2 in book lateral or horizontal gene transfer denotes

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Unformatted text preview: ization: One copy acquires a new function, such as expression in a different tissue or a different specificity, and the other maintains its original function. (This may result in faster sequence change, especially for amino acid replacements.) selection acts on the gene expressing itself in another tissue or specificity. 3. Subfunctionalization: Both copies are partially compromised due to mutations, such that they share same function as the single ancestral copy In general, if selection acts on the duplicated locus, it will probably favor a change in function (di erent pathway or process, or expression in di erent tissue or stage) two people each break an arm, both copies get worse but need both to get certain jobs done. Just not as well as they could the first time around. Neofunctionalization: This is the most interesting case because it is the way that genes with new functions originate There are many cases of paralogous genes that have different functions. Neofunctionalization: When a gene acquires a new function, we predict that there will be positive selection on the duplicate copy Neofunctionalization: Evidence of positive selection Lateral Gene Transfer (section 15.2 in book) Lateral (or horizontal) gene transfer denotes any transfer, exchange or acquisition of genetic material that differs from the normal mode of transmission from parents to offspring (vertical transmission) Vertical)evolution) Horizontal*evolution! Lateral gene transfer (LGT) refers to the transfer/acquisition of genes within a generation and can occur within a genome (transposable elements) or between members of different taxa Easier way to get new genes without using gene replication and new function. This is when you get genes from a source besides your parents. How do genes get transferred laterally? Uptake of DNA is frequent, but for LGT to be evolutionarily meaningful, it must be integrated into the cell/genome and heritable How$can$genes$get$transferred$laterally? mechanisms of gene transfer in bacteria ! Transduction:via!bacteriophage- Conjugation:direct!contact- (from Redfield, Nat. Rev. Genet. 2001) Transformation:integrating!free...
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This note was uploaded on 04/08/2014 for the course BIO 370 taught by Professor Edwards during the Spring '08 term at University of Texas at Austin.

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