Year: 2022

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

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

"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

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

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

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

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

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

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