Q.Describe transposons.

A transposon is a mobile DNA element that can change its position within the genome.

Transposons, or transposable elements, are DNA sequences flanked by specific terminal repeat sequences that allow them to excise (or copy) themselves and insert at a new site in the genome, a process mediated by an enzyme called transposase that many transposons encode themselves. Barbara McClintock first discovered this phenomenon in the 1940s while working with maize (Zea mays), where she found that certain "controlling elements" moving in and out of genes controlling kernel colour caused the variegated colour patterns she observed -- work for which she was later awarded the Nobel Prize. Transposons are now known to be widespread across prokaryotic and eukaryotic genomes and are an important source of genetic variation and mutation. This mobility distinguishes a transposon from an intron, a non-coding intervening sequence that is transcribed but then spliced out of the pre- …

Transposons are mobile genetic elements capable of moving within the genome.

Discovered by Barbara McClintock in maize, transposons (transposable elements) are DNA sequences that can excise or copy themselves and insert at new genomic locations, sometimes disrupting genes or altering gene expression, and they are important both as a source of genetic variation and as tools in genetic engineering. Pili are bacterial surface appendages used in conjugation, plasmids are small extrachromosomal circular DNA molecules that are n …