Which genetic element intrinsically carries genes needed for its own integration into a host chromosome?

Introduction / Context:
Integration of mobile DNA into chromosomes underlies genome plasticity, antibiotic resistance spread, and genetic engineering tools. Elements differ in whether they encode the machinery for movement.

Given Data / Assumptions:

• Transposons encode transposase (and often accessory factors) enabling cut-and-paste or copy-and-paste movement.
• Many plasmids do not encode integration systems; some can integrate via recombination but not all carry integrases.
• “Tandons” is not a recognized genetic element.

Concept / Approach:
By definition, a transposon is a segment of DNA able to move to new genomic sites, typically flanked by inverted repeats. Its enzyme(s) catalyze excision/insertion or replicative transposition into the host chromosome or plasmids.

Step-by-Step Solution:
Identify which element has dedicated integration machinery: transposon.Exclude generic replicons and plasmids that may not encode such functions.Reject nonexistent categories.

Verification / Alternative check:
Experimental mutagenesis using transposons (for example, Tn5, Tn10) relies on their encoded transposase for chromosomal insertions.

Why Other Options Are Wrong:

• Replicon: replication competency does not imply mobility/integration.
• Plasmids: many are extrachromosomal only unless aided by recombination.
• “Tandons” and housekeeping operons: not mobile elements.

Common Pitfalls:
Equating “plasmid” with “integrative plasmid”; only specialized elements carry integration genes.

Final Answer:
Transposons with transposase/integrase functions