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COMPETITION AND COOPERATION. "Cooperation among lower-level units leads to nascent higher-level units. Conflicts among lower-level units can then undermine these emerging units. If conflicts can be mediated, however, then fully formed higher-level units can emerge. These new units can outcompete individual lower-level units and proliferate." https://lnkd.in/dNEtvR8 View in LinkedIn

EVOLVING YEAST CLUSTERS. "The multicellular clusters are uniclonal, minimizing within-cluster genetic conflicts of interest. Simple among-cell division of labor rapidly evolved. Early multicellular strains were composed of physiologically similar cells, but these subsequently evolved higher rates of programmed cell death (apoptosis), an adaptation that increases propagule production." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

EXPERIMENTAL SETUP. "Experimental evolution of multicellularity. We subjected the unicellular yeast Saccharomyces cerevisiae to an environment in which we expected multicellularity to be adaptive. We observed the rapid evolution of clustering genotypes that display a novel multicellular life history characterized by reproduction via multicellular propagules, a juvenile phase, and determinate growth." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

SELECTION LEVEL. "The evolution of multicellularity requires an increasing role for natural selection among multicellular individuals, relative to selection among cells within individuals." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

LACK OF TRANSITIONAL FORMS. "Understanding the evolution of complex multicellular individuals from unicellular ancestors has been extremely challenging, largely because the first steps in this process occurred in the deep past (>200 million years ago). As a result, transitional forms have been lost to extinction, and little is known about the physiology, ecology, and evolutionary processes of incipient multicellularity." https://lnkd.in/d3qm3Gr View in LinkedIn

REPEATED BUT RARE EVENTS. "Even though multicellularity has evolved dozens of times in the last 3.5 billion years, this transition is still rare (occurring, most recently, ~200 MYA in the brown and the volvocine algae)." https://lnkd.in/dU8HRX5 View in LinkedIn

REPEATED MULTICELLULAR EVENTS. "Compared with other major transitions in evolution that occurred just once (for example, the origin of eukaryotes), multicellularity has evolved repeatedly." https://lnkd.in/dU8HRX5 View in LinkedIn

MULTICELLULARITY IN YEAST. "Recent study claims to have evolved multicellular yeast in the laboratory de novo." https://lnkd.in/dNEtvR8 View in LinkedIn

PREVIOUSLY, we looked at the example of E. Coli grown in very controlled conditions for thousands of generations, spontaneously developing the ability to metabolize citrate. Now we look at another example of controlled evolution experiments with the development of multicellularity in yeast. View in LinkedIn

CONFLICT MEDIATION. "Yet by successfully mediating these conflicts, eukaryotes may have paved the way for repeated evolution of multicellularity, which could occur simply by coopting the existing within-cell mechanisms of conflict mediation into between-cell ones." Sounds easy. https://lnkd.in/dNEtvR8 View in LinkedIn