BIMM 120 Chapter Notes - Chapter 2: Power Law, Epistasis, Mutation Rate
26 Oct 2018
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Long-term dynamics of adaptation in asexual populations: wiser et al 2013. Observations show that fitness trajectory was much higher than those with low mutation rate. Conclusions: adaptation can continue for a long time for asexual organisms, even in a constant environment, fitness increases because small advantages are important over long time scales in large populations. Sustained fitness gains and variability in fitness trajectories in the long-term evolution experiment with escherichia coli: lenski et al 2015. From previous experiment, continue for an additional 10,000 generations to see if the(cid:396)e"s an upper limit on increasing fitness. Conducted more than 1100 new competitive fitness assays: found that power law still fit new data better than hyperbolic model, found variability in fitness among populations causes differences in mean fitness. Due to differences in mutation rate that evolved over time: results imply that both adaptation and divergence can continue indefinitely even in a constant environment.
