dna fingerprinting and forensic - … 12, 2015 · mr. chan ingin pergi ke hongkong ... zone of 200...
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INTRODUCTION OF BIOTECHNOLOGYINTRODUCTION OF BIOTECHNOLOGY
DNAFINGERPRINTING
AND FORENSIC
20142014
ENDRIKA WIDYASTUTI
INSUFFICIENT EVIDENCE ?Mr. Chan ingin pergi ke Hongkonguntuk tinggal bersama anaknya.Sebelum pergi ke Hongkong, Mr.Chan harus menunjukkandokumen tes laboratorium padaPihak Imigrasi bahwa Mr. Chanmemiliki hubungan kekerabatandengan anaknya.Akhirnya Mr. Chan menjalankan tesgolongan darah. Akan tetapigolongan darahnya tidak samadengan anaknya, sehingga berkaspengurusan visa Mr. Chan ditundaoleh pihak imigrasi. Mr. Chanmemberitahu pihak imigrasi bahwahubungan kekerabatan tidakhanya dibuktikan melalui golongandarah saja.
• Mengapa Golongan Darahtidak selalu mencerminkanada/tidaknya hubungankekerabatan?
• Apakah ada tes lain yangdapat digunakan untukmembuktikan hubungankekerabatan antara Mr. Chandan Anaknya?
4
Blood group typing is much lesssensitive.
May use DNA fingerprint to providebiological evidence as a proof in apaternity test.
Blood group typing is much lesssensitive.
May use DNA fingerprint to providebiological evidence as a proof in apaternity test.
...OF THE LIVING AND THE DEAD
• investigation of anydeath
• the living – inabilityto identifythemselves,immigration,inheritance
MORPHOLOGICAL CHARACTERISTICS
• only by MATCHING theparameters
• specific featurepossesed by theindividual
• height, weight andgeneral physique
• hair color and length,moustache, skinpigmentation, eye color
• clothing, jewellery,ornaments
• facial appearance, age
FINGERPRINTS
• position of minutedefects on theridges
• no less than 16points of similarity
• chances foridentical fingerprint:1:64 billion
IDENTITY FROM TEETH
• identification of thedead, bite marks,estimation of age
• commonlycomparison ofantemortem dentalchartings with thedirect examination ofthe teeth
• mass disasters• no previous records –
age, sex and ethnicorigin
IDENTIFICATION OF THEORIGIN OF TISSUE OR SAMPLES
• blood, semen,saliva, stains onbodies, weapons,clothing
• matching remains
• resolution ofpaternity, maternityand inheritancedisputes
THE INDIVIDUALITY OF CELLS
• blood grups and Rhfactor – possibility toexclude 93% of non-matching samples
• replaced with DNAanalysis of humantissue and fluid
TATOOS AND BODY PIERCING
• there has to becomparison
• photographs anddrawings if visualidentification is notpossible
IDENTIFICATION BY DNA PROFILING
• nearly 100% in exclusionand in identification
• 10% are active genes• 90 % are “silent” – zone
of 200 to 14 000 repeatsof identical sequencesof bases are constantand transmitted fromparents – ESSENTIAL forDNA analysis!
• “bar code”
• risk of contamination• blood, hair with roots;
samples of spleen;buccal smears;
vaginal, anal andpenile swabs
• paternity/maternitytesting
• every bar in the “barcode” must have comefrom either the father ormother, half from each
IDENTITY OF DECOMPOSED ORSKELETALIZED REMAINS
• are the remains actuallybones?
• are the remains human?• one or more bodies?• what sex are the
bones? – pelvis and skull• age, height, race?• can a personal identity
be discovered?• YouTube - Crime 360:
Human BoneIdentification
FACIAL RECONSTRUCTION FROMSKULLS
• measuring the averagesoft-tissue thickness atmany points on the skulland rebuilding this layerwith plasticine onunknown skull
• computerizedreconstruction
• individuality of faces?• what about eyes and
lips?
ACTIVITY 8.1
a) There are 46 pairs of chromosomes ineach nucleus of a human cell.Chromosomes are made of DNA andproteins.
b) DNA determines the bodycharacteristics of an organism.
c) DNA may be extracted from redblood cells found in a blood sample.
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1.Decide whether the followingstatements are TRUE or FALSE.
FALSE
TRUE
TRUE
ACTIVITY 8.1
e) The Hair and Teeth of the same person arecomposed of same DNA molecules.
f) Identical twins have different base sequences ofDNA .
g) In the DNA structure, adenine (A) will only link withcytosine (C) and guanine (G) will only link withthymine (T).
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TRUE
FALSE
FALSE
Define DNA FINGERPRINTING
Preparation of DNAFINGERPRINTING
Putting DNA to the TEST
Familial Relationships and DNAPROFILE
CASE STUDY
Define DNAFINGERPRINTING
Chemical structure ofDNA always same, butthe order of basepairsare differs
DNA fingerprints arebased on parts of anindividual’s DNA thatcan by used foridentification.
DNA fingerprinting is used for identification.• DNA fingerprinting depends on the probability of a
match.– Many people have the
same number ofrepeats in a certainregion of DNA.
– The probability that twopeople share identicalnumbers of repeats inseveral locations isvery small.
(mother) (child 1) (child 2) (father)
– Individual probabilities are multiplied to find theoverall probability of two DNA fingerprints randomlymatching.
– Several regions of DNA areused to make DNA fingerprints.
1 1 1 1500 90 120 5,400,000 1 chance in 5.4 million peoplex x = =
• DNA fingerprinting is used in several ways.
– evidence in criminalcases
– paternity tests– immigration requests– studying biodiversity
Define DNA FINGERPRINTING
Preparation of DNAFINGERPRINTING
Putting DNA to the TEST
Familial Relationships and DNAPROFILE
CASE STUDY
DNA COLLECTION &COMPARISON
• DNA samples can be from:Salivabloodhair strandsskinfinger or toe nails,tooth with root material
DNA COLLECTION &COMPARISON
• How is blood collected?• Blood on Clothing?
• Investigators submit whole pieces ofclothing or they may use a sterilecloth square and a small amount ofdistilled water
• Dried blood on furniture?• Investigators send the whole object to
the lab• Dried blood on a wall, tub or some
other object too big or difficult tomove to the lab?
• Investigators scrape the blood sampleinto a sterile container for furtheranalysis
MAKING DNA FINGERPRINTS
• DNA fingerprinting is a laboratory procedure thatrequires six steps:
• 1: Isolation of DNA.
• 2: Cutting, sizing, and sorting.• Special enzymes called restriction enzymes are used to
cut the DNA at specific places
• 3: Transfer of DNA to nylon.The distribution of DNA pieces
• is transferred to a nylon sheet• by placing the sheet on the gel• and soaking them overnight.
• 4-5: Probing.Adding radioactive or colored probes to the nylon sheetproduces a pattern called the DNA fingerprint.
• 4-6: DNA fingerprint.• The final DNA fingerprint is built by using several probes
(5-10 or more) simultaneously.
RFLPRESTRICTION FRAGMENT LENGTH POLYMORPHISM
• Analyzes variable lengthsof DNA fragments
• One of the originalapplications of DNAanalysis
• Not used as muchanymore because itrequires a large quantityof DNA sample andsamples degraded by theenvironment do not workwell with RFLP
RestrictionFragmentLengthPolymorphismRFLP
Allele 1
Allele 2
GAATTCGTTAAC
GAATTCGTTAAC
CTGCAGGAGCTC
CGGCAGGCGCTC
PstI EcoRI
1 2 3
3Fragment 1+2DifferentBase PairsNo restriction site
+
M A-1 A-2
Electrophoresis ofrestriction fragments
M: MarkerA-1: Allele 1 FragmentsA-2: Allele 2 Fragments
THIS METHOD ANALYSESTHE LENGTH OF THESTRANDS OF DIFFERENTDNA MOLECULES. THEDNA IS BROKEN INTOSMALL PIECES BYRESTRICTION ENZYMES.THEN ALL THOSE SMALLPIECES BECOMESEPARATED BY GELELECTROPHORESIS.RFLP, UNFORTUNATELY, ISNOT USED AS MUCHANYMORE.
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PCRPOLYMERASE CHAIN REACTION
• Used to makemillions of exactcopies of DNA froma biological sample
• Allows very smallsamples to beanalyzed, such as asample of a few skincells
• Must be very carefulaboutcontamination inthis process
USED FOR DNA FINGERPRINTING AND PATERNITY TESTING. PCR IS USEDTO ENLARGE A FEW PIECES OF DNA WHICH WOULD CREATE THOUSANDS
TO MILLIONS OF COPIES OF THAT ONE SAMPLE OF DNA.
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WHICH IS SHORT TANDEMREPEAT, IS THE MOST WIDELY
USED DURING CRIMINALINVESTIGATIONS. STR
ANALYZES HOW MANY TIMESBASE PAIRS REPEATTHEMSELVES ON A
PARTICULAR LOCATION ONA STRAND OF DNA. THIS
METHOD IS A PCR-BASEDTOOL BECAUSE IT USES SOME
COMPONENTS OF THE PCRMETHOD.
40STRSHORT TANDEM REPORT
DNA COMPARISON &ANALYSIS
• A DNA profile iscreated….how??
Markers are found bydesigning small piecesof DNA (probes) thatwill seek out and bindto complementaryDNA sequences. Thiscreates a distinctpattern. Again, onemarker is not usuallyunique, but with fouror five regions thematch is likely
DNA COMPARISON &ANALYSIS
The DNA profiles are compared with samples fromsuspects to find possible matches.
DNA COMPARISON &ANALYSIS
If there are no suspects, anational database calledCODIS may be used to findpotential suspects.
• More on CODIS:• Stands for Combined DNA Index System• National Network that helps identify leads for crimes with
no suspects• Three tiers: Local (LDIS), State (SDIS), National (NDIS)• Uses 13 DNA regions that vary from person to person• Looks for matches at more than one location on a
genome for more accurate results
Analysis ofStained Gel
Determinerestriction fragmentsizes
• Create standard curveusing DNA marker
• Measure distancetraveled by restrictionfragments
• Determine size of DNAfragments
Identify the relatedsamples
Define DNA FINGERPRINTING
Preparation of DNAFINGERPRINTING
Putting DNA to the TEST
Familial Relationships and DNAPROFILE
CASE STUDY
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Activity 8.5DNA Fingerprint Analysis
Case 1
Mr. Chan’s family consists of mom, dad and four kids. The parentshave one daughter and one son together, another daughter is from themother’s previous marriage, and the other son is adopted. Here arethe DNA analysis results:
1. Which child is adopted? Why?
2. Which child is from the mother’s previous marriage? Why?
3. Who are the own children of Mr and Mrs Chan?
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Activity 8.5Answers:• Child 4 is adopted.• Child 2 is the child from the mother’s
previous marriage.• Child 1 and Child 3 are own children of
Mr and Mrs Chan.
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Activity 8.5
Case 2A blood sample from a crimescene was collected. DNAsamples of the victim and thepotential suspects (June,Scarlet and John) were alsocollected for DNA analysis.The DNA profile is shown.Now, you should be able toidentify the potential murderer.
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Activity 8.5
Answers:• All of the DNA fragments of Scarlet can be
found in the crime scene sample makingher the most likely suspect.
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Activity 8.5
Extended discussions:1. Both June and Scarlet have the same
DNA fragments (“8” and “12”), why?2. Why DNA evidence must be combined
with the traditional forms of evidencesuch as eyewitness accounts?
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Activity 8.5Answers:
1. This pattern may arise if the two women are related orif this pattern were common in population.
2. Someone’s DNA is found at a crime scene does notmean that they committed the crime because of thefollowing reasons:(i)The DNA sample may be contaminated by theenvironment.(ii) The sample may be a mixture of more than oneperson’s DNA.(iii) The DNA evidence may be degraded or brokendown.
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