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Ascenso y caída del bisonte de la estepa beringio
Beth Shapiro1, Alexei J Drummond, Andrew Rambaut
1Henry Wellcome Ancient Biomolecules Centre, Oxford University, South Parks Road, Oxford OX13PS, UK.
Science (New York, N.Y.)
|November 30, 2004
Resumen
Los datos genéticos revelan que las poblaciones de bisontes del Pleistoceno disminuyeron debido al cambio climático, no a la caza humana. Esto desafía la teoría de la extinción causada por el hombre para los grandes mamíferos de la Edad de Hielo.
Área de la Ciencia:
- La paleogenómica es la paleogenómica.
- Paleontología Cuaternaria Paleontología cuaternaria.
- Biología evolutiva de los mamíferos Biología evolutiva de los mamíferos
Sus antecedentes:
- Las extinciones de la megafauna del Pleistoceno tardío a menudo se atribuyen a la caza excesiva humana.
- El papel del cambio ambiental frente al impacto humano sigue siendo objeto de debate.
- Las poblaciones de bisontes en Beringia son clave para comprender estas dinámicas de extinción.
Objetivo del estudio:
- Para investigar los impulsores de la disminución de la población en el bisonte del Pleistoceno tardío utilizando ADN antiguo.
- Reconstruir la historia genética del bisonte en Beringia a lo largo de las épocas del Pleistoceno y el Holoceno.
- Para probar la hipótesis de que la actividad humana causó la extinción de los grandes mamíferos.
Principales métodos:
- Análisis de ADN antiguo de restos de bisontes.
- Aplicación de los métodos estadísticos bayesianos para la reconstrucción filogenética.
- Correlación de datos genéticos con registros paleoclimáticos y arqueológicos.
Principales resultados:
- Las poblaciones de bisontes en Beringia eran genéticamente diversas hasta aproximadamente 37.000 años antes del presente.
- Una disminución significativa en la diversidad genética comenzó hace unos 37.000 años.
- Esta disminución coincidió con el inicio de los cambios ambientales del último ciclo glacial.
- La evidencia arqueológica indica escasas poblaciones humanas en el este de Beringia hasta más de 15.000 años después.
Conclusiones:
- Los cambios ambientales durante el último ciclo glacial, no la depredación humana, probablemente causaron la disminución de la diversidad genética de los bisontes.
- Los hallazgos cuestionan la teoría prevaleciente de las extinciones de la megafauna impulsadas por el hombre al final del Pleistoceno.
- Los estudios paleogenómicos son cruciales para reevaluar el impacto del clima frente a los humanos en los ecosistemas del pasado.
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