gene editing tool.

2. • New gene editing
technology
• Based on bacterial
immune system
• Cost of genetic
engineering shrunk
by 99%.
• 1st discovered in
E.coli

3. Introduction
• Bacteria and viruses have been fighting since the dawn of life.
• Bacteria fail to resist most of the time.
• sometimes, bacteria survive and they activate their most effective
antivirus system.
• They save a part of the virus DNA in their own genetic code in a
DNA archive called CRISPR.
• When the virus attacks again, the bacterium quickly makes an RNA
copy from the DNA archive and arms a secret weapon, a protein
called Cas9.

4. Repeats
• Identical
sequences
Spacer DNA
• Unique
• Matches up
perfectly with
viral DNA

5. •Cas9 (or "CRISPR-associated protein 9") is an enzyme
•It recognizes and cleaves specific strands of viral DNA
that are complementary to the CRISPR sequence.
•Cas9 protein has sixdomains
•The Rec I domain is the largest and is responsible for
binding guide RNA.
•The role of the REC II domain is not yet well
understood.
•The arginine-rich bridge helix is for initiating cleavage
activity.
•The PAM-Interacting domain responsible for initiating
binding to target DNA.
•The HNH and RuvC are nuclease domains that cut
single-stranded DNA.

6. CRISPR SYSTEM AND MECHANISM
Spacer acquisition
crRNA processing
Interference

7. SPACER AQUISITION
• In viral DNA there are specific
tags called PAM (Protospacer
Adjacent Motif).
• PAM is present upstream of
recombinant site of cas proteins
in viral dna.
• Cas1 and Cas2 recognize PAM and
degrade the dna and copies to its
spacer part.

8. crRNA PROCESSING
• Firstly the coding strand of
CRISPR is transcribed.

9. crRNA PROCESSING
• tracrRNA: trans-activating crRNA
• It binds to CRISPR repeats.
• Cas9 and RNase III cut the RNA to form a complex with spacer repeat and
tracrRNA.
• tracrRNA+crRNA= guideRNA

10. INTERFERENCE
• gRNA will be integrated with cas
protein to form a complex.
• When the virus attacks second
time, cas will recognize PAM in
viral DNA.
• crRNA will recognize the
complementary sequence
adjacent to PAM.
• gRNA-cas complex binds to viral
DNA.
• cas will create double strand
break(DSB).

11. DNA Repair
For blunt ends:
• Homologous Recombination

12. For sticky end
• Non Homologous End Joining
(NHEJ)

14. PROS
• Introduction and removal of one gene at a
time.
• Possible to manipulate many different
genes in a cell line, plant or animal very
quickly, reducing the process from taking a
number of years to a matter of weeks.
• High degree of flexibility and accuracy in
cutting and pasting DNA.
• It is also different in that it is not species-
specific, so can be used on organisms
previously resistant to genetic engineering
• Very low cost
CONS
• OFF target effects
• Mosaic effect
• Ethical and social issues
• Bioweapon

15. Application
• This technique used to selectively silence specific sections of
the gene in our work.
• We design a short DNA which will be complementary to our
gene of interest.
• CRISPR is dramatically accelerating the pace of research in
nearly every biological field

19. Edit crops to be more nutritious
• Snip out the allergens in peanuts.
• To make bananas survive a deadly fungal disease
• Make food tastier or more nutritious
• Better survivors of heat and stress.

20. Stop genetic diseases
• Hypertrophic cardiomyopathy, Huntington’s disease or cystic
fibrosis
• BRCA-1 and 2 mutations linked to breast and ovarian cancers.
• Scientists have even shown that CRISPR can knock HIV
infections out of T cells.
• However, only tested this on cells in the lab.

21. Gene Drive
• Modify not just a single organism but an entire species.
• Genetically modify mosquitoes to only produce male offspring
and then use a gene drive to push that trait through an entire
population. Over time, the population would go extinct.

22. Gene drive

23. Designer Baby
• Baby whose genetic makeup has been selected or altered,
often to include a particular gene or to remove genes
associated with disease.
• In 2019 Chinese twins Lulu and Nana were edited as embryos.

24. CONCLUSION
 Summing it all up, CRISPR has its advantages and
disadvantages ranging from ethical concerns
 Fastest, cheapest and most precise way of editing genes.
 This scientific breakthrough has the ability to eliminate
diseases, solve world hunger, provide unlimited clean
energy.
 CRISPR has potentially given us direct access to the source
code of life and at the same time has given hope to millions
of people.