Multicellular life is one of the most astonishing wonders on Earth, but why and how does it arise in the first place, and at what cost? To help answer these questions, we exposed single-celled algae to predators and watched them evolve into multicellular life. Within a year, they had formed groups of cells to avoid being eaten – but at a price.
Chen, I-C. K. & M. D. Herron. 2019. Predators drive the evolution of multicellularity. The Science Breaker 257. doi: 10.25250/thescbr.brk257
The Project Outcomes Report for our recently ended NSF grant (known variously as DEB-1723293, DEB-1457701, and DEB-1456652) is now available on grants.gov:
Life comes in two forms: single-celled (organisms made up of only one cell) and multi-celled (organisms made up of many cells, alike or different). Multicellular life has evolved from unicellular ancestors many times across the tree of life, and the resulting radiations have transformed nearly every ecosystem on Earth. Ancestors of animals, plants, fungi, several groups of seaweeds, and filamentous bacteria underwent the transition from single- to multi-celled life in the deep past. While each of these origins is a replicate experiment with the potential to inform our understanding of how and why multicellular life evolved, the window through which we see these ancient events is blurry. Extinctions, subsequent evolution, and a spotty fossil record obscure our view. Experimental evolution enables us to time-travel, making it possible to clearly observe the evolution of multicellularity as it occurs in the lab. This project integrated experimental, bioinformatic, theoretical, and comparative approaches to understand how multicellularity and related traits have evolved, and how they can evolve.
A new paper describing the results of a yeast evolution experiment has been published in Evolution. Jordan Gulli exposed nascent multicellular “snowflake yeast” to an environment in which solitary multicellular clusters experienced low survival. In response, snowflake yeast evolved to form cooperative groups composed of thousands of multicellular clusters.
The time-lapse videos Josh Borin recorded, which show growth of unicellular and multicellular isolates described in the new Scientific Reports paper, are now available on YouTube. Although the videos for this open access paper are available for download from the publisher, several commenters have complained that they are not viewable on all platforms. Hopefully they are now viewable by everyone.