In many species, consistent behavioural differences among individuals are linked to fitness variation.
The crucial condition here is fitness variation (b).
The criterion of fitness variation requires only that some variants affect fitness.
The former gives the clue for fitness variation, and incorporating genomics tools may allow identification of the genes that are actually evolving (Lee & Mitchell-Olds, 2006).
Recall, however, that in Endler's model, if fitness variation (that is, traits that enhance fitness) is not present, then the change in a particular trait will be due to drift.
Fitness data were analyzed using t-tests with unequal variances; the greater fitness variation of small versus large populations precludes the use of standard ANOVA.
Experiments with large population samples from microcosms allow estimation of the mean fitness and fitness variation that takes into account the genetic diversity within microcosms.
The accessibility of new genomic resources, high-throughput molecular technologies and analytical approaches such as genome scans have made finding genes contributing to fitness variation in natural populations an increasingly feasible task [12], [13].
Given that inbreeding depression is more marked for such characters, we should expect that the effect of the environment on inbreeding depression will be greater across environmental axes that themselves explain a greater proportion of fitness variation.
In summary, this paper provides a general quantitative evaluation of the relative importance of mutator pathways compared to non-mutator pathways in tumorigenesis, accounting for fitness variation and selection, thus directly addressing the major historical criticisms of the mutator hypothesis.
Despite statistically significant variation among microcosms, the microcosms evolved primarily in parallel (Figure 5) for relative fitness, mean colony size, colony size diversity and fitness variation within microcosms (Ix = 0.218, CI: 0.102 0.398) as the confidence intervals (determined by bootstrapping the data 1,000,000 times) for these traits do not include one.
