Lesson Objectives
At the end of this lesson you should be able
to
1.Outline
the four stages involved in DNA
profiling
2.Define the process of DNA profiling
3.Give two applications of DNA profiling
4.Define genetic screening
DNA PROFILING
1980 - American researchers
discovered non-coding regions
of DNA
1984 - Professor Alec Jeffries
developed the process of DNA
profiling
1987 - First conviction based
on DNA evidence
Principle of DNA Profiling
All human chromosomes have sections of DNA with
no known functions
These sections have short base sequences
These sequences repeat over and over
They are inherited from parents
Their length and position are unique to each person
DNA PROFILING
A process or technique of analysis
revealing unique patterns of an
individual’s DNA
involving non-coding regions
NON-CODING REGIONS
(VNTR)
STAGES INVOLVED
Cells broken down to release DNA
2. DNA strands cut into fragments
3. Fragments separated
4. Pattern of fragments analysed
1.
1. DNA EXTRACTION
2. DNA CUTTING
The DNA is cut up into
fragments using
restriction enzymes
This gives lots of
fragments
The fragments are
different sizes
3. FRAGMENT SEPARATION
Samples containing the
fragments are placed into
individual wells in a gel
using a pipette
This is known as electrophoresis
ELECTROPHORESIS
Fragments separated
by length
DNA (negatively
charged)
Moves towards +ve
terminal
Shorter fragments
move faster
4.DNA TRANSFER
DNA is split into single
strands using an
alkaline solution
DNA fragments
transferred from gel to
filter paper or nylon
membrane
The Gel, with filter
paper attached, is
removed & separated
5. ANALYSIS
Radioactive probe in
solution binds to DNA
X-ray film
Revealing a pattern
of bands
Applications of Genetic Screening

Paternity disputes

Forensic Science

Genetic Screening

Genetic Archaeology
FORENSIC SCIENCE
FAMILY RELATIONSHIPS
COMMON CONCERNS
Quality of sample
Mistakes and inaccuracy
Interpretation
Privacy
Evidence from criminal investigations
Who should use DNA fingerprinting
Cost effective
Ethnic problems
Genetic Screening
Genetic Screening is used to :
Test individuals who are at high risk of
having or passing on a specific genetic
disorder
Screening Tests
Antenatal serum screening for Down
Syndrome
Antenatal carrier screening for Sickle Cell
Anaemia
Predictive testing for hereditary cancers
Predictive testing for cystic fibrosis
Newborn screening for phenylketonuria,
cystic fibrosis and hypothyroidism.
Creating DNA Fingerprint
simulation
http://www.pbs.org/wgbh/nova/sheppard/lab01.html
What have you learned?
Can you ………………
1.Discuss
the stages involved in DNA
profiling
2.Define the process of DNA profiling
3.Give two applications of DNA profiling
4.Define genetic screening
End