Biology 1002B Lecture Notes - Experimental Evolution, Gene Duplication, Open Reading Frame
21 Apr 2013
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Lecture 21: experimental evolution: potentiation, actualization and refinement. For new ability to appear, the bacterial populations went through three successive evolutionary steps: Further refining" mutations, which involved duplications of the rearranged dna sequence, were needed for robust growth under such conditions: characteristics of model systems that can be used for experimental evolution. Subject cells and organisms to selective pressure and look at the outcome. Model systems have very fast life cycles: short generation time to look at evolution in real time, origins of genetic novelty (variation) Gene duplication: one of the two copies usually gets lost through deletion or degeneration. If it gets retained, only one gets to stay the same. Neo-functionalization: mutate faster than the other gene by changing structure. Sub-functionalization: change promoter/regulation (expressed in different conditions) Genome rearrangement: shift promoter closer to another gene, design of lenski"s long term evolutionary experiment (lee) with e. coli. Spontaneous mutation usually either bad or neutral.
