Composite and noncomposite transposons

Lecture on Composite and noncomposite transposons. http://shomusbiology.weebly.com/ Download the study materials here- http://shomusbiology.weebly.com/bio-m... A composite transposon is similar in function to simple transposons and Insertion Sequence (IS) elements in that it has protein coding DNA segments flanked by inverted, repeated sequences that can be recognized by transposase enzymes. A composite transposon, however, is flanked by two separate IS elements which may or may not be exact replicas. Instead of each IS element moving separately, the entire length of DNA spanning from one IS element to the other is transposed as one complete unit. Composite transposons will also often carry one or more genes conferring antibiotic resistance. A transposable element (TE) is a DNA sequence that can change its position within the genome, sometimes creating mutations and altering the cell's genome size. Transposition often results in duplication of the TE. Barbara McClintock's discovery of these jumping genes early in her career earned her a Nobel prize in 1983.[1] TEs make up a large fraction of the C-value of eukaryotic cells. They are generally considered "junk DNA". In Oxytricha, which has a unique genetic system, they play a critical role in development.[2] They are also very useful to researchers as a means to alter DNA inside a living organism. Source of the article published in description is Wikipedia. I am sharing their material. © by original content developers of Wikipedia. Link- http://en.wikipedia.org/wiki/Main_Page