Final answer:
An autonomous transposable element (TE) can move or replicate independently within a genome, while a nonautonomous TE relies on the assistance of an autonomous TE for movement.
Step-by-step explanation:
An autonomous transposable element (TE) is capable of moving or replicating itself independently within a genome. It contains all the necessary genetic elements required for its movement. On the other hand, a nonautonomous TE lacks some of these necessary elements and relies on the assistance of autonomous TEs for movement or replication.
While nonautonomous TEs cannot move on their own, they can still move within a genome through a process called transposition. Transposition occurs when an autonomous TE recognizes and mobilizes a nonautonomous TE, causing it to be copied and inserted into a new location in the genome.
For example, in maize plants, the Ac (autonomous) and Ds (nonautonomous) elements are commonly found. Ac elements are fully functional and can move independently, while Ds elements rely on Ac elements for their movement. Ac elements recognize Ds elements and catalyze their transposition to new genomic locations.