BIOL239 Lecture 22: set22_transposons.pdf
12 Sep 2014
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Document Summary
Small segments of dna (50 - 10,000 bp) which are able to move from one position to another in the genome. Can be present in thousands of copies throughout the genome e. g. human genome ~40% consists of transposable elements. Work by marcus rhoades (1930s) and barbara mcclintock (1950s) with corn inferred the presence of transposable elements. Need not be sequences that do anything for or against the organism. Many are regarded as selfish," carrying only information required for their own propagation. Why is there so much junk" dna? www. rps. psu. edu/probing/junkdna. html. Prokaryotes carry insertion sequences (is) and transposons (tn) Dna elements that can excise themselves and move from place to place within the genome. Code for a transposase enzyme, which cuts at the irs and cuts the host dna for is movement. Complex structure, more than 1 gene e. g. , resistance genes. Code for a transposase enzyme, which cuts at the irs and cuts the host dna for movement.
