DNA sequencing determines the order of nucleotides in DNA. It was first discovered in the late 1800s and early 1900s. In the 1970s, methods for DNA sequencing were developed using primer extension strategies and specific nucleotide labeling. The Maxam-Gilbert method uses purine and pyrimidine specific chemicals to cleave the DNA, while Sanger's dideoxynucleotide method uses chain termination with no 3' OH groups. DNA sequencing is important for fields like molecular medicine, forensics, evolution, and agriculture. It allows detection of bacteria and sequencing of the M13 bacteriophage.

1. Dna sequencing

2. What is DNA sequencing ?
• Determining order of nucleotides

3. • DNA first discovered by Friedrich Miescher in
1869
• Oswald Avery, Colin Macleod and Maclyn
McCarty demonstrated that purified DNA could
change one strain of bacteria into another
• In 1953 James Watson and Francis Crick put
forward double helix model of DNA
• Foundation of sequencing protein was first laid
by Sanger
HISTORY

4. • The first method for determining DNA
sequence involved a location specific primer
extension strategy, established by Ray Wu in
1970
• DNA polymerase catalysis and specific
nucleotide labelling used
• Between 1970 and 1973 R. Padmahabhan
and colleagues that this method can be used
to identify any DNA sequence
• Sanger adopted primer extension strategy to
develop rapid DNA sequences
• Later Maxam and Gilbert also developed
sequencing method

5. • Why is DNA sequencing important ?
Molecular medicines
Bioarchaeology, Anthropology, Evolution
and Human migration

6. DNA Forensics
Detect bacteria and other organisms that
pollute air
Agriculture, livestock breeding and
bioprocessing

7. Maxam-Gilbert method
Sangers
dideoxynucleotide
method
Bacteriophage M13

8. MAXAM GILBERT METHOD

9. • Allan Maxim and Walter Gilbert developed a
method for sequencing single stranded dna
• Purines dimethyl sulphate
• Pyrimidines hydrazine
• Breaking of glyosidic bonds between ribose
sugar and base

10. Dimethyl
Sulphate
Piperdine
Guanine
Hydrazine
Piperdine
Thymine
+
Cytosine
Guanine
+
Adenine
Dimethyl
sulphate
Piperdine
Formic
acid
Cytosine
Hydrazine
Piperdine
Nacl

12. • Discovered by Scientist Sanger
• Also know as dideoxy method or chain
termination method
• 2 main things to be done :
1. Denature the DNA
2. Labelling
SANGER SEQUENCING

13. DIDEOXYNUCLEOTIDE

14. • In DNA nucleotides are bond to each other
by phosphodiester bond
• In case of no 3’OH no it cannot form a
phosphodiester bond
• CHAIN TERMINATION

19. SEQUENCING USING BACTERIOPHAGE M13

21. BY PRIMER WALKING

22. • Molecular Biology by David P Clark
• Cell and Molecular Biology (6th edition) by
Gerald Karp
REFERENCES

23. THANK YOU