Lecture 3 - Forensic DNA Analysis Flashcards
What can change DNA?
Bone marrow transfusion or presence of cancer cells
Why is DNA useful?
That DNA is (mostly) the same no matter what cell type, throughout the person’s life - stable
What sources of DNA are useful in body identification?
Finger/toenails
Body tissue
Bone
Teeth
Why is hair more complicated for DNA profiling?
Hair needs to be pulled from head due to root material needed
What are the types of DNA samples?
Case samples
Reference samples (case specific)
DNA profile databank
Where are DNA case samples taken from?
Crime scene - either taken directly or indirectly, sample taken on swab or tape or directly from fabric
Where are DNA reference samples taken from?
From complainants
From suspects
From other people involved (First responders, ambulance staff, other household members, sexual partners)
Where are DNA in the DNA profile databank taken from?
Criminal Investigations (Bodily Samples) Act 1995
From convicted criminals (permanently held)
From volunteers (can be removed on request)
From people Police intend to charge (temporarily held)
What are the three databanks in DNA Databank Profile Matching?
DNA Profile Databank
Crime Sample Databank
YSTR Crime Sample Databank
What are the profiles in the DNA profile databank from?
Profiles from people
What are the profiles in the crime sample databank from?
Profiles from crimes
What are the profiles in the YSTR crime sample databank from?
YSTR haplotypes from crimes
Why are DNA profiles matched against itself?
To link suspects with previous cases
What does the YSTR technique target?
YSTR technique only targets sample Y DNA in crime scene sample
Why do we have the YSTR crime sample databank?
Useful for SA cases, Y chromosome passed from father to son unchanged, can detect patterns of offending