Transposons are segments of DNA that can move and allow genes to be transferred to a host organism’s chromosome, interrupting or modifying the function of a gene.

Transposition is a precise process in which a defined DNA segment is excised from one DNA molecule and moved to another site in the same or different DNA molecule or genome. It can create phenotypically significant mutations and alter the cell’s genome size. The mechanism of transposition can be either “copy and paste” or “cut and paste.” 

Transposons in bacteria usually carry an additional gene for a function other than transposition—often for antibiotic resistance. In bacteria, transposons can jump from chromosomal DNA to plasmid DNA and back, allowing for the transfer and permanent addition of genes such as those encoding antibiotic resistance (multi-antibiotic resistant bacterial strains can be generated in this way).

A transposon is designed to interrupt a gene in such a way that it causes maximal genetic widespread destruction. Specifically, the transposon contains signals to trim expression of an interrupted gene at the site of the insertion and then restart the expression of a second trimmed gene. This method has been used to identify oncogenes.

Transposon System: The sleeping beauty transposon system applications.

The Sleeping Beauty transposon system is a synthetic DNA transposon designed to introduce precisely defined DNA sequences into the chromosomes of an organism.

Practice Questions

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Biology Question Pack, Vol 2. Passage 16 Question 105

Key Points

• Transposons allow genes to be transferred to a host organism’s chromosome, interrupting or modifying the function of a gene.

• Transposons contain signals to trim expression of an interrupted gene, thus inactivating it.

• Transposons are widely used tools in biology, frequently utilized for insertion mutagenesis, large-scale gene disruption studies, and gene tagging.

Key Terms

transposons: a segment of DNA that can move to a different position within a genome

transposable: able to be transposed (in any sense)

oncogenes: a gene which in certain circumstances can transform a cell into a tumor cell

transposition: when a DNA sequence that can change its position within a genome

excised: cut out.

genome:  the whole of an organisms hereditary information encoded in its DNA

phenotypically: the observable physical characteristics of an organism, as determined by both genetic makeup and environmental influences.