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Axial Skeleton

The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Laura Ab Wilson – 1st expert on this subject based on the ideXlab platform

  • Regionalization of the Axial Skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes?
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts. Results We report that in five of the clades surveyed, Lepisosteidae, Esocidae, Belonidae, Sphyraenidae and Fistulariidae, vertebrae are added preferentially to the abdominal region. In Lepisosteidae, Esocidae, and Belonidae, increasing abdominal vertebral count was also significantly related to increasing fineness ratio, a measure of elongation. Two clades did not preferentially add abdominal vertebrae: Saurichthyidae and Aulostomidae. Both of these groups show the development of a novel caudal region anterior to the insertion of the anal fin, morphologically differentiated from more posterior caudal vertebrae. Conclusions The preferential addition of abdominal vertebrae in fishes with an elongate body shape is consistent with the existence of a conservative positioning module formed by the boundary between the abdominal and caudal vertebral regions and the anterior insertion of the anal fin. Dissociation of this module is possible, although less probable than changes in the independently evolving abdominal region. Dissociation of the Axial Skeleton-median fin module leads to increased regionalization within the caudal vertebral column, something that has evolved several times in bony fishes, and may be homologous with the sacral region of tetrapods. These results suggest that modularity of the Axial Skeleton may result in somewhat predictable evolutionary outcomes in bony fishes.

  • regionalization of the Axial Skeleton in the ambush predator guild are there developmental rules underlying body shape evolution in ray finned fishes
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background
    A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts.

  • Regionalization of the Axial Skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes?
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background
    A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts.

Erin E Maxwell – 2nd expert on this subject based on the ideXlab platform

  • Regionalization of the Axial Skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes?
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts. Results We report that in five of the clades surveyed, Lepisosteidae, Esocidae, Belonidae, Sphyraenidae and Fistulariidae, vertebrae are added preferentially to the abdominal region. In Lepisosteidae, Esocidae, and Belonidae, increasing abdominal vertebral count was also significantly related to increasing fineness ratio, a measure of elongation. Two clades did not preferentially add abdominal vertebrae: Saurichthyidae and Aulostomidae. Both of these groups show the development of a novel caudal region anterior to the insertion of the anal fin, morphologically differentiated from more posterior caudal vertebrae. Conclusions The preferential addition of abdominal vertebrae in fishes with an elongate body shape is consistent with the existence of a conservative positioning module formed by the boundary between the abdominal and caudal vertebral regions and the anterior insertion of the anal fin. Dissociation of this module is possible, although less probable than changes in the independently evolving abdominal region. Dissociation of the Axial Skeleton-median fin module leads to increased regionalization within the caudal vertebral column, something that has evolved several times in bony fishes, and may be homologous with the sacral region of tetrapods. These results suggest that modularity of the Axial Skeleton may result in somewhat predictable evolutionary outcomes in bony fishes.

  • regionalization of the Axial Skeleton in the ambush predator guild are there developmental rules underlying body shape evolution in ray finned fishes
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background
    A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts.

  • Regionalization of the Axial Skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes?
    BMC Evolutionary Biology, 2013
    Co-Authors: Erin E Maxwell, Laura Ab Wilson

    Abstract:

    Background
    A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The Axial Skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the Axial Skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts.

Yuji Makino – 3rd expert on this subject based on the ideXlab platform

  • Developmental biology and etiology of Axial Skeleton: Lessons from a mouse model of spondylocostal dysostosis and spondylothoracic dysostosis
    Journal of Oral Biosciences, 2013
    Co-Authors: Yuji Makino, Kazuo Kaneko, Akira Yamaguchi, Tadahiro Iimura

    Abstract:

    Abstract Skeletal patterning is tightly linked to embryonic morphogenesis. Accumulated evidence on genotype–phenotype analyses in model animals and human has uncovered molecular signals that participate in skeletal size, shape, and spatial organization. Embryonic morphogenesis endows morphological information to groups of skeletal precursors. Accordingly, some of the congenital skeletal disorders are manifested as defects in embryogenesis prior to skeletal tissue differentiation and pathologically categorized as dysostosis. Spondylocostal dysostosis (SCDO) and spondylothoracic dysostosis (STDO) are skeletal disorders that are highly specific to the Axial Skeleton, vertebrae, and ribs, whose embryonic origin is the segmented mesodermal structure called somite. The genes responsible for these diseases have recently been identified and are operated during somite formation. Current investigations on organogenesis of mouse models of SCDO and STDO uncovered the existence of more complicated regulatory steps for the spatiotemporal organization of the Axial Skeleton than the original view of direct link between morphogenesis and skeletal patterning. Molecular and cellular findings in Axial Skeleton development are expected to contribute to develop more efficient therapeutic strategies against common medical problems.

  • spatiotemporal disorder in the Axial Skeleton development of the mesp2 null mouse a model of spondylocostal dysostosis and spondylothoracic dysostosis
    Bone, 2013
    Co-Authors: Yuji Makino, Yu Takahashi, Rieko Tanabe, Yoshihiro Tamamura, Takashi Watanabe, Mayu Haraikawa, Miwako Hamagaki, Kenji Hata, Jun Kanno

    Abstract:

    Abstract Spondylocostal dysostosis (SCDO) is a genetic disorder characterized by severe malformation of the Axial Skeleton. Mesp2 encodes a basic helix–loop–helix type transcription factor that is required for somite formation. Its human homologue, Mesp2, is a gene affected in patients with SCDO and a related vertebral disorder, spondylothoracic dysostosis (STDO). This work investigated how the loss of Mesp2 affects Axial Skeleton development and causes the clinical features of SCDO and STDO. We first confirmed, by three-dimensional computed tomography scanning, that Mesp2-null mice exhibited mineralized tissue patterning resembling the radiological features of SCDO and STDO. Histological observations and in situ hybridization probing for extracellular matrix molecules demonstrated that the developing vertebral bodies in Mesp2-null mice were extensively fused with rare insertions of intervertebral tissue. Unexpectedly, the intervertebral tissues were mostly fused longitudinally in the vertebral column, instead of exhibiting extended formation, as was expected based on the caudalized properties of Mesp2-null somite derivatives. Furthermore, the differentiation of vertebral body chondrocytes in Mesp2-null mice was spatially disordered and largely delayed, with an increased cell proliferation rate. The quantitative three-dimensional immunofluorescence image analyses of phospho-Smad2 and -Smad1/5/8 revealed that these chondrogenic phenotypes were associated with spatially disordered inputs of TGF-β and BMP signaling in the Mesp2-null chondrocytes, and also demonstrated an amorphous arrangement of cells with distinct properties. Furthermore, a significant delay in ossification in Mesp2-null vertebrae was observed by peripheral quantitative computed tomography. The current observations of the spatiotemporal disorder of vertebral organogenesis in the Mesp2-null mice provide further insight into the pathogenesis of SCDO and STDO, and the physiological development of the Axial Skeleton.