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Los genes Hox en braquiópodos y priapúlidos y la evolución del protostomo
R de Rosa1, J K Grenier, T Andreeva
1Laboratoire de Biologie Cellulaire 4, CNRS UPRESA Q8080, Université Paris-Sud, Orsay, France.
Nature
|July 3, 1999
Resumen
El análisis genético de Hox apoya las relaciones evolutivas de los principales animales. Los conjuntos de genes clave en los protostomas revelan el potencial de desarrollo bilateral temprano antes de la radiación del clado mayor.
Área de la Ciencia:
- Biología del desarrollo evolutivo Biología del desarrollo evolutivo
- La filogenia de los metazoos
- Genética y biología del desarrollo.
Sus antecedentes:
- Comprender la evolución temprana del plan corporal de los animales requiere el conocimiento de la filogenia metazoaria y los cambios genéticos.
- Filogenias recientes proponen una Bilateria con tres ramas: deuterostomas, lophotrochozoos y ecdysozoos.
Objetivo del estudio:
- Investigar si los complementos del gen Hox en las filas de los protóstomos reflejan las relaciones filogenéticas establecidas.
- Para revelar la evolución temprana del potencial regulador del desarrollo en los bilaterales.
Principales métodos:
- Análisis filogenético del ARN ribosómico 18S.
- Identificación y comparación de complementos de genes Hox a través de las filas críticas de protostomas.
Principales resultados:
- El gen Hox complementa las relaciones filogenéticas espejo, apoyando los clados lophotrochozoan y ecdysozoan.
- Un par divergente de genes Hox posteriores apoya el ensamblaje lophotrochozoan (braquiópodo, anelido).
- Un gen Hox posterior distinto apoya el clado ecdizozoario (priapulidos, nematodos, artrópodos).
Conclusiones:
- Los antepasados de los principales linajes de protostomas poseían al menos de ocho a diez genes Hox.
- La expansión y diversificación significativa del gen Hox fue anterior a la irradiación de los tres principales clados bilaterales.
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