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THE ENERGY EXPLANTATION. "Any evolutionary transition in which the lower-level units carry out energy conversion and allocation will be extraordinarily challenging. This is the central reason why eukaryotes only evolved once." https://lnkd.in/dNEtvR8 View in LinkedIn

"METABOLIC REGULATION, however, may be achieved by extending within-cell signalling derived during the conflictual stages of the origin of eukaryotes to between-cell signalling. The extent to which mitochondrial pathways connect to within- and between-cell signalling may provide an indication that this has occurred." https://lnkd.in/dNEtvR8 View in LinkedIn

COMPETITIVE ELEMENTS. "In the transition to multicellularity, lower-level units again can take up more than their share of substrate and allocate it into selfish replication. Because there is no structure analogous to the nucleus, genome transfer is impossible, and genomic deletion in somatic cells is not commonly found." https://lnkd.in/dNEtvR8 View in LinkedIn

YEAST DIVISION OF LABOR. "We also observed the evolution of division of labor within the cluster: most cells remain viable and reproduce, but a minority of cells become apoptotic. Apoptotic cells act as break points within multicellular clusters, allowing snowflake yeast to produce a greater number of propagules from a given number of cells. This is functionally analogous to germ-soma differentiation, where cells specialize into reproductive and nonreproductive tasks. These results demonstrate that multicellular traits readily evolve as a consequence of among-cluster selection." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

EUKARYOTIC NIGHTMARE. "Moving energy-converting membranes internally allowed eukaryotes to transcend surface-to-volume constraints. This clever engineering solution, however, turned into a levels-of-selection nightmare: the lower-level units could selfishly allocate energy into their own replication. This was the principal conflict in the origin of eukaryotes. Genomic transfer was likely not initially effective in mediating this conflict." https://lnkd.in/dNEtvR8 View in LinkedIn

PHENOTYPE SHIFT. "We observed adaptation of multicellular traits, indicating a shift in selection from individual cells to multicellular individuals. In response to selection for even more rapid settling, snowflake-phenotype yeast adapted through changes in their multicellular life history, increasing the length of the juvenile phase that precedes production of multicellular propagules." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

AH, THOSE FUSSY DETAILS. "Biological details can complicate these theoretical generalities." https://lnkd.in/dNEtvR8 View in LinkedIn

RAPID EVOLUTION IN VITRO. "Here we report on the de novo evolution of a two-stage life cycle in the unicellular alga C. reinhardtii. In our experiments, we find that simple multicellularity can evolve rapidly in C. reinhardtii. Like most extant multicellular organisms, we find that multicellular C. reinhardtii possesses a life history that alternates between uni- and multicellular stages." https://lnkd.in/dU8HRX5 View in LinkedIn

ALTERNATIVE OPTIONS. "Instead, the unicellular bottleneck may have evolved in the absence of genetic conflict for other reasons, creating a multicellular body plan largely immune to future intercellular conflicts as a side-effect. This key trait may therefore catalyse the evolution of multicellular complexity, facilitating the origin and expansion of cellular division of labour." https://lnkd.in/dU8HRX5 View in LinkedIn

EVIDENCE LACKING. "Although there is little doubt that a unicellular bottleneck serves the present function of preventing among-cell conflicts in large multicellular organisms, there is no direct evidence that it originally arose as an adaptation for this function." https://lnkd.in/dU8HRX5 View in LinkedIn