There is nothing in this or any similar standard definition of evolution that requires that genetic change in the average size, shape, or any other trait be maintained for a hundred, a thousand, or a million years before it can truly be called evolution.
Mutations that changed glucose metabolism or acid tolerance conferred no proliferative advantage so that neither phenotypic trait was maintained in the intraductal populations.
The physiological mechanisms associated with leaf unfolding are genetically controlled and so these traits are maintained when trees are transplanted to new environments (Körner and Basler 2010; Ghelardini et al. 2014).
"This study provides a very clear, compelling confirmation that genetic variation in important traits is maintained by tradeoffs between components of fitness such as survival and reproduction," Bonduriansky says.
Genetic variance for economic traits is maintained by the increase in frequency of rare alleles, new mutations, and changes in selection goals and management.
One of the key assumptions of theories of sexual selection is that the signal reliability of male traits is maintained by bearing costs due to predators [20].
Long-term investigation into patterns of selection provides insight into how phenotypic variation in fitness-related traits is maintained, and how populations adapt to variable environmental conditions [ 1].
This enables not only the discovery of larger number of QTLs with relatively smaller phenotypic effect but also provides a cost-effective means for evaluation of the frequency of segregating QTLs in outbred populations which is important for further understanding how genetic variation underlying phenotypic traits is maintained in the wild.
Further, pollen being the main mode of gene flow, genetic differentiation in quantitative traits was maintained by natural selection (Bloomfield et al. [2011]).
A central problem is that the predominating empirical research tradition has focused on male traits, yet the key question is whether female choice traits are maintained because of direct effects on female fitness or because of indirect genetic effects in offspring that may be associated with such traits.
