Biology 1202B Lecture Notes - Lecture 7: Chromosome Segregation, Chromatin, Retrotransposon
23 Aug 2016
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Generating diversity iii: origins of variation recombination and meiosis. If populations have genetic variability, they have the potential to evolve. Natural selection causes certain variants to leave more offspring that others. Over time, the relative proportions of different variants will change. Ultimate source of genetic diversity is mutation of genetic sequence (often resulting from errors during dna replication) Genetic recombination cutting and pasting dna backbones into new combinations. Genetic recombination is very widespread in nature. Without genetic recombination, reproduction is asexual and offspring will simply be identical clones of their parents. Genetic recombination requires the following: 2 dna molecules that differ from one another, a mechanism for bringing the dna molecules into close proximity, collection of enzymes to cut, exchange and paste the dna back together. The sugar-phosphate backbone is held together by strong covalent bonds, whereas the base pairs are held together through relatively weak hydrogen bonds.
