CRIME SETTINGS
You are a forensic biologist at Miami Dade Crime lab. You received a blood sample from a murder crime scene. The serology unit determined that this sample was not from the victim because the blood type is A+ and the victim was O-. You extracted the DNA from this sample and determined the STR profile. You can see here:
Later on, the detective sent you two reference samples from two suspects. You extracted the DNA from each sample and determined the STR profiles:
1. Record the alleles found at each locus for each of the three profiles in the following table. The first line has been done for you. Record some similarities and differences between the crime scene profile and the two suspects.
Locus Crime Scene Suspect A Suspect B
D3 15,16 14,15 15,16
vWA
FGA
D8
D21
D18
D5
D13
D7
2. Determine the frequency of the crime scene profile. Use the following table. Note the alleles of each locus and the frequencies based on the table of frequencies attached. Determine the locus frequency according to the example:
Locus Allele 1 Frequency Allele 2 Frequency Locus Frequency
D3 15 0.26159 16 0.25331 =(2)x(0.26159)x(0.25331)=0.13253
vWA
FGA
D8 15 0.11424 15 0.11424 = (0.11424)2=0.01305
D21
D18
D5
D13
D7
3. Calculate the Frequency of the Profile or the Match Probability for the Crime Scene Profile using the following equation: MP = (frequency of locus 1) x (frequency of locus 2) x (frequency of locus 3) x(frequency of locus N)…
4. Calculate the Random Match Probability (RMP) for the Crime Scene Profile. Use the equation from the powerpoint.
5. What are your conclusions? Who was the killer?
6. Record all the procedures and results in the lab report. Include pictures of the STR profiles, tables and your calculations.