See this abstract from Molecular Ecology*:
There is increasing evidence that phenotypic plasticity can promote population divergence by facilitating phenotypic diversification and, eventually, genetic divergence. When a ‘plastic’ population colonizes a new habitat, it has the possibility to occupy multiple niches by expressing several distinct phenotypes. These initially reflect the population’s plastic range but may later become genetically fixed by selection via the process of ‘genetic assimilation’ (GA). Through this process multiple specialized sister lineages can arise that share a common plastic ancestor – the ‘flexible stem’. Here, we review possible molecular mechanisms through which natural selection could fix an initially plastic trait during GA. These mechanisms could also explain how GA may contribute to cryptic genetic variation that can subsequently be coopted into other phenotypes or traits, but also lead to nonadaptive responses. We outline the predicted patterns of genetic and transcriptional divergence accompanying flexible stem radiations. The analysis of such patterns of (retained) adaptive and nonadaptive plastic responses within and across radiating lineages can inform on the state of ongoing GA. We conclude that, depending on the stability of the environment, the molecular architecture underlying plastic traits can facilitate diversification, followed by fixation and consolidation of an adaptive phenotype and degeneration of nonadaptive ones. Additionally, the process of GA may increase the cryptic genetic variation of populations, which on one hand may serve as substrate for evolution, but on another may be responsible for nonadaptive responses that consolidate local allopatry and thus reproductive isolation. (paywall) – Ralf F. Schneider, Axel Meyer, How plasticity, genetic assimilation and cryptic genetic variation may contribute to adaptive radiations, More.
What’s interesting about this account is the relatively relaxed (thus more correct) attitude to speciation, an oblique sign of weakening Darwinism. Darwinism depends on the concept of speciation. When speciation just isn’t very clear, Darwinism just isn’t very clear.
* Special issue: Molecular Mechanisms of Adaptation and Speciation: Integrating Genomic and Molecular Approaches
See also: Are there really 1000 “species” of cichlid?
Red wolf not endangered, a hybrid?
Nothing says “Darwin snob” like indifference to the mess that the entire concept of speciation is in
Follow UD News at Twitter!