QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 16 February 2005
doi: 10.1242/dev.01701

This Article Figures Only Full Text Full Text (PDF) Supplementary Material All Versions of this Article: dev.01701v1 132/6/1349    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in Development Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hejnol, A. Articles by Schnabel, R. Search for Related Content PubMed PubMed Citation Articles by Hejnol, A. Articles by Schnabel, R. Social Bookmarking                         What's this?

The eutardigrade Thulinia stephaniae has an indeterminate development and the potential to regulate early blastomere ablations

Technische Universität Braunschweig, Institut für Genetik, Spielmannstrasse 7, D-38106 Braunschweig, Germany

^* Author for correspondence (e-mail: r.schnabel{at}tu-bs.de)

Accepted 23 December 2004

We present a detailed analysis of the cell lineage of the tardigrade Thulinia stephaniae with a 4D-microscopy system (3D time-lapse recording). The recording, of the entire development from embryogenesis until hatching, allowed us to analyze the fate of single descendants from early blastomeres up to germ layer formation and tissue development. The embryo undergoes an irregular indeterminate cleavage pattern without early fate restriction. During gastrulation, mesodermal and endodermal precursors, and a pair of primordial germ cells migrate through a blastopore at the prospective position of the mouth. Our results are not consistent with earlier descriptions of mesoderm formation by enterocoely in tardigrades. The mesoderm in Thulinia stephaniae originates from a variable number of blastomeres, which form mesodermal bands that later produce the serial somites. The nervous system is formed by neural progenitor cells, which delaminate from the neurogenic ectoderm. Early embryogenesis of Thulinia stephaniae is highly regulative, even after laser ablations of blastomeres at the two- and four-cell stages `normal' juveniles are formed. This has never been observed before for a protostome. Germ cell specification occurs late during development between the sixth and seventh cell generation. Comparing the development of other protostomes with that of the Tardigrada, which occupy a basal position within the Arthropoda, suggests that an indeterminate cleavage and regulatory development is not only part of the ground pattern of the Arthropoda, but probably of the entire Ecdysozoa.

Key words: Tardigrade, Ablation experiments, Indeterminate, Cell lineage, 4D-microscopy, Arthropoda, Ecdysozoa, Mesoderm

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

Related articles in Development:

Tardigrade development dissected

Development 2005 132: e602. [Full Text]  

Tardigrade development dissected

Development 2005 132: e602. [Full Text]  

This article has been cited by other articles:

				M. J Telford, S. J Bourlat, A. Economou, D. Papillon, and O. Rota-Stabelli The evolution of the Ecdysozoa Phil Trans R Soc B, April 27, 2008; 363(1496): 1529 - 1537. [Abstract] [Full Text] [PDF]

				P. Ungerer and G. Scholtz Filling the gap between identified neuroblasts and neurons in crustaceans adds new support for Tetraconata Proc R Soc B, February 22, 2008; 275(1633): 369 - 376. [Abstract] [Full Text] [PDF]