Individual Report on Gel Electrophoresis
Individual report on gel electrophoresis
Date: 22/9/2011
Aim: To find the the suspect of the crime by comparing the DNA bands from the two suspects, the victim and the evidence.
Results:
Suspect 1 Suspect 2 Victim Evidence
Suspect 1 Suspect 2 Victim Evidence
Wells
DNA band
Agarose gel
(immersed in buffer solution during electrophoresis
Wells
DNA band
Agarose gel
(immersed in buffer solution during electrophoresis
Deduction:
Suspect 2 is excluded as the source the evidence, but Suspect 1 cannot be excluded.
This is because both DNA bands from Suspect 1 match with that from the evidence, thus Suspect 1 cannot be excluded as a source of the DNA. On the other hand, Suspect 2 does not have any matching bands with the evidence, so Suspect 2 can be excluded.
Limitations and possible solutions: * For unrelated persons, one in four bands may match by chance. However, only two bands are compared for each person, which is not enough to make any accurate conclusion. More DNA fragments of different tandem repeats should be used as the samples, so as to result in more bands for comparison. * The DNA bands are not very visible. The DNA should be stained with fluorescence instead of a dye for better detection.
Conclusion:
DNA fingerprinting is very useful in forensic science. DNA extracted from tissue samples in the crime scene can be used to compare with the DNA from the suspect and the victim, determining whether the suspect can be excluded from the
Date: 22/9/2011
Aim: To find the the suspect of the crime by comparing the DNA bands from the two suspects, the victim and the evidence.
Results:
Suspect 1 Suspect 2 Victim Evidence
Suspect 1 Suspect 2 Victim Evidence
Wells
DNA band
Agarose gel
(immersed in buffer solution during electrophoresis
Wells
DNA band
Agarose gel
(immersed in buffer solution during electrophoresis
Deduction:
Suspect 2 is excluded as the source the evidence, but Suspect 1 cannot be excluded.
This is because both DNA bands from Suspect 1 match with that from the evidence, thus Suspect 1 cannot be excluded as a source of the DNA. On the other hand, Suspect 2 does not have any matching bands with the evidence, so Suspect 2 can be excluded.
Limitations and possible solutions: * For unrelated persons, one in four bands may match by chance. However, only two bands are compared for each person, which is not enough to make any accurate conclusion. More DNA fragments of different tandem repeats should be used as the samples, so as to result in more bands for comparison. * The DNA bands are not very visible. The DNA should be stained with fluorescence instead of a dye for better detection.
Conclusion:
DNA fingerprinting is very useful in forensic science. DNA extracted from tissue samples in the crime scene can be used to compare with the DNA from the suspect and the victim, determining whether the suspect can be excluded from the