Which of the following will help you distinguish between the two final suspects?
You are a forensic technician working on a DNA sample obtained from a crime scene. Your job is to compare the unknown DNA sample with known DNA samples collected from five different suspects. Preliminary analysis using only a few DNA markers revealed that the unknown sample could possibly match two of the suspects. After consulting the case file, you find out that these two suspects are brothers (but not twins). You realize that you will have to do a more detailed analysis on the samples so that you can distinguish between the brothers and determine which brothers' DNA matches the unknown sample.
A. single nucleotide polymorphisms (SNPs)
B. human genome map
C. linkage data
D. markers on the Y chromosome
Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain?
Gather Content
· What do you already know about genetic maps and DNA markers?
Consider Possibilities
· Consider the different answer options. Which can you rule out?
Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
A. single nucleotide polymorphisms (SNPs)
Clarify Question
· What is the key concept addressed by the question?
o This question addresses the use of genetic maps and DNAmarkers.
· What type of thinking is required?
o You need to Analyze the information given, using logic, to dissect the problem and determine the answer.
· What key words does the question contain?
o DNA markers are features in the DNA that can be analyzed, and often differ between individuals. Forensics is the use of scientific methods to analyze crime data.
Gather Content
· What do you already know about genetic maps and DNA markers?
o Genetic maps provide information about the location and distances between genes.
o The human genome map was created using a few individuals to represent a generic human genome – but it does not encompass all of human genetic diversity.
o DNA markers are features in the DNA that can differ between individuals, and be used to match or disinguish two samples of DNA.
Consider Possibilities
· Consider the different answer options. Which can you rule out?
o Since we need to distinguish the DNA of the two brothers based on the fine details, the human genome map will not be useful. It would be far too expensive and complicated to produce a genome map for each of the suspects.
o Linkage data is also not useful – that only provides general distances between genes, and is not specific for individuals.
Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
o Consider the two remaining choices: markers on the Y chromosome, and SNPs.
o Since the two suspects are brothers, how different are their Y chromosomes? Not very! They will likely be the same since they presumably received their Y from the same father. (With the exception of some possible recombination in the pseudoautosomal region).
o Would single nucleotide polymorphisms (SNPs) be useful? Yes! They are exactly the kind of detailed fine feature that is likely to vary even between closely-related individuals.
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
o This question required you to Analyze the information given, using logic, to dissect the problem and determine the answer.
o Did you recognize that you needed a source of information that reflected the fine structure differences in individual DNA?
o Did you recognize that their Y chromosomes would be the same?
You might also like to view...
The neuromuscular junction is incorrectly described in which of the following statements?
A) Neurotransmitters are stored in vesicles in the axon terminal. B) The sarcolemma is the plasma membrane of a muscle cell. C) Acetylcholine binds receptors in the synaptic cleft. D) T tubules carry action potentials into the muscle cell. E) Acetylcholine binding allows sodium ions to enter the muscle cell.
The antifungal drug that can be used to treat serious systemic fungal infections is ________.
A. amphotericin B B. metronidazole C. sulfa drugs D. griseofulvin E. nystatin
The "endosymbiont theory" states that eukaryotic cells work together to form a multicellular organism.
a. true b. false
Phil was exposed to parasitic worms on a recent field trip to the tropics. Under these conditions, which antibody levels would be higher than normal?
A. IgG B. IgA C. IgM D. IgD E. IgE