scholarly journals Developmental Evolution of Hypaxial Muscles: Insights From Cyclostomes and Chondrichthyans

2021 ◽  
Vol 9 ◽  
Author(s):  
Rie Kusakabe ◽  
Masako Tanaka ◽  
Shigeru Kuratani
Keyword(s):  
Temporal Order ◽  
Evolutionary Mechanisms ◽  
Evolutionary Pathway ◽  
Primitive Form ◽  
Developmental Evolution ◽  
Skeletal Musculature ◽  
Sequential Addition ◽  
Living Species ◽  
Body Patterns ◽  
And Function

Jawed vertebrates possess two distinct groups of muscles in the trunk (epaxial and hypaxial muscles) primarily defined by the pattern of motor innervation from the spinal cord. Of these, the hypaxial group includes muscles with highly differentiated morphology and function, such as the muscles associated with paired limbs, shoulder girdles and tongue/infrahyoid (hypobranchial) muscles. Here we summarize the latest findings on the evolutionary mechanisms underlying the morphological variety of hypaxial musculature, with special reference to the molecular insights obtained from several living species that diverged early in vertebrate evolution. Lampreys, extant jawless vertebrates, lack many of derived traits characteristic of the gnathostomes, such as jaws, paired fins and epaxial/hypaxial distinction of the trunk skeletal musculatures. However, these animals possess the primitive form of the hypobranchial muscle. Of the gnathostomes, the elasmobranchs exhibit developmental mode of hypaxial muscles that is not identical to that of other gnathostomes in that the muscle primordia relocate as coherent cell aggregates. Comparison of expression of developmental genes, including Lbx genes, has delineated the temporal order of differentiation of various skeletal muscles, such as the hypobranchial, posterior pharyngeal and cucullaris (trapezius) muscles. We have proposed that the sequential addition of distal muscles, associated with expression of duplicated Lbx genes, promoted the elaboration of skeletal musculature. These analyses have revealed the framework of an evolutionary pathway that gave rise to the morphological complexity and diversity of vertebrate body patterns.

scholarly journals Rewiring of an ancestral Tbx1/10-Ebf-Mrf network for pharyngeal muscle specification in distinct embryonic lineages

2016 ◽  
Author(s):  
Theadora Tolkin ◽  
Lionel Christiaen
Keyword(s):  
Molecular Basis ◽  
Skeletal Muscles ◽  
Temporal Order ◽  
Regulatory Factor ◽  
Pharyngeal Muscle ◽  
Linear Cascade ◽  
Founder Cells ◽  
Muscle Groups ◽  
And Function

Skeletal muscles arise from diverse embryonic origins, yet converge on common regulatory programs involving muscle regulatory factor (MRF)-family genes. Here, we compare the molecular basis of myogenesis in two separate muscle groups in the simple chordate Ciona: the atrial and oral siphon muscles. Here, we describe the ontogeny of OSM progenitors and characterize the clonal origins of OSM founders to compare mechanisms of OSM specification to what has been established for ASM. We determined that, as is the case in the ASM, Ebf and Tbx1/10 are both expressed and function upstream of Mrf in the OSM founder cells. However, regulatory relationships between Tbx1/10, Ebf and Mrf differ between the OSM and ASM lineages: while Tbx1/10, Ebf and Mrf form a linear cascade in the ASM, Ebf and Tbx1/10 are expressed in the inverse temporal order and are required together in order to activate Mrf in the OSM founder cells.

Comparison of the Pectoral and Pelvic Skeletons and of some other Bones and their Phylogenetic Implications in the Aulorhynchidae and Gasterosteidae (Pisces)

1971 ◽  
Vol 28 (3) ◽  
pp. 427-442 ◽  
Author(s):  
Joseph S. Nelson
Keyword(s):  
Mosaic Pattern ◽  
Primitive Form ◽  
Phylogenetic Implications ◽  
Living Species

Study of the pectoral and pelvic skeletons and some other bones in recognized species of the seven genera comprising the related families Aulorhynchidae (tubesnouts) and Gasterosteidae (sticklebacks) showed that the two families differ in several respects, with no one living species appearing to be intermediate. The genera Aulorhynchus, Aulichthys, Spinachia, Apeltes, and Gasterosteus each have distinctive characteristics not found in any other genus of the two families. Gasterosteus wheatlandi is the only species of the two families that lacks both the posttemporal and the supracleithrum. The interrelations of the genera form a mosaic pattern and there is no acceptable basis in the characters examined for postulating a phylogeny within the Gasterosteidae or for selecting a living species as being a primitive form or the most closely allied to the Aulorhynchidae.

Convergence, parallelism, and function of extreme parietal callus in diverse groups of Cenozoic Gastropoda

Paleobiology ◽  
2020 ◽  
pp. 1-26
Author(s):  
Carlie Pietsch ◽  
Brendan M. Anderson ◽  
Lauren M. Maistros ◽  
Ethan C. Padalino ◽  
Warren D. Allmon
Keyword(s):  
Body Size ◽  
Functional Ecology ◽  
Low Density ◽  
Shell Microstructure ◽  
Shell Surface ◽  
Microscopy Imaging ◽  
Living Species ◽  
Essential Contribution ◽  
And Function ◽  
Diverse Groups

Abstract We use scanning electron microscopy imaging to examine the shell microstructure of fossil and living species in five families of caenogastropods (Strombidae, Volutidae, Olividae, Pseudolividae, and Ancillariidae) to determine whether parallel or convergent evolution is responsible for the development of a unique caenogastropod trait, the extreme parietal callus (EPC). The EPC is defined as a substantial thickening of both the spire callus and the callus on the ventral shell surface such that it covers 50% or more of the surface. Caenogastropods as a whole construct the EPC convergently, using a variety of low-density, poorly organized microstructures that are otherwise uncommon in caenogastropod non-callus shell construction. Within clades, however, we see evidence for parallelism in decreased regulation in both the shell and callus microstructure. Low-density and poorly ordered microstructure—such as used for the EPC—uses less organic scaffolding and is less energetically expensive than normal shell microstructure. This suggests the EPC functions to rapidly and inexpensively increase shell thickness and overall body size. Tests of functional ecology suggest that the EPC might function both to defend against crushing predation through increased body size and dissipation of forces while aiding in shell orientation of highly mobile gastropods. These interpretations hinge on the current phylogenetic placement of caenogastropod families, emphasizing the essential contribution of phylogeny when interpreting homoplasy.

Flowering of Australia's Rainforests

2021 ◽  
Author(s):  
Geoff Williams
Keyword(s):  
Climate Change ◽  
Habitat Restoration ◽  
Evolutionary Pathway ◽  
Current State ◽  
New Information ◽  
Major Species ◽  
Conservation Concern ◽  
And Function ◽  
The Impact ◽  
Pollinator Fauna

The Flowering of Australia’s Rainforests provides a comprehensive introduction to the pollination ecology, evolution and conservation of Australian rainforest plants, with particular emphasis on subtropical rainforests and their associated pollinators. This significantly expanded second edition includes new information on the impact of climate change, fire, fragmentation and invasive species. Rainforests continue to be a focus of global conservation concern, not only from threats to biodiversity in general, but to pollinators specifically. Within Australia, this has been emphasised by recent cataclysmic fire impacts, ongoing extreme drought events, and the wider consideration of climate change. This second edition strengthens coverage of these issues beyond that of the first edition. The Flowering of Australia’s Rainforests makes timely contributions to our understanding of the nature and function of the world’s pollinator fauna, plant-reproduction dependencies, and the evolutionary pathway that has brought them to their current state and function. Illustrated with 150 colour plates of major species and rainforest formations, this reference work will be of value to ecologists and field naturalists, botanists, conservation biologists, ecosystem managers and community groups involved in habitat restoration.

scholarly journals Alan Cyril Walker. 23 August 1938—20 November 2017

2019 ◽  
Vol 67 ◽  
pp. 449-467
Author(s):  
Leslea J. Hlusko ◽  
Peter S. Ungar
Keyword(s):  
Homo Erectus ◽  
Early Adopter ◽  
Dental Microwear ◽  
Form And Function ◽  
Microwear Analysis ◽  
Living Species ◽  
Late Twentieth ◽  
And Function ◽  
Late Twentieth Century ◽  
Bony Morphology

Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps in our knowledge of primate evolution, such as elucidating the Miocene world of Proconsul and finding the transitional ‘Black Skull’ of Australopithecus aethiopicus and the skeleton of a Homo erectus boy. In addition to discovering these remarkable fossils, Alan was essential in bringing a palaeobiological approach to the laboratory interpretation of their bony morphology. He used the relationships between form and function in living species as a baseline for understanding the past, he pioneered dental microwear analysis to infer diet and was an early-adopter of the use of microCT to explore the internal structure of primate ear bones. Beyond these scientific accomplishments, however, it was Alan's grace and generosity that truly set him apart from his peers. As the patriarch of an extensive intellectual family of students, postdocs and colleagues, Alan taught by example how to be intellectually creative, brave, meticulous, generous and kind. His legacy will long be felt in both the science and the culture of palaeoanthropology.

scholarly journals Lytic bacteriophage have diverse indirect effects in a synthetic cross-feeding community

2019 ◽  
Author(s):  
Lisa Fazzino ◽  
Jeremy Anisman ◽  
Jeremy M. Chacón ◽  
Richard H. Heineman ◽  
William R. Harcombe
Keyword(s):  
Microbial Communities ◽  
Indirect Effects ◽  
Microbial Interactions ◽  
Lytic Bacteriophage ◽  
Evolutionary Mechanisms ◽  
E Coli ◽  
Final Yield ◽  
Community Growth ◽  
And Function ◽  
T7 Phage

AbstractBacteriophage shape the composition and function of microbial communities. Yet, it remains difficult to predict the effect of phage on microbial interactions. Specifically, little is known about how phage influence mutualisms in networks of cross-feeding bacteria. We modeled the impacts of phage in a synthetic microbial community in whichEscherichia coliandSalmonella entericaexchange essential metabolites. In this model, phage attack of either species was sufficient to inhibit both members of the mutualism; however, the evolution of phage resistance ultimately allowed both species to attain yields similar to those observed in the absence of phage. In laboratory experiments, attack ofS. entericawith P22virphage followed these modeling expectations of delayed community growth with little change in the final yield of bacteria. In contrast, whenE. coliwas attacked with T7 phage,S. enterica, the non-host species, reached higher yields compared to no-phage controls. T7 increased non-host yield by releasing consumable cell debris and by driving evolution of phage resistantE. colithat secreted more carbon. Additionally,E. colievolved only partial resistance, increasing the total amount of lysed cells available forS. entericato consume. Our results demonstrate that phage can have extensive indirect effects in microbial communities, and that the nature of these indirect effects depends on metabolic and evolutionary mechanisms.

scholarly journals Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives

2010 ◽  
Vol 277 (1685) ◽  
pp. 1139-1147 ◽  
Author(s):  
Marcelo R. Sánchez-Villagra
Keyword(s):  
Life History ◽  
Developmental Plasticity ◽  
Ecological Factors ◽  
Evolutionary Mechanisms ◽  
Allometric Relations ◽  
Living Species ◽  
New Space ◽  
Absolute Age ◽  
Growth Features ◽  
Indirect Information

The study of fossilized ontogenies in mammals is mostly restricted to postnatal and late stages of growth, but nevertheless can deliver great insights into life history and evolutionary mechanisms affecting all aspects of development. Fossils provide evidence of developmental plasticity determined by ecological factors, as when allometric relations are modified in species which invaded a new space with a very different selection regime. This is the case of dwarfing and gigantism evolution in islands. Skeletochronological studies are restricted to the examination of growth marks mostly in the cement and dentine of teeth and can provide absolute age estimates. These, together with dental replacement data considered in a phylogenetic context, provide life-history information such as maturation time and longevity. Palaeohistology and dental replacement data document the more or less gradual but also convergent evolution of mammalian growth features during early synapsid evolution. Adult phenotypes of extinct mammals can inform developmental processes by showing a combination of features or levels of integration unrecorded in living species. Some adult features such as vertebral number, easily recorded in fossils, provide indirect information about somitogenesis and hox-gene expression boundaries. Developmental palaeontology is relevant for the discourse of ecological developmental biology, an area of research where features of growth and variation are fundamental and accessible among fossil mammals.

Evolution of a highly active and enantiospecific metalloenzyme from short peptides

Science ◽  
2018 ◽  
Vol 362 (6420) ◽  
pp. 1285-1288 ◽  
Author(s):  
Sabine Studer ◽  
Douglas A. Hansen ◽  
Zbigniew L. Pianowski ◽  
Peer R. E. Mittl ◽  
Aaron Debon ◽  
...  
Keyword(s):  
Chemical Reactivity ◽  
Catalytic Efficiency ◽  
Simultaneous Optimization ◽  
Zinc Binding ◽  
Short Peptides ◽  
Enzyme Design ◽  
Evolutionary Pathway ◽  
Highly Active ◽  
And Function ◽  
Order Structures

Primordial sequence signatures in modern proteins imply ancestral origins tracing back to simple peptides. Although short peptides seldom adopt unique folds, metal ions might have templated their assembly into higher-order structures in early evolution and imparted useful chemical reactivity. Recapitulating such a biogenetic scenario, we have combined design and laboratory evolution to transform a zinc-binding peptide into a globular enzyme capable of accelerating ester cleavage with exacting enantiospecificity and high catalytic efficiency (kcat/KM~ 106M−1s−1). The simultaneous optimization of structure and function in a naïve peptide scaffold not only illustrates a plausible enzyme evolutionary pathway from the distant past to the present but also proffers exciting future opportunities for enzyme design and engineering.

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