1. USE OF DNA TECHNOLOGY: DNA PROFILING

2. USES OF DNA TECHNOLOGY DNA Profiling Parentage Testing Genealogy Genetic Screening Genetically Modified Organisms

3. DNA PROFILING Method to identify an individual based upon their DNA Used in: Criminal investigations Parentage Testing

4. UNDERLYING PRINCIPLE Over 99.9% of our DNA is identical across all people BUT this means some is different

5. UNDERLYING PRINCIPLE In our different DNA: Variable number tandem repeats (VNTRs) DNA made up of repetitive sequences that can be found in different numbers for different people STRs: short tandem repeats (2-5nt long) LTRs: long tandem repeats

6. UNDERLYING PRINCIPLE

7. VNTRs: Are genetic… The number of repeats in any given VNTR would have been passed down from a parent

8. UNDERLYING PRINCIPLE VNTRs: Are very numerous in our genome Take home message: The number of repeats in each VNTR is unique amongst individuals (unless identical twins) You share roughly 50% of these repeats in common with your parents and siblings

9. DNA PROFILING OVERVIEW Uses PCR to amplify VNTRs and then gel electrophoresis to visualize the DNA fragments created This creates a unique DNA profile for each person

10. DNA PROFILING: PCR Primers are designed to “bookend” a VNTR of interest Primers need to anneal to a conserved region of DNA that is identical to each person

11. UNDERLYING PRINCIPLE

12. DNA PROFILING: PCR Primers are designed to “bookend” a VNTR of interest Primers need to anneal to a conserved region of DNA that is identical to each person PCR will therefore give different fragments lengths based on how many repeats a person has

13. DNA PROFILING: GEL ELECTROPHORESIS After the PCR, DNA is run on a gel to visualize the lengths of the DNA products

14. UNDERLYING PRINCIPLE

15. DNA PROFILING To accurately identify a person and reduce false positives: U.S. examines 13 separate VNTRs UK has a system with 11 VNTRs Both of these have VNTRs that are found on different chromosomes Think “Law of Independent Assortment”

16. DNA PROFILING Criminal Investigations: Identifying who an unknown DNA sample belongs to

17. DNA PROFILING Paternity Testing: Identifying who the father/parents of a child are