Module 9: Forensic DNA Analysis Flashcards
DNA
- packed into chromosomes inside cells
- phosphate group, sugar, nitrogenous base ( adenine, thymine, guanine, cytosine)
Who discovered that portions of a person’s DNA sequence are unique to that person and can be used for ID. DNA fingerprinting.
Sir Alec Jeffreys et al
What portion?
Short Tandem Repeat - contain sequence of letters that are repeated numerous times
- ~3% of the human genome
- act as fillers/ spaces between the coding regions of the DNA
- inherited from parents
Restriction Fragment Length Polymorphisms
Use restriction enzymes
Combined DNA Index System (CODIS)
FBI database for DNA of convicted, unsolved crime-scene evidence, and profiles oof missing people
How many loci sites are tested for matching DNA?
13
True or False
Identical twins will have matching 13 loci.
True. While only 1 in 1 billion for not.
Methods in Forensic DNA Analysis
- PCR
Sources of DNA samples
- saliva
- buccal swabs
- blood
- semen
- sweat
- hair
- skin
- other tissues
Application of FDNA Analysis
- solving crimes
- missing persons cases
- exoneration
- victim identificaion in mass casualty incidents
- wildlife forensics
Challenges in FDNA Analysis
- contamination
- sample quality (degradation)
- interpretation (sample mixture)
FDNA Analysis in the PH
- rules on DNA evidence approved on Oct 15, 2007
- RA No. 9255 - DNA evidence for paternity
