Components of fitness become effectively neutral in equilibrium populations.

If, because of trade-offs or similar considerations, components of fitness are negatively correlated in equilibrium populations, they may then exhibit no correlation with total fitness. Lack of correlation with fitness is a fundamental characteristic of selective neutrality. Hence, selectively important traits become subsumed under neutral traits when the definition of neutrality is extended to include factors (genetic or phenotypic) that "behave as if they are neutral."