What would you think if you heard that we are able to edit our DNA? What about that we are able to genetically modify our human embryos? Would you be surprised? Would you think it’s not true? Impossible? It is possible and we are able to achieve this science with a tool called CRISPR, or “Clustered Regularly Interspaced Short Palindromic Repeats” (Doudna, J, 2015). It can be controversial. Biologists can use it for almost anything, such as making your offspring have no genetic diseases. A major use of CRISPR is to learn about what certain genes and cells actually do. CRISPR will enable researchers to precisely knock out certain genes as well as add or remove genetic marks and investigate the effects. CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats, cells have the ability to detect broken DNA and repair it. This new and fascinating tool was found by complete accident by a group of scientists that were trying to do a basic research project. The scientists who discovered CRISPR had no way of knowing that they had discovered something so revolutionary. There was nothing close to CRISPR out in the field so they didn’t even understand what they had found. “In 1987, Yoshizumi Ishino and colleagues at Osaka University in Japan published the sequence of a gene called iap belonging to the gut microbe E. coli. To better understand how the gene worked, the scientists also sequenced some of the DNA surrounding it. They hoped to find spots where proteins landed, turning iap on and off. But instead of a switch, the scientists found something incomprehensible” (Zimmer, C, 2015). At least one group of scientists in China has already used CRISPR on human embryos, catching the attention of other scientist’s and the possibility of gene editing. In June, a committee at the US National Institutes of Health approved a proposal to use CRISPR–Cas9 to help cancer therapies that rely on enlisting a patient’s T cells, a type of immune cell to help them get better (Reardon, S, 2016). By this approval, they are now able to start practicing helping cancer patients potentially get better and beat cancer, which has not been done before. CRISPR-Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence. “An enzyme called Cas9 acts as a pair of ‘molecular scissors’ that can cut the two strands of DNA at a specific location in the genome so that bits of DNA can then be added or removed. There is a piece of RNA called guide RNA, this consists of a small piece of pre-designed RNA sequence (about 20 base pairs long) located within a longer RNA scaffold. The scaffold part binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. This makes sure that the Cas9 enzyme cuts at the right point in the genome. The guide RNA is designed to find and bind to a specific sequence in the DNA. The guide RNA has RNA bases that are complementary to those of the target DNA sequence in the genome. This means that, at least in theory, the guide RNA will only bind to the target sequence and no other regions of the genome. The Cas9 follows the guide RNA to the same location in the DNA sequence and makes a cut across both strands of the DNA. At this stage the cell recognises that the DNA is damaged and tries to repair it” (Facts, 2016). Scientists can use the DNA repair to introduce changes to one or more genes in the genome of a cell of interest. CRISPR-Cas9 has potential as a tool for treating a wide range of medical conditions that have a genetic component, including cancer, hepatitis B or even high cholesterol. It is likely to be many years before CRISPR-Cas9 is used routinely in humans, but much research is still focusing on its use in animal models or isolated human cells, with the aim to eventually use the technology to routinely treat diseases in humans. Why is CRISPR important? Why do we need this type of technology? CRISPR/Cas9 is a revolutionary step forward in genetic engineering because it is simpler and less expensive than techniques founded before, and almost any lab can use this process. They can study the genes of humans, key diseases, economically important food, endangered animals, and more. In earlier stages of development, he organisms that were able to be studied were limited to a small handful, such as fruit flies and Arabidopsis (a small flowering plant). Now almost any organism can be studied. CRISPR can be used to eliminate mutations and diseases. There are endless ways where CRISPR can be used, in almost every form of life. It can be used to fix mistakes in the human genome that cause disorders or diseases. It could eliminate diseases that are caused by genetic mutations, such as anaemia, haemophilia, cystic fibrosis, Huntington’s disease, and Duchenne muscular dystrophy. In Vitro Fertilization (IVF) is the most common and most effective type of assisted reproductive technology to help women become pregnant. The IVF procedure involves fertilizing an egg outside the body, in a laboratory dish, and then implanting it in a woman’s uterus. The eggs are collected through a minor surgical procedure known as “follicular aspiration”. After a few hours the sperm eventually enters the egg. However, sometimes the sperm is directly injected into the egg, this process is known as an Intracytoplasmic Sperm Injection, or ICSI. IVF is so successful, “Only 24 percent of IVF embryos which are implanted in women are born alive and well, according to data from UK public health authorities – figures in the rest of the developed world are fairly similar. The research team believe that the birth rate could shoot up to around 74 percent with this new imaging technique once they perfect it” (Nordqvist, J, 2016). The fertilized egg then divides and becomes an embryo. At some centers they offer pre-implantation genetic diagnosis which can screen an embryo for genetic disorders. Scientist’s are then able to genetically modify the embryo to see if there are any dangerous disorders present. They can go in the embryo and wipe out the disease the egg carries, with this type of advanced technology the scientists could also be used to pick and choose the traits the child has when its born. For example, freckles and dimples, hair and eye color, the list goes on. A U.S. team of researchers have published the first demonstration that CRISPR can efficiently repair a failing gene in a human embryo, like genetic diseases that could cause a heart condition for example. (Servick, K, 2017). While CRISPR can be controversial, we are now able to modify sections of our genetic code with a tool called CRISPR-Cas9. Biologists can use it for almost anything. We can investigate the ways our genes work and how we are able to modify them. It can help women get pregnant when they couldn’t on their own and it could help parents who have genetic diseases in their family tree save their children from not ever getting those diseases. We are able to edit our genetic code with this amazing discovery and our lives will never be the same. What will we be able to do in 20 years? 50? The world is ready to find out.
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