The evolutionary origin of chordate segmentation: revisiting the enterocoel theory

@article{Onai2018TheEO,
  title={The evolutionary origin of chordate segmentation: revisiting the enterocoel theory},
  author={Takayuki Onai},
  journal={Theory in Biosciences},
  year={2018},
  volume={137},
  pages={1-16}
}
  • T. Onai
  • Published 2018
  • Biology, Medicine, Computer Science
  • Theory in Biosciences
One of the definitive characteristics of chordates (cephalochordates, vertebrates) is the somites, which are a series of paraxial mesodermal blocks exhibiting segmentation. The presence of somites in the basal chordate amphioxus and in vertebrates, but not in tunicates (the sister group of vertebrates), suggests that the tunicates lost the somites secondarily. Somites are patterned from anterior to posterior during embryogenesis. How such a segmental pattern evolved from deuterostome ancestors… Expand
Morphogenetic mechanisms forming the notochord rod: The turgor pressure‐sheath strength model
  • Yuuri Yasuoka
  • Biology, Medicine
  • Development, growth & differentiation
  • 2020
TLDR
Biological features specific to notochord cells, which have been well studied using clawed frogs, zebrafish, and tunicates, are focused on, and turgor pressure‐sheath strength model, proposed in this review, is examined in light of quantitative molecular data and mathematical simulations, illuminating the evolutionary origin of theNotochord. Expand
Enhancer evolution in chordates: Lessons from functional analyses of cephalochordate cis‐regulatory modules
  • Yuuri Yasuoka
  • Biology, Medicine
  • Development, growth & differentiation
  • 2020
TLDR
Accumulating data from functional studies analyzing amphioxus cis‐regulatory modules (CRMs) in model systems of other chordate groups help to solve fundamental questions of chordate evolution, such as neural crest cells, placodes, a forebrain/midbrain, and genome duplication. Expand
A stochastic differential game approach toward animal migration
  • H. Yoshioka
  • Medicine, Computer Science
  • Theory in Biosciences
  • 2019
TLDR
This paper theoretically suggests that the sub-additivity of the performance index, the index to be optimized through the migration, critically affects the resulting strategy, and the computational results with the established scheme are consistent with the theoretical predictions and support importance of the sub theadditivity property. Expand
Periodic Orbits and Global Stability for a Discontinuous SIR Model with Delayed Control
We propose and analyse a mathematical model for infectious disease dynamics with a discontinuous control function, where the control is activated with some time lag after the density of the infectedExpand
Constrained control approach for monotone systems: application to tumour chemotherapy
TLDR
This study develops a set-point regulation approach for a certain class of systems subject to input and state constraints which leads to closed-loop strongly monotone systems and finds some well-organised controllers that satisfy the mentioned control objectives. Expand

References

SHOWING 1-10 OF 100 REFERENCES
Amphioxus and the evolution of head segmentation.
TLDR
Studies of developmental genes in amphioxus and vertebrates, which have demonstrated conservation of the mechanisms of anterior-posterior patterning in the two groups, have shed new light on this controversy. Expand
Hox gene expression in the hemichordate Saccoglossus kowalevskii and the evolution of deuterostome nervous systems.
TLDR
The nested ectodermal expression of hox gene expression during the development of the direct-developing hemichordate Saccoglossus kowalevskii suggest that they play a general patterning role in the anterior/posterior regionalization of the ectoderm of bilaterians rather than being uniquely associated with the development and evolution of central nervous systems. Expand
Conservation of Brachyury (T) genes in amphioxus and vertebrates: developmental and evolutionary implications.
TLDR
It is proposed that roles of Brachyury in notochord differentiation are more ancient than roles in mesoderm formation, and that the latter are shared by cephalochordates and all vertebrates. Expand
On the origin of vertebrate somites
TLDR
It is proposed that Notch signalling and the Fringe/Delta cassette for dorso-ventral boundary formation in the archenteron that separates somites from the gut in an amphioxus-like ancestral chordate were co-opted for anteroposterior segmental boundary Formation in the vertebrate anterior PSM during evolution. Expand
Is the vertebrate head segmented?—evolutionary and developmental considerations
  • S. Kuratani
  • Biology, Medicine
  • Integrative and comparative biology
  • 2008
TLDR
The vertebrate head is characterized by a lack of segmental generative constraint in its mesoderm, because Classical segmental theories are now refuted because they attempted to equate the vertebrates head with that of the amphioxus, whose rostral somites are considered primary segments, which are absent from vertebrates. Expand
What are Head Cavities? — A History of Studies on Vertebrate Head Segmentation
TLDR
Molecular developmental data have shed new light on the vertebrate head problem, explaining that head mesoderm evolved, not by the modification of rostral somites of an amphioxus-like ancestor, but through the polarization of unspecified paraxial mesderm into head Mesoderm anteriorly and trunk somites posteriorly. Expand
Dorsoventral Patterning in Hemichordates: Insights into Early Chordate Evolution
TLDR
It is suggested that the common ancestor of hemichordates and chordates did not use its Bmp-Chordin axis to segregate epidermal and neural ectoderm but to pattern many other dorsoventral aspects of the germ layers, including neural cell fates within a diffuse nervous system. Expand
Ancestral mesodermal reorganization and evolution of the vertebrate head
TLDR
Reorganization of ancient mesoderm was likely involved in the evolution of the vertebrate head and suppression of mesodermal involution in vertebrate embryos by inhibition of convergence and extension recapitulates amphioxus-like dorsal mesod Germ formation. Expand
Early development of cephalochordates (amphioxus)
  • L. Holland, T. Onai
  • Biology, Medicine
  • Wiley interdisciplinary reviews. Developmental biology
  • 2012
TLDR
The Phylum Chordata includes three groups—Vertebrata, Tunicata, and Cephalochordata, where the eggs are small and relatively non‐yolky and the cell fates determined gradually as development proceeds are determined. Expand
A stem-deuterostome origin of the vertebrate pharyngeal transcriptional network
TLDR
The findings suggest that hemichordate and vertebrate gills are homologous as simple endodermal outpockets from the foregut, and that much vertebrate pharyngeal complexity arose coincident with the incorporation of cranial paraxial mesoderm and neural crest-derived mesenchyme within pharynGEal arches along the chordates and vertebrates stems, respectively. Expand
...
1
2
3
4
5
...