lesson objectives at the end of this lesson you should be able to 1. outline the four stages...
TRANSCRIPT
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 profiling3.Give two applications of DNA profiling4.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
1. Cells broken down to release DNA2. DNA strands cut into fragments3. Fragments separated4. Pattern of fragments analysed
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
ELECTROPHORESISFragments separated by length
DNA (negatively charged)
Moves towards +ve terminal
Shorter fragments move faster
4.DNA TRANSFERDNA 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
Revealing a pattern of bands
X-ray film
Applications of Genetic Screening
Paternity disputes
Forensic Science
Genetic Screening
Genetic Archaeology
FORENSIC SCIENCE
FAMILY RELATIONSHIPS
COMMON CONCERNS
Quality of sampleMistakes and inaccuracyInterpretationPrivacyEvidence from criminal investigations Who should use DNA fingerprintingCost effectiveEthnic 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.
http://www.pbs.org/wgbh/nova/sheppard/lab01.html
Creating DNA Fingerprint simulation
What have you learned?
Can you ………………
1.Discuss the stages involved in DNA profiling
2.Define the process of DNA profiling3.Give two applications of DNA profiling4.Define genetic screening
End