2. 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

3. 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

4. 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

5. DNA PROFILING A process or technique of analysis revealing unique patterns of an individual’s DNA involving non-coding regions

6. NON-CODING REGIONS (VNTR)

7. STAGES INVOLVED 1. Cells broken down to release DNA 2. DNA strands cut into fragments 3. Fragments separated 4. Pattern of fragments analysed

8. 1. DNA EXTRACTION

9. 2. DNA CUTTING The DNA is cut up into fragments using restriction enzymes This gives lots of fragments The fragments are different sizes

10. 3. FRAGMENT SEPARATION Samples containing the fragments are placed into individual wells in a gel using a pipette This is known as electrophoresis

11. ELECTROPHORESIS Fragments separated by length DNA (negatively charged) Moves towards +ve terminal Shorter fragments move faster

12. 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

13. 5. ANALYSIS Radioactive probe in solution binds to DNA Revealing a pattern of bands X-ray film

14. Applications of Genetic Screening Paternity disputes Forensic Science Genetic Screening Genetic Archaeology

15. FORENSIC SCIENCE

16. FAMILY RELATIONSHIPS

17. COMMON CONCERNS Quality of sample Mistakes and inaccuracy Interpretation Privacy Evidence from criminal investigations Who should use DNA fingerprinting Cost effective Ethnic problems

18. Genetic Screening Genetic Screening is used to : Test individuals who are at high risk of having or passing on a specific genetic disorder

19. 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.

20. http://www.pbs.org/wgbh/nova/sheppard/lab01.html Creating DNA Fingerprint simulation

21. 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

22. End