Question

question 5
dna band pattern diagram (image of a gel)
lane source band pattern (from top to bottom/horizontally)
1 crime scene sample
2 suspect a
3 suspect b
4 suspect c
(each represents a dna band. the positions indicate fragment sizes. each color represents one sample.)
which suspect, if any, left their dna at the crime scene?
a suspect a
b suspect b
c suspect c
d no matching samples

Explanation:

DNA fingerprinting (gel electrophoresis) works by separating DNA fragments by size. The band patterns (which relate to fragment sizes) of the crime - scene sample and suspects are compared. If a suspect's band pattern (fragment sizes) exactly matches the crime - scene sample's band pattern, then that suspect's DNA was at the crime scene. Looking at the band patterns:

• Suspect A (Lane 2) has a green band pattern. The crime - scene sample (Lane 1) has a red band pattern. No match.
• Suspect B (Lane 3) has a blue band pattern. The crime - scene sample (Lane 1) has a red band pattern. No match.
• Suspect C (Lane 4) has a grey band pattern. The crime - scene sample (Lane 1) has a red band pattern. No match.

Answer:

d. No matching samples