Optimal phenotype

The production of toxins is only one aspect of plant defense strategy. As a result of the persistent battle of plants and herbivores, many optimized phenotypes have evolved, such as the preferential accumulation of alkaloids in tissues with a pattern that is consistent with predictions of optimal defense theory,65 i.e., the defense metabolites are allocated preferentially to tissues with a high probability of attack.66 The inducibility of pathways leading to plant secondary compounds as a strategy to minimize the costs of plant defense is a result of permanent optimization. One of a few examples of inducible alkaloid biosynthesis is the different Nicotiana species that exhibit dramatic wound-induced increases of nicotine, nomicotine, or anabasine.67... 

Miller If the optimal phenotype— that is the unmutated genome, the species-typical genome—represents high g, then as you accumulate more and more deleterious mutations that each have pleiotropic effects in multiple systems, they re going to introduce the correlations between deficits in multiple systems. This will in turn introduce higher intercorrelations at lowerg levels. 

If the optimal phenotype varies regionally, genetic variation will tend to be maintained. The controversial idea that differences between human races and ethnic groups in intelligence may be partly genetic depends on the validity of the scenario that there has been geographic variation in optimal intelligence level (e.g. Rushton 1995). 

The whole point of fitness indicators is to advertise differences in heritable fitness between individuals. This gives them some unusual features as biological adaptations, compared to ordinary survival adaptations (Miller 2000, Miller Todd 1998). Survival adaptations usually evolve to be genetically and developmentally canalized to create the optimal phenotype, leading to low apparent heritabihty and minimal differences between conspecifics. By contrast, fitness indicators evolve to be costly, complex displays that are so difficult to grow, maintain and produce that only the highest-fitness individuals can afford to produce them in the optimal, most sexually attractive form. Whereas survival adaptations tend to minimize between-individual differences, fitness indicators tend to amplify them dramatically (Hasson 1990, Pomiankowski Moller 1995, Rowe Houle 1996). 

The ultimate goal of lead optimization is to produce compounds that will elicit the desired cellular and organismal phenotype when dosed at appropriate concentrations. During the course of lead optimization activities it is common for pharmacologists to evaluate compounds not only using in vitro enzyme activity assays but also in cell-based assays as well. A question that often arises at this stage of drug discov-... 

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