Skip to content
New summer mock series is live Attempt timed papers for SSC, banking, and engineering entrances with updated syllabi for this season. View exams
Login Register

#DNA transposons

2 public questions tagged with this topic.

Transposable elements

DNA transposons move via

DNA transposons move without RNA stage; transposase binds terminal inverted repeats, assembles paired-end complex, introduces staggered double-strand cuts at donor site releasing element with 3'-OH ends that attack target DNA phosphodiester backbone. Host repair polymerases fill single-stranded gaps generating target site duplications characteristic of insertion. Information transfer remains as DNA throughout, distinguishing cut-and-paste transposition from retrotransposition. Copy number usually preserved unless donor gap repaired from sister chromatid yielding increase, balancing genome stability. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 10: DNA Transposon DNA Intermediate Pathway

View Details
Transposable elements

DNA transposons belong to which class?

Classification scheme distinguishes Class I retrotransposons mobilizing via RNA intermediate and Class II DNA transposons moving via DNA intermediate. DNA transposons belong to Class II because they encode transposase that excises DNA copy and inserts elsewhere without reverse transcription. Mechanism is cut-and-paste, generating short target site duplications upon insertion. Class II includes bacterial IS elements, Tc1/mariner superfamily, and P-elements. This categorization reflects fundamental enzymatic requirement and impact on copy number dynamics compared to replicative Class I expansion strategies. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.

Ref: Watson et al., Molecular Biology of the Gene, 7th ed., Chapter 12: Class II Designation for DNA Transposons

View Details