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Arrays in rays: terminal addition in echinoderms and its correlation with gene expression.

Publication ,  Journal Article
Mooi, R; David, B; Wray, GA
Published in: Evolution & development
November 2005

The echinoderms are deuterostomes that superimpose radial symmetry upon bilateral larval morphology. Consequently, they are not the first animals that come to mind when the concepts of segmentation and terminal addition are being discussed. However, it has long been recognized that echinoderms have serial elements along their radii formed in accordance with the ocular plate rule (OPR). The OPR is a special case of terminal growth, forming elements of the ambulacra that define the rays in echinoderms. New elements are added at the terminus of the ray, which may or may not be marked by a calcified element called the terminal plate (the "ocular" of sea urchins). The OPR operates in every echinoderm, from the occasionally bizarre fossils of the Cambrian to the most familiar extant taxa. Using the OPR and other criteria of recognition, echinoderm body wall can be divided into two main regions: extraxial components are associated with the somatocoels, axial components (formed in accordance with the OPR) with the hydrocoel. We compare patterns of development in axial regions of echinoderms with those found in the anterior-posterior axes of the earliest echinoderms as well as other invertebrates. Although axial and extraxial skeletons appear to be composed of the same biomineral matrix, the genes involved in patterning these two skeletal components are likely distinct. During development of the axial skeleton, for instance, the genes engrailed and orthodenticle are expressed in spatial and temporal patterns consistent with the OPR. Other genes such as distal-less seem to demarcate early ontogenetic boundaries between the axial rudiment and the extraxial larval body. There is a complex and pervasive reorganization of gene expression domains to produce the highly divergent morphologies seen in the Echinodermata. We integrate morphological and genetic information, particularly with respect to the origins of radial symmetry in the rudiment, and the concomitant development of the rays.

Duke Scholars

Published In

Evolution & development

DOI

EISSN

1525-142X

ISSN

1520-541X

Publication Date

November 2005

Volume

7

Issue

6

Start / End Page

542 / 555

Related Subject Headings

  • Gene Expression Regulation, Developmental
  • Echinodermata
  • Developmental Biology
  • Body Patterning
  • Biological Evolution
  • Animals
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 0608 Zoology
  • 0603 Evolutionary Biology
 

Citation

APA
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ICMJE
MLA
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Mooi, R., David, B., & Wray, G. A. (2005). Arrays in rays: terminal addition in echinoderms and its correlation with gene expression. Evolution & Development, 7(6), 542–555. https://doi.org/10.1111/j.1525-142x.2005.05058.x
Mooi, Rich, Bruno David, and Gregory A. Wray. “Arrays in rays: terminal addition in echinoderms and its correlation with gene expression.Evolution & Development 7, no. 6 (November 2005): 542–55. https://doi.org/10.1111/j.1525-142x.2005.05058.x.
Mooi R, David B, Wray GA. Arrays in rays: terminal addition in echinoderms and its correlation with gene expression. Evolution & development. 2005 Nov;7(6):542–55.
Mooi, Rich, et al. “Arrays in rays: terminal addition in echinoderms and its correlation with gene expression.Evolution & Development, vol. 7, no. 6, Nov. 2005, pp. 542–55. Epmc, doi:10.1111/j.1525-142x.2005.05058.x.
Mooi R, David B, Wray GA. Arrays in rays: terminal addition in echinoderms and its correlation with gene expression. Evolution & development. 2005 Nov;7(6):542–555.
Journal cover image

Published In

Evolution & development

DOI

EISSN

1525-142X

ISSN

1520-541X

Publication Date

November 2005

Volume

7

Issue

6

Start / End Page

542 / 555

Related Subject Headings

  • Gene Expression Regulation, Developmental
  • Echinodermata
  • Developmental Biology
  • Body Patterning
  • Biological Evolution
  • Animals
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 0608 Zoology
  • 0603 Evolutionary Biology