UNIVERSITI TEKNOLOGI MARAFACULTY OF CHEMICAL ENGINEERING
GENETICS LABORATORY(CBE561)
NAME / ID : 1) SITI AISHAH BINTI SULAIMAN (2010653746)
2) NUR ATHIKA SHAKIRA BT JAIS (2010285582)
3) MARINA BT YUSOFF (2010672752)
4) NOR FARAHIDA BT ABU BAKAR (2010811294)
5) ADIBAH DAYANA BT AHMAD (2010837536)
EXPERIMENT : The isolation of genetic material by using PCR
DATE PERFORMED : 6th June 2012
PROG/CODE : Bachelor of Engineering (Hons.) in Chemical & Bioprocess Engineering / EH222 4B
SUBMIT TO : Dr. Tan Huey Ling ( )/ Mdm. Nurul Huda Mohamed Safri( )
NO Title Allocated Marks % Marks %
1 Abstract 52 Introduction 53 Aims 54 Theory 55 Apparatus 56 Procedure 107 Results 108 Calculations 109 Discussion 2010 Conclusion 1011 Recommendations 512 References 513 Appendix 5
TOTAL 100
Remarks:
Checked by;
Date :
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TABLE OF CONTENTS
No. Contents Page
1. Abstract 3
2. Introduction 4
3. Objective 5
4. Theory 5-6
5. Apparatus 7
6. Experimental procedures 8-9
7. Results 10
8. Calculations 11
9. Discussion 12-13
10. Conclusion 14
11. Recommendations 15
12. References 15
13. Appendices 16
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ABSTRACT
Polymerase chain reaction (PCR) allows researchers to amplify DNA in a test tube. This
process uses an enzyme derived from heat-resistant bacteria. The steps of PCR are driven by
changes in temperature.
Polymerase chain reaction, or PCR, uses repeated cycles of heating and cooling to
make many copies of a specific region of DNA. First, the temperature is raised to near
boiling, causing the double-stranded DNA to separate, or denature, into single strands. When
the temperature is decreased, short DNA sequences known as primers bind, or anneal, to
complementary matches on the target DNA sequence. The primers bracket the target sequence
to be copied. At a slightly higher temperature, the enzyme Taq polymerase, shown here in
blue, binds to the primed sequences and adds nucleotides to extend the second strand. This
completes the first cycle. In subsequent cycles, the process of denaturing, annealing and
extending are repeated to make additional DNA copies. After three cycles, the target sequence
defined by the primers begins to accumulate. After 30 cycles, as many as a billion copies of
the target sequence are produced from a single starting molecule.
The four micro test tubes was obtained and labelled as yellow tubes for lambda DNA,
violet tube for Pstl lambda digest, green tube for EcoR1 lambda digest and orange tube for
Hind iii lambda digest. The components was mixed by gently flicking the tube with finger
been tapping gently on the table to collect liquid to the tube bottom. The tube in a centrifuge
is pulse-spin to collect all the liquid to the bottom, or gently been trapped on the benchtop and
then the four micro test tubes was being incubated. After that, the agarose gel electrophoresis
was prepared. Next, 10ul of each sample is loaded into separate wells in the gel chamber and
the liquid is placed carefully on the electrophoresis chamber. When the electrophoresis is
completed, the power is turned off and the top of the chamber is removed. The gel and tray is
been removed carefully from the gel box. After that, the result that obtained was analysed and
if the band does not appear clearly then the gel was stained and the gel was being analyse
once again.
Based on the result, it shows that EcoR1 and Hind III had the most similar band size.
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INTRODUCTION
DNA cloning in cells remains the best method for preparing large quantities of a
particular gene or other DNA sequence. However, when the source of DNA is impure, the
polymerase chain reaction or PCR is quicker and more selective. In this technique, any
specific target segment with one or many DNA molecules can be quickly amplified in a test
tube. With automation, PCR can make billions of copies of target segment of DNA in few
hours significantly faster than the days it would take to obtain the same number of copies by a
screening DNA library for a clone for a desired gene and it replicate within a host cells.
In the PCR procedure, a three step cycle brings about a chain reaction that produces an
exponentially growing population of identical DNA molecules. During each cycle, the
reaction mixture is heated to denature the DNA strands and cooled to allow the annealing
(hydrogen bonding) of short, single stranded DNA primers complementary to sequence an
opposite strands at each end of the target sequence; finally, a heat-stable DNA polymerase
extends the primers in 5’-3’ direction. If a strand DNA polymerase were used, the protein
would be denatured along with the DNA during the first step and would have to be replaced
after each cycle. The key to automating PCR was the of an unusual heat-stable DNA
polymerase, first isolated from the cells of a bacterial species living in a hot spring, that could
withstand the heat at the start of each cycle. Only minute amounts of DNA need to be present
in a starting material, and this DNA can be partially degraded state, as long as few molecules
contain the complete target sequence. By the end of the third cycle, one-fourth of the
molecules are identical to the target segment, with both strands the appropriate length. With
each successive cycle, the number of target segment molecules of the correct length doubles,
soon greatly outnumbering all other DNA molecules in the reaction.
Usually, gel electrophoresis is a widely used in the analysis of nucleic acids and
proteins. Agarose gel electrophoresis is used for the preparation and analysis of DNA. It is
a procedure that separates molecules on the basis of their rate of movement through a gel
under the influence of an electrical field. DNA is negatively charged and when placed in an
electrical field, DNA will migrate towards the positive pole (anode). An agarose gel is used to
slow the movement of DNA and separate by size. Within an agarose gel, linear DNA migrates
inversely proportional to the log10 of their molecular weight.
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OBJECTIVE
To setting up the Polymerase Chain Reactions
To run electrophoresis of Polymerase Chain Reactions product
To answer question based on Polymerase Chain Reactions
THEORY
The polymerase chain reaction (PCR) is a molecular genetics technique for making multiple
copies of a gene, and is also part of the gene sequencing process. Gene copies are made using
a sample of DNA and the technology is good enough to make multiple copies from one single
copy of the gene found in the sample. PCR amplification of a gene to make millions of copies,
allows for detection and identification of gene sequences using visual techniques based on
size and charge of the piece of DNA. Under controlled conditions, small segments of DNA
are generated by enzymes known as DNA polymerases that add complimentary
deoxynucleotides (dNTPs) to a piece of DNA known as the template. A smaller piece of
DNA, called primers is used as a starting point for the polymerase. Primers are small man-
made pieces of DNA (oligomers), usually between 15 and 30 nucleotides long. They are made
by knowing or guessing short DNA sequences at the very ends of the gene being amplified.
During PCR, the DNA being sequenced is heated and the double strands separate. Upon
cooling, the primers bind to the template and create a place for the polymerase to begin. PCR
was made possible by the discovery of thermophiles and thermophilic polymerase enzymes.
This is an enzyme that maintains structural integrity and functionality after heating at high
temperatures.
As the name implies, it is a chain reaction, a small fragment of the DNA section of interest
needs to be identified which serves as the template for producing the primers that initiate the
reaction. One DNA molecule is used to produce two copies, four, eight and so forth. This
continuous doubling is accomplished by specific proteins known as polymerases. Polymerase
is an enzymes that are able to string together individual DNA building blocks to form long
molecular strands. Polymerases require a supply of DNA building blocks which is the
nucleotides consisting of the four bases adenine (A), thymine (T), cytosine (C) and guanine
(G). They also need a small fragment of DNA, known as the primer, to which they attach the
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building blocks as well as a longer DNA molecule to serve as a template for constructing the
new strand. If these factors are supplied, this enzyme will construct exact copies of the
templates. The polymerase chain reaction serves to copy DNA. It uses repeated cycles, each
of which consists of three steps:
4.1: Denaturing
The reaction solution containing DNA molecules , polymerases, primers (serve as starting
DNA) and nucleotides (which are attached to the primers) is heated to 95°C. This causes the
two complementary strands to separate, a process known as denaturing or melting.
4.2: Annealing
Lowering the temperature to 55°C causes the primers to bind to the DNA, a process known
as hybridization or annealing. The resulting bonds are stable only if the primer and DNA
segment are complementary. The polymerases then begin to attach additional complementary
nucleotides at these sites, thus strengthening the bonding between the primers and the DNA.
4.3: Extension
The temperature is again increased to 72°C. This is the ideal working temperature for the
polymerases used, which add further nucleotides to the developing DNA strand. At the same
time, any loose bonds that have formed between the primers and DNA segments that are not
fully complementary are broken. Each time these three steps are repeated the number of
copied DNA molecules doubles. After twenty cycles, about a million molecules are cloned
from a single segment of double stranded DNA.
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APPARATUS
PCR tubes
Cap less micro centrifuge tube
Pipette
Pipette tip
Ice
Thermal cycle
Pulse spin
Electrophoresis
Gel box
MATERIALS
Template DNA
Blue MMP
Orange G Loading Dye
Agarose gel
Ice
Allele ladder
METHOD
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5.1: Setting up the PCR Reactions
1. Five PCR tubes are labelled as CS, A, B, C and D by including our groups members. The PCR tubes are placed into a cap less micro centrifuge tube on ice.
2. 20μl of appropriate template DNA is transferred correctly into labelled tube by follows table below.
Label PCR tubes Add DNA template Add Master mix + primers
CS + your initials 20μl Crime Scene DNA 20μl MMP(blue)
A+ your initials 20μl Suspect A DNA 20μl MMP(blue)
B+ your initials 20μl Suspect B DNA 20μl MMP(blue)
C+ your initials 20μl Suspect C DNA 20μl MMP(blue)
D+ your initials 20μl Suspect D DNA 20μl MMP(blue)
3. 20μl ot MMP (master mix + primers) are transfer into each of 5 PCR tubes containing template DNA. Pipette up and down to mix. Cap each tube after adding blue MMP.
4. Capped PCR tubes are placed in their adaptors on ice.
5. Tubes are placed in the thermal cycler when instructed to do so. Thermal cycle for PCR is programmed.
5.2: Electrophoresis of PCR Products
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1. Gel electrophoresis equipment is set up as instructed.
2. Five PCR tubes are obtained from the previous lesson. The PCR tube is placed in cap less tube and pulse-spin in a balanced micro centrifuge for a few seconds to collect all liquid to the bottom of the tubes.
3. 10 μl of Orange G loading dye (from the tube labelled LD) is transfer into each PCR tubes. Pipet up and down to mix and pulse spin to collect liquid in the bottom of the tubes.
4. An agarose gel is placed in the gel electrophoresis apparatus. The well of the agarose gel is checked near the black (negative) electrode and the base of the gel is near the red (positive) electrode.
5. The electrophoresis chamber is filled with enough 1XTAE buffers to cover the gel. This required about 275 ml of 1 X TAE buffer.
6. Load 20 μl of the sample by using a clean tip for each sample into six wells of the gel in the following order:
Lane Sample Load volume
1 Allele Ladder 20 μl
2 Crime Scene 20 μl
3 Suspect A 20 μl
4 Suspect B 20 μl
5 Suspect C 20 μl
6 Suspect D 20 μl
7. The lid on the gel box is secure. The lid is attached to the base in only one orientation: red to red and black to black. The electrical lead is connected to power supply.
8. The power supply and electrophoresis sample is turn on at 100 V for 30 minutes.
9. Fast Blast DNA stain is used to stain the sample.
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RESULT
Ladder(bp)
Crime scene (bp)
Suspect A(bp)
Suspect B(bp)
Suspect C(bp)
Suspect D (bp)
15000
1000 1000 1000
700 700 700
500 500400300 300 300 300200 200 200100
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CALCULATIONS
Calculation in preparation of agarose gel
1g = 1% agarose
1g agarose = 100ml of buffer
4g agarose = 400ml of buffer
8 agarose gel = 400ml of buffer
M1V1 = M2V2
(500)(V1) = (1)(3)
V = 0.06L
3 - 0.06 = 2.94 L H20
50 X TAE H2O
(0.06 L TAE) ÷3 2.94 L H2O÷3
0.02 L TAE 0.98 L H2O
20ml 9.80ml
Master mix primer (MMP) stock for 8 groups
= 1000 µL of Master Mix + 20 µL crime scene investigator primer
Mix well & pulse-spin to bring contents to the bottom of the tube
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DISCUSSION
Crime is an action or omission that constitutes an offense that may be prosecuted by the state
and is punishable by law. In other words, crime is an action or an instance of negligence that
is deemed injurious to the public welfare or morals or to the interests of the state and that is
legally prohibited. Crime can occurs in various forms and to anyone, not limited to gender,
age or place. Nowadays, rape, murderer is not a new thing to our ears. The lack of witnesses,
lack of evidences, and lack of brave people to come forward and give witnesses to a crime
scene led to a new discovery of technology that can uphold justice.
For sure, the criminals would not leave any evidence at the crime scene, the samples
obtained from the crime scene found usually too small and almost impossible to be analyst.
Thanks for technologies that make it easier for human to uphold justice. As for the forensic
lab analysis, non-coding DNA is used in a method of distinguishing between individuals by
analysing patterns in their DNA. Non-coding DNA describes components of an organism's
DNA sequences that do not encode for protein sequences which not transcribed into
messenger RNA to code for proteins.
In this study, firstly PCR technique is used. Basically, PCR act to amplify the DNA
segment. This is done by denaturing the DNA sample, having primers anneal then extension
of the annealed primers by polymerase and the process being repeated multiple times.
Secondly, we used gel electrophoresis. When putting DNA sample above the gel, different
size of DNA will move at different speed and different length of pathway. DNA is negatively
charged particle and will move towards the positively charged pole above the agarose gel.
This allow the DNA to separate by size, as the size is lighter, it will accelerates faster towards
the opposite pole, thus comparisons can be made to the ladder and the crime scene DNA.
With the aid of PCR or polymerase chain reaction method, any segment or target
sequence within the DNA sample can be copied many times (amplified). PCR requires
double-stranded DNA containing the target sequence, a heat-resistance polymerase, all four
nucleotides, and two 15 to 20 nucleotide DNA strands that serve as primers. One primer is
complementary to one end of the target sequence on one strand; second primer is completely
to the other end of the sequence on the other strand.
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Theoretically, the suspected criminal is individual C. At the end of the experiment we
realized that some error occur during conducting our experiment as the results deviate from
the theory There are two bands that possess the same genotype which is 7-3. The result shows
that the suspect individuals are suspect’s B and D.
Based on our analysis, individual B is suspected to be a crime scene sample whereas
individual D is suspected to be the criminals (suspect C). This is because they possess the
same genotype which is 7-3, the other three suspects are genotype of 5-2, 10-3, and 10-2
respectively. The DNA of each of them had two segments that each migrated displaying that
they were in the same size, thus suspect D which is actually C was proven to be at the crime
scene by the PCR technique. There are some errors that will be discussed further in next
paragraph.
During conducting this experiment, it is compulsory for student to label the sample for
each test tube, the macro and the micro one. Our group forgot to label the small test tube
which results in wrong finding. At the end of the experiment only we realize that we have
mixed the sample without labelled them correctly. This finally leads to confusing of sample
crime scene DNA. Another important thing that results in error our experiments are lack of
pipette. Students have to share the same pipette tip for different types of chemical used. The
sharing of pipette tip during pipetting those chemical reagents into the tube results in mixing
of various samples. One pipette tip should be use in transferring of only one chemical.
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CONCLUSION
Based on the experiment, PCR or Polymerase Chain Reaction can be used to amplify a
specific region of the DNA, when DNA samples from spots of blood or hair roots do not give
enough material for forensic analysis. The primers and probes used act as a genetic marker to
differentiate individuals.
As a conclusion the aim of this experiment , (to understand in details the useful of Polymerase
Chain Reaction (PCR) and how to conduct the procedures, manage to find the real suspect by
comparing the sample DNA and the suspect DNA using the gel electrophoresis and knowing
what are the uses of restriction endonucleases in DNA sequence) are not completely achieved
as the third objectives that is manage to find the real suspect is failed. This is due to the some
error occur during labelling the suspect’s sample.
Based on this forensic analysis and discussions above, the genotype of crime scene is 7-3. The 4
suspects have genotype of 10-3, 5-2, 7-3 and 10-2.Suspect C genome matches the crime scene
sample genome. Therefore, another suspect such as A,B,D are considered to be excluded from
the crime. This is because, based on the PCR results, the DNA for suspects A,B and D does
not match to the crime sample genome. To conclude, suspect’s C was proven as a criminal.
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RECOMMENDATIONS
There are some recommendations to the viewers in the future regarding this experiment so as
to conduct this study well:
• It is advisable for the student to not over stain the agarose gel as it will takes a longer time to
bring the gel into neutral color. Thus, the longer time taken to observe the movement of bands
above the gel.
• Make sure that the solutions are brought to centrifugation so as to allow it to mix well.
• Preparation of excess stock for DNA primer is suggested instead of assuming it to be enough
throughout this study. This excess stock can be used if there is a mistake occurs involving so
much consuming of stock solution or spillage.
• If the tip of pipette is not enough, it is recommended to wash them with distilled water
properly for other uses. This can prevent mixing of various chemicals used.
• Make sure that the pipette used is accurate because in this experiment.For a better result,
make sure that the gel is slowly poured into its container so as to avoid formation of bubbles.
Bubbles can cause error in reading the result. It can be removed with a pipette tip.
REFERENCE
1. Bustamante, I T, Mata, FS, et al (2007) Application of chemometric tools for
automatic classification and profile extraction of DNA samples in forensic tasks,
Analytical Chimica Acta, 595, pg 43-50
2. Campbell N. Reece J & Meyers N. Biology, 7th Edition, pg 402-406. Pearson
Education, Australia 2006.
3. Lodish, H. Berk, A., et al (2004). Molecular Cell Biology, pg 87-89, W H Freeman
andcompany, New York.
4. Laboratory Studies in Applied Genetics (21 April 2009). Methods manual. Retrieved
on 9th November 2011 from
http://www.jblearning.com/samples/076371075X/Wheelis_CH03_025%20copy.pdf
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APPENDIX
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