In your research, you are comparing the transcriptome and the proteome for two related species. One gene in species B has a similar transcript but a much smaller protein than in species A, and the protein seems to be nonfunctional. What do you predict about this gene? (Select all that apply)A) It is a pseudogene.B) It will have an increased number of persistant mutations in species B.C) It probably has a stop codon early in the coding region.D) It probably has a defect in the enhancer region.E) It probably is not methylated correctly.
What will be an ideal response?
A, B, C
Clarify Question
• What is the key concept addressed by the question?
o This question addresses pseudogenes.
• What type of thinking is required?
o This question is asking you to take what you already know and apply it to this unfamiliar situation.
• What key words does the question contain and what do they mean?
o The transcriptome is the set of all transcripts in a cell (i.e., mRNAs and other RNAs).
o The proteome is the set of all proteins in a cell.
Gather Content
• What do you already know about pseudogenes?
o Pseudogenes are genes that have recently in evolution become nonfunctional, often due to a frameshift or nonsense mutation that create an early STOP.
Consider Possibilities
• Consider the different answer options. Which can you rule out?
o Can you predict that this gene has a defect in the enhancer region? No, because it is being transcribed normally-only the protein is wrong.
o Can you predict that this gene is not methylated correctly? No, because that would affect its transcriptional expression, but that aspect is normal.
Choose Answer
• Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
o Can you predict that this gene is a pseudogene? Yes, it fits the description of a pseudogene.
o Can you predict that this gene will have an increased number of persistant mutations in species B? Yes, because there is no selection against mutations in a nonfunctional gene.
o Can you predict that this gene probably has a stop codon early in the coding region? Yes, that would explain why the protein is smaller and nonfunctional.
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 asked what you would predict about a nonfunctional gene.
o The question required you to take what you already know and apply it to this unfamiliar situation.
o Did you recognize that this scenario describes a pseudogene?
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