Biology 2581B Lecture Notes - Lecture 7: Holliday Junction, Heteroduplex, Dna Repair
1 Mar 2019
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Document Summary
Basic mechanism and consequences of recombination as described by holliday model. Begins with single-stranded breaks and exchange of backbones. Heteroduplex: double stranded dna in which one backbone is from each of the two parents. Centromeres have to separate from each other, 2 possible ways to resolve. Holliday intermediate: can cut the top in a vertical strand, cut it horizontally: need to cut 2 backbones, holliday model predicts noncrossover or crossover recombinant dna, horizontal cut = noncrossover; vertical cut = crossover, both outcomes contain heteroduplex. Basic mechanism and consequences of recombination as described by double strand break model. 3" end invades the other backbone because they"re complementary. Displacement loop forms (d-loop), very common because of homologous pairing. Repairing mismatches in hd dna can result in gene (allele) conversion. Mismatch in that snp (heteroduplex isn"t perfectly complementary), mismatch repaired by excision repair.
