In genetics, what is the name of a DNA segment that can move to a new location in the genome?

In genetics, a DNA segment that can move to a new location in the genome is called a transposable element.

Transposable elements are also known as transposons or “jumping genes.” Some move directly as DNA, while others are copied into RNA and then converted back into DNA before insertion elsewhere. Their movement can alter gene activity or disrupt a gene if they insert into an important sequence.

Barbara McClintock discovered mobile genetic elements in maize during the 1940s. Her work showed that chromosome regions could change position and influence visible traits in corn kernels. She received the Nobel Prize in Physiology or Medicine in 1983 for this discovery.

Transposable elements make up a substantial fraction of many genomes, including the human genome. Most human copies are inactive, but their ancient insertions have helped shape genome evolution. They should not be confused with plasmids, which are usually separate DNA molecules rather than mobile segments within chromosomes.