1. Solving mysteries using DNA technology
DNA Detectives
Solving mysteries using DNA technology
Presented by Dawn Crisologo and Justin Guce
Biology Unit, PSHS – Main Campus,
Diliman, Quezon City

2. THE SCENE DNA fingerprinting in the Biology classroom
Basic features of DNA
Restriction enzymes
How DNA fingerprinting works
Simulation activity
Real world and scientific applications
Ethical issues

3. Why teach DNA fingerprinting?
Extension activity to lessons on the molecular basis of inheritance
Real-world connections
Link to biotechnology careers and industries
Integration of science and technology with society
Images from and

4. DNA 101: Basic features

5. Restriction enzymes
named after bacterial genus, species, strain, and type
e.g. EcoR1
Genus: Escherichia
Species: coli
Strain: R
recognize specific base sequences in DNA and cut DNA at these recognition sites
e.g. GAATTC
Restriction site
Palindrome
Fragment 2
Fragment 1

6. Organism from which derived Target sequence (cut at *) 5' -->3'
Enzyme
Organism from which derived
Target sequence (cut at *) 5' -->3'
Ava I
Anabaena variabilis
C* C/T C G A/G G
Bam HI
Bacillus amyloliquefaciens
G* G A T C C
Bgl II
Bacillus globigii
A* G A T C T
Eco RI
Escherichia coli RY 13
G* A A T T C
Eco RII
Escherichia coli R245
* C C A/T G G
Hae III
Haemophilus aegyptius
G G * C C
Hha I
Haemophilus haemolyticus
G C G * C
Hind III
Haemophilus inflenzae Rd
A* A G C T T
Hpa I
Haemophilus parainflenzae
G T T * A A C
Kpn I
Klebsiella pneumoniae
G G T A C * C
Mbo I
Moraxella bovis
*G A T C
Pst I
Providencia stuartii
C T G C A * G
Sma I
Serratia marcescens
C C C * G G G
SstI
Streptomyces stanford
G A G C T * C
Sal I
Streptomyces albus G
G * T C G A C
Taq I
Thermophilus aquaticus
T * C G A
Xma I
Xanthamonas malvacearum
C * C C G G G

7. DNA Fingerprinting 101
technique used to distinguish between individuals of the same species using only DNA samples
relies on the ability of restriction enzymes to cut DNA from different individuals into fragments of different lengths
invented by Alec Jeffreys of the University of Leicester (1985)
Images from and

8. Uniquely you Sequence repeats in the human genome
Variable Number of Tandem Repeats (VNTR)
Amplified Fragment Length Polymorphisms (AmpFLP)
Short Tandem Repeats (STR)
10 – 13 sites needed for criminal investigations
4 sites to establish parentage
Single Nucleotide Polymorphisms (SNP)
Y-STR analysis
Mitochondrial DNA (mtDNA) analysis

9. DNA Fingerprinting Procedures
DNA extraction and isolation
Cutting by restriction enzymes
Loading of samples into the electrophoretic gel
Running samples through the gel
Visualization of bands
Analysis and comparison of profiles obtained
DNA Fingerprinting Procedures
Images from images.jupiterimages.com, and

10. Real-world applications
Crime scene investigations
Genealogy
Paternity-testing
Animal-relatedness
Anthropology studies
Disease-causing organisms
Food identification
Human remains
Monitoring transplants

11. Some ethical issues Fairness in the use of genetic information
Privacy and confidentiality of genetic information
Psychological impact and stigmatization due to an individual's genetic differences
Clinical issues involving implementation of standards and quality-control measures in testing
Uncertainties associated with gene tests for diseases