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Las secuencias genómicas nucleares revelan que los osos polares son un linaje de oso antiguo y distinto
Frank Hailer1, Verena E Kutschera, Björn M Hallström
1Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325 Frankfurt am Main, Germany. frashai@gmx.net
Science (New York, N.Y.)
|April 21, 2012
Resumen
Los osos polares evolucionaron de los osos pardos mucho antes de lo que se pensaba, hace unos 600.000 años. Los datos genómicos de Multilocus revelan su distinta trayectoria evolutiva, aclarando los antiguos eventos de hibridación.
Área de la Ciencia:
- Biología evolutiva Biología evolutiva.
- La genómica es la genómica.
- Especiación de los mamíferos.
Sus antecedentes:
- Estudios recientes sugieren que la matrilina del oso polar (ADN mitocondrial) evolucionó de los osos pardos en el Pleistoceno tardío.
- Esto indicaba una especiación y adaptación potencialmente rápidas a los entornos árticos.
Objetivo del estudio:
- Para determinar con precisión la historia evolutiva y el tiempo de divergencia de los osos polares utilizando datos del genoma nuclear.
- Para investigar posibles eventos pasados de hibridación entre osos polares y osos pardos.
Principales métodos:
- Se analizaron datos de alta resolución de múltiples loci independientes del genoma nuclear.
- Se realizaron análisis de coalescencia bayesiana en una amplia muestra de osos polares, osos pardos y osos negros.
Principales resultados:
- Los análisis de coalescencias bayesianas colocaron a los osos polares fuera del clado de los osos pardos.
- La divergencia fue fechada en el Pleistoceno medio, hace aproximadamente 600.000 años (338-934 kya).
- Los resultados confirmaron el ADN mitocondrial introgresivo del oso pardo en los osos polares debido a la hibridación pasada.
Conclusiones:
- Los análisis genómicos multilocus son esenciales para resolver historias evolutivas complejas.
- La evolución del oso polar se produjo en una escala de tiempo más larga que la indicada anteriormente por los datos matrilineos.
- Los hallazgos proporcionan una línea de tiempo más precisa para la adaptación y especiación del oso polar.
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