Forensic Uses of DNA

Question 1

Describe the use of short tandem repeats as a forensic DNA technique.

Answer 1

Common tandem repeats are <1% of DNA. DNA is extracted and amplified with PCR. Fragments separated with capillary electrophoresis. Fluorescence recorded using a laser. Prob of a match is calculated.

Question 2

Describe the use of mitochondrial DNA as a forensic DNA technique.

Answer 2

Inherited through maternal line. Results expressed as differences from standard sequence. Used for highly degraded samples when relatives in maternal line available b/c cells have more copies of mito DNA than nuclear DNA.

Question 3

Describe the use of y chromosome short tandem repeats as a forensic DNA technique.

Answer 3

used in sexual assault cases or paternity cases. can type male relative who is paternally related to alleged father.

Question 4

Describe the use of restriction fragment length polymorphism as a forensic DNA technique.

Answer 4

obsolete and time consuming. requires lots of samples

Question 5

Use of hardy weinberg equilibrium in forensics. What are the assumptions?

Answer 5

With multiple alleles, multiply probabilities. Used to determine the probability that two individuals might share a particular marker pattern. Assumptions: large pop, random mating, free of migration, no natural selection, no mutations

Question 6

What are the forensic uses of DNA?

Answer 6

1. ID unknown sample
2. molecular autopsy
3. paternity testing
4. missing persons/mass disasters
5. convicted felon database - CODIS
6. historical investigation
7. military uses