Significance Of Phenotypic Plasticity Research Articles

Genetic diversity and detection of candidate loci associated with alternative morphotypes in a tailed amphibian

Abstract Phenotypic changes in response to environmental cues allow organisms to adapt and enhance their fitness in a given habitat. Despite the significance of phenotypic plasticity in the evolution and ecology of natural populations and the ongoing development of new genomic tools, the underlying genetic basis is still largely unknown. Herein, we examined the underlying mechanisms of genetic and phenotypic divergence among alternative morphs of a natural population of the Greek smooth newt (Lissotriton graecus). The studied population consists of fully aquatic individuals exhibiting facultative paedomorphosis, the retention of larval traits such as gills, and individuals that have passed metamorphosis (paedomorphic vs. metamorphic newts). Based on the single nucleotide polymorphisms (SNPs) obtained, we observed low genetic divergence between the two alternative morphs and similar levels of gene diversity on neutral markers. Despite the observed high gene flow between the morphs, an Fst approach for outliers detected candidate loci putatively associated with the alternative morphs that mapped to four genes. These identified genes have functional roles in metabolic processes that may mediate the persistence of alternative ontogenetic trajectories.

Adapting to Change

Adapting to Change

The Integrative Biology of Phenotypic Plasticity

Gene-environment interactions are of interest not only for the study of human behavior but have also become a focus of research on other species. Recent developments in the field of plasticity studies, which examines such interactions, are given a thorough survey in Pigliucci’s new book. The first in a series of monographs on integrative biology edited by Samuel Scheiner, Phenotypic Plasticity summarizes the results of research in many disciplines, giving equal time to plants and animals. Following a discussion of the definition and history of plasticity, there are chapters on the genetics of plasticity and the significance of phenotypic plasticity in molecular and developmental biology and ecology, each of which can be read independently and provides an informative review of the field with which it deals. This project is motivated in part by recent debates about the influences of nature and nurture on human behavior. Genetic determinists such as Jensen maintain that the human intelligence quotient depends on genotype whereas Gould, Lewontin, and others have emphasized the importance of environmental factors. Pigliucci presents phenotypic plasticity as a way of moving beyond the gene-environment dichotomy because in many cases plasticity results from non-additive interactions between genotype and environment.

Signal perception, differential expression within multigene families and the molecular basis of phenotypic plasticity

Abstract. This Introduction to the Special Issue of Plant, Cell and Environment on ‘Sensing the Environment’is concerned with the molecular mechanisms that may link the perception of environmental signals with the evocation of those specific developmental responses that collectively are known as phenotypic plasticity. The significance of phenotypic plasticity at the evolutionary, developmental and ecological levels is outlined, and it is argued that the extent of an individual's adaptability to environmental conditions must be a reflection of the extent and sophistication of the controls over the synthesis and action of specific proteins. Reviewing evidence from a selected range of plant enzymes and regulatory proteins, it is proposed that differential regulation of the expression of members of multigene families may represent the molecular basis of phenotypic plasticity.

Shell shape plasticity in Late Pennsylvanian myalinids (Bivalvia)

Analyses of shell shape variation in epifaunal and semi-infaunal myalinids from the LaSalle “cyclothem” attest to the extensive shape plasticity of some Late Pennsylvanian myalinids. Mean shell shapes differ significantly within and among species across three nearshore facies. Discriminant analyses of Fourier biometric data categorized by taxonomic, populational (habitat), life-mode, and “multi-species habitat assemblage”” discriminant groups reveal patterns of shape change and variation across an inferred environmental stress gradient in addition to taxonomic and life-mode shape differences. Fourier harmonic data are good indicators of shape differences between epifaunal and semi-infaunal life modes. Mean shapes of epifaunal species vary among habitats. Within-habitat shell shape convergence occurred between Myalina glossoidea and M. (Orthomyalina) slocomi. Interpopulational shape divergence occurred among all populations of M. (Orthomyalina) slocomi, M. glossoidea, and M. wyomingensis. Within-species variation among habitats produced significant mean shape differences among each of three “multi-species habitat assemblages.” Results indicate that a portion of the variation is of ecophenotypic origin.Mean interspecific shape differences reflect internal functional organization and life modes. Intraspecific shape differences among epifaunal species could reflect physical and biotic habitat variables. Several harmonic amplitudes vary in concert with inferred environmental variation among habitats. Although biologic interpretation of harmonic data is problematic, parallel trends in fifth harmonic amplitudes of epifaunal species mirror inferred differences in water turbulence among habitats and could reflect shape variation related to byssal attachment.Stress gradient trends in intraspecific shape variability cannot be collectively explained by either of the antithetical stability-diversity-variation hypotheses. Each species exhibits a different nonmonotonic trend. Maximal levels of intraspecific variation within each species occurred within different habitats. Within-species differences in levels of variation could result from genetic variation among populations as well as ecophenotypic influences. Comparative studies of ontogenetic shape change between valves of individuals, among individuals, and among populations are necessary to determine the relative influence of environmental variables on shape variation and evolutionary significance of phenotypic plasticity.