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[Urbilateria, a complex organism?]
Jean-Pierre Cornec1, André Gilles
1EA 3781 EGEE (Evolution, Génome, Environnement). Université de Provence, Aix-Marseille I, Centre St-Charles, case 36, 3, place Victor-Hugo, 13331 Marseille, France. corprepa@up.univ-mrs.fr
Medecine Sciences : M/S
|May 12, 2006
Summary
This study reveals that the antero-posterior segmentation in bilaterians, crucial for body plan development, is a conserved process. It suggests a common, segmented ancestor for all triblastic metazoans.
Area of Science:
- Developmental biology
- Evolutionary biology
- Genetics
Context:
- The bilaterian bauplan (body plan) is characterized by antero-posterior segmentation.
- Understanding the common ancestor of triblastic metazoans (Urbilateria) requires examining this segmentation.
- Segmentation is a fundamental process in the development of many animal groups.
Purpose:
- To establish the characteristics of Urbilateria, the common ancestor of triblastic metazoans.
- To analyze the morphological, anatomical, and functional aspects of antero-posterior segmentation.
- To investigate the ontogenesis and genetic underpinnings of segmentation in Annelids, Arthropods, and Chordates.
Summary:
- This paper synthesizes data on antero-posterior segmentation, a key feature of the bilaterian body plan.
- It examines the emergence of segmentation during the development of Annelids, Arthropods, and Chordates, identifying genetic bases.
- The study highlights the conserved, two-phase process of segmentation involving a posterior proliferative zone, common to protostomes and deuterostomes.
Impact:
- Provides evidence for a unitary character of segmentation modalities across major bilaterian lineages.
- Demonstrates conserved gene expression patterns and signaling pathways involved in segmentation.
- Reinforces the concept of a segmented Urbilateria as the common ancestor of Bilaterians based on structural and molecular congruence.