Body Plan of Sea Urchin Embryo: An Ancestral Type Animal

Akasaka, Koji; Shimada, Hiraku

doi:10.2108/zsj.18.757

Cited by 4 publications

(4 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other recent molecular studies substantiate our observation that Hemicentrotus, the closest relative of Strongylocentrotus intermedius, is a member of the genus Strongylocentrotus (Biermann 1998;Meeds et al 2001). Hemicentrotus is the main echinoid target of developmental research in Japan, and a large number of studies have examined the early embryology and regulation of development in this species (Akasaka and Shimada 2001;Kitamura et al 2002;Tokuoka et al 2002). The close relationship between Hemicentrotus and the other major research vehicle, S. purpuratus, makes it likely that results from these two species will be more similar than results from S. purpuratus and S. franciscanus.…”

Section: Phylogeny Of Strongylocentrotid Sea Urchinssupporting

confidence: 79%

“…This species was once placed in the genus Strongylocentrotus by Mortensen in 1903, but he later included it in a monotypic genus Hemicentrotus because it had exactly three tube feet pore pairs per arch in test plates rather than three to four as in S. intermedius (Mortensen 1943;Jensen 1974). Hemicentrotus is the main echinoid target of developmental research in Japan, and a large number of studies have examined the early embryology and regulation of development in this species (Akasaka and Shimada 2001;Kitamura et al 2002;Tokuoka et al 2002). Other recent molecular studies substantiate our observation that Hemicentrotus, the closest relative of Strongylocentrotus intermedius, is a member of the genus Strongylocentrotus (Biermann 1998;Meeds et al 2001).…”

Section: Phylogeny Of Strongylocentrotid Sea Urchinsmentioning

confidence: 99%

See 1 more Smart Citation

Phylogeny and development of marine model species: strongylocentrotid sea urchins

Biermann

Kessing

Palumbi

2003

Evolution and Development

View full text Add to dashboard Cite

The phylogenetic relationships of ten strongy-locentrotid sea urchin species were determined using mitochondrial DNA sequences. This phylogeny provides a backdrop for the evolutionary history of one of the most studied groups of sea urchins. Our phylogeny indicates that a major revision of this group is in order. All else remaining unchanged, it supports the inclusion of three additional species into the genus Strongylocentrotus (Hemicentrotus pulcherrimus, Allocentrotus fragilis, and Pseudocentrotus depressus). All were once thought to be closely related to this genus, but subsequent revisions separated them into other taxonomic groupings. Most strongylocentrotid species are the result of a recent burst of speciation in the North Pacific that resulted in an ecological diversification. There has been a steady reduction in the complexity of larval skeletons during the expansion of this group. Gamete attributes like egg size, on the other hand, are not correlated with phylogenetic position. In addition, our results indicate that the rate of replacement substitutions is highly variable among phylogenetic lineages. The branches leading to S. purpuratus and S. franciscanus were three to six times longer than those leading to closely related species.

show abstract

Section: Phylogeny Of Strongylocentrotid Sea Urchinssupporting

confidence: 79%

Section: Phylogeny Of Strongylocentrotid Sea Urchinsmentioning

confidence: 99%

Phylogeny and development of marine model species: strongylocentrotid sea urchins

Biermann

Kessing

Palumbi

2003

Evolution and Development

View full text Add to dashboard Cite

show abstract

“…According to the larva-first school (Nielsen 2000;Akasaka and Shimada 2001), the original metazoans were sexually mature creatures resembling pelagic larvae that only later became the immature stage when breeding adults were added terminally to the life history. In contrast, the direct-development-first school (Minelli 2009;Lacalli 2010) proposes that adults that were originally benthic and that a larval stage was only later interpolated into the life history.…”

Section: Garstang's Scenarios In Light Of Molecular Biologymentioning

confidence: 99%

Walter Garstang: a retrospective

Holland

2011

Theory Biosci.

View full text Add to dashboard Cite

Although, Walter Garstang died over 60 years ago, his work is still cited--sometimes praised, but sometimes belittled. On the negative side, he often appropriated ideas of others without attribution, ignored earlier studies conflicting with his theories, and clung to notions like inheritance of acquired characters, progressive evolution, and saltation after many of his contemporaries were advancing toward the modern synthesis. Moreover, his evolutionary scenarios--especially his derivation of vertebrates from a sessile ascidian--have not been well supported by recent work in developmental genetics and molecular phylogenetics. On the positive side, Garstang firmly established several points of view that remain useful in the age of evolutionary development (evo-devo). He popularized the valid idea that adaptive changes in larvae combined with shifts in developmental timing (heterochrony) could radically change adult morphology and provide an escape from overspecialization. Moreover, his re-statement of the biogenetic law is now widely accepted: namely, that recapitulation results when characters at one stage of development are required for the correct formation of other characters at subsequent stages (his stepping stone model). In other words, ontogeny creates phylogeny because some developmental features are constraints, favoring particular evolutionary outcomes while excluding others. This viewpoint is a useful basis for advancing concepts of homology and for comparing the phylogeny of ontogenies across a series of animals to ascertain the timing and the nature of the underlying ontogenetic changes.

show abstract

“…For example, Xenopus embryos are dorsalized or ventralized upon the application of LiCl (Kao et al , 1986;Regen and Steinhardt, 1988;Yamaguchi and Shinagawa, 1989). Although LiCl is suggested to affect the Wnt signaling system (McGrew et al , 1992;Brannon and Kimelman, 1996;Vonica et al , 2000;Akasaka and Shimada, 2001), it is still unclear why and how LiCl influences many aspects of morphogenesis and cell differentiation. Disruption of axial structure caused with LiCl in mouse embryo is not mediated through the beta-catenin/Lef-1 pathway involved in the Wnt signaling system (Rogers and Varmuza, 2000).…”

Section: Licl Strengthens Cell Contactmentioning

confidence: 99%