Lesson ObjectivesAt 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 PROFILING1980 - American researchers discovered non-coding regions of DNA1984 - Professor Alec Jeffries developed the process of DNA profiling

1987 - First conviction based on DNA evidence

Principle of DNA ProfilingAll 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 INVOLVED1. 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 enzymesThis gives lots of fragmentsThe 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 CONCERNSQuality 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 TestsAntenatal serum screening for Down

SyndromeAntenatal carrier screening for Sickle Cell

AnaemiaPredictive testing for hereditary cancersPredictive testing for cystic fibrosisNewborn 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