Interacting cells driving the evolution of multicellular life cycles

Abstract

7Evolution of complex multicellular life begun from the emergence of life cycle in-8 volving formation of cell clusters. Opportunity for cells to interact within clusters pro-9 vided them an advantage over unicellular life forms. However, what kind of interactions 10 may lead to the evolution of multicellular life cycles? Here, we combine evolutionary 11 game theory with a model for the emergence of multicellular groups to investigate how 12 cell interactions can influence reproduction modes during the early stages of the evo-13 lution of multicellularity. We identify evolutionary optimal life cycles as those which 14 maximize the population growth rate. Among all interactions captured by two-player 15 games, only eight life cycles were found to be evolutionarily optimal. Moreover, the 16 vast majority of games promotes either of two classes of life cycles: (i) splitting into 17 unicellular propagules or (ii) fragmentation into two offspring clusters of equal (or al-18 most equal) size. Our findings indicate that the three most important characteristics, 19 determining whether multicellular life cycles will evolve, are average performance of 20 homogeneous groups, heterogeneous groups, and solitary cells.21

Evolution of simple multicellular life cycles in dynamic environments

“…Our present model uses the minimal set of processes necessary for the multicellular life cycle: birth, growth and reproduction of cell colonies. A number of other factors might influence the evolution of life cycles as well: aggregation of cells [45,46], group death [21], cell death [45,47], interactions between different cell types [48][49][50], the geometry of groups [51] and so forth. However, given the current state of the field, the understanding of evolutionary dynamics of life cycles even in the minimal set-ups is missing.…”

Evolution of simple multicellular life cycles in dynamic environments

“…Our present model uses the minimal set of processes necessary for the multicellular life cycle: birth, growth, and reproduction of cell colonies. A number of other factors might influence the evolution of life cycles as well: aggregation of cells [Garcia and De Monte, 2013, Amado et al, 2018], group death [Pichugin et al, 2017], cell death [Amado et al, 2018, Pichugin and Traulsen, 2018], interactions between different cell types [Garcia et al, 2014, 2015, Gao et al, 2019], the geometry of groups [Libby et al, 2014], and so forth. However, given the current state of the field, the understanding of evolutionary dynamics of life cycles even in the minimal setups is missing.…”

Evolution of irreversible somatic differentiation

“…In [Gao et al, 2019], we have shown that a population of organisms, which begin their life cycle from the same state but have a stochastic development, eventually grows exponentially with the rate λ given by the solution of…”