Polyphenic differences between individuals arise not through differences at the genome level but as a result of specific cues received during development. Polyphenisms often involve entire suites of characters, as shown dramatically by the polyphenic castes found in many social insect colonies. An understanding of the genetic architecture behind polyphenisms provides a novel means of studying the interplay between genomes, gene expression and phenotypes. Here we discuss polyphenisms and molecular genetic tools now available to unravel their developmental bases in insects. (...) We focus on several recent studies that have tracked gene-expression patterns during social insect caste determination. BioEssays 23:62–68, 2001. Published 2001 John Wiley & Sons, Inc. (shrink)

Polyphenic differences between individuals arise not through differences at the genome level but as a result of specific cues received during development. Polyphenisms often involve entire suites of characters, as shown dramatically by the polyphenic castes found in many social insect colonies. An understanding of the genetic architecture behind polyphenisms provides a novel means of studying the interplay between genomes, gene expression and phenotypes. Here we discuss polyphenisms and molecular genetic tools now available to unravel their developmental bases in insects. (...) We focus on several recent studies that have tracked gene‐expression patterns during social insect caste determination. BioEssays 23:62–68, 2001. Published 2001 John Wiley & Sons, Inc. (shrink)

Phenotypic Evolution explicitly recognizes organisms as complex genetic-epigenetic systems developing in response to changing internal and external environments. As a key to a better understanding of how phenotypes evolve, the authors have developed a framework that centers on the concept of the Developmental Reaction Norm. This encompasses their views: (1) that organisms are better considered as integrated units than as disconnected parts (allometry and phenotypic integration); (2) that an understanding of ontogeny is vital for evaluating evolution of adult forms (ontogenetic (...) trajectories, epigenetics, and constraints); and (3) that environmental heterogeneity is ubiquitous and must be acknowledged for its pervasive role in phenotypic expression. (shrink)

The concept of reaction norms plays a crucial role in connecting molecular and evolutionary biology.