Evolutionary modification of cell lineage in the direct-developing sea urchin Heliocidaris erythrogramma.

Published

Journal Article

The sea urchin Heliocidaris erythrogramma undergoes direct development, bypassing the usual echinoid pluteus larva. We present an analysis of cell lineage in H. erythrogramma as part of a definition of the mechanistic basis for this evolutionary change in developmental mode. Microinjection of fluoresceinated tracer dye and surface marking with vital dye are used to follow larval fates of 2-cell, 8-cell, and 16-cell blastomeres, and to examine axial specification. The animal-vegetal axis and adult dorsoventral axis are basically unmodified in H. erythrogramma. Animal cell fates are very similar to those of typically developing species; however, vegetal cell fates in H. erythrogramma are substantially altered. Radial differences exist among vegetal blastomere fates in the 8-cell embryo: dorsal vegetal blastomeres contribute proportionately more descendants to ectodermal and fewer to mesodermal fates, while ventral vegetal blastomeres have a complementary bias in fates. In addition, vegetal cell fates are more variable than in typical developers. There are no cells in H. erythrogramma with fates comparable to those of the micromeres and macromeres of typically developing echinoids. Instead, all vegetal cells in the 16-cell embryo can contribute progeny to ectoderm and gut. Alterations have thus arisen in cleavage patterns and timing of cell lineage partitioning during the evolution of direct development in H. erythrogramma.

Full Text

Duke Authors

Cited Authors

  • Wray, GA; Raff, RA

Published Date

  • April 1989

Published In

Volume / Issue

  • 132 / 2

Start / End Page

  • 458 - 470

PubMed ID

  • 2924998

Pubmed Central ID

  • 2924998

Electronic International Standard Serial Number (EISSN)

  • 1095-564X

International Standard Serial Number (ISSN)

  • 0012-1606

Digital Object Identifier (DOI)

  • 10.1016/0012-1606(89)90242-x

Language

  • eng