Previous studies showed a low nonsynonymous divergence in highly expressed genes, owing to a higher selection constraint on these genes [ 24, 25].
In a similar fashion, multi-spacer typing (MST), based on the assumption that intergenic spacers are more variable than genes owing to a lower selection pressure, combines sequences from the most variable intergenic spacers between aligned genomes of bacterial strains instead of genes [ 54].
At pathological level, there are emerging data to suggest that at least some of the observed discordance may be owing to an inappropriate selection of patients who could benefit from antiHER2 treatments.
Weak purifying selection owing to a small effective population size would suffice.
But relaxed selection owing to a single generation of hatchery culture seems an unlikely explanation for dramatic declines in fitness unless salmon carry an extraordinary standing genetic load (e.g. Launey and Hedgecock 2001).
Taken together, the data support a model in which the X has a slightly lower mutation rate but nevertheless experiences a higher substitution rate at most functional sequence classes owing to a greater efficacy of positive natural selection (Charlesworth et al. 1987; Kirkpatrick and Hall 2004).
But owing to inconsistent selection, an obsession with size and a lack of any obvious game-plan, his sides are invariably a mess. .
The inability to get different growth rates in H and L lines may be owing to the selection regime which selected for higher growth rates in either of the nutrient concentrations.
An alternative in these cases is selection mapping, in which selective sweeps (a reduction or elimination of genetic polymorphism in a region owing to strong selection) are searched [ 2, 5- 8].
Managers and policy makers must recognize that not only may there be evolution in a managed population owing to direct selection on traits, but there will often also be indirect evolutionary consequences of a given environmental change or management action mediated by other community members.
