Chapter 11 Bio

Chapter 11 Bio - Symmetric heteroduplex: formed from...

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11.1 Homologous Recombination HR does not occur: segregate randomely during meitotic divitio n\ HR can. . Repair 2xsrand breaks 1x strand gaps at replication forks Restart forks Maintain telomeres Crossing over occurs in both mitosis and meiosis Mitosis: between nonsister chromatids of homologos hcormosomes to prodice adjacent somatic ell clones of different genotypes 2:2 segregation: refoection of constancy of gene which only changes at a very low freq. due to mutationj Meitotic products: tetrads deviate from 2:2 Gene conversion Often associated with a reciprocal crossover of flanking genes Sometimes incomplete, giving a meitoc prodict that has two genotypes, with 1 or a few DNA mismactches called a heteroduplex DNA 11.4.6.9.10.13 11.4 Holiday Model: model for HR in meiosis Recombination begins after replication
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Unformatted text preview: Symmetric heteroduplex: formed from symmetric exchange of single DNA strand between duplexes Holliday Junction: crossed strand structure, can move down paired chromatics by branch migration Resolution: HJ cleaved to make 2 separate duplexes East west: noncrossover products (patch) North south: crossover products (splice) Mtchmatch repair restore original genotype or change genotype (A a) 3:1 and 1:3 conversion RecA protein: promotes pairing of 1x strand DNA with similar DNA sequences in vitro or in vivo, strand invasion D loop:when one end of invading strand displaces a strand with identical or nearly identical seq. ATP hydroloysis: promotes RecA dissociation from 1x strand after exchange...
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Chapter 11 Bio - Symmetric heteroduplex: formed from...

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