Human Heredity 11th Edition by Michael Cummings

Exercise 4

A crime is committed, and the only piece of evidence the police are able to gather is a small bloodstain. The forensic scientist at the crime lab is able to: ? extract DNA from the blood,
? cut the DNA with a restriction enzyme,
? separate the fragments by electrophoresis, and
? transfer the DNA from a gel to a membrane and probe with radioactive DNA.
Probe 1 is used to visualize the pattern of bands. The forensic scientist compares the band pattern in the evidence (E) with the patterns from the suspects (S1, S2). The first probe is removed, the membrane is hybridized using another probe (Probe 2), and the band patterns are compared. This process is repeated for Probe 3 and Probe 4.
A) Based on the results of this testing, can either of the suspects be excluded as the one who committed the crime?
B) If so, which one? Why?
C) Is the pattern from the evidence consistent with the band pattern of one of the suspects? Which one?