Introduction to DNA Rizwan

8/9/2019 Introduction to DNA Rizwan

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DNA stands for deoxyribonucleic acid


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Structure of DNA

DNA exist in the form of a twisted

double helix and governs various

inheritance traits

Length of DNA in a cell is 180cm.

Each chromosome consist of two

DNA molecules.

Each DNA molecule is hydrogen

bonded

Nuclear protein called histones ,

the complex of DNA and histones

being referred to as chromatin,

structurally stabilize the helix.


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STRUCTURE OF DNA


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Each nucleotide is

composed of phosphate,

deoxyriboes sugar, and

organic nitrogenousbases, such as adenine

(A), guanine (G), cytosin

(C), thiamine (T).

DNA molecule resembles

a twisted loop ladder withfour kinds of stair-steps,

A-T , T-A , C-G or G-C


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A

P

s

P

P

s

Ps

P

s

P

s

P

s

P

s

P

s

P

s

P

P

s

P

s

s

P

s = Sugar

= Phosphate

AC

GT

CG

T


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A =Adenine

T =Thymine

G =Guanine

C =Cytosine

UnitsDouble Helix

GAT

C

DNA- What it looks likeDNA- What it looks like


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DNA is Blueprint

of

Life

GENETIC LANGUAGE

A Z 26 LETTERS

37 LETTERS


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BOOK OF LIFE 3.2 BILION LETTERS IN

HUMAN DNA


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BOOKCHAPT

ERS paragraph sentence Word letter

Human cell nucleus chrompsomes Locii (gene) DNA


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Chromosomes Exist in pairs

Father Mother


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1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

17 18 19 20 21 22 X Y

CHROMOSOMESCHROMOSOMES


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CHROMOSOMES

FOR NORMAL

HUMAN BEINGS

CHROMOSOMES

FOR NORMAL

HUMAN BEINGS

4646

FATHERFATHER

46 CHROMOSOMES46 CHROMOSOMES

MOTHERMOTHER

46 CHROMOSOMES46 CHROMOSOMES


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Q) What does DNA mean?Q) What does DNA mean?

A) Deoxyribonucleic AcidA) Deoxyribonucleic Acid

Q) Where does DNA come

Q) Where does DNA comefrom?from?

A) 1/2 from momA) 1/2 from mom

A) 1/2 from dadA) 1/2 from dadBlue print of lifeBlue print of life

Q) What does DNA mean?Q) What does DNA mean?

A) Deoxyribonucleic AcidA) Deoxyribonucleic Acid

Q) Where does DNA come

Q) Where does DNA comefrom?from?

A) 1/2 from momA) 1/2 from mom

A) 1/2 from dadA) 1/2 from dadBlue print of lifeBlue print of life

DNADNADNADNA


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Maternal

Chromosome

Maternal

Chromosome

Paternal

Chromosome

Paternal

Chromosome

Where does DNA come from?Where does DNA come from?


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Cell TypesCell Types

BloodBlood

SweatSweat

Hair RootsHair RootsSalivaSaliva

Vaginal SecretionVaginal SecretionSemenSemen

SAME

Various TissueVarious Tissue

Where can DNA be found?Where can DNA be found?


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How does DNA help us?

Practical application of DNA

Fingerprinting

In cases of sexual offences

In case of unsuspicious deaths

Dispute of paternity / maternity Criminal identification

Personal identification


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What is DNA finger printing

It is a technique of decoding of geneticinformation for the furtherance of justice.

The chemical structure of everyones DNA issame

The only difference is in the sequence ofbase pairs

Every person has different sequence ofbase pair

This unique pattern give every individualspecific fingerprint (DNA fingerprint


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How is DNA fingerprinting done?

Scientist use a small no of DNA

secquences that are known to

vary among individuals a great

deal, and analyze those to get a

certain probability of a match.

Steps:-


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TECHNIQUES

RFLP

PCR

STR

mDNA

Y-Chromosomal DNA


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Step 1:-

Isolation of DNA from rest of the cellular material

Step 2:-

Denaturing the DNA, either by heating of or

chemically treating DNA in to gel, so that allthe DNA is rendered single-stranded.

Step 3:-

Blotting the DNA, this allows to identify, in aparticular persons DNA the occurrence and frequency

of the particular genetic pattern.


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The pure DNAis suspended in

a liquid

The pure DNAis suspended in

a liquid


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- Blood

- Hair Roots

- Saliva- Sweat

- Semen

- Various Tissue

- Blood

- Hair Roots

- Saliva- Sweat

- Semen

- Various Tissue

Chemical

DNADNA

Isolation ofDNAIsolation ofDNA


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Genetic Material

DNA

Genetic Material

DNA

Cellular WasteCellular Waste

Extraction of DNA from

rest of the cellular waste


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Blotting the DNA


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EXTRACTION

QUANTITATION

PCR CHECKING OF AMPLIFIED PRODUCT

PAGE (poly acrylamide gel electrophoresis)

DOCUMENTATION SEQUENCING

STEPS


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Step 2:-

Creating a hybridization reaction

Binding occurs b/w base pairs

A-T two H-bonds

C-G three H-bonds


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Denaturing the DNA:- Radioactive probe is allowed to bind with the

single strand DNA

Only the area bind with the probe will be

shown up on the film.

Radioactive Probe

Radioactive Probe


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G

T

A

G

A

A T

C

A

T

C

T

Heat

Step one of a single cycleStep one of a single cycle


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T

Step two of a single cycleStep two of a single cycle


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Step three of a single cycleStep three of a single cycle

T


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Every strand of DNA has pieces

that contain genetic information

(exons)And

Pieces that contain no geneticinformation are Introns.

Introns contain repeated

sequence of base pairs calledVNTRs


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Short Tandem Repeats

AGAT AGAT AGAT AGAT

Short Tandem Repeats

AGAT AGAT AGAT AGAT

AGAT AGAT AGAT AGAT AGAT AGAT AGAT 7

AGAT AGAT AGAT AGAT AGAT 5

(Core sequence AGAT)

STRSTR


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VNTRs

(Variable Number Tendem Repeat)

To determine if a person has a

particular VNTR, the above

process is applied and DNAsequence is amplified and then

studied.

Example:-


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1 Cycle2 Cycles

3 Cycles

4 Cycles

5 Cycles

30 Cycles

AmplificationAmplification

DNA

PCR (Polymerase Chain Reaction)PCR (Polymerase Chain Reaction)


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Amplified

DNA

Amplified

DNA

DNA

Profile

DNA

Profile

Analysis of amplified DNAAnalysis of amplified DNA


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DNADNA

SolutionSolution

(making copies)(making copies)

AmplificationAmplification


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A given person VNTR come from geneticinformation donated by his parents.

It is not possible to have VNTR other than his

parents. So Mrs John (blue) and Mr John (yellow) and their

four clildren D1 Mrs John (blue) daughter

D2 Mr John (yellow) step daughter (red) S1 Mr & Mrs John

S2 Mr & Mrs adopted son (light and & dark green)


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Mr & Mrs John and their children genetic information

Mrs John (blue)

Mr John (yellow)

D1 daughter of Mr& Mrs John (blue &yellow)

D2 Mr John(yellow) stepdaughter (red)

S1 Mr & Mrs John

S2 Mr & Mrsadopted son (lightand & dark green)

Documents

Introduction to DNA Rizwan