What is a key role of transposons in genome evolution?

• A. They code for tRNA molecules
• B. They are only found in prokaryotes
• C. They move within the genome causing insertions, deletions, and regulatory changes
• D. They are ancient remnants with no current function

Answer: (C)

Transposons drive genome evolution mainly through their mobility inside the genome, which reshapes DNA and regulation. When a transposon moves, it can insert into a gene and disrupt its coding sequence, or land near regulatory regions and alter promoters, enhancers, or silencers. Excision or rearrangements caused by transposon activity can create deletions, duplications, or inversions, generating new genetic combinations. This ongoing shuffling generates variation that natural selection can act on, fueling evolutionary change. They aren’t limited to prokaryotes and aren’t merely ancient fossils with no current role; many transposons are still active or have been repurposed by the host. They also aren’t primarily about coding tRNA molecules.