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La dinámica de la evolución molecular en más de 60.000 generaciones

Benjamin H Good^1,2,3,4,5, Michael J McDonald^1,2,6, Jeffrey E Barrick^7,8

¹Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

|October 19, 2017

Resumen

La dinámica evolutiva se estudió en Escherichia coli durante 60,000 generaciones. A pesar de la disminución de las ganancias de aptitud, se observaron adaptaciones rápidas y variantes en competencia, lo que revela procesos evolutivos complejos.

Área de la Ciencia:

Biología evolutiva
Evolución de los microbios
La genómica

Sus antecedentes:

Los resultados evolutivos dependen de la dinámica de la mutación.
Observar la evolución genómica a largo plazo es un desafío.

Objetivo del estudio:

Para analizar la dinámica de la evolución molecular en poblaciones experimentales.
Investigar la adaptación durante períodos prolongados y genomas enteros.

Principales métodos:

Secuenciación metagenómica de todo el genoma de doce poblaciones de Escherichia coli.
Muestreo a intervalos de 500 generaciones durante 60.000 generaciones.

Principales resultados:

Las firmas de adaptación rápida persistieron durante todo el experimento.
Varias variantes beneficiosas compitieron simultáneamente.
Las interacciones ecológico-evolucionarias llevaron a la coexistencia de clado y la evolución en curso.
La epistasis y la contingencia histórica alteraron los objetivos de selección a lo largo del tiempo.

Conclusiones:

La adaptación a largo plazo en un entorno constante es compleja y dinámica.
Los objetivos de la selección natural pueden cambiar durante la adaptación.
Los procesos estocásticos y las interacciones ecológicas dan forma a las trayectorias evolutivas.

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