RNA strands of SARS-CoV-2, Cas13b binds to the RNA and destroys the part of the virus needed to replicate, “Once the virus is recognized, the CRISPR enzyme is activated and chops up the virus,” said Lewin. She continues to explain that although the COVID-19 vaccines are highly effective, there is still a clear and urgent need for treatment once the disease is contracted. The ideal treatment would be an antiviral drug that could be taken shortly after the patients tested positive for COVID-19, “That’s what we hope to achieve one day with this gene scissors approach.” 

CRISPR Cas9 technology

Having written in previous blog posts about my mother’s struggles with COVID-19, my dad also had a very different yet real struggle. Like most people, my dad, having somehow not contracted COVID from my mom at the beginning of quarantine, was very fearful of getting sick himself. Fortunately, my dad has still never had COVID (knock on wood). This is great because he has remained healthy; however, it also had downsides. For my brother and me, being both kids and relatively healthy, when we contracted COVID in mid-August, it was nothing more than a rough cold. A cold that, after ten days, not only was gone but enabled me to feel some sense of temporary immunity to the virus and allowed me to feel comfortable going out with friends and returning to some level of normalcy. My dad never got this. Because he never contracted COVID, he lived a completely secluded life until this past February (when he gave up and began going out in public). If my family and I went to a mall, he would wait in the car. If we ate out, he would wear a mask the whole time and not eat until we got home. The fear for my dad was not specifically getting covid but not having some antiviral drug to take once he contracted the virus. A solution like Dr. Lewins would have been and still would be a life-changer for many families who still live in fear of getting sick from COVID-19.  

Although this breakthrough in RNA CRISPR technology is remarkable, the study was performed in lab dishes and is still waiting for testing on animals or humans. Additionally, CRISPR technology medicines have not been approved to treat any diseases. Unfortunately, we are probably a couple of years away from a widely available treatment. 

CRISPR to the Rescue

If you are reading this right now, it means you are not blind. Aren’t you so fortunate to have healthy vision? Others aren’t as lucky. The genetic disorder of blindness is something that effects many people.  However, what if I told you that there may be a way to prevent the passing of a genetic mutation such as blindness? It’s called CRISPR.

Before I get into how CRISPR can help prevent blindness, must know what CRISPR is. CRISPR, short for CRISPR-Cas9, is a tool used for editing genes of organisms by modifying the DNA. By changing the DNA sequence, this causes for a change in gene function. Essentially, CRISPR acts as a scissor that is able to cut and edit the DNA sequence.

The way genes are manipulated is by having the components of one CRISPR sent over to another CRISPR, which then alters the structure of the sequence manually, and is called “gene editing”. This phenomenon was discovered only in 2017 when a University in Japan was able to capture and reveal to the world the exact process of this gene editing. Genes are compromised of chemical bases that bind together to form a sequence and every sequence creates something different. For example the sequence GATC when genetically edited with CRISPR can turn into CATG by just switching the C and G. This may seem small but can have a much larger effect on the organism.

This method can directly be used to alter the genetic mutation that causes blindness in a person by finding the spot in the genetic code in that is the root of the mutation and editing it to become normal. Another new way that CRISPR gene editing can be used is to combat sickle cell disease. This disease that causes the creation of mutated hemoglobin resulting in blood clots can also be fixed. Sickle cell disease effects 100,000 people in the US, and can only currently be treated with bone marrow transplants, but this can lead to other health issues according to Dr. Markus Mapara who studies CRISPR. DNA orbit animated

Through CRISPR, as found by Dr. Dounda and Dr. Charpentier, they can direct the Cas9 protein part of CRISPR, through a programable RNA, to locate specific areas of genetic code, in particular ones that are the root of a mutation that causes health issues such as Sickle cell disease. As we mentioned before, the CRISPR can then remove and replace the specific area with one that doesn’t result in the genetic mutation.

While there may be other treatments for these diseases, CRISPR is certainly the safer, healthier, and more effective way to combat them. They also haven’t had too much research on it yet, so we are only getting more and more information as time goes on. I personally don’t have any genetic mutations that I know of, but I know many people who do and who this could help. Hopefully we will be able to master the technique and put an end to genetic mutations!

 

A Life Saving Treatment: CRISPR Gene Editing

A proud, hard-working father is what Paddy Doherty looked up to all of his life until a sudden heart attack that took the life of his dad. What would you do if someone you love is unexpectedly gone without a goodbye?

His father had a career in construction and various home improvement projects which kept him active until his 60s until Doherty first caught glimpses of a worrying decline in his dad’s health. “I noticed him getting breathless on walks. He’d stop for a while and maybe make an excuse for stopping, saying, ‘Oh, isn’t that a lovely tree’ or whatever,” said Doherty, who lives in Ireland. Doctors chalked it up to angina, or chest pain caused by reduced blood flow to the heart, symptomatic of an underlying heart problem.

After his dad died, the true cause was discovered: a rare disease called transthyretin (ATTR) amyloidosis, characterized by a misfolded protein that builds up in the heart and interferes with normal function. As learned in AP Biology, misfolded proteins are caused by the lack of chaperonins that are present in cells to provide a secure hydrophilic environment. The misfolded proteins cannot achieve their native state and are contorted into shapes that are unfavorable to the environment it’s in. The formation of oligomers and aggregates occurs in the cell when a critical concentration of misfolded protein is reached. Aggregated proteins inside the cell often lead to the formation of an amyloid-like structure, which eventually causes different types of degenerative disorders and ultimately cell death.

 

Structure of Wild Type Human Transthyretin in Complex with Tafamidis, PDB 6E6Z

“Patients left untreated with this type of amyloidosis develop heart failure, low blood pressure, horrible bowel disturbance, and eventually become incontinent of urine and feces,” said Julian Gillmore, nephrologist and head of the National Amyloidosis Centre at University College London. “It’s a truly awful, gradually progressive disease that is ultimately fatal.”

In February last year, Doherty began to experience the same early breathing symptoms his father had had. As an avid hiker who had trekked the Himalayas, he was surprised to find himself getting winded on local hill walks. Testing confirmed that Doherty had a hereditary form of ATTR amyloidosis.

But there was one bit of good news: If Doherty had been diagnosed even a year earlier, no treatment options would have been available to him — an all-too-common situation for over 30 million U.S. patients with rare diseases. But Gillmore, Doherty’s doctor, offered him the chance to participate in an early-stage clinical trial using CRISPR, a groundbreaking genome editing therapy with the potential to cure his ATTR amyloidosis in a single dose.

CRISPR logo

“I had no side effects and left the facility after two days,” Doherty said. “The walk that I felt breathless on, which is a steep kind of mountain walk through a forest, I’m doing that every Sunday now.” CRISPR-Cas9 allows researchers to alter the DNA of living things at will. It works like genetic scissors that can insert, repair or edit individual genes to rewrite the code of life. The system itself consists of two molecules — a protein known as Cas9 that works like scissors and a guide RNA that takes Cas9 to the right place in the genome — that can be inserted into cells or the bloodstream.

In the case of the clinical trial on patients with ATTR amyloidosis, Gillmore and his colleagues aimed to edit the malfunctioning gene itself and demonstrate for the first time that direct infusion of CRISPR molecules into the bloodstream is safe effective.

The hereditary form of ATTR amyloidosis affects roughly 50,000 people worldwide with a large cluster of patients like Doherty with roots in Donegal County, Ireland. Because circulating transthyretin is made almost entirely in the liver — and everything that enters the bloodstream is carried to the liver to metabolize — the researchers realized they could simply inject patients with the CRISPR-based therapy.

The therapy, called NTLA-2001, appeared to knock out the mutated gene as intended. Only six patients were tested in total, but the three who received the higher of two doses — including Doherty — saw their transthyretin levels drop by an average of 87 percent after 28 days. The results remain preliminary, and several more patients will need to be tested before the trial is complete.

Doherty said he hopes his family members and fellow Donegal residents will be able to benefit from CRISPR as much as he has. Fortunately, testing shows his two daughters did not inherit ATTR amyloidosis. And along with his father, Paddy’s uncle and cousin both died of the disease.

“When the trial is over, I hope that CRISPR is available and affordable for all amyloidosis patients,” Doherty said. “If a pharmaceutical company can mass-produce something like that and sell it at a good price, it would be a godsend.”

Using CRISPR to Treat Cancer Causers

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology’s origin stems from a 1987 discovery of specific genetic sequences inside the genome of Escherichia Coli; however, it wasn’t until 2007 which introduced practical usages of CRISPR. While CRISPR is seemingly a natural phenomenon, scientists quickly acknowledged its potential and began researching practical usages of it. Scientists discovered that certain bacteria, such as E. Coli, use CRISPR as an antiviral mechanism. CRISPR’s capabilities intrigue scientists because it offers a differentCRISPR illustration gif animation 1 approach that is more precise, quicker, and cheaper for altering an organism’s genome to better suit it for survival. Whether CRISPR is being used to treat genetic mutations that lead to cancer or drought-resistant plants, CRISPR’s applications can be applied nearly anywhere on the genetic level. CRISPR-Cas9 works by combining a protein that can snip DNA strands with a molecule that guides it to the site of concern. “When bacteria survive a viral attack, they incorporate snippets of the virus’s DNA into their genomes. Those stolen segments are called ‘CRISPR.’ If the virus attacks again, the bacteria use those CRISPR segments as a template to create strands of RNA that home in on the corresponding sequence in the virus’s genome. The CRISPR RNA carries along a protein called Cas9 to the target location on the DNA. The protein disarms the virus by cutting its DNA at that spot” (c&en.org).

One particular area of concern where CRISPR technology may provide some aid is the p53 and associated genes. According to Cancer.gov, the “p53 gene makes a protein found inside the nucleus of cells and plays a key role in controlling cell division and cell death. Mutations (changes) in the p53 gene may cause cancer cells to grow and spread in the body” (Cancer.gov). P53 pathwaysCells that have this mutated p53 gene lack the ability to control cell division and death. We’ve learned in AP Biology that the interphase cells go through before undergoing mitosis, and cytokinesis is extremely important to ensure that they divide and grow properly. But if something goes wrong during G1, S, or G2, that could lead to uncontrolled cell growth and division and cancer. Targeting p53 using CRISPR technology has some limitations, though. CRISPR is much less effective against p53 that is active, but both inactivated and mutated p53 allow for uncontrolled growth, leading to cancer. So, the scientists at Karolinska Institute propose that p53 inhibition is the most effective way to manipulate p53 to be better suited for CRISPR treatments. Preventing further mutation of p53 became the key concern because this leads to extra complexities and danger to associated genes.

Preventing similar genes from DNA damage is key to preventing uncontrolled cell growth. The researchers “identified a network of linked genes with mutations that have a similar effect to p53 mutations, and shown that the transient inhibition of p53 is a possible pharmaceutical strategy for preventing the enrichment of cells with such mutations” (Karolinska Institute). Furthermore, the scientists studied the DNA damage response as a possible answer in developing a more accurate guide to RNA sequences, which are used to guide CRISPR where a DNA sequence requires editing. The scientists claim that “We believe that the up-regulation of genes involved in the DNA damage response can be a sensitive marker for how much unspecific (‘off-target’) activity a guide RNA has, and can thus help in the selection of ‘safer’ guide RNAs.”

Cancer has been a seemingly unsolvable problem for generations. Any step taken to further our capabilities for handling cancer is a good step, and eventually, we will reach a point where cancer is hopefully a disease of the past. Utilizing CRISPR to its fullest potential will take time, but scientists are hopeful that it will be an absolute game-changer in the fight against cancer and other genetic diseases.

CRISPR: A Possible Solution to Genetic Diseases?

A few decades ago in science fiction, there were talks of things like genetic modification in babies. This was more along the lines of creating the ‘perfect’ human, rather than using genetic modification to stop certain genetic illnesses. An example of this is in the 1997 movie, Gattaca, where we see an unmodified (genetically) person struggle to live in a world of genetically modified people. While it is fiction, it showed how being able to alter someone’s genetic flaws can go a long way. Despite, at the time, this seeming to just be science fiction, some of these concepts of gene alteration might become reality. These concepts becoming reality would all be due  to CRISPR.

CRISPR logo

Some of you might be thinking, “what is CRISPR?,” and that’s okay because before researching it I was thinking the same thing. CRISPR is a type of genetic engineering technique in molecular biology. This technique allows for the modification of genomes in a living organism. This technique is actually based off of CRISPR-Cas9 antiviral defense system, which can cut genomes. This has inspired CRISPR to contain Cas9 nuclease complexed with gRNA. This is the sent into a cell and is able to cut a cell’s genome at a certain position. This allows for specific genomes to be removed, as well as allowing new ones to be added. So in summary, CRISPR is a method of removing certain genomes of a cell, and in some cases replacing and/or adding a genome as well.

Now that CRISPR has been explained and we know what it is as well as how it works, we are now able to look at studies involving it. While CRISPR seems great and all, Heidi Ledford posted an article about how the use of CRISPR in embryos can cause some unwanted changes to the embryo. While experimenting, researches found that the use of CRISPR on an embryo can not only cause unwanted changes at the genome target site, but it can also cause changes near the genome target site. While some of you may think that the pros out-weigh the cons in this instance, geneticist Gaétan Burgio states that, “the on-target effects are more important and would be much more difficult to eliminate.” The on-target effects (negative) are so bad that it may not be worth doing even if it is to eliminate genetic diseases.  The idea that the cons outweigh stopping a genetic disease shocked me, as in our biology class we talked about genes and genetic diseases, and how even though they can be extremely rare, they can be irreversible, life changing, and in some cases fatal. This rejects the idea that the pros could out-weigh the cons, which puts a pin in this genetic modification breakthrough.

After looking at CRISPR as well as the research shown on genetic modification of embryos, I have realized how far we still are from elimination of genetic diseases. Despite issues arising in the experiment, I hope that they can put CRISPR to good work in order to stop the seemingly impermeable genetic diseases. And who knows, if we can master genetic modification with CRISPR, the ideas presented in Gattaca could soon seem like reality.

 

 

Could Christmas Island rats make a comeback? Thanks to CRISPR gene editing, they might!

From climate change to overhunting by humans, there are many factors which contribute to the extinction of species in the animal kingdom. The Christmas Island rat, also known as Maclear’s rat, went extinct a century ago in what is believed to be the first and only case of extinction of a species due to disease. It has always been believed that once a species goes extinct, it is gone for good. That is until recently when scientists began experimenting with “de-extinction” efforts to bring back the Christmas Island rat.

As published March 9 in the science journal, Current Biologya team of paleo geneticists from the University of Copenhagen recently conducted a study into gene sequencing the Christmas Island rat, in order to estimate the possibilities of future gene editing experiments which could bring the species “back to life”. The process of genetic editing for de-extinction efforts, as explained by the research team in their abstract, consists of first identifying the genome of the species and then editing the genes of similar species to make it more similar to that of that extinct one. The team used frozen somatic cells of the extinct rats, cells with a 2n number of chromosomes which are made during the process of mitosis. The team was able to sequence the rats’ genome, aside from some small portions which remain missing. They then had to identify the modern species which they could gene edit. Their findings established that the Christmas Island rat shares around 95% of DNA with the modern Norway brown rat. At this point, it

Now that the rat’s genome has been sequenced to the best of the team’s ability and a similar species has been identified, the gene editing possibilities are endless, especially with CRISPR technologies and techniques. “CRISPR” stands for Clustered Regularly Interspaced Short Palindromic Repeats in DNA sequencing. This system was discovered by a group of scientists, led by Dr. Emmanuelle Charpentier. CRISPR uses Cas9, an enzyme which cuts DNA at specified sections as guided by RNA. There are three different types of edits drone with CRISPR technology: disruption, deletion, or correction/insertion. Disruption editing is when the DNA is cut at one point and base pairs are either added or removed to inactivate a gene. Deletion editing is when the DNA is cut at two points and a larger sequence of pairs is removed. Correction/insertion editing is when a new gene is added into a sequence using homology directed repair.

Thomas Gilbert, the lead scientist on the team, says that he would like to conduct CRISPR gene editing experiments on living species of rats before attempting to replicate the DNA of an extinct species. For example, attempting to mutate the DNA of the Norway brown rat into that of the common black rat. Once this experiment is conducted, the possibilities of reviving the Christmas Island rat will be more clear. Until then, we can only hope! Do you think it’s possible to see the Christmas Island rat revived anytime soon?

How Does Activation of p53 Effect the Use of CRISPR?

In a study conducted at Karolinska Institutet in Sweden, researchers looked into CRISPR gene editing and how that can play a critical role in mutated cancer cells as well as the medical field. CRISPR is “programmed to target specific stretches of genetic coding and to edit DNA at the precise location;” specifically, the CRISPR system binds to the DNA and cuts it, therefore, shutting the targeted gene off. Researchers can also permanently alter genes in living cells and organisms, and in the future, using this method they may even be used to treat genetic causes of diseases. Although CRISPR sounds amazing, will it really be as great as it seems?

CRISPR CAS9 technology

CRISPR

There are a few obstacles that need to be overcome before CRISPR can even become regularly administered in hospitals. The first is to understand how cells will behave once they are subjected to DNA damage which is caused by CRISPR in a controlled manner. When cells are damaged they activate a protein called p53 which has negative and positive effects on the procedure. The technique is less effective when p53 is activated, however, when p53 is not activated cells can grow uncontrollably and become cancerous. Cells, where p53 is not activated, have a higher survival rate when subjected to CRISPR and because of this can accumulate in mixed cell populations. Researchers have also found a network of linked genes that have a similar effect to p53 mutations, so inhibiting p53 also prevents these cells from mutating. 

Long Jiang, a doctoral student at the Department of Medicine at Karolinska Institutet, says that “it can be contrary to inhibit p53 in a CRISPR context. However, some literature supports the idea that p53 inhibition can make CRISPR more effective.” By doing this it can also counteract the replication of cells with mutations in p53 as well as genes that are associated with the mutations. This research established a network of possible genes that should be carefully controlled for mutations during CRISPR. This will hopefully allow for mutations to be regulated and contained more efficiently.

DNA, or deoxyribonucleic acid, is a long molecule that contains a genetic code; “like a recipe book it holds all the instructions for making the proteins in our bodies.” Most DNA is found in the nucleus of the cell, but a small amount can also be found in the mitochondria. DNA is a key part of reproduction because genetic heredity comes from the passing down of DNA from parents to offspring. Altering this DNA can have an impact on a number of someone’s physical characteristics. CRISPR does just that. It can be used to edit genes by finding a specific piece of DNA inside a cell and then modifying it. Since CRISPR is so new, it has its positives and negatives, but overall it is a groundbreaking discovery. 

DNA double helix horizontal

DNA

In conclusion, even though cells seem to gain p53 mutations from CRISPR, it has been discovered that most of the cell mutations were there from the start. Even though this is still an issue, we don’t know to what extent it can cause greater harm, so it will be exciting to see the new discoveries in the future!

How CRISPR Can Help Individuals Overcome Obesity

Fat, which is made up of cells that have been distended with greasy or oily materials, or triglycerides, is required for the body to function, but it may also be hazardous if consumed in excess. Fat cells are distinct from other cells such that they lack surface receptors and constitute only a small percentage of the cells in fat tissue. While restricting diets can assist those who are obese lose weight, the results are typically solely temporary. If only there were a way to target fat cells specifically… Well, there just might be!

Breast tissue showing fat necrosis 4X

A group of doctors discuss a potential prospective breakthrough utilizing CRISPR-Cas9, a technology that has proven particularly elusive in the study of adipose tissue, in a recent publication published in the Journal of Biological Chemistry. Their study was tested on mice, in order to see how it worked and what it targeted. The gene-editing technology CRISPR-Cas9 changes genes by precisely cutting DNA and then allowing natural DNA repair mechanisms to take charge. This technology has changed the ability of deleting or inserting certain genes of interest into an organism. Cas9, an enzyme that can break DNA strands as well as a piece of RNA that directs the Cas9 enzyme to a specific location in the genome for modification, is encased in a non-harmful virus and supplied to the cells being studied. The equipment has also been used to study the heart, liver, neurons, and skin cells, to name a few. However, brown fat adipose cells have never been studied.

Brown fat cell

Using CRISPR-Cas9 components, the physicians were eventually able to target brown fat adipose cells. In mature mice, they were able to knock off the UCP1 gene, which specifies brown adipose tissue and allows it to generate heat. They discovered that knockout mice were able to adjust to the absence of the gene and maintain their body temperature under freezing settings, indicating the existence of additional mechanisms involved in temperature regulation. Overall, the CRISPR interference system assisted mice in losing about twenty percent of their body weight, proving that CRISPR can accurately target fat cells.

3LFM FAT Mass and Obesity Associated (Fto) Protein

Genetics can have a significant impact on the quantity of fat cells you are born with. However, the proportion of tendency to becoming overweight differs by individual. For example, in some people, genes account for just 25 percent of the tendency, but in others, the genetic effect might be as high as 70 percent to 80 percent. Obesity is most commonly associated with the FTO gene. This FTO gene is not found in everyone. For example, around 20 percent of white people have a variation of the gene that increases their risk of obesity. The FTO gene is located on chromosome 16, which is one of the 23 pairs of chromosomes in humans. While this chromosome pair represents under 3 percent of the total DNA in cells, if FTO is present, it can affect whether if one is obese or not, depending on the alleles of the gene. CRISPR has the potential to target this gene as well as other genes that affect body weight, such as brown fat adipose cells.

Diagram of Chromosome 16

Your health is essential for the rest of your life! A healthy lifestyle can aid in the prevention of chronic diseases and long-term ailments. The alleles on the FTO gene can have an impact on your health and are linked to type 2 diabetes, obesity, and other health concerns.

How CRISPR Technology Can Potentially Reverse Extinction

Though Christmas Island rats went extinct over one hundred years ago, Anna Gibbs in sciencenews describes how genetically modifying the Norway brown rat would essentially reincarnate the Christmas Island rat. CRISPR is a relatively new technology that can be used to edit the genes of animals and has changed the science world of extinction. It works by editing “an existing animal’s genome so that it resembles that of the desired extinct animal… making that proxy as similar to the extinct species”.

Gibbs explains how using this technology, scientists compared fragments of the extinct rat’s genetic makeup, the Christmas Island rat, to that of their living relative, the Norway brown rat. By taking DNA from two preserved skin samples of the Christmas IslanRattus norvegicus - Brown rat 04d rat, the scientists were able to recover 95% of their genome. They compared the samples of the extinct species with the Norway brown rat and found that their genomes were very similar, 95% to be exact. Because of evolutionary divergence between the two species, the last 5% of the genetic information was lost forever. The missing genes were mostly located in the regions that controlled the rat’s immune responses and sense of smell. If they were to edit the Norway brown rat’s genome to resemble that of the Christmas Island rat, the differences in smell would be detrimental to their survival. This tiny difference in their genomes would prevent scientists from being able to recover the extinction of the Christmas Island rat. 

Though the scientists didn’t intend on actually reincarnating the rats, Gilbert says that what they discovered “could prove useful for people working on even more ambitious projects, like bringing back the wooly mammoth”. The hurdles of CRISPR technology lie in the tiny details of genetic engineering, even the smallest difference can prevent de-extinction. Ben Novak, a leading scientist at a nonprofit that uses genetic engineering for conservation projects, says that though there are MaclearsRatSkullways to capture some of the missing data, “the fact that some data will always be missing is a limitation that de-extinction scientists have already come to terms with”. The goal of de-extinction isn’t to completely recreate the extinct species but rather to formulate a new species out of the old that will fool its environment and live on. As we learned in AP biology this year, our bodies contain DNA polymerases that are constantly proofreading our DNA strands to make sure all of our nucleotides are correctly paired. If they are not, they are programmed to cut out the incorrect segment and replace it with the correct nucleotides. We even have a DNA ligase that acts as the glue in our DNA and keeps everything together. If the DNA polymerase were unable to detect the incorrect nucleotide matchup then it would stay and end up as a permanent mutation in the next cell division. Errors with the DNA polymerase, such a tiny part of our whole working body, are alike to the small error in CRISPR technology. The inability to recover all of the genomes due to the tiniest difference will cause scientists to miss out on the reincarnation of animals lost forever. 

Overall, though CRISPR findings are really “awesome”, it may not be the best use of money when we are struggling to keep our rhinos alive. In my opinion, CRISPR is not worth the funding until we are able to figure out how to recover 100% of the extinct genome. Comment your opinion on whether CRISPR should continue to receive additional funding, essentially is it worth it knowing we will never recover 100% of the extinct genome? 

CRISPR Gene Editing: The Future of Food?

Biology class has taught me a lot about genes and DNA – I know genes code for certain traits, DNA is the code that makes up genes, and that genes are found on chromosomes. I could even tell two parents, with enough information, the probabilities of different eye colors in their children! However, even with all this information, when I first heard “gene editing technology,” I thought, “parents editing what their children will look like,” and while this may be encapsulated in the CRISPR gene editing technology, it is far from its purpose! So, if you’re like me when I first started my CRISPR research, you have a lot to learn! Let’s dive right in!

CRISPR

Firstly, what is CRISPR Gene Editing? It is a genetic engineering technique that “edits genes by precisely cutting DNA and then letting natural DNA repair processes to take over” (http://www.crisprtx.com/gene-editing/crispr-cas9).  Depending on the cut of DNA, three different genetic edits can occur: if a single cut in the DNA is made, a gene can be inactivated; if two separate DNA sites are cut, the middle part of DNA will be deleted, and the separate cuts will join together; and if the same two separate pieces of DNA are cut, but a DNA template is added, the middle part of DNA that would have been deleted can either be corrected or completely replaced. This technology allows for endless possibilities of advancements, from reducing toxic protein to fighting cancer, due to the countless ways it can be applied. Check out this link for some other incredible ways to apply CRISPR technology!

In this blog post however, we will focus on my favorite topic, food! Just a few months ago, the first CRISPR gene-edited food went on the market! In Japan, Sicilian Rouge tomatoes are now being sold after the Tokyo-based company, Sanatech Seed, edited them to contain an increased amount of y-aminobutyric acid (GABA). “GABA is an amino acid and neurotransmitter that blocks impulses between nerve cells in the brain” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). It supposedly (there is scarce scientific evidence of its role as a health supplement) lowers blood pressure and promotes relaxation. In the past, bioengineers have used CRISPR technology to “develop non-browning mushrooms, drought-tolerant soybeans and a host of other creative traits in plants,” but this is the first time the creation is being sold to consumers on the market (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/)!

Tomatoes

So, how did Sanatech Seed do it? They took the gene editing approach of disabling a gene with the first method described above, making a single cut in the DNA. By doing so, Sanatech’s researchers inactivated the gene that “encodes calmodulin-binding domain (CaMBD)” in order to increase the “activity of the enzyme glutamic acid decarboxylase, which catalyzes the decarboxylation of glutamate to GABA, thus raising levels of the molecule” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). These may seem like big words, but we know from biology that enzymes speed up reactions and decarboxylation is the removal of carbon dioxide from organic acids so you are already familiar with most of the vocabulary! Essentially, bioengineers made a single cut in DNA inside of the GABA shunt (a metabolic pathway) using CRISPR technology. They were therefore able to disable the gene that encodes the protein CaMBD, and by disabling this gene a certain enzyme (glutamic acid decarboxylase) that helps create GABA from glutamate, was stimulated. Thus, more activity of the enzyme that catalyzes the reaction of glutamate to GABA means more GABA! If you are still a little confused, check out this article to read more about how glutamate becomes GABA which will help you better understand this whole process – I know it can be hard to grasp!

After reading all of this research, I am sure you are wondering if you will soon see more CRISPR-edited food come onto the market! The answer is, it depends on where you are asking from! Bioengineered crops are already hard to sell – many countries have regulations against such food and restrictions about what traits can actually be altered in food. Currently, there are some nutritionally enhanced food on the market like soybeans and canola, and many genetically modified organisms (GMOs), but no other genome-edited ones! The US, Brazil, Argentina, and Australia have “repeatedly ruled that genome-edited crops fall outside of its purview” and “Europe has essentially banned genome-edited foods” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). However, if you are in Japan, where the tomatoes are currently being sold, expect to see many more genome edited foods! I know I am now hoping to take a trip to Japan soon!

Thank you so much for reading! If you have any questions, please ask them below!

Are Genes Inherited from Neanderthals Protecting People Against COVID-19?

Neanderthals, from roughly 40,000 years ago, have had an impact on protecting people, that contain a specific haplotype on chromosome 12, from having severe symptoms due to the Sars-COV-2 virus. Researchers conducted a study that showed a ~22% decrease in severe illness connected to a gene inherited from Neanderthals.   

Neanderthals evolved in western Eurasia -the largest continental area consisting of Europe and Asia- about half a million years ago, living mostly separated from early modern humans in Africa. Neanderthals likely developed certain genes allowing them to fight off infectious diseases during the time of their existence. Due to natural selection, which is when animals with the most favorable traits for survival will survive to reproduce and pass on their genes, these neanderthals were able to evolve and pass on the favorable gene allowing modern humans today to fight off Sars-Cov-2. Through natural selection, the haplotype, on chromosome 12, linked to protection against certain viruses has been passed on. This specific haplotype has helped people during the current pandemic to stay out of the hoHuman male karyotpe high resolution - Chromosome 12spital. 

This study discovered that this specific haplotype on chromosome 12 contains three helpful genes: OAS1, OAS2, and OAS3. These genes encode for a specific enzyme called oligoadenylate synthetase. As we learned in AP Biology, enzymes are created by free ribosomes in the cytosol; the ribosomes manufacture proteins(a chain of amino acids), such as enzymes for cellular reactions. The oligoadenylate chain triggers ribonuclease L. The ribonuclease L, also known as RNase L, is only activated when a viral infection enters the body; it breaks down the viral RNA molecules, leading to autophagy. This enzyme breaks down the viral Sars-Cov-2 RNA and slows/stops the spread of the virus in the body. 

Many people have been trying to find ways to move forward from this pandemic and return to our previous form of normal life. Scientists may be able to use this information about this specific haplotype on chromosome 12 with gene editing technologies, such as CRISPR, to help individuals slow and later stop the spread of COVID-19. Research like this may be one way to be able to return to a normal life-style and keep people out of hospitals from COVID-19. As we continue on in AP Biology this year, I look forward to learning about the idea of genes and gene editing as I will have more knowledge to touch back on this research study. Do you think that this is a possible solution to the COVID-19 pandemic?

 

 

Embryo Gene Editing can Ensure Offspring Do Not Inherit a Deafness Gene!

Denis Rebrikov, A scientist in Russia has done research regarding ways in which he can edit the genome sequence of an embryo in order to prevent the fetus from developing certain gene mutations, specifically in this case a hearing problem or possible complete deafness. His plans are very controversial to some, who believe the possible risks of very harmful mutations to DNA that would be passed onto direct and future offspring, outweigh the possible benefits. However, some people find this scientific possibility to be worth the risk, if it means not passing a potentially very harmful gene down to offspring. If these methods are done correctly, it should alter the genome sequence in the embryo so that future offspring off that embryo will not inherit the negative mutation.

One couple shared their story in detail, in which both parties have a hearing deficiency, the man with partial deafness, and the woman completely deaf. Their biggest hope is to have children who will not inherit hearing issues, because of the apparent challenges they have had to face themselves because of them. They would be the first couple to perform this gene editing on an IVF embryo, so they obviously have some reservations. One of those being publicity, but more importantly the potential risks of using the CRISPR genome editor. They already have a daughter with hearing loss, but they never chose to test her genes for mutations, nor did they get her a cochlear implant to aid her hearing, because of the potential risks of that. When they finally tested her genes, they learned that she had the same common hearing loss mutation called 35delG in both her copies of a gene called GJB2. The parents then tested themselves, realizing they were both 35delG homozygous, meaning their daughter’s mutations were not unique to her, they had been inherited.

If either the mother or father had a normal copy of the GJB2 gene, a fertility clinic could have more easily created embryos by IVF and tested a few cells in each one to select a heterozygote–with normal hearing–to implant. At this stage, Denis Rebrikov informed them that CRISPR genome editing would be their only option. However, the process presents possibly deal breaking risks, such as mosaicism, in which a gene edit might fail to fix the deafness mutation, which could create other possible dangerous mutations like genetic disorders or cancer. The couple has not decided to go through with the editing just yet, but it is something they are open to in the future as more possible new research or test subjects become available.

Explaining the CRISPR Method: “The CRISPR-Cas9 system works similarly in the lab. Researchers create a small piece of RNA with a short “guide” sequence that attaches (binds) to a specific target sequence of DNA in a genome. The RNA also binds to the Cas9 enzyme. The modified RNA is used to recognize the DNA sequence, and the Cas9 enzyme cuts the DNA at the targeted location… Once the DNA is cut, researchers use the cell’s own DNA repair machinery to add or delete pieces of genetic material, or to make changes to the DNA by replacing an existing segment with a customized DNA sequence.” -US National Library of Medicine Genetics Home Reference

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Woman with a hearing aid 

If you had the opportunity to alter something in the gene’s of your baby’s embryo, would you? Under what circumstances would you consider this, and what risks might stop you from deciding to do it? Comment down below.

 

 

Genetically Modified Babies?

A decade or two ago, the idea of being able to modify embryos was straight out of a science-fiction movie. However, last November, Chinese scientist He Jiankui genetically modified twin girls’ embryos to have resistance to the HIV virus using a process called CRISPR. His actions have sparked a global panic, as many people feel that current regulations are not enough to keep the scientific community’s actions ethical.

To understand this issue, it is important to understand its individual components. CRISPR is a gene-editing tool that was discovered in 2007 and became widely used in 2013. Essentially, a scientist decides what portion of DNA they would like to alter, and transcribes the sequence into RNA. This RNA finds the portion of DNA with the specific code and then the Cas9 enzyme “cuts” the DNA, allowing a new sequence of DNA to take its place.

The image depicts functions of CRISPR Cas9 technology.

Dr. He used CRISPR Cas9 technology to try to block the HIV pathways in twin girls while they were still embryos. As this experiment was recent, the long-term effects of it are unclear. In addition, as these girls were not developed at the time of their gene editing, they did not give consent to have a treatment that could be detrimental to their health. Furthermore, looking at the Centers for Disease Control website, HIV is primarily acquired by the use of unsafe needles to inject drugs and sexual contact. Using clean needles and condoms can greatly decrease one’s risk of getting HIV, and if a HIV-positive person takes suppression medicines, the viral content of HIV in their blood can become undetectable. Dr. He’s actions gave the twin girls undue risk, with little possible benefit.

In the future, this method of gene editing may be used to prevent or treat genetic diseases, but people have little knowledge of the long-term implications of using this technology on embryos. At the moment, the lack of global legislation regarding this gene-editing technology leaves a lot to be wondered about the future of this tool. According to Victor Dzau who works in the United States National Academy of Medicine, “The silver lining is that the world was awakened by the conduct of Dr. He, and we are all working very, very hard with all good intentions to make sure that this doesn’t happen again—not in the fashion that He did it. And that someday, if and when the technology is ready—and I think all of us are very bullish about this technology—that it will be helping humankind in the right way, knowing the risks and knowing the benefits.” After Dr. He’s experiment, many are in favor of halting the use of CRISPR on human embryos for at least five more years, so more research can be done on the subject. However, legislation, which the world has seen little of, holds a stronger weight than mere recommendations. In Russia, Denis Rebrikov is planning to create CRISPR babies, and regulations in the country regarding his specific goals remain unclear. How will CRISPR embryo editing evolve in the coming decades? Will CRISPR gene editing be as common someday as IVF is today?

 

Using CRISPR to Protect the World’s Chocolate

Cacao tree and bean

Around the world, in places 20º North and South of the equator, cacao is grown.  Growing in tropical environments, cacao trees grow pods that contain beans that are the primary ingredient of chocolate.  Unfortunately, fungal infestations have recently had a devastating impact on cacao farms, causing a wide range of diseases in the trees.  The worldwide chocolate business which employs 50 million people, is at serious risk.

Scientists have begun to develop CRISPR technology that can alter the DNA of cacao plants to make them more resistant to both fungal and viral diseases.  CRISPR is a gene-editing technology that works like a molecular pair of scissors, removing sections of DNA and replacing them with new ones.

Candy company Mars Inc. has supported the Innovative Genomics Institute in using CRISPR to engineer better cacao trees.  It will take five to seven years for the genetically engineered cacao trees to grow their pods, so until then, we can’t be certain that the project has been successful.

The lessons learned by the scientists on this project are important as they translate into work that can be done on other, important food plants such as cassava, rice, and wheat.

For the original article on this project, click here.

 

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