Which one of the following does NOT use RNA sequencing?
- Mapping transcription initiation sites
- Long non-coding RNA profiling
- Alternative polyadenylation profiling
- Mammalian epigenome sequencing
Rephrasing the question:
What is RNA sequencing used for?
RNA sequencing is used for all these choices except mammalian epigenome sequencing (option 4).
This question doesn’t really require you to know how each of these techniques is performed – you can answer the question simply by understanding their purpose!
RNA sequencing is the process by which we sequence RNA by first creating a complementary cDNA strand by reverse transcription, which can then be sequenced by standard techniques.
The RNA sequence can give us information about the final protein, the coding/non-coding portions of the transcript, the regulatory elements within the mRNA that affects its stability or translation, and its posttranslational modifications (like the 5’ cap and polyA tail).
Logically, the option that would NOT involve RNA sequencing is the one that does NOT deal with RNA, transcription, or translation.
Options 1 and 2 (mapping transcription initiation site and long non-coding RNA profiling) are linked to transcription, and option 3 (alternative polyadenylation profiling) deals with post-translational modification of the mRNA. Option 4 (mammalian epigenome sequencing) relates to the epigenetic modification of DNA (by DNA methylation or histone modification) and is the only one that deals with information at the DNA level solely, so RNA sequencing would not be useful here.
This is a part B question – a question with a clear, direct answer – but sharpening your part C critical thinking skills sometimes helps with these questions too!