BIOL 2P02 Lecture Notes - Lecture 13: Transposable Element, Dna Profiling, Reverse Transcriptase
17 Oct 2016
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Document Summary
The problem of dna content and genome composition: highly repeated dna fraction (-10% in human genome) 20-80% of total dna (~45% in humans: gene length sequences, known coding sequences. The term transposable genetic element is used to describe a dna sequence that can occasionally move (transpose) from one position on a chromosome to another position. First identified in plants (corn) by barbara mcclintock in the 1940s. Effect of transposable elements causes different colours in corn. Can be negative in humans because it can immobilize genes that could potentially protect the human body from diseases. Specific types of these elements have other names including jumping genes, roving genes, controlling elements, cassettes, and transposons. An element is cut out of one site in a chromosome and pasted into a new site. No change in gene number: copy-and-paste. An element is replicated and once copy is inserted at a new site while one copy remains at the original site.
