Sinistral equal‐size spiral cleavage of the indirectly developing polychaete <i>Hydroides elegans</i>

Arenas-Mena, César

doi:10.1002/dvdy.21164

Cited by 22 publications

(35 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cleavage orientation is typically fixed within species (with occasional reversals), and overwhelmingly clockwise (dextral) going from the four-to eight-cell stage when viewed from the animal pole in fully spirally cleaving groups [69]. Nonetheless, a few examples of invariant sinistral cleavage at the eight-cell stage are known in polychaetes [70], bivalves [71] and sinistrally coiled gastropod species [45,72]. Surprisingly, given the generally determinate cleavage seen in spiralian protostomes [73], the chirality of early cleavage is not fixed in a wide range of taxa (table 3).…”

Section: Stochastic Determination Of Direction Of Asymmetrymentioning

confidence: 99%

What determines direction of asymmetry: genes, environment or chance?

Palmer¹

2016

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

One contribution of 17 to a theme issue 'Provocative questions in left -right asymmetry'. Conspicuous asymmetries seen in many animals and plants offer diverse opportunities to test how the development of a similar morphological feature has evolved in wildly different types of organisms. One key question is: do common rules govern how direction of asymmetry is determined (symmetry is broken) during ontogeny to yield an asymmetrical individual? Examples from numerous organisms illustrate how diverse this process is. These examples also provide some surprising answers to related questions. Is direction of asymmetry in an individual determined by genes, environment or chance? Is direction of asymmetry determined locally (structure by structure) or globally (at the level of the whole body)? Does direction of asymmetry persist when an asymmetrical structure regenerates following autotomy? The answers vary greatly for asymmetries as diverse as gastropod coiling direction, flatfish eye side, crossbill finch bill crossing, asymmetrical claws in shrimp, lobsters and crabs, katydid sound-producing structures, earwig penises and various plant asymmetries. Several examples also reveal how stochastic asymmetry in mollusc and crustacean early cleavage, in Drosophila oogenesis, and in Caenorhabditis elegans epidermal blast cell movement, is a normal component of deterministic development. Collectively, these examples shed light on the role of genes as leaders or followers in evolution.This article is part of the themed issue 'Provocative questions in leftright asymmetry'.

show abstract

Section: Stochastic Determination Of Direction Of Asymmetrymentioning

confidence: 99%

What determines direction of asymmetry: genes, environment or chance?

Palmer¹

2016

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

show abstract

“…In polychaetes with a feeding trochophore, blastomeres A, B, C and D are of equal size (Anderson, 1966). In Hydroides, the D quadrant becomes apparent in the 60-cell embryo after the asymmetric division of 2d2 into the large animal-side descendant 2d21 and the small vegetal-side sister 2d22, whereas the divisions of equivalent blastomeres 2a2, 2b2 and 2c2 are indistinguishable among quadrants (Arenas-Mena, 2007b). It remains untested if equal size in Hydroides corresponds with equal developmental potential.…”

Section: Spiral -Sinistral-equal Cleavage In Hydroides and Early Genementioning

confidence: 99%

“…In Hydroides elegans the spiral cleavage is sinistral: the third cleavage that initiates the "spiral" phase is tilted in a counterclockwise orientation as seen from the animal pole (Arenas-Mena, 2007b). The distribution of dextral and sinistral cleavage among species in the genus remains uncertain.…”

Section: Spiral -Sinistral-equal Cleavage In Hydroides and Early Genementioning

confidence: 99%

“…Subsequently, the transcription factor Tbx2/3 is expressed in dorsal cells of all three germ layers (Arenas-Mena, 2013) in a pattern generally similar to the expression of its sea urchin ortholog, which has a dorsal specification role (Gross, 2003). The conserved expression suggests the possibility of an ancestral role of Tbx2/3 in dorsal specification shared by protostomes and deuterostomes (Arenas-Mena, 2013).In Hydroides elegans the spiral cleavage is sinistral: the third cleavage that initiates the "spiral" phase is tilted in a counterclockwise orientation as seen from the animal pole (Arenas-Mena, 2007b). The distribution of dextral and sinistral cleavage among species in the genus remains uncertain.…”

mentioning

confidence: 90%

“…The animal-vegetal compartments are partially blurred by animal cap cells that apparently migrate from the animal to the vegetal hemispheres through a small dorsal gap in the ciliary band (Mead, 1897;Treadwell, 1901;Arenas-Mena and Wong, 2007). Subsequent to spiral cleavage, gastrulation and ectoderm (Anderson, 1966 (Anderson, 1966;Arenas-Mena, 2007b). a,…”

mentioning

confidence: 99%

See 2 more Smart Citations

Development of a feeding trochophore in the polychaete Hydroides elegans

Arenas-Mena¹,

Li²

2014

Int. J. Dev. Biol.

Self Cite

View full text Add to dashboard Cite

Hydroides elegans is an indirectly developing polychaete with equal spiral cleavage, gastrulation by invagination, and a feeding trochophore. Expression of several transcription factors and differentiation genes has been characterized. Comparative analysis reveals evolutionarily conserved roles. For example, the synexpression of transcription factors FoxA and Brachyury suggests homology of primary and secondary gut openings in protostomes and deuterostomes, and the expression of Sall suggests similar regulatory controls in the posterior growth zone of bilaterians. Differences in gene expression suggest regulatory differences control gastrulation by invagination in polychaetes with a feeding trochophore and gastrulation by epiboly in polychaetes without a feeding trochophore. Association of histone variant H2A.Z with transcriptional potency and its expression suggest a developmental role during both embryogenesis and the larva-to-adult transformation. Methods are being developed for experimental exploration of the gene regulatory networks involved in trochophore development in Hydroides. It is unknown if polychaete feeding trochophores evolved from a larval stage already present in the life cycle of the last common ancestor of protostomes and deuterostomes. Previous evolutionary scenarios about larval origins overemphasize the discontinuity between larval and adult development and require the early evolution of undifferentiated and transcriptionally potent "set aside" cells. Indirect development may proceed by developmental remodeling of differentiated cells and could have evolved after gradual transformation of juveniles into larvae; undifferentiated and transcriptionally potent cells would have evolved secondarily. Comprehensive characterization of gene regulatory networks for feeding trochophore development may help resolve these major evolutionary questions. KEY WORDS: bilaterian, posterior growth, serpulid, annelidHydroides elegans, a polychaete with a feeding trochophore Characterization of polychaetes with a feeding trochophore, such as Hydroides elegans ( Fig. 1 and Table 1), is relevant to understand the developmental evolution of complex life cycles in spiralians. Embryonic development in polychaetes conforms to the presence or absence of a feeding trochophore (Fig. 2). In the genus Hydroides (Eupomatus), embryogenesis ends in a feeding trochophore endowed with an equatorial ciliary band, a protonephridium, various sensory organs, and a functional gut formed after gastrulation by invagination (Hatschek, 1885;Shearer, 1911). Blastomeres 4d and 2d22 are inconspicuous and fated to contribute to the mesodermal and ectodermal portions of the segmented body that will have primarily a reproductive role; the Int. J. Dev. Biol. 58: 575-583 (2014) growth and proliferation of 4d and 2d22 are feeding-dependent. In contrast, during embryogenesis in polychaetes without feeding larvae, blastomeres 4d and 2d are relatively large and immediately engage in the formation of segments (Fig. 2). In addition to la...

show abstract

Developing Models for Lophotrochozoan and Annelid Biology

Halanych

Borda

2009

Annelids in Modern Biology

View full text Add to dashboard Cite

Sinistral equal‐size spiral cleavage of the indirectly developing polychaete Hydroides elegans

Cited by 22 publications

References 52 publications

What determines direction of asymmetry: genes, environment or chance?

What determines direction of asymmetry: genes, environment or chance?

Development of a feeding trochophore in the polychaete Hydroides elegans

Developing Models for Lophotrochozoan and Annelid Biology

Contact Info

Product

Resources

About