Practice question

Non-autonomous transposable elements lack internal coding regions for transposition enzymes yet retain critical cis sequences including terminal inverted repeats or primer binding sites recognized by transposases provided by autonomous partners elsewhere in genome. This parasitic dependence limits independent movement; they mobilize only when compatible autonomous element expresses trans-acting enzyme. Examples include MITEs derived from DNA transposons and SINEs relying on LINE proteins. Despite small size, non-autonomous elements achieve very high copy numbers exploiting enzymatic machinery of autonomous families. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.