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Keywords:

  • germ line;
  • echinoderm;
  • inductive germ-cell determination;
  • posterior enterocoel

Background: Echinodermata is a diverse phylum, a sister group to chordates, and contains diverse organisms that may be useful to understand varied mechanisms of germ-line specification. Results: We tested 23 genes in development of the sea star Patiria miniata that fall into five categories: (1) Conserved germ-line factors; (2) Genes involved in the inductive mechanism of germ-line specification; (3) Germ-line associated genes; (4) Molecules involved in left–right asymmetry; and (5) Genes involved in regulation and maintenance of the genome during early embryogenesis. Overall, our results support the contention that the posterior enterocoel is a source of the germ line in the sea star P. miniata. Conclusions: The germ line in this organism appears to be specified late in embryogenesis, and in a pattern more consistent with inductive interactions amongst cells. This is distinct from the mechanism seen in sea urchins, a close relative of the sea star clad. We propose that P. miniata may serve as a valuable model to study inductive mechanisms of germ-cell specification and when compared with germ-line formation in the sea urchin S. purpuratus may reveal developmental transitions that occur in the evolution of inherited and inductive mechanisms of germ-line specification. Developmental Dynamics 243:568–587, 2014. © 2013 Wiley Periodicals, Inc.