Biology 2581B Lecture Notes - Lecture 21: Reverse Transcriptase, Retrotransposon, Transpose
28 Apr 2016
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Lecture 21: transposable elements and variations in chromosome numbers. Transposable elements are jumping genes, or genes that jump from place to place in a genome. They vary between species and exist in many organisms. Transposable elements were first discovered by barbara mcclintock in the different colours of maize. Her proposal went against the dogma of the time where they thought that dna was untouchable and pristine. There are two classes of transposable elements: retrotransposons/retroposons: transpose via reverse transcription from an rna intermediate which gets transcribed into a single dna intermediate. Then it gets replicated to a double stranded dna and integrated into the genome. Requires a reverse transcriptase enzyme which is encoded within the transposable element. The sequence is pasted inbetween two repeated sequences. The repeat sequences are generated from sticky ends cut by restriction enzymes (recall that restriction cut sites are palindromic). More information below: transposons: transpose dna directly without an rna intermediate.
