We found that most students wrote down words associated with 1) the four principles of natural selection, including 'survival of the fittest', 'variation', 'reproduction', and 'inheritance', 2) the result of natural selection, including 'change'evolution'on'descentent with modification', and 3) beneficial selection, including 'adaptation' and 'advancement'advancement
Second, in our framework, s b denotes the (beneficial) selection coefficient for heterozygotes.
To induce production of LasB in the group-beneficial selection, the resistant mimic was engineered to constitutively express lasB (see Supplementary Text and Supplementary Figures 4 and 5, Supporting Information).
Together, these results indicate that resistance should not spread within a microbial population under group-beneficial selection, even if grown in a viscous or spatially structured environment, as long as the colony-to-colony distance is smaller than the diffusion distance of secreted goods.
The importance of this influence is illustrated by the unique example of the ovary-biased genes that apparently do not rely on the activation/repression mechanism and strongly accumulate on the X chromosome in perfect agreement with the female-beneficial selection model [ 7, 29].
This can be important when one allele in a particular haplotype is strongly beneficial: natural selection can drive a selective sweep that will also cause the other alleles in the haplotype to become more common in the population; this effect is called genetic hitchhiking or genetic draft.
If a gene is beneficial, natural selection is likely to be the major determinant of its equilibrium frequency; the rate of sporadic mutation to that gene will play at most a minor role.
It has been argued that dominance is the likely genetic basis of heterosis [ 12, 13], therefore explicitly including dominance in the GS model may be beneficial for selection of purebreds for crossbred performance.
However, because the mutations found by Ellison and Bachtrog are beneficial, natural selection tend to favor individuals where the mutation has spread over those where it has been reversed.
By putting emphasis on loci that are closely linked to causative loci, genomic prediction holds the promise to be particularly beneficial for selection on traits that are difficult or expensive to measure, that are sex-linked, or that are expressed late in life.
On the other hand, if fitness differences between mutant and wild type are sufficiently large, stochastic fluctuations are overruled by deterministic selective forces which can lead to accelerated fixation of a beneficial mutant (positive selection), or its rapid removal as a consequence of strong selective constraints (purifying selection).
