2. INTRODUCTION
WHAT EXACTLY DNA
DNA STRUCTURE DISCOVERY
STRUCTURE OF DNA
DNA SEQUENCING DISCOVERY
WHY IS GENOME SEQUENCING IMPORTANT
WHY IS THE KNOWLEDGE ABOUT THE HUMAN
GENOME
IS INTERESTING
GENOME TRIVIA
RNA SEQUENCING
BBASIC METHOD OF DNA SEQUENCING
3.
4. DNA sequencing is the process of determining the nucleic
acid sequence – the order of nucleotides in DNA. It
includes any method or technology that is used to
determine the order of the four
bases: adenine, guanine, cytosine, and thymine. The
advent of rapid DNA sequencing methods has greatly
accelerated biological and medical research and discovery.
5. What exactly is DNA
Deoxyribonucleic acid more commonly known as DNA is a complex
molecule that contains all of the information necessary to build and
maintain an organism all living things have DNA within their cell in fact
nearly Every cell in a multicellular organism causes the full set of DNA
required for that organism
https://www.youtube.com/watch?v=2JUu1WqidC4
6. DNA structure Discovery
Deoxyribonucleic acid was first discovered and isolated by Frederick Miescher in 1869
but it remained under study for many decades because proteins rather than DNA was
thought to hold the genetic blueprint to life .
The situation changed after 1944 as a result of Some experiment by Oswald Avery
macleod and mccarty demonstrating that purified DNA could change one strain of
bacteria into another.
This was the first time that DNA was shown capable of transforming the properties of
cell .
In 1953 James Watson and Francis Crick put forward the double helix model of DNA
based on crystal lized X-ray structures beiniisg studied by Rosalind Franklin.
According to the model DNA is composed of two strands of nucleotides coiled around
each other linked Together by hydrogen bond and running in opposite direction. Each
strand is composed of four complementary nucleotides --ADENINE (A), CTOSINE (C)
,GUANINE (G) and THYMINE (T)-with an "A" on one strand always paired with "T" on
the other strand and "C"always paired with "G".
They proposed that such a structure allowed each strand to be used to reconstruct the
other and Idea Central to the passing on heredity information between generation
8. This Photo by Unknown Author is licensed under CC BY-SA
9. Knowledge of the sequence of a DNA segment has many uses.
1.The
arrangement of
nucleotides in
DNA determined
the sequence of
amino acids in
proteins, which
in turn helped
determine the
function of a
protein
2.It helps in
basic biological
research, in
numerous
applied fields
such as medical
diagnosis,
biotechnology,
forensic biology,
virology, and
biological
systematics.
3.Comparing
healthy and
mutated DNA
sequences can
diagnose
different
diseases including
various cancers
4.characterize
antibody repertoire,
and can be used to
guide patient
treatment.
10. HISTORICALLY THERE ARE TWO MAIN METHODS OF DNA
SEQUENCING
1.THE DIDEOXYNUCLEOTIDE CHAIN TERMINATION METHOD(BY FRED
SANGER)
2.THE CHEMICAL DEGRADATION METHOD (BY MAXAM & GILBERT)
MODERN SEQUENCING EQUIPMENTS USES THE PRINCIPLES OF
SANGER METHOD
HENCE, WE WILL DISCUSS IT IN DETAIL FURTHER…
11. BY FRED SANGER
Sanger sequencing, also known as
the “chain termination method”, is
a method for determining the
nucleotide sequence of DNA.
The method was developed by two
time Nobel Laureate
Frederick Sanger and his colleagues
in 1977, hence the name the Sanger
Sequence.
27. DNA MIGRATE FROM THE
NEGTIVE POLE TOWARDS THE
POSITIVE POLE , DUE TO THE
NEGTIVE CHARGE IMPARTED BY
THEIR PHOSPHATE BACKBONE
THE SMALLER LIGHTER
LENGTHS OF DNA
MIGRATE FURTHER TO THE
BOTTOM OF THE
ELECTROPHORESIS PLATE.
THIS IS WHY WE SEE THESE
BAND PATTERN ALONG THE
LENGHTS OF THE PLATE
28.
29. Sanger sequencing targets a specific region of template DNA using an oligonucleotide sequencing primer, which binds to the DNA adjacent to
the region of interest. (There must be an area of known sequence close to the target DNA.)W In order to determine the sequence, Sanger
sequencing makes use of chemical analogs of the four nucleotides in DNA. These analogs, called dideoxyribonucleotides (ddNTPs), are
missing the 3´ hydroxyl group that is required for 5’ to 3’ extension of a DNA polynucleotide chain. By mixing ddNTPs that have been
labeled with a different color for each base, unlabeled dNTPs, and template DNA in a polymerase-driven reaction, strands of each possible
length are produced when the ddNTPs are randomly incorporated and terminate the chain. The extension products are then separated by
electrophoresis, resolved to single-nucleotide differences in size. The chain-terminated fragments are detected by their fluorescent labels, with
each color identifying one of the terminating ddNTPs.
