1st discussion
Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism's DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed. A recent one is known as CRISPR-Cas9, which is short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9. Ethical concerns arise when genome editing, using technologies such as CRISPR-Cas9, is used to alter human genomes. Most of the changes introduced with genome editing are limited to somatic cells, which are cells other than egg and sperm cells. These changes affect only certain tissues and are not passed from one generation to the next. However, changes made to genes in egg or sperm cells (germline cells) or in the genes of an embryo could be passed to future generations. CRISPR-Cas9 was adapted from a naturally occurring genome editing system in bacteria. The bacteria capture snippets of DNA from invading viruses and use them to create DNA segments known as CRISPR arrays. The CRISPR arrays allow the bacteria to "remember" the viruses (or closely related ones). If the viruses attack again, the bacteria produce RNA segments from the CRISPR arrays to target the viruses' DNA. The bacteria then use Cas9 or a similar enzyme to cut the DNA apart, which disables the virus. Genome editing is of great interest in the prevention and treatment of human diseases. Currently, most research on genome editing is done to understand diseases using cells and animal models. Scientists are still working to determine whether this approach is safe and effective for use in people. It is being explored in research on a wide variety of diseases, including single-gene disorders such as cystic fibrosis, hemophilia and sickle cell disease. It also holds promise for the treatment and prevention of more complex diseases, such as cancer, heart disease, mental illness, and human immunodeficiency virus (HIV) infection.
2nd discussion
Genome editing, which is also called gene editing is a group of technologies that give scientists the ability to change an organism's DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. CRISPR-Cas9 is the most recent type of genome editing and was adapted from a naturally occurring genome editing system in bacteria. The bacteria capture snippets of DNA from invading viruses and use them to create DNA segments known as CRISPR arrays. The CRISPR arrays allow the bacteria to technically remember the viruses, or the closely related ones. If the viruses attack again, the bacteria produce RNA segments from the CRISPR arrays to target the viruses' DNA. The bacteria then use Cas9 or a similar enzyme to cut the DNA apart, which disables the virus.
There is a lot of ethical concerns with this type of editing. Some say that it should not be attempted at this time because, well its just not the time. Safety is a big concern though it has been deemed safe with researchers, it should not be used with clinical reproduction purposes because the risk cannot be justified. It can however be used as a treatment for disease, which is now the main purpose of this type of gene editing. Physicians might eventually be able to prescribe targeted gene therapy to make corrections to patient genomes and prevent, stop, or reverse disease. Despite the potential of CRISPR-Cas9 in cancer treatment, some challenges remain to be solved for clinical application. The continuous advances in CRISPR-Cas9 will increase safety and effective of therapy for patients with cancer.
3rd discussion
CRISPR technology is a tool that allows researchers to change DNA sequences and altering gene functions. Researchers are hoping to be able to correct genetic defects and treat and prevent diseases. CRISPRs are highly specialized stretches of DNA and the Cas9 is a protein enzyme that can mimmick scissors for molecules - it can cut strands of DNA. Similar natural defense systems can be found in bacteria, they attack viruses and other gene invaders. “Until 2017, no one really knew what this process looked like. In a paper published Nov. 10, 2017, in the journal Nature Communications, a team of researchers led by Mikihiro Shibata of Kanazawa University and Hiroshi Nishimasu of the University of Tokyo showed what it looks like when a CRISPR is in action for the very first time. [A Breathtaking New GIF Shows CRISPR Chewing Up DNA
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]” CRISPR is an acronym for clusters of regularly interspaced short palindromic repeats. It is a unique part of the DNA with specific characteristics, nucleotide repeats and spacers (also known as the building blocks of DNA) and spacers that are bits of DNA interspersed among the repeated sequences. The spacers are from viruses that previously attacked the organism. The spacers are like a memory holder and allows the cell to recognize dangerous viruses and allows it to fight off future attacks.
The enzyme known as Cas9 cuts foreign DNA. Normally, the protein binds two RNA molecules, the crRNA and tracrRNA. The molecules will guide the protein to a site to cut out bad DNA molecules. In two separate regions the Cas9 cuts the two strands of the DNA double helix. This is known as a double stranded break. The Cas9 is careful to not just cut anywhere in the genome.
Genome editing is when the encoded instructions in a DNA sequence is changed. The CRISPR-Cas9 cuts or breaks the DNA and tricks the cells into making the desired changes. Scientists have found that Cas9s can be programmed to change and region of DNA by changing the nucleotide sequence of the crRNA. Genome editing requires only a guide RNAQ and a Cas9 proteind. The cell’s repair mechanisms immediately introduce mutations to the genome once the DNA strand is cut. One way that the repair is made is known as non-homologous end joining - meaning the pieces get “glued” back together. This method often leads to undesired mutations. The other method of repair happens when the gap is filled with nucleotides. Scientists can manage or control this DNA template in order to correct a mutation. According to researchers, the CRISPR-Cas9 technology is close to four times more user friendly than the outdated technology known as TALENS. Some of the diseases that researchers believe can be corrected using the technology are cystic fibrosis, cataracts, anemia and possibly eliminating malaria. CRISPR technology can also be applied to food and agriculture industries in an effort to increase crop yields, improve drought tolerance and increase certain nutritional components of the food produced.
Unfortunately the CRISPR-Cas9 technology isn’t yet 100% effective. In a study utilizing rice, gene editing success ranged from 50-80%. These results clearly leave much to be desired when considering applying the technology to people, fetuses in particular. There have been occasions observed where DNA is cut in areas other than the desired target. This can lead to undesirable mutations. Even when the DNA is cut correctly there is a chance that the edit to the gene may not be made exactly right.
Some of the risks of using the CRISPR technology are that genetic diversity can become limited in a target population and can impact other organism populations through crossbreeding. If a mutation is generated in an embryo, these DNA cells may be passed on to future generations. Is it far of us to decide what future generations should look or feel like or what the food they eat may be like? Do we know enough about DNA and genetics in order to really decide what is best for future generations and put our decisions into motion? What is the defining moment when the technology is being utilized for therapeutic purposes and not simply to enhance or choose specific characteristics? In response to some of these questions the National Academies of Sciences, Engineering and Medicine have set forth guidelines in genome editing. They recommend that the technology only be used on genes to target serious diseases and only when there are no other reasonable treatment options. They also strongly urge continued oversight as clinical trials continue.
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