CSB349H1 Lecture Notes - Lecture 3: Gene Duplication, Neural Crest, Reverse Transcriptase
4 Oct 2012
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Last lecture: most of the human genome doesn"t have genes it has repetitive sequences. Gene duplication and divergence: duplicate the gene and make small changes in it to create new sequences/function. Gene duplication: our genes use the same the same mechanisms to duplicate as the repeat sequences do (reverse transcription, etc). A gene is transcribed into rna, which can then be converted back to a dna sequence via reverse transcription to produce a new and different copy of the dna which is then inserted into the genome. The new copy may have the same function and it may not! Tandem duplication results in another copy of the dna sequence right beside the original one. Subfunctionalization: the two genes divide up the function of the ancestral gene. Neofunctionalization: one copy gets a diff function. Example: haemoglobin: there used to only one ancestral gene but now there are diff copies (fetal, embryonic, adult) and all have dramatic differences in their expression patterns.
