DNA segments that can move from one genomic location to another are known as what?
Correct Answer: Transposons
Introduction / Context:Mobile DNA elements reshape genomes across evolution. They can insert, excise, or copy themselves, influencing gene regulation, genome size, and mutational landscapes in both prokaryotes and eukaryotes.
Given Data / Assumptions:
- We are considering DNA sequences that change position within a genome.
- Movement may be cut-and-paste or copy-and-paste.
- Terminology distinguishes endogenous mobile elements from exogenous agents.
Concept / Approach:Such sequences are called transposons (or transposable elements). DNA transposons use transposase for excision/integration, while retrotransposons use an RNA intermediate and reverse transcription.
Step-by-Step Solution:
Identify the defining feature: intragenomic mobility.Map to terminology: "transposons" is the accepted umbrella term.Exclude external agents (viruses) and non-mobile genomic features (introns, centromeres).Thus, the correct term is transposons.Verification / Alternative check:Classic McClintock maize elements and modern genomic surveys reveal abundant transposable element families that relocate or copy within genomes.
Why Other Options Are Wrong:
- Retroviruses: infectious agents requiring packaging and cell-to-cell transmission.
- Introns: noncoding segments removed by splicing; not mobile by default.
- Moving elements (generic): imprecise; the precise term is transposons.
- Centromeres: structural chromosomal loci; not mobile elements.
Common Pitfalls:Confusing retroviruses with endogenous retrotransposons; while related mechanisms exist, the term sought is transposons.
Final Answer:Transposons