Given the dramatic changes associated with metamorphosis, selection could differ before and after metamorphosis, and opposing selection might be more common than complimentary selection [ 5, 6].
Average dN/ dS ratios indicate that the regions around LCRs may be tightly controlled, as negative selection appears to be far more common than positive selection.
This prediction is consistent with the general observation that obligatory sex is more common, whereas sexual selection is often stronger, among animals than among plants: Plants do exert intense selection on pollen, which is indicative of the quality of gametes as well as the ability of the mate to produce gametes that are effectively dispersed [ 34, 35].
"This approach seems to allow much more subtle and much more common signals of selection to be detected," says evolutionary geneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
If HIV-infection increases the severity of malaria or impairs immune clearance, will drug use become more common, strengthening the selection for resistance?
However, there are situations where these rare traits can increase organisms' fitness and thus become more common through natural selection.
In contrast, when cooperators are more common the direction of selection changes and selection pressures lead to an increase in frequency of cooperators (blue areas in Figure 2).
Elsewhere in France and beyond, however, a more common response to his selection was, who?
If a mutation helped bacteria thrive in this new environment, it might become more common because of natural selection.
When a distasteful animal comes to resemble a more common distasteful animal, natural selection favours individuals that even very slightly better resemble the target.
