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La evolución de la regulación de Hoxa11 en los vertebrados está relacionada con el estado pentadactilo
Yacine Kherdjemil1,2, Robert L Lalonde3, Rushikesh Sheth1
1Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.
Nature
|October 6, 2016
Resumen
La evolución del desarrollo de las extremidades implicó una transición de aletas polidactílicas a extremidades pentadactílicas. La regulación genética, específicamente la expresión de Hoxa11 y Hoxa13, fue crucial para establecer el estado pentadactilo en tetrápodos.
Área de la Ciencia:
- Biología del desarrollo evolutivo
- Genómica comparada
- Paleontología de los vertebrados
Sus antecedentes:
- La transición de la aleta a la extremidad es un evento evolutivo clave que permite la vida terrestre.
- Los primeros tetrápodos poseían extremidades polidactilosas, a diferencia de las extremidades pentadactil de la mayoría de los tetrápodos existentes.
- Los mecanismos genéticos que subyacen a la transición a las extremidades pentadáctiles siguen siendo en gran medida desconocidos.
Objetivo del estudio:
- Investigar el papel de los genes Hoxa11 y Hoxa13 en el desarrollo de las extremidades pentadactilas.
- Identificar los elementos reguladores que controlan la expresión de Hoxa11 y Hoxa13 durante la evolución de las extremidades.
- Para entender el origen evolutivo de los mecanismos de patrones de extremidades.
Principales métodos:
- Análisis de los patrones de expresión génica en modelos de ratón.
- Estudios funcionales que incluyen manipulación genética y ensayos de actividad de potenciadores.
- Análisis comparativo de la regulación génica entre tetrápodos y peces (peces cebra).
Principales resultados:
- La expresión mutuamente exclusiva de Hoxa11 y Hoxa13 es esencial para la formación de las extremidades pentadactilas.
- Un potenciador que impulsa la transcripción antisentido en el locus Hoxa11, activado por HOXA13 y HOXD13, media esta exclusión.
- Este potenciador regulador está ausente en el pez cebra, lo que sugiere su aparición durante la transición de aleta a extremidad.
Conclusiones:
- La evolución de la regulación de Hoxa11, incluida la adquisición de un potenciador específico, fue un paso crítico en la transición de las extremidades polidactilas a las pentadactilas.
- Esta innovación reguladora facilitó el establecimiento de la estructura característica de las extremidades pentadactilas en los tetrápodos.
- La comprensión de estos mecanismos genéticos proporciona información sobre la evolución de la diversidad morfológica en los vertebrados.
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