BIOL239 Lecture : Transposable Elements Transposons, Insertion Sequences, Inverted repeats, retrotransposons and how they work
16 Oct 2011
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Transposable elements: small segments (50-10,000 base pairs) of dna that are able to excise themselves and move from one place to another in the genome jumping genes . May move, or copy themselves (cut& paste or copy & paste) Selfish carry only information required for their own propagation. Marcus rhoades & barbara mcclintock did experiments of transposable elements in corn. Prokaryotes: carry insertion sequences & transposons, both cut and paste. Have terminal inverted repeats (ir= inverted repeat) Have transposase gene which codes for transposase enzyme. Transposase cuts at inverted repeats and cuts the host. Host cell then uses ligase to repair itself (see slide 7) Middle codes for transposase gene, but also one or more other genes (see slide 9) speckling: transposons moved out of some cells. Ends are inverted repeats 10-200 bp long. Carry a transposase gene and one or two other genes. Reverse transcriptase to copy to double stranded dna molecule.
