scholarly journals The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages

2014 ◽  
Vol 281 (1781) ◽  
pp. 20133120 ◽  
Author(s):  
Thomas A. Stewart ◽  
W. Leo Smith ◽  
Michael I. Coates
Keyword(s):  
De Novo ◽  
Morphological Evolution ◽  
Structural Complexity ◽  
Teleost Fishes ◽  
Dorsal Midline ◽  
Fin Rays ◽  
Limited Function ◽  
Repeated Evolution ◽  
Living Species ◽  
Anatomical Evidence

Adipose fins are appendages found on the dorsal midline between the dorsal and caudal fins in more than 6000 living species of teleost fishes. It has been consistently argued that adipose fins evolved once and have been lost repeatedly across teleosts owing to limited function. Here, we demonstrate that adipose fins originated repeatedly by using phylogenetic and anatomical evidence. This suggests that adipose fins are adaptive, although their function remains undetermined. To test for generalities in the evolution of form in de novo vertebrate fins, we studied the skeletal anatomy of adipose fins across 620 species belonging to 186 genera and 55 families. Adipose fins have repeatedly evolved endoskeletal plates, anterior dermal spines and fin rays. The repeated evolution of fin rays in adipose fins suggests that these fins can evolve new tissue types and increased structural complexity by expressing fin-associated developmental modules in these new territories. Patterns of skeletal elaboration differ between the various occurrences of adipose fins and challenge prevailing hypotheses for vertebrate fin origin. Adipose fins represent a powerful and, thus far, barely studied model for exploring the evolution of vertebrate limbs and the roles of adaptation and generative biases in morphological evolution.

scholarly journals Variation in pleiotropic hub gene expression is associated with interspecific differences in head shape and eye size in Drosophila

2021 ◽  
Author(s):  
Elisa Buchberger ◽  
Anıl Bilen ◽  
Sanem Ayaz ◽  
David Salamanca ◽  
Cristina Matas de las Heras ◽  
...  
Keyword(s):  
Natural Variation ◽  
Compound Eye ◽  
Genetic Manipulation ◽  
Morphological Evolution ◽  
Morphological Diversity ◽  
Network Evolution ◽  
Head Shape ◽  
Eye Size ◽  
Recurrent Mutations ◽  
Repeated Evolution

Abstract Revealing the mechanisms underlying the breath-taking morphological diversity observed in nature is a major challenge in Biology. It has been established that recurrent mutations in hotspot genes cause the repeated evolution of morphological traits, such as body pigmentation or the gain and loss of structures. To date, however, it remains elusive whether hotspot genes contribute to natural variation in the size and shape of organs. Since natural variation in head morphology is pervasive in Drosophila, we studied the molecular and developmental basis of differences in compound eye size and head shape in two closely related Drosophila species. We show differences in the progression of retinal differentiation between species and we applied comparative transcriptomics and chromatin accessibility data to identify the GATA transcription factor Pannier (Pnr) as central factor associated with these differences. Although the genetic manipulation of Pnr affected multiple aspects of dorsal head development, the effect of natural variation is restricted to a subset of the phenotypic space. We present data suggesting that this developmental constraint is caused by the co-evolution of expression of pnr and its co-factor u-shaped (ush). We propose that natural variation in expression or function of highly connected developmental regulators with pleiotropic functions is a major driver for morphological evolution and we discuss implications on gene regulatory network evolution. In comparison to previous findings, our data strongly suggests that evolutionary hotspots are not the only contributors to the repeated evolution of eye size and head shape in Drosophila.

scholarly journals Divergent synthesis of complex diterpenes through a hybrid oxidative approach

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. 799-806 ◽  
Author(s):  
Xiao Zhang ◽  
Emma King-Smith ◽  
Liao-Bin Dong ◽  
Li-Cheng Yang ◽  
Jeffrey D. Rudolf ◽  
...  
Keyword(s):  
Natural Products ◽  
De Novo ◽  
Biological Activities ◽  
Structural Complexity ◽  
Enzymatic Oxidation ◽  
Chemical Tools ◽  
Skeletal Rearrangements ◽  
Skeletal Diversity

Polycyclic diterpenes exhibit many important biological activities, but de novo synthetic access to these molecules is highly challenging because of their structural complexity. Semisynthetic access has also been limited by the lack of chemical tools for scaffold modifications. We report a chemoenzymatic platform to access highly oxidized diterpenes by a hybrid oxidative approach that strategically combines chemical and enzymatic oxidation methods. This approach allows for selective oxidations of previously inaccessible sites on the parent carbocycles and enables abiotic skeletal rearrangements to additional underlying architectures. We synthesized a total of nine complex natural products with rich oxygenation patterns and skeletal diversity in 10 steps or less from ent-steviol.

scholarly journals Jaw protrusion enhances forces exerted on prey by suction feeding fishes

2008 ◽  
Vol 5 (29) ◽  
pp. 1445-1457 ◽  
Author(s):  
Roi Holzman ◽  
Steven W Day ◽  
Rita S Mehta ◽  
Peter C Wainwright
Keyword(s):  
Prey Capture ◽  
Species Variation ◽  
Total Force ◽  
Teleost Fishes ◽  
Independent Source ◽  
Hydrodynamic Approach ◽  
Bony Fishes ◽  
Jaw Protrusion ◽  
Living Species ◽  
Prey Remains

The ability to protrude the jaws during prey capture is a hallmark of teleost fishes, widely recognized as one of the most significant innovations in their diverse and mechanically complex skull. An elaborated jaw protrusion mechanism has independently evolved multiple times in bony fishes, and is a conspicuous feature in several of their most spectacular radiations, ultimately being found in about half of the approximately 30 000 living species. Variation in jaw protrusion distance and speed is thought to have facilitated the remarkable trophic diversity found across fish groups, although the mechanical consequences of jaw protrusion for aquatic feeding performance remain unclear. Using a hydrodynamic approach, we show that rapid protrusion of the jaws towards the prey, coupled with the spatial pattern of the flow in front of the mouth, accelerates the water around the prey. Jaw protrusion provides an independent source of acceleration from that induced by the unsteady flow at the mouth aperture, increasing by up to 35% the total force exerted on attached, escaping and free-floating passive prey. Despite initiating the strike further away, fishes can increase peak force on their prey by protruding their jaws towards it, compared with a ‘non-protruding’ state, where the distance to prey remains constant throughout the strike. The force requirements for capturing aquatic prey might have served as a selective factor for the evolution of jaw protrusion in modern fishes.

scholarly journals The origin of a new fin skeleton through tinkering

2015 ◽  
Vol 11 (7) ◽  
pp. 20150415 ◽  
Author(s):  
Thomas A. Stewart
Keyword(s):  
Teleost Fishes ◽  
Regular Pattern ◽  
Developmental Context ◽  
Fin Rays ◽  
Adipose Fin ◽  
Developmental Programme

Adipose fins are positioned between the dorsal and caudal fins of many teleost fishes and primitively lack skeleton. In at least four lineages, adipose fins have evolved lepidotrichia (bony fin rays), co-opting the developmental programme for the dermal skeleton of other fins into this new territory. Here I provide, to my knowledge, the first description of lepidotrichia development in an adipose fin, characterizing the ontogeny of the redtail catfish, Phractocephalus hemioliopterus . Development of these fin rays differs from canonical lepidotrich development in the following four ways: skeleton begins developing in adults, not in larvae; rays begin developing at the fin's distal tip, not proximally; the order in which rays ossify is variable, not fixed; and lepidotrichia appear to grow both proximally and distally, not exclusively proximodistally. Lepidotrichia are often wavy, of irregular thickness and exhibit no regular pattern of segmentation or branching. This skeleton is among the most variable observed in a vertebrate appendage, offering a unique opportunity to explore the basis of hypervariation, which is generally assumed to reflect an absence of function. I argue that this variation reflects a lack of canalization as compared with other, more ancient lepidotrichs and suggest developmental context can affect the morphology of serial homologues.

scholarly journals Long-term molecular evolutionary rate determines intraspecific genetic diversity

2019 ◽  
Author(s):  
Jiaqi Wu ◽  
Takahiro Yonezawa ◽  
Hirohisa Kishino
Keyword(s):  
Genetic Diversity ◽  
De Novo ◽  
Early Stage ◽  
Morphological Evolution ◽  
Biological Traits ◽  
Gene Trees ◽  
Intraspecific Genetic Diversity ◽  
Molecular Evolutionary Rates ◽  
Species Specific

AbstractWhat determines genetic diversity and how it connects to the various biological traits is unknown. In this work, we offer answers to these questions. By comparing genetic variation of 14,671 mammalian gene trees with thousands of individual genomes of human, chimpanzee, gorilla, mouse and dog/wolf, we found that intraspecific genetic diversity is determined by long-term molecular evolutionary rates, rather than de novo mutation rates. This relationship was established during the early stage of mammalian evolution. Expanding this new finding, we developed a method to detect fluctuations of species-specific selection on genes as the deviations of intra-species genetic diversity predicted from long-term rates. We show that the evolution of epithelial cells, rather than of connective tissue, mainly contributes to morphological evolution of different species. For humans, evolution of the immune system and selective sweeps subjected by infectious diseases are most representative of adaptive evolution.

scholarly journals Anti-predator defence drives parallel morphological evolution in flea beetles

2010 ◽  
Vol 278 (1715) ◽  
pp. 2133-2141 ◽  
Author(s):  
Deyan Ge ◽  
Douglas Chesters ◽  
Jesús Gómez-Zurita ◽  
Lijie Zhang ◽  
Xingke Yang ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Ecological Factors ◽  
Taxonomic Significance ◽  
Elliptic Fourier Analysis ◽  
Leaf Beetles ◽  
Diversification Rates ◽  
Flea Beetles ◽  
Repeated Evolution ◽  
Outline Analysis ◽  
Predator Defence

Complex morphological or functional traits are frequently considered evolutionarily unique and hence useful for taxonomic classification. Flea beetles (Alticinae) are characterized by an extraordinary jumping apparatus in the usually greatly expanded femur of their hind legs that separates them from the related Galerucinae. Here, we examine the evolution of this trait using phylogenetic analysis and a time-calibrated tree from mitochondrial ( rrnL and cox1 ) and nuclear (small subunits and large subunits) genes, as well as morphometrics of femora using elliptic Fourier analysis. The phylogeny strongly supports multiple independent origins of the metafemoral spring and therefore rejects the monophyly of Alticinae, as defined by this trait. Geometric outline analysis of femora shows the great plasticity of this structure and its correlation with the type and diversity of the metafemoral springs. The recognition of convergence in jumping apparatus now resolves the long-standing difficulties of Galerucinae–Alticinae classification, and cautions against the value of trait complexity as a measure of taxonomic significance. The lineage also shows accelerated species diversification rates relative to other leaf beetles, which may be promoted by the same ecological factors that also favour the repeated evolution of jumping as an anti-predation mechanism.

scholarly journals Functional morphology of the fin rays of teleost fishes

2013 ◽  
Vol 274 (9) ◽  
pp. 1044-1059 ◽  
Author(s):  
Brooke E. Flammang ◽  
Silas Alben ◽  
Peter G.A. Madden ◽  
George V. Lauder
Keyword(s):  
Functional Morphology ◽  
Teleost Fishes ◽  
Fin Rays

scholarly journals Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Catherine G. Klein ◽  
Davide Pisani ◽  
Daniel J. Field ◽  
Rebecca Lakin ◽  
Matthew A. Wills ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Teleost Fishes ◽  
Mass Extinctions ◽  
Dispersal Patterns ◽  
Extinction Event ◽  
Living Species ◽  
Rapid Diversification ◽  
Molecular Dataset ◽  
Global Biodiversity ◽  
Mass Extinction Event

AbstractMass extinctions have repeatedly shaped global biodiversity. The Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of numerous vertebrate groups, and its aftermath saw the rapid diversification of surviving mammals, birds, frogs, and teleost fishes. However, the effects of the K-Pg extinction on the evolution of snakes—a major clade of predators comprising over 3,700 living species—remains poorly understood. Here, we combine an extensive molecular dataset with phylogenetically and stratigraphically constrained fossil calibrations to infer an evolutionary timescale for Serpentes. We reveal a potential diversification among crown snakes associated with the K-Pg mass extinction, led by the successful colonisation of Asia by the major extant clade Afrophidia. Vertebral morphometrics suggest increasing morphological specialisation among marine snakes through the Paleogene. The dispersal patterns of snakes following the K-Pg underscore the importance of this mass extinction event in shaping Earth’s extant vertebrate faunas.

scholarly journals Differential Gene Expression Between Polymorphic Zooids of the Marine Bryozoan Bugulina stolonifera

2020 ◽  
Vol 10 (10) ◽  
pp. 3843-3857
Author(s):  
Kira A. Treibergs ◽  
Gonzalo Giribet
Keyword(s):  
Gene Expression ◽  
Division Of Labor ◽  
Differential Gene Expression ◽  
High Throughput Sequencing ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Cdna Libraries ◽  
Living Species ◽  
Differential Gene

Bryozoans are a diverse phylum of marine and freshwater colonial invertebrates containing approximately 6,300 described living species. Bryozoans grow by budding new physiologically connected colony members (zooids) from a founding individual that forms from a metamorphosed larva. In some species these zooids come in different shapes and sizes and are specialized to serve different tasks within the colony. A complex interaction of genotype, environment, and developmental pathway shapes zooid fate, however, the specific mechanisms underlying the establishment of this division of labor remain unknown. Here, the first characterization of differential gene expression between polymorphic zooids of a bryozoan colony is presented. The development of different zooid types of lab-cultured Bugulina stolonifera colonies including feeding autozooids, avicularia (derived non-feeding zooids that are homologous to feeding autozooids but shaped like a bird’s beak), and rhizoids (a branching network of non-feeding anchoring zooids) was explored using RNA sequencing, de novo transcriptome assembly, and differential gene expression analyses. High throughput sequencing of cDNA libraries yielded an average of 14.9 ± 1.3 (SE) million high-quality paired-end reads per sample. Data for the first de novo transcriptome assemblies of B. stolonifera and the first characterization of genes involved in the formation and maintenance of zooid types within a bryozoan colony are presented. In a comparison between autozooid and avicularium tissues, 1,097 significant differentially expressed genes were uncovered. This work provides a much-needed foundation for understanding the mechanisms involved in the development of polymorphic zooids and the establishment of division of labor in bryozoans.

scholarly journals Generation of the squamous epithelial roof of the 4th ventricle

2018 ◽  
Author(s):  
Florent Campo-Paysaa ◽  
Jonathan DW Clarke ◽  
Richard JT Wingate
Keyword(s):  
Cell Fate ◽  
Squamous Epithelium ◽  
De Novo ◽  
Dorsal Midline ◽  
Direct Transformation ◽  
Squamous Cells ◽  
Roof Plate ◽  
The Veil ◽  
Rhombic Lip ◽  
4Th Ventricle

SummaryWe use the transparency of zebrafish embryos to reveal the de novo generation of a simple squamous epithelium and identify the cellular architecture in the epithelial transition zone that ties this squamous epithelium to the columnar neuroepithelium within the embryo’s brain. The simple squamous epithelium of the rhombencephalic roof plate is pioneered by distinct mesenchymal cells at the dorsal midline of the neural tube. Subsequently a progenitor zone is established at the interface between columnar epithelium of the rhombic lip and the expanding squamous epithelium of the roof plate. Surprisingly this interface consists of a single progenitor cell type that we have named the veil cell. Veil cells express gdf6a and constitute a lineage restricted stem zone that generates the squamous roof plate by direct transformation and asymmetrically fated divisions. Experimental restriction of roof plate expansion leads to extrusion of veil cell daughters and squamous cells, suggesting veil cell fate is regulated by the space available for roof plate growth.

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