Information is encoded In the structure of our DNA molecule. So , if you change the instruction of the DNA code you can change various beings.

But, with the help of CRISPR we can change the DNA code of humans with a great accuracy!

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We have been editing the DNA for quite a while .

• Gene Therapy on the mouse.
• Growth hormones , etc
• We have genitally modified vegetables

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Okay, so you might ask we have been editing genes for quite a while now. It may be genetically modified fruits , terminating pregnancies before hand base on tests. But why is CRISPR a major breakthrough?

Now we can edit genes with technical precision , and high accuracy. This was not possible before.

Theory

“The actual cutting is done by a nuclease called Cas9. Cas9 has two active cutting sites, one for each strand of the DNA's double helix. Cas9 does this by unwinding foreign DNA and checking whether it is complementary to the 20 basepair spacer region of the guide RNA (the spacer region RNA). If it is, the foreign DNA gets chopped up.”
Therefore CAS9 a enzyme that deleted the the DNA and CRISPR is a number of sequences instructing CAS9 to perform the function.
Wikipedia

Genome Editing

Meaning

When the bacterium detects a virus it produces 2 short strands or RNA . Once RNA strand matches the virus. These 2 RNAS together form a complex Called Cas9. It is an enzyme that can cut DNA. It destroys the virus.

It can cut any DNA, by changing the guide RNA. The cell tries to repair the cut, this can lead to various form of mutations..
What we humans want to do is Replacing a mutant gene with a healthy copy, with the help of a desired sequence. This can be done in stem cells, and in fertilized eggs. One of the most intriguing parts of Cas9 is that It can target various DNAS at once.

Applications

1. Eradicate Diseases

https://www.pexels.com/photo/clinic-doctor-health-hospital-40559/
CRISPR can be used to locate unwanted genes are eradicate them. Diseases such as HIV , Cancer. It may take while but with effective research we might be headed into a bright future.

2. Agriculture

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Gentically modified crops , are already present. But changing the properties of various fruits and vegetables can be useful in various ways. For eg: Tomatoes that last longer, vegetables with more vitamins.

Data collected from :

Genome Editing
Genome Editing with CRISPR-Cas9
Wikipedia

I and @jenkinrocket both have covered this topic. check out the article

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