Genetic on-off switch key to evolution of complex life
20 June 2010
Magazine issue 2765. Subscribe and save
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A SIMPLE on-off switch may have been key to the evolution of complex life.
How colonies of single cells evolved into multicellular organisms has long been a puzzle. The process requires single cells to band together and divide the tasks of life. To do so, some cells must give up their ability to reproduce.
To investigate, Sergey Gavrilets of the University of Tennessee in Knoxville created a mathematical model describing a colony of identical cells able to survive and reproduce. He assumed trade-offs between the tasks: being better at reproducing made cells worse at survival, and vice versa. In the simplest case, the colony evolved into organisms made of cells that were mediocre at both tasks.
But that changed when Gavrilets included genes that could suppress the activity of one trait or the other. A colony of cells could now improve both traits at the same time, by making some cells exclusively reproducers and others survivors. This led cells to completely specialise in less than a million generations – an evolutionary blink of an eye (PLoS Computational Biology, DOI: 10.1371/journal. pcbi.1000805).