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Evidencia de que los mecanismos de desarrollo de las aletas evolucionaron en la línea media de los primeros
Renata Freitas1, GuangJun Zhang, Martin J Cohn
1Department of Zoology, University of Florida, PO Box 118525, Gainesville, Florida 32611, USA.
Nature
|August 1, 2006
Resumen
La evolución de las aletas de los vertebrados utilizó programas genéticos compartidos a pesar de diferentes orígenes embrionarios. Las aletas medianas en tiburones y lampreas se desarrollan a partir de somitas, revelando mecanismos de desarrollo antiguos que son anteriores a los apéndices emparejados.
Área de la Ciencia:
- Biología del desarrollo evolutivo Biología del desarrollo evolutivo
- La genómica comparada es una genómica comparada.
- Paleontología de los vertebrados.
Sus antecedentes:
- Los apéndices pareados son una innovación clave de los vertebrados para la locomoción.
- Los primeros vertebrados tenían aletas medianas pero carecían de aletas emparejadas.
- Los mecanismos de desarrollo de las aletas pueden haberse originado en estructuras de línea media.
Objetivo del estudio:
- Investigar la base genética del desarrollo de la aleta mediana en tiburones.
- Comparar los mecanismos de desarrollo de las aletas medianas y emparejadas.
- Rastrear los orígenes evolutivos de los genes de desarrollo de aletas.
Principales métodos:
- Utilizó marcadores moleculares para identificar tipos de células en las aletas medianas de tiburones.
- Se analizaron los patrones de expresión de los genes Hoxd y Tbx18.
- Análisis extendido de las aletas medianas de las lampreas.
Principales resultados:
- El desarrollo de la aleta mediana del tiburón utiliza programas genéticos similares a los apéndices emparejados.
- Las aletas medianas surgen del mesodermo somítico, las aletas emparejadas del mesodermo de la placa lateral.
- Los patrones de expresión génica de Hoxd y Tbx18 se conservan en las aletas medianas.
- Las aletas medianas de Lamprey también se desarrollan a partir de somitas y expresan genes ortólogos.
Conclusiones:
- Los mecanismos moleculares compartidos subyacen al desarrollo de las aletas medianas y emparejadas.
- El desarrollo de las aletas probablemente se originó en el mesodermo somítico de los primeros vertebrados.
- Los apéndices pareados evolucionaron a través de la redistribución de estos mecanismos ancestrales.
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