Are glucocorticoids good indicators of disturbance across populations that exhibit cryptic variation in contaminant tolerance?

2021 ◽  
Author(s):  
G. Shidemantle ◽  
N. Buss ◽  
J. Hua
Keyword(s):  
Cryptic Variation

scholarly journals Cryptic variation and its manifestation in the Lower Trentonian Rafinesquina lineage (Ordovician, New York State)

1992 ◽  
Vol 6 ◽  
pp. 292-292
Author(s):  
Robert Titus
Keyword(s):  
New York ◽  
Genetic Variation ◽  
Natural Selection ◽  
New York State ◽  
Ecological Factors ◽  
Stabilizing Selection ◽  
Rapid Population Growth ◽  
York State ◽  
Cryptic Variation ◽  
Adaptive Peak

Species populations commonly carry a great deal of genetic variation which is not expressed in individual phenotypes. Cryptic variation can be carried in recessive alleles, in cases of heterosis, or where modifier genes inhibit expression of the hidden trait. Other genetic and ecological factors also allow cryptic variation. Stabilizing selection prevents the expression of hidden traits; normalizing selection weeds out the deviants and canalizing selection suppresses their traits. Together the two keep the species near the top of the adaptive peak. Cryptic variation balances a species' need to be well-adapted to its environment and also for it to maintain a reserve of variation for potential environmental change. Expression of cryptic traits is rare and is usually associated with times of greatly reduced natural selection and rapid population growth, when the lower slopes of the adaptive peak are exposed.A possible example of the manifestation of cryptic traits occurs within the lower Trentonian Rafinesquina lineage of New York State. The two most commonly reported species of the genus have been reappraised in terms of cryptic variation. Extensive collections of Rafinesquina “lennoxensis” reveal far more intergrading morphotypes than had hitherto been recognized. The form which Salmon (1942) described is broadly U-shaped with sulcate margins. It grades into very convex forms as well as sharply-defined or convexly geniculate types. Of great importance, all forms grade into the flat, U-shaped, alate R. trentonensis, which is, by far, the most common and widespread lower Trentonian member of the genus. The R. “lennoxensis” assemblage has a very narrow biostratigraphy, being confined to a few locations in the upper Napanee Limestone. This places it in a quiet, protected, low stress, lagoonal setting behind the barrier shoal facies of the Kings Falls Limestone.The R. “lennoxensis” assemblage does not constitute a natural biologic species; it is reinterpreted as an assemblage of phenodeviants occupying a low stress, low natural selection lagoon facies. All such forms should be included within R. trentonensis. Given the evolutionary plasticity of this genus, extensive cryptic variation is not surprising.

scholarly journals Extensive intraspecies cryptic variation in an ancient embryonic gene regulatory network

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yamila N Torres Cleuren ◽  
Chee Kiang Ewe ◽  
Kyle C Chipman ◽  
Emily R Mears ◽  
Cricket G Wood ◽  
...  
Keyword(s):  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Recombinant Inbred Lines ◽  
Single Species ◽  
C Elegans ◽  
Cryptic Variation ◽  
Absolute Requirement ◽  
Natural Isolates ◽  
Gene Regulatory ◽  
Metazoan Phylogeny

Innovations in metazoan development arise from evolutionary modification of gene regulatory networks (GRNs). We report widespread cryptic variation in the requirement for two key regulatory inputs, SKN-1/Nrf2 and MOM-2/Wnt, into the C. elegans endoderm GRN. While some natural isolates show a nearly absolute requirement for these two regulators, in others, most embryos differentiate endoderm in their absence. GWAS and analysis of recombinant inbred lines reveal multiple genetic regions underlying this broad phenotypic variation. We observe a reciprocal trend, in which genomic variants, or knockdown of endoderm regulatory genes, that result in a high SKN-1 requirement often show low MOM-2/Wnt requirement and vice-versa, suggesting that cryptic variation in the endoderm GRN may be tuned by opposing requirements for these two key regulatory inputs. These findings reveal that while the downstream components in the endoderm GRN are common across metazoan phylogeny, initiating regulatory inputs are remarkably plastic even within a single species.

Canalization, Cryptic Variation, and Developmental Buffering

Variation ◽  
2005 ◽  
pp. 131-158 ◽  
Author(s):  
Ian Dworkin
Keyword(s):  
Cryptic Variation ◽  
Developmental Buffering

CONTRIBUTIONS TO THE KNOWLEDGE OF CAMBODIAN CYPERACEAE

2019 ◽  
Vol 76 (2) ◽  
pp. 197-220
Author(s):  
K. Tremetsberger ◽  
S. Hameister ◽  
D. A. Simpson ◽  
K.-G. Bernhardt
Keyword(s):  
Phylogenetic Analysis ◽  
Southeast Asia ◽  
Phylogenetic Tree ◽  
Internal Transcribed Spacer ◽  
Sequence Data ◽  
Its Sequences ◽  
Cryptic Variation ◽  
The Family ◽  
History Of ◽  
Rapid Radiations

To date, there are very few sequence data for Cyperaceae from mainland Southeast Asia. The aim of the present study was to contribute nuclear ribosomal internal transcribed spacer (ITS) sequences of selected species of Cambodian Cyperaceae to the overall phylogeny of the family. We generated ITS sequences of 38 accessions representing 26 species from Cambodia and used these sequences for phylogenetic analysis together with similar sequences from the National Center for Biotechnology Information GenBank. Our results corroborate recent phylogenetic work in the family and largely confirm established tribal relationships. The backbone of the phylogenetic tree of species-rich genera that have undergone rapid radiations is often weakly resolved (e.g. in Fimbristylis and in the C4 clade of Cyperus). Cryptic variation was revealed in the taxonomically difficult group of Fimbristylis dichotoma, with samples of this taxon appearing in two distinct clades within Fimbristylis. Further addition of geographically spread accessions of taxa will improve our understanding of the complex biogeographical history of the genera in the family. Eleocharis koyamae Tremetsb. & D.A.Simpson is proposed as a new name for E. macrorrhiza T. Koyama.

The Lower Eastern Layered Series of Rhum

1985 ◽  
Vol 122 (5) ◽  
pp. 459-468 ◽  
Author(s):  
John W. Faithfull
Keyword(s):  
Magma Chamber ◽  
Olivine Gabbro ◽  
Layered Series ◽  
Geochemical Evidence ◽  
Fine Grained ◽  
Cryptic Variation ◽  
Mineral Phases

AbstractThe Lower Eastern Layered Series (LELS) comprises approximately units 1–5 of previous workers. Remapping has revealed considerable along-strike lithological variation in the units of the LELS. It is suggested, on the basis of field and geochemical evidence, that two layers formerly regarded as ‘conformable intrusive sheets of fine-grained olivine gabbro’, may be evolved alii valite layers rather than later intrusions. Xenolith suites, in these layers and elsewhere, indicate a component derived from the roof or walls of the magma chamber. Cryptic variation is more extensive in the LELS than in other parts of Rhum: olivine forsterite content varies from 85.6 to 70, and clinopyroxene Mg×100/(Mg+Fe) varies from 88 to 74. Postcumulus effects and subsolidus re-equilibration have altered the initial compositions of the mineral phases. The data are consistent with a model of repeated replenishment by picritic magma, although the replenishing liquids may have been slightly less magnesian than those subsequently available, during the formation of the upper ELS.

scholarly journals Natural cryptic variation in epigenetic modulation of an embryonic gene regulatory network

2020 ◽  
Vol 117 (24) ◽  
pp. 13637-13646 ◽  
Author(s):  
Chee Kiang Ewe ◽  
Yamila N. Torres Cleuren ◽  
Sagen E. Flowers ◽  
Geneva Alok ◽  
Russell G. Snell ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Phenotypic Diversity ◽  
Epigenetic Modification ◽  
Genomic Variation ◽  
Bzip Transcription Factor ◽  
Rnai Pathway ◽  
Cryptic Variation ◽  
Organ Systems ◽  
Gene Regulatory ◽  
Epigenetic Modulation

Gene regulatory networks (GRNs) that direct animal embryogenesis must respond to varying environmental and physiological conditions to ensure robust construction of organ systems. While GRNs are evolutionarily modified by natural genomic variation, the roles of epigenetic processes in shaping plasticity of GRN architecture are not well understood. The endoderm GRN inCaenorhabditis elegansis initiated by the maternally supplied SKN-1/Nrf2 bZIP transcription factor; however, the requirement for SKN-1 in endoderm specification varies widely among distinctC. eleganswild isotypes, owing to rapid developmental system drift driven by accumulation of cryptic genetic variants. We report here that heritable epigenetic factors that are stimulated by transient developmental diapause also underlie cryptic variation in the requirement for SKN-1 in endoderm development. This epigenetic memory is inherited from the maternal germline, apparently through a nuclear, rather than cytoplasmic, signal, resulting in a parent-of-origin effect (POE), in which the phenotype of the progeny resembles that of the maternal founder. The occurrence and persistence of POE varies between different parental pairs, perduring for at least 10 generations in one pair. This long-perduring POE requires piwi-interacting RNA (piRNA) function and the germline nuclear RNA interference (RNAi) pathway, as well as MET-2 and SET-32, which direct histone H3K9 trimethylation and drive heritable epigenetic modification. Such nongenetic cryptic variation may provide a resource of additional phenotypic diversity through which adaptation may facilitate evolutionary changes and shape developmental regulatory systems.

scholarly journals Cryptic Variation in Morphological Evolution: HSP90 as a Capacitor for Loss of Eyes in Cavefish

Science ◽  
2013 ◽  
Vol 342 (6164) ◽  
pp. 1372-1375 ◽  
Author(s):  
N. Rohner ◽  
D. F. Jarosz ◽  
J. E. Kowalko ◽  
M. Yoshizawa ◽  
W. R. Jeffery ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Cryptic Variation
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