Biology 1001A Lecture Notes - Lecture 1: Sister Chromatids, Genetic Recombination, Meiosis
Document Summary
Recombination requires 2 dna double helices, a mechanism for bringing the dna into close proximity, and a collection of enzymes to cut, exchange, and paste. Most of the recombination occurs between regions of dna that are very similar but not identical: homologous. Allows different dna molecules to line up and recombine. Homologous regions of dna are paired by using enzymes that separate hydrogen bonds of one double-helix and allow the bases to reassociate with complementary bases in a homologous chromatid. Involves cutting sugar-phosphate backbones of dna molecules and then linking those of non-sister chromatids. Results in 2 recombined double helices in which the original red dna is now covalently bound to the blue dna. Sexual reproduction depends on meiosis: meiosis is a specialized process of cell division that recombines dna sequences and produces cells with half the number of chromosomes present in somatic cells of a species.
