BIOA01H3 Lecture Notes - Lecture 15: Rolling Circle Replication, Hfr Cell, Pilus

• School: Ryerson University
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Mark Fitzpatrick

Document Summary

Week of october 1st: dna, the stuff of heredity. Ultimate source of genetic diversity is mutation of dna sequence. Since mutations are usually very rare, diversity amplified through various mechanisms that shuffle existing mutations into novel combinations. Cutting and pasting of dna backbones into new combinations called genetic recombination. Allows jumping genes to move, inserts some viruses into chromosome of their hosts, underlies spread of antibiotic resistance among bacteria and achaea, and is at the heart of meiosis in eukaryotic organisms. In its most general sense, genetic recombination requires the following: two dna molecules that differ from one another, mechanism for bringing dna molecules into close proximities, collection of enzymes to cut , exchange , and paste dna back together. Two similar double helixes lie close together. Most recombination that occurs in this chapter are between regions of dna that are very similar, but not identical. Homology allows different dna molecules to line up and recombine precisely.