Biology 1002B Lecture Notes - Lecture 7: Dna Replication, Eukaryote, Alu Element

• School: Western University
• Department: Biology
• Course: Biology 1002B
• Professor: Beth Mac Dougall- Shackleton

Document Summary

Lecture 9: origin of variation: mechanism of proofreading and likely result of proofreading defects. If mismatched, dna polymerase backs up and fixes it with a built in deoxyribonuclease. These distortions provide a recognition site for the enzymes catalyzing mismatch repair. They then remove a portion of the helix (along with the improperly paired bases) and dna polymerase fills the gap. The repair is then sealed by dna ligase. Transposons: transposons are insertion sequences plus . The dna copy is then inserted at a new location by breaking and rejoining the dna backbones. Implications of insertion of mobile elements into dna. Transposons must be in contact with the insertion site to jump from one place to another. Cnvs affect 35% of genes (each person probably has about 1000) Structure of is elements, transposons, retrotransposons and retroviruses. Is (insertion sequence) elements (bacterial elements): inverse repeats, code only for their own mobility (transposase)