DNA Flashcards
DNA is unique for all individuals except ______
identical twins.
DNA is formed by _____ of DNA from his or her parents with half coming from the mother and half from the father.
combination
The _____ DNA is found in all cells of the body.
same
Your DNA ______ change through your life.
Does NOT
DNA is a ____; _____; _____ and _____ evidence
physical
biological
transfer
trace
Any cellular material left at a crime scene may be a useful source of ____.
DNA
DNA is unique except for?
a. Twins
b. Siblings
c. Identical twins
d. None.
c.Identical twins
You are investigating a rape case. You collected and submitted the victim’s underwear with alleged seminal stain.
What standard biological sample from the accused would you submit?
a. Semen
b. Blood
c. Buccal swab
d. Tissue sample
Buccal swab
You are investigating a murder.
The male victim, who is still unidentified, was apparently beaten to death and put inside a bag before being dumped on the sidewalk.
What biological evidence would you ask the SOCO to collect from the victim?
a.Nail clippings
b.Tissue sample
c.A and b.
c.A and b.
- You are investigating a murder.
- The male victim, who is still unidentified, was apparently beaten to death and put inside a bag before being dumped on the sidewalk.
What standard samples would you collect and compare to the DNA profile generated from the victim’s tissue sample?
a. Parent’s buccal swabs
b. Used personal belongings
c. His twin’s buccal swabs
d. Any of these
c.His twin’s buccal swabs
You are investigating a cold case.
A rape incident that occurred 20 years ago, where the previous investigator was able to collect the victim’s underwear with alleged seminal stain.
The underwear is still kept safe in your evidence room.
An eyewitness surfaced, pointing to a suspect. You were able to arrest the suspect.
Is it possible to use the evidence collected 20 yrs ago for DNA analysis?
a.Yes
b.No
a.Yes
You are investigating an alleged kidnapping case.
You have a lead to the identity of the kidnappers but every raid you conduct, they manage to escape with the victim.
In their last safe house, you were able to collect bloodstain samples from the concrete.
What reference standard sample could you collect to prove that the bloodstain is from the victim, thus linking the safehouse to the crime?
a.Secondary Standards
b.Primary Standards
a.Secondary Standards
Functions of DNA analysis
- Forensic examinations
- Questioned paternity and maternity
- Disaster Victim Identification
- Court testimony
- Conduct lectures and training
- Assist in collection of biological evidence (eg. Luminol testing, scene of crime opereations, etc)
DNA Case Processing
- Documentation and Screening
- Sampling and Extraction of DNA
- DNA Amplification
- DNA Detection
- Data Interpretation and Report Making
- Releasing of Report
The DNA Branch staff checks and receives evidence with appropriate letter request. He decks the case to an analyst.
The receiving staff turns over the evidence to the evidence custodian.
The decked DNA analyst withdraws the evidence from the evidence custodian and document the evidence though photos and notes.
Documentation and Screening
This is performed in a contamination controlled room where biological specimen is processed to isolate and quantitate its DNA.
The analyst works on a sterile bio-safety hood equipped with exhaust and anti-biohazard filters.
Sampling and Extraction of DNA
Sampling and Extraction of DNA
The ________ uses validated commercial extraction kits in isolating DNA from the biological evidence submitted.
PNPCL DNA
Sampling and Extraction of DNA
-incubates the sample at temperature and mixing speed that will protect the DNA.
Thermo mixer
Sampling and Extraction of DNA
-separates the DNA from other cellular components based on their differing densities.
Centrifuge
Sampling and Extraction of DNA
The approximate quantity and the quality of DNA obtained is measured through a _________.
spectrophotometer
- In a sterile PCR (Polymerase Chain Reaction) hood, the analyst prepares the extracted DNA for amplification.
- _______ reagents are added to the DNA sample.
- The enzymatic process of DNA replication (PCR) is mimicked through the use of a thermal cycler.
- Specific regions (loci) of the target DNA are amplified.
- DNA Amplification
Validated Short Tandem Repeat (STR)
DNA Amplification
_______or PCR machine subjects the DNA to the required temperatures for DNA amplification.
Currently the PNPCL DNA Lab uses three (3) PCR machines
Thermal cycler
- ________ are added to the amplicons to make it detectable by the genetic analyzer machine
- Plates with amplicons, negative and positive control, and ladder in placed in the genetic analyzer.
DNA detection reagents
- Data Interpretation and Report Making
- The ___________ is entered in the US FBI CODIS (Combined DNA Index System) database and searched for any match.
- DNA analysis result interpretations reported by the analyst are backed by statistical calculations using the software CODIS Popstats.
PNPDNA
DNA profile generated