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

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

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

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

Who is the father? © 2016 Paul Billiet ODWS

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

..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

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

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

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