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La reconstrucción del locus de la amilasa humana revela las duplicaciones antiguas que siembran la variación moderna
Feyza Yilmaz1, Charikleia Karageorgiou2, Kwondo Kim1
1The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
Science (New York, N.Y.)
|October 17, 2024
Resumen
El número de copias del gen de la amilasa salival humana (AMY1) varía, con más copias vinculadas a las dietas ricas en almidón. El ADN antiguo revela un haplotipo AMY1 común de tres copias que existió hace 800,000 años, con números de copias en aumento en los agricultores europeos.
Área de la Ciencia:
- La genética evolutiva humana
- Antropología molecular
- Genética de las poblaciones
Sus antecedentes:
- El número de copias del gen de la amilasa salival humana (AMY1) está asociado con el consumo de almidón en la dieta.
- Los mapas precisos de variación del haplotipo son cruciales para los análisis evolutivos de AMY1.
- Los estudios anteriores carecían de datos de haplotipos resueltos por secuencia para obtener información evolutiva completa.
Objetivo del estudio:
- Para crear un mapa de variación de haplotipo de resolución de nucleótidos para el gen AMY1 humano.
- Investigar la historia evolutiva y las presiones de selección en la variación del número de copias de AMY1.
- Explorar el papel de los cambios en el número de copias de AMY1 en la adaptación humana a la dieta.
Principales métodos:
- Identificación de 30 haplotipos AMY1 distintos en la resolución de nucleótidos en 98 individuos.
- Análisis de la evolución de la secuencia de codificación bajo selección negativa.
- Análisis genómico de haplotipos en homínidos arcaicos y genomas humanos antiguos.
- Investigación de la recombinación homóloga no alelica en los reordenamientos del gen AMY1.
- Análisis de la frecuencia de las variaciones del número de copias de AMY1 en las antiguas poblaciones de agricultores europeos.
Principales resultados:
- Se identificaron 30 haplotipos AMY1 estructuralmente distintos con resolución de nucleótidos.
- Las secuencias de codificación AMY1 evolucionan bajo selección negativa.
- Un haplotipo AMY1 común de tres copias se originó hace al menos 800,000 años.
- La recombinación homóloga no alelica recurrente impulsa los reordenamientos del número de copias de AMY1.
- Aumento de la frecuencia de las amplificaciones del número de copias de AMY1 en los agricultores europeos durante los últimos 4000 años.
Conclusiones:
- El gen AMY1 tiene una profunda historia evolutiva con un haplotipo conservado de tres copias que se remonta al menos a hace 800.000 años.
- La expansión del número de copias de AMY1 en los agricultores europeos probablemente representa una respuesta adaptativa al aumento del almidón en la dieta.
- La comprensión de la variación del haplotipo AMY1 proporciona información crítica sobre la adaptación humana a los cambios en la dieta.
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