Anteroposterior patterning in hemichordates and the origins of the chordate nervous system.
Cell
; 113(7): 853-65, 2003 Jun 27.
Article
em En
| MEDLINE
| ID: mdl-12837244
ABSTRACT
The chordate central nervous system has been hypothesized to originate from either a dorsal centralized, or a ventral centralized, or a noncentralized nervous system of a deuterostome ancestor. In an effort to resolve these issues, we examined the hemichordate Saccoglossus kowalevskii and studied the expression of orthologs of genes that are involved in patterning the chordate central nervous system. All 22 orthologs studied are expressed in the ectoderm in an anteroposterior arrangement nearly identical to that found in chordates. Domain topography is conserved between hemichordates and chordates despite the fact that hemichordates have a diffuse nerve net, whereas chordates have a centralized system. We propose that the deuterostome ancestor may have had a diffuse nervous system, which was later centralized during the evolution of the chordate lineage.
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MEDLINE
Assunto principal:
Vertebrados
/
Cordados não Vertebrados
/
Regulação da Expressão Gênica no Desenvolvimento
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Padronização Corporal
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Invertebrados
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Sistema Nervoso
Limite:
Animals
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article