Practice question

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.