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40. DNA fingerprinting is used in many situations to help identify individuals. Analyze the situation below before answering the questions that follow.
A man was attacked and robbed, but remembers nothing of the incident because he fell and hit his head. He has numerous cuts and abrasions from the event, and blood was found under his fingernails. A piece of torn clothing with a bloodstain on it was also found at the scene.
Two people were seen near the crime scene. Both males, they say they don't know each other and just happened to be near the scene at the time of the attack. One of the males has a fresh scratch across his face, while the other male has a scratch on his right arm.
It's not clear from observations of the crime scene how many individuals were involved in the crime. Two males have reportedly been robbing individuals in the vicinity. There's a rumor that the two are brothers.
a. Explain two DISTINCT uses that DNA fingerprinting could be used for in this situation. In particular, what are two important issues that should be resolved to help clarify the identity of the individuals of the body fluids found at the scene?
b. How could you test one of these issues using DNA fingerprinting without using blood samples from the scene of the crime.
Please help!
Thanks
-MC
They don't know each other? DNA can show if they are brothers.
Were they in a scuffle? DNA under the fingernails might be matched to the men who don't know each other.
a. Two distinct uses of DNA fingerprinting in this situation could be:
1. Identifying the attacker: DNA fingerprinting can be used to compare the DNA profile of the blood found under the victim's fingernails to the DNA profiles of the two males near the scene. If there is a match with one of the males' DNA, it could indicate that he was involved in the crime.
To resolve the issue of identifying the individuals from the body fluids found at the scene, the DNA samples from the bloodstain and the blood under the victim's fingernails can be collected and analyzed using DNA fingerprinting techniques. The DNA profiles obtained can then be compared to the DNA profiles of the two males near the crime scene. If there is a match between the DNA profiles, it would provide strong evidence to identify the attacker.
2. Determining the relationship between the two males: The rumor that the two males may be brothers raises the question of whether they are both involved in the crime together. DNA fingerprinting can be used to compare the genetic relatedness between the two males by analyzing their DNA profiles. If the DNA profiles indicate a high degree of shared genetic markers, it would support the possibility that they are brothers.
To resolve the issue of determining the relationship between the two males, DNA samples can be collected from both individuals (e.g., from saliva, hair, or cheek swabs), and their DNA profiles can be compared using DNA fingerprinting techniques. The analysis would involve identifying shared genetic markers and determining the probability of the two individuals being brothers.
b. One of the issues that can be tested without using blood samples from the crime scene is determining the relationship between the two males. DNA fingerprinting can still be used for this purpose by collecting DNA samples from the two males themselves. As mentioned earlier, samples of saliva, hair, or cheek swabs can be collected non-invasively to obtain their DNA. The DNA profiles derived from these samples can then be compared to assess the degree of genetic relatedness between the two males and determine if they are indeed brothers. This approach eliminates the need to rely solely on the blood samples from the crime scene and provides information about the relationship directly from the individuals involved.