ZakariaRostamitehrani CRISPERHumans have been genetically modifyingplants and animals for thousands of years throw selective breeding. Earlyhumans did that by selecting a phenotype that they liked or benefited them in agriculturein animals and plants, and made them reproduce and pass their genetic code tothe next generation. However, they did not understand what they really weredoing until humans discovered the code of life Deoxyribonucleic acid. DNA is amolecule that codes for proteins, enzymes and it codes for development of aliving organism, so it has all the genetic codes that shape a living organism.This means that DNA is more like a cookbook with all the instruction in it, andchanging this receipt changes the product of it.
Scientists have been trying tochange this code of life for years, but all the methods for engineering DNA areexpensive and unpractical. However, in 2015 a new technology called CRISPER-Cas9was found by Charles Gersbach, a bioengineer at Duke University in Durham,which is reliable, accurate and economical. CRISPER technology is very popularthese days and there is a bright future ahead of it.CRISPER-Cas9 was found when scientistswere looking at bacteria and how they fight and get resist the bacteria phages.Bacteria phages kill millions of bacteria every day, however, some bacteriasurvive the attack and develop immunity towards that specific type of phage.The way that bacteria stays safe towards these attacks was the key to easy andprecise genetic engineering.
A bacteria phage attacks a bacterium by insertingits own genetic code (DNA or RNA) inside the bacteria’s nucleus and using itsresources to reproduce and make new viruses. When bacterium survives an attack,it saves a part virus’s DNA inside a DNA archive with their own genetic codecalled CRISPER. Later, if this bacterium is attacked again, it will use thisinformation to overcome a second attack by the same type of virus. When it’sneeded, the bacterium uses an enzyme called Cas9 to overcome the new phageattack. In case of a new attack, the bacteriummakes a guide RNA from the CRISPER archive. Cas9 which is an enzyme uses thatguide RNA and tries to find a DNA fragment that matches with the nucleotides ofthat specific RNA.
When Cas9 finds the right DNA fragment, it cuts the fragmentout from the bacterium’s DNA. Thus, phage’s genetic code is inactivated and thebacterium stays safe from getting harmed. Since this enzyme uses a guide RNA toidentify the target DNA sequence, it’s very accurate and it cuts the DNAmolecule like a DNA surgeon. This enzyme can also be redesigned andbiochemically reengineered which gives researchers the advantage of creating amore accurate and useful molecule.
CRISPER-Cas9 is a very convenient tool tobe used for gene editing. In a near future, it can be used to fix geneticdiseases such as sickle-cell anemia which is a disease caused by a mutation inchromosome XI. This technology can also be used to cure diseases such as AIDSand cancer. For instance, genetically modified white blood cells can bedesigned that don’t get affected by HIV, and they are better cancer cellhunters.
These examples are only small sides of this technology’s capabilitiesin curing sicknesses that were incurable in the past, and now because ofCRISPER-Cas9, they can be cured. Another capability that this technique has isdesigning human embryos. Human zygotes can be genetically modified to fixdetected diseases even before the baby is born. They can be designed to have abetter IQ and physic and to prevent sicknesses such as obesity and Alzheimer’sthat can have genetic roots.
These examples of CRISPER’s capabilities used tobe dreams of researchers, but now thanks to CRISPER-Cas9 technology they canturn into realities that will change humanity forever.Reference”CRISPR:gene editing is just the beginning.” NatureNews, Nature Publishing Group, www.
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