Gene Editing.

1. GENE EDITING

2. • Gene editing is a group of technologies that give
scientist the ability to change an organisms
DNA.
• It is a type of genetic engineering in which DNA
is inserted, deleted or replaced in the genome
of living organisms using engineered nucleases
or “molecular scissors”.

3. • These nucleases create site specific double
stranded breaks at desired locations in the
genome.
• The induced double stranded breaks are
repaired through NHEJ or HDR.

5. CONCEPT
• A common approach in modern biological
research is to modify the DNA sequence
(genotype) of an organism and observe the
impact of this change in the
organism(phenotype)

6. • Several approaches to genome editing have
been developed.
• A recent one is known as CRISPR – CAS 9
(Clustered Regularly Interspaced Short
Palindromic Repeats).
• Cas 9 ( CRISPR associated protein 9).

7. • CRISPR – Cas 9 system has generated a lot if
excitement in the scientific community because
it is faster, cheaper, more accurate and efficient
than other existing genome editing methods.
• It was adopted from a naturally occuring
genome editing system in bacteria.

8. • The bacteria captures 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.
• If the viruses attack again, the bacteria
produce RNA segments from the CRISPR
arrays to target viruses DNA.

9. • The bacteria then use Cas 9 or a similar enzyme
to cut the DNA apart which disables the virus.
• The CRISPR- Cas 9 system works similarly in the
lab.
• Researchers create a small piece of RNA with a
short guide sequence that attaches to a specific
target sequence of DNA in a genome.

10. • The RNA also binds to the CAS-9 enzyme.
• As in bacteria, the modified RNA is used to
recognize the DNA sequence and the Cas 9
enzyme cuts the DNA at the targeted location.

11. • The CRISPR – CAS9 system consists of two key
molecules that introduce a change (mutation)
into the DNA.
• 1) An enzyme called Cas 9.
• 2) A piece of RNA called guide RNA(gRNA)
which consists of a small piece of pre designed
RNA sequence located within a longer RNA
scaffold.

15. USES
1) RESEARCH: It can be used to change the DNA
in cells or organisms to understand their
biology and how they work.
2) TREAT DISEASES: It is used to modify human
blood cells that are then put back into the
body to treat conditions such as Leukemias
and AIDS.

16. • It could also be used to treat infections such
as MRSA and simple genetic conditions such
as muscular dystrophy and haemophilia.
• 3) BIOTECHNOLOGY: It has been used in
agriculture to genetically modify crops to
improve their yields and resistance to disease
and drought.

17. Other genome editing methods
• Zinc finger nucleases.
• TALEN ( Transcriptor Activator Like Effector
Nuclease)

18. TAKE HOME MESSAGE
• Genome editing is a technique used to
precisely and efficiently modify DNA within a
cell.
• It involves making cuts at specific DNA
sequences with enzymes called engineered
nucleases.

19. • Genome editing can be used to add, remove
or alter DNA in the genome.
• By editing the genome the characteristics of a
cell or an organism can be changed.
• Gene editing methods are
• CRISPR- CAS 9
• Zinc finger nuclease
• TALEN

20. • GENE EDITING

21. REFERENCE
• INTERNET