A novel ontogenetic pathway in hybrid embryos between species with different modes of development

Development ◽  
1999 ◽  
Vol 126 (9) ◽  
pp. 1937-1945
Author(s):  
E.C. Raff ◽  
E.M. Popodi ◽  
B.J. Sly ◽  
F.R. Turner ◽  
J.T. Villinski ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Unexpected Result ◽  
Larval Form ◽  
Closely Related Species ◽  
Developmental Program ◽  
Evolutionary Changes ◽  
Indirect Development ◽  
Type Larva ◽  
Developmental Features ◽  
Feeding Larva

To investigate the bases for evolutionary changes in developmental mode, we fertilized eggs of a direct-developing sea urchin, Heliocidaris erythrogramma, with sperm from a closely related species, H. tuberculata, that undergoes indirect development via a feeding larva. The resulting hybrids completed development to form juvenile adult sea urchins. Hybrids exhibited restoration of feeding larval structures and paternal gene expression that have been lost in the evolution of the direct-developing maternal species. However, the developmental outcome of the hybrids was not a simple reversion to the paternal pluteus larval form. An unexpected result was that the ontogeny of the hybrids was distinct from either parental species. Early hybrid larvae exhibited a novel morphology similar to that of the dipleurula-type larva typical of other classes of echinoderms and considered to represent the ancestral echinoderm larval form. In the hybrid developmental program, therefore, both recent and ancient ancestral features were restored. That is, the hybrids exhibited features of the pluteus larval form that is present in both the paternal species and in the immediate common ancestor of the two species, but they also exhibited general developmental features of very distantly related echinoderms. Thus in the hybrids, the interaction of two genomes that normally encode two disparate developmental modes produces a novel but harmonious ontongeny.

Growth and heterosis of hybrids of two closely related species of Pacific sea urchins (Genus Echinometra) in Okinawa

Aquaculture ◽  
2005 ◽  
Vol 245 (1-4) ◽  
pp. 121-133 ◽  
Author(s):  
M. Aminur Rahman ◽  
Tsuyoshi Uehara ◽  
John M. Lawrence
Keyword(s):  
Related Species ◽  
Sea Urchins ◽  
Closely Related Species

Multiple components of feather microstructure contribute to structural plumage colour diversity in fairy-wrens

2019 ◽  
Vol 128 (3) ◽  
pp. 550-568 ◽  
Author(s):  
Marie Fan ◽  
Liliana D’alba ◽  
Matthew D Shawkey ◽  
Anne Peters ◽  
Kaspar Delhey
Keyword(s):  
Plumage Colour ◽  
Structural Elements ◽  
Closely Related Species ◽  
Microscopic Scale ◽  
Colour Variation ◽  
Multiple Components ◽  
Spongy Layer ◽  
Evolutionary Changes ◽  
Genetic And Environmental Factors ◽  
Feather Microstructure

AbstractClosely related species often differ in coloration. Understanding the mechanistic bases of such differences can reveal whether evolutionary changes in colour are driven by single key mechanisms or changes in multiple pathways. Non-iridescent structural plumage colours in birds are a good model in which to test these questions. These colours result from light absorption by pigments, light scattering by the medullary spongy layer (a nanostructure found within barbs) and contributions from other structural elements. Fairy-wrens (Malurus spp.) are a small clade of closely related birds that display a large diversity of ornamental structural colours. Using spectrometry, electron microscopy and Fourier analysis, we show that 30 structural colours, varying from ultraviolet to blue and purple, share a similar barb morphology. Despite this similarity, we find that at the microscopic scale, variation across multiple structural elements, including the size and density of the keratin cortex, spongy layer and melanin, explains colour diversity. These independent axes of morphological variation together account for sizeable amounts of structural colour variability (R2 = 0.21–0.65). The coexistence of many independent, evolutionarily labile mechanisms that generate colour variation suggests that the diversity of structural colours in this clade could be mediated by many independent genetic and environmental factors.

scholarly journals Phylogenomic analysis of echinoderm class relationships supports Asterozoa

2014 ◽  
Vol 281 (1786) ◽  
pp. 20140479 ◽  
Author(s):  
Maximilian J. Telford ◽  
Christopher J. Lowe ◽  
Christopher B. Cameron ◽  
Olga Ortega-Martinez ◽  
Jochanan Aronowicz ◽  
...  
Keyword(s):  
Convergent Evolution ◽  
Sea Urchins ◽  
Phylogenetic Signal ◽  
Strong Support ◽  
Phylogenomic Analysis ◽  
Phylogenetic Studies ◽  
Phylogenetic Methods ◽  
Complete Dataset ◽  
Type Larva ◽  
Molecular Phylogenetic

While some aspects of the phylogeny of the five living echinoderm classes are clear, the position of the ophiuroids (brittlestars) relative to asteroids (starfish), echinoids (sea urchins) and holothurians (sea cucumbers) is controversial. Ophiuroids have a pluteus-type larva in common with echinoids giving some support to an ophiuroid/echinoid/holothurian clade named Cryptosyringida. Most molecular phylogenetic studies, however, support an ophiuroid/asteroid clade (Asterozoa) implying either convergent evolution of the pluteus or reversals to an auricularia-type larva in asteroids and holothurians. A recent study of 10 genes from four of the five echinoderm classes used ‘phylogenetic signal dissection’ to separate alignment positions into subsets of (i) suboptimal, heterogeneously evolving sites (invariant plus rapidly changing) and (ii) the remaining optimal, homogeneously evolving sites. Along with most previous molecular phylogenetic studies, their set of heterogeneous sites, expected to be more prone to systematic error, support Asterozoa. The homogeneous sites, in contrast, support an ophiuroid/echinoid grouping, consistent with the cryptosyringid clade, leading them to posit homology of the ophiopluteus and echinopluteus. Our new dataset comprises 219 genes from all echinoderm classes; analyses using probabilistic Bayesian phylogenetic methods strongly support Asterozoa. The most reliable, slowly evolving quartile of genes also gives highest support for Asterozoa; this support diminishes in second and third quartiles and the fastest changing quartile places the ophiuroids close to the root. Using phylogenetic signal dissection, we find heterogenous sites support an unlikely grouping of Ophiuroidea + Holothuria while homogeneous sites again strongly support Asterozoa. Our large and taxonomically complete dataset finds no support for the cryptosyringid hypothesis; in showing strong support for the Asterozoa, our preferred topology leaves the question of homology of pluteus larvae open.

The Breeding Evidence Indicating Two Genetic Types of Females of Ips tridens Mannerheim) (Coleoptera: Scolytidae)

1964 ◽  
Vol 96 (1-2) ◽  
pp. 117-118 ◽  
Author(s):  
G. R. Hopping
Keyword(s):  
Sex Ratio ◽  
Related Species ◽  
Mortality Factor ◽  
Unexpected Result ◽  
Closely Related Species ◽  
Inner Bark ◽  
Genetic Types ◽  
Stage Of Development ◽  
Gallery System ◽  
Entrance Hole

Members of the genus Ips are polygamous. The male excavates the entrance hole and a small nuptial chamber between the inner bark and sapwood. The females then enter and each excavates an egg gallery starting from the nuptial chamber. The number of females per gallery system ranges from 1 to 5 but the most common number is 3. This sex ratio of approximately 3 ♀ ♀: 1 ♂ has been attributed to some mortality factor more lethal to the males in some stage of development. Breeding of isolated pairs under laboratory conditions was carried out primarily to determine the variability between individuals from the same brood and between individuals from different broods. The objective was to resolve the complex of closely related species in the Ips tridens–I. engelmanni group. An unexpected result was a clarification of the sex ratio problem.

scholarly journals Life History Divergence in Livebearing Fishes in Response to Predation: Is There a Microevolution to Macroevolution Barrier?

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 179 ◽  
Author(s):  
Mark C. Belk ◽  
Spencer J. Ingley ◽  
Jerald B. Johnson
Keyword(s):  
Life History ◽  
Evolutionary Biology ◽  
Offspring Size ◽  
Population Divergence ◽  
Female Size ◽  
Trait Variation ◽  
Closely Related Species ◽  
Trait Divergence ◽  
Evolutionary Changes ◽  
Established Species

A central problem in evolutionary biology is to determine whether adaptive phenotypic variation within species (microevolution) ultimately gives rise to new species (macroevolution). Predation environment can select for trait divergence among populations within species. The implied hypothesis is that the selection resulting from predation environment that creates population divergence within species would continue across the speciation boundary such that patterns of divergence after speciation would be a magnified accumulation of the trait variation observed before speciation. In this paper, we test for congruence in the mechanisms of microevolution and macroevolution by comparing the patterns of life history divergence among three closely related species of the livebearer genus Brachyrhaphis (Poeciliidae), namely B. rhabdophora, B. roseni, and B. terrabensis. Within B. rhabdophora, populations occur in either predator or predator-free environments, and have been considered to be at a nascent stage of speciation. Sister species B. roseni and B. terrabensis are segregated into predator and predator-free environments, respectively, and represent a post-speciation comparison. Male and female size at maturity, clutch size, and offspring size (and to a lesser extent reproductive allocation) all diverged according to predation environment and differences were amplified through evolutionary time, i.e., across the speciation boundary. Variation observed among nascent species differentiated by predation environment is a good predictor of variation among established species differentiated by predation environment. We found no evidence for different processes or different levels of selection acting across the speciation boundary, suggesting that macroevolution in these species can be understood as an accumulation of micro-evolutionary changes.

scholarly journals Annelids shed light on the evolution of spiralian development

2017 ◽  
Vol 95 (10) ◽  
pp. 705-712 ◽  
Author(s):  
Elaine C. Seaver
Keyword(s):  
Experimental Studies ◽  
Mechanistic Explanation ◽  
Experimental Investigations ◽  
Molecular Signaling ◽  
Cell Fates ◽  
Evolutionary Changes ◽  
Capitella Teleta ◽  
Developmental Features ◽  
Molecular Signaling Pathway ◽  
Inductive Signal

Spiralian development is characterized by stereotypic cell geometry and spindle orientation in early cleavage stage embryos, as well as conservation of ultimate fates of descendent clones. Diverse taxa such as molluscs, annelids, flatworms, and nemerteans exhibit spiralian development, but it is a mystery how such a conserved developmental program gives rise to such diverse body plans. This review highlights examples of variation during early development among spiralians, emphasizing recent experimental studies in the annelid Capitella teleta Blake, Grassle and Eckelbarger, 2009. Intracellular fate mapping studies in C. teleta reveal that many of its cells’ fates are shared among spiralians, but it also has a novel origin for trunk mesoderm (3c and 3d micromeres). Studies have identified an inductive signal in spiralians that has “organizing activity” and that influences cell fates in the surrounding embryo. Capitella teleta also has an organizing activity; however, surprisingly, it is localized to a different cell, it signals at a different developmental stage, and likely utilizes a distinct molecular signaling pathway compared with that in molluscs. A model is presented to provide a mechanistic explanation of evolutionary changes in the cellular identity of the organizer. Detailed experimental investigations in spiralian embryos demonstrate variation in developmental features that may influence the evolution of novel forms.

Ritualization and social communication in Rhesus monkeys

1966 ◽  
Vol 251 (772) ◽  
pp. 285-294 ◽  
Keyword(s):  
Related Species ◽  
Rhesus Monkeys ◽  
Penile Erection ◽  
Developmental Stages ◽  
Evolutionary Time ◽  
Closely Related Species ◽  
Evolutionary Origins ◽  
Evolutionary Changes ◽  
Lower Vertebrates ◽  
The Comparative Study

The concept of ritualization, as used in the study of the signal movements of lower vertebrates, refers primarily to the evolutionary changes which such movements have undergone in adaptation to their function in communication. In this context, the term is thus used in reference only to movements which have such a function, and only when there is evidence that the resultant signal has undergone changes which make it more effective in that role. Many movements which influence the behaviour of others (e.g. penile erection, eating and drinking in rhesus monkeys, according to Altman 1962) have apparently not been ritualized, though homologous movements in other species may have been (e.g. penile erection in squirrel monkeys (Ploog & Maclean 1963)). The changes involved have almost invariably been evolutionary ones, and thus reference to ritualization implies evidence that the properties of the signal have changed on an evolutionary time scale. This usually comes from the comparative study of contemporary closely related species. Just as the comparison, between related species, of morphological structures may suggest not only homologies but also views as to the evolutionary origins of the homologous structures, so also does comparison of patterns of behaviour. In addition, just as comparison within a species of related structures, such as the segmental limbs of a crustacean, or of different developmental stages of the same structure, can provide evidence of the course of evolution, so also can comparison of related movement patterns (e.g. Lorenz 1935, 1941; Tinbergen 1952, 1959, 1962).

scholarly journals Genome Size Doubling Arises From the Differential Repetitive DNA Dynamics in the Genus Heloniopsis (Melanthiaceae)

2021 ◽  
Vol 12 ◽  
Author(s):  
Jaume Pellicer ◽  
Pol Fernández ◽  
Michael F. Fay ◽  
Ester Michálková ◽  
Ilia J. Leitch
Keyword(s):  
Genome Size ◽  
Repetitive Dna ◽  
High Throughput Sequencing ◽  
Evolutionary Dynamics ◽  
Dna Dynamics ◽  
Closely Related Species ◽  
Sequencing Technologies ◽  
Genomic Landscape ◽  
Evolutionary Changes ◽  
Low Coverage

Plant genomes are highly diverse in size and repetitive DNA composition. In the absence of polyploidy, the dynamics of repetitive elements, which make up the bulk of the genome in many species, are the main drivers underpinning changes in genome size and the overall evolution of the genomic landscape. The advent of high-throughput sequencing technologies has enabled investigation of genome evolutionary dynamics beyond model plants to provide exciting new insights in species across the biodiversity of life. Here we analyze the evolution of repetitive DNA in two closely related species of Heloniopsis (Melanthiaceae), which despite having the same chromosome number differ nearly twofold in genome size [i.e., H. umbellata (1C = 4,680 Mb), and H. koreana (1C = 2,480 Mb)]. Low-coverage genome skimming and the RepeatExplorer2 pipeline were used to identify the main repeat families responsible for the significant differences in genome sizes. Patterns of repeat evolution were found to correlate with genome size with the main classes of transposable elements identified being twice as abundant in the larger genome of H. umbellata compared with H. koreana. In addition, among the satellite DNA families recovered, a single shared satellite (HeloSAT) was shown to have contributed significantly to the genome expansion of H. umbellata. Evolutionary changes in repetitive DNA composition and genome size indicate that the differences in genome size between these species have been underpinned by the activity of several distinct repeat lineages.

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