1. Aka DNA finger printing
DNA profiling
Aka DNA finger printing
© 2016 Paul Billiet ODWS

2. We’re all (nearly) unique
Most DNA is highly conservative from one person to the next
A few small domains (0.1%) are very variable.
© 2016 Paul Billiet ODWS

3. Applications Crime scene investigations
Paternity suites and family relationships
Archaeology
Human/family ancestry
Exonerate persons wrongly accused of crimes
Identify catastrophe victims
Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers)
Detect bacteria and other organisms that may pollute air, water, soil, and food
Match organ donors with recipients in transplant programs
Determine pedigree for seed or livestock breeds
Authenticate consumables such as burgers, caviar and wine.
© 2016 Paul Billiet ODWS

4. Procedure Sample of tissue or cell DNA extracted DNA amplified by PCR
DNA fragmented using restriction enzymes
Gene probes added to identify fragments
Patterns of fragments of DNA of known origin & unknown compared
Control fragments of DNA and ladders used.
© 2016 Paul Billiet ODWS

5. Who is the father?
© 2016 Paul Billiet ODWS

6. Restriction Fragment Length Polymorphism (RFPL)
Restriction enzymes cut the DNA at particular base sequences
The presence or absence of these sequences in the genome will give different lengths of DNA fragments when they are cut using a particular restriction enzyme
The DNA fragments are separated by electrophoresis
DNA probes identify the sequences
Patterns of DNA fragments on the gel can be used to compare DNA from different samples.
© 2016 Paul Billiet ODWS

7. ..gatagatagatagatagatagatagatagata..
Short Tandem Repeats (STRs)
Within the human genome there are regions where a short base sequence is repeated many times
The number of repeats is very variable
Identified repeats are cut out using a restriction enzyme
The DNA fragments separated by electrophoresis
The different repeats are identified by DNA probes with radioactive or fluorescent markers
Samples with the same STRs will show the same pattern on the electrophoresis gel.
© 2016 Paul Billiet ODWS

8. Mitochondrial DNA Analysis
Mitochondrial DNA (mtDNA)
Useful for analysing older tissue samples
Useful for analysing hair, bones or teeth
Inherited down the maternal line.
© 2016 Paul Billiet ODWS

9. Y-chromosome Analysis
Inherited down the paternal line
Complements mtDNA analysis.
© 2016 Paul Billiet ODWS

10. Problems Cost Today limited to matches with 4 to 6 probes
Few probes = greater chance of miss match
Contamination of samples
Degradation of DNA with time.
© 2016 Paul Billiet ODWS