Conversely, small genomes often lack genes encoding transcription factors, which might increase the selection pressure for the presence of operons.
Since recombination rate correlates positively with the likelihood of fixing beneficial mutations in D. melanogaster in general [29] the direct interaction between host and parasite molecules might have increased selection for cluster formation in regions of higher recombination rates for these classes of genes (Fig. 2) and thus increased the efficacy of natural selection.
Either way, the high parasite infection intensities might be a result of environmental stress, and will further increase selection on MHC and other immune genes.
Therefore the overall estimate of bias might increase with the selection of a less rigorous cut off.
Conserved genes are duplicated relatively more often [ 22], although shortly after duplication the evolutionary rate might increase, as the purifying selection is weaker [ 23, 24], and the selection pattern in the two copies may be different [ 25].
This, in turn, might increase the efficiency of selection against ΔmtDNA elements through nuclear suppressor loci in the larger, male-rich AF16 lines than in lines of other strains experiencing identical bottleneck (transfer) sizes.
Giving consideration to farmers' preferences for improvements in animal traits when designing genetic selection tools such as selection indexes might increase the uptake of these tools.
As an extension of this modification, performing ECG screening via home visit in selected cases might increase screening uptake as well, although selection of these cases might prove difficult.
Here, then, is a possible example from nature where migration among populations in different selection regimes might increase additive genetic variation (also see Alleaume-Beharira et al. 2006; Lopez et al. 2008).
Other more important variables, especially those for characterizing natural selection (e.g., the frequency of usage of optimal codons [ 45]), might increase the explanatory power of natural selection on codon usage patterns of virus genomes.
