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Las tasas de evolución del ADN mitocondrial en los tiburones son lentas en comparación con los mamíferos
A P Martin1, G J Naylor, S R Palumbi
1Department of Zoology, University of Hawaii, Honolulu 96822.
Nature
|May 14, 1992
Resumen
Las velocidades de reloj molecular varían significativamente entre las especies de vertebrados. La evolución del ADN mitocondrial del tiburón es de siete a ocho veces más lenta que en los primates, lo que requiere calibraciones específicas del taxón para una datación molecular precisa.
Área de la Ciencia:
- Biología evolutiva Biología evolutiva.
- Evolución molecular de la evolución molecular.
- La genómica es la genómica.
Sus antecedentes:
- Las tasas de evolución del ADN mitocondrial (ADNmt) se calibran principalmente en los primates.
- Un reloj molecular constante a través de los vertebrados es ampliamente asumido pero no probado.
- Las suposiciones anteriores pueden conducir a estimaciones de tiempo de divergencia inexactas.
Objetivo del estudio:
- Para probar la hipótesis de la constancia del reloj molecular en los vertebrados.
- Para examinar la variación de la secuencia de ADN mitocondrial en tiburones.
- Para comparar las tasas evolutivas entre los tiburones y otros grupos de vertebrados.
Principales métodos:
- Se analizó la variación de la secuencia de ADNmt en 13 especies de tiburones.
- Genes secuenciados de citocromo b y citocromo oxidasa I. genes.
- Comparó las tasas de sustitución con datos de primates y ungulados, incluidas las especies separadas por el istmo de Panamá.
Principales resultados:
- Las tasas de sustitución del ADNmt del tiburón son de siete a ocho veces más lentas que en los primates o ungulados.
- Esta diferencia de velocidad no es atribuible al sesgo de nucleótidos, la selección o la elección de genes.
- Se han confirmado tasas más lentas en especies de tiburones recientemente divergentes.
Conclusiones:
- El reloj molecular no es constante en todos los taxones de vertebrados.
- El uso de calibraciones basadas en primates para otros grupos es inapropiado.
- Las calibraciones específicas de taxones son esenciales para los estudios evolutivos moleculares de alta resolución.
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