While the population mean phenotype follows the moving optimum, generation-to-generation rates of phenotypic change in haldanes fluctuate as a consequence of nonselective factors such as genetic drift, environmental variance and fluctuations in the phenotypic variance.
Single-factor ANOVA was used to detect statistically significant differences between the strain mean phenotype values.
Consequently, the population will initially evolve slowly, and the lag between the optimum and the population mean phenotype will increase (the population 'slips off' the fitness peak).
The population mean phenotype is close to its current optimum, but this optimal value now begins to change over time at a rate k per generation.
For any phenotype of interest, the deviation of the hemiclone family mean from the population mean phenotype gives a direct estimate of the breeding value of a gamete.
This geometric mean principle governs the evolutionary interplay of genes controlling mean phenotype and genes controlling phenotypic variation, such as genetic regulators of the epigenetic machinery.
Aside from putative epigenetic inheritance, Feinberg and coworkers proposed a model in which DNA mutations could, via epigenetic mechanisms, modify phenotypic variability without changing the mean phenotype [ 159].
The mean phenotype in this case is and the phenotypic variance is (15) where r = r12 is the recombination rate between the two loci.
Phenotypic evolution is relatively straightforward: the mean phenotype will approach the new optimum exponentially (because the fitness gradient decreases in the vicinity of the optimum) (Lande 1976b).
We show how mapping success is affected by a mutation's effect on the mean phenotype as well as its effects on phenotypic variance and fitness.
How should the average phenotype in the next generation compare with the mean phenotype in our population right now? Can you make a specific prediction about the magnitude of this evolutionary change?
