Humans have been genetically modifying
plants and animals for thousands of years throw selective breeding. Early
humans did that by selecting a phenotype that they liked or benefited them in agriculture
in animals and plants, and made them reproduce and pass their genetic code to
the next generation. However, they did not understand what they really were
doing until humans discovered the code of life Deoxyribonucleic acid. DNA is a
molecule that codes for proteins, enzymes and it codes for development of a
living 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, and
changing this receipt changes the product of it. Scientists have been trying to
change this code of life for years, but all the methods for engineering DNA are
expensive and unpractical. However, in 2015 a new technology called CRISPER-Cas9
was found by Charles Gersbach, a bioengineer at Duke University in Durham,
which is reliable, accurate and economical. CRISPER technology is very popular
these days and there is a bright future ahead of it.
CRISPER-Cas9 was found when scientists
were looking at bacteria and how they fight and get resist the bacteria phages.
Bacteria phages kill millions of bacteria every day, however, some bacteria
survive 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 and
precise genetic engineering. A bacteria phage attacks a bacterium by inserting
its own genetic code (DNA or RNA) inside the bacteria’s nucleus and using its
resources 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 code
called CRISPER. Later, if this bacterium is attacked again, it will use this
information to overcome a second attack by the same type of virus. When it’s
needed, the bacterium uses an enzyme called Cas9 to overcome the new phage
In case of a new attack, the bacterium
makes a guide RNA from the CRISPER archive. Cas9 which is an enzyme uses that
guide RNA and tries to find a DNA fragment that matches with the nucleotides of
that specific RNA. When Cas9 finds the right DNA fragment, it cuts the fragment
out from the bacterium’s DNA. Thus, phage’s genetic code is inactivated and the
bacterium stays safe from getting harmed. Since this enzyme uses a guide RNA to
identify the target DNA sequence, it’s very accurate and it cuts the DNA
molecule like a DNA surgeon. This enzyme can also be redesigned and
biochemically reengineered which gives researchers the advantage of creating a
more accurate and useful molecule.
CRISPER-Cas9 is a very convenient tool to
be used for gene editing. In a near future, it can be used to fix genetic
diseases such as sickle-cell anemia which is a disease caused by a mutation in
chromosome XI. This technology can also be used to cure diseases such as AIDS
and cancer. For instance, genetically modified white blood cells can be
designed that don’t get affected by HIV, and they are better cancer cell
hunters. These examples are only small sides of this technology’s capabilities
in curing sicknesses that were incurable in the past, and now because of
CRISPER-Cas9, they can be cured. Another capability that this technique has is
designing human embryos. Human zygotes can be genetically modified to fix
detected diseases even before the baby is born. They can be designed to have a
better IQ and physic and to prevent sicknesses such as obesity and Alzheimer’s
that can have genetic roots. These examples of CRISPER’s capabilities used to
be dreams of researchers, but now thanks to CRISPER-Cas9 technology they can
turn into realities that will change humanity forever.
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