Did the first chordates organize without the organizer?

TitleDid the first chordates organize without the organizer?
Publication TypeJournal Article
Year of Publication2005
AuthorsKourakis MJ, Smith WC
JournalTrends Genet
Volume21
Issue9
Pagination506-10
Date Published2005 Sep
ISSN0168-9525
KeywordsAnimals, Biological Evolution, Body Patterning, Chordata, Chordata, Nonvertebrate, Embryonic Development, Organizers, Embryonic, Xenopus laevis
Abstract

Models of vertebrate development frequently portray the organizer as acting on a largely unpatterned embryo to induce major components of the body plan, such as the neural plate and somites. Recent experiments examining the molecular and genetic basis of major inductive events of vertebrate embryogenesis force a re-examination of this view. These newer observations, along with a proposed revised fate map for the frog Xenopus laevis, suggest a possible reconciliation between the seemingly disparate mechanisms present in the ontogeny of the common chordate body plan of vertebrate and invertebrate chordates. Here, we review data from vertebrates and from an ascidian urochordate and propose that the organizer was not present at the base of the chordate lineage, but could have been a later innovation in the lineage leading to vertebrates, where its role was more permissive than instructive.

DOI10.1016/j.tig.2005.07.002
Alternate JournalTrends Genet.
PubMed ID16023252
Grant ListHD041434 / HD / NICHD NIH HHS / United States
HD38701 / HD / NICHD NIH HHS / United States