A nonadaptive explanation for macroevolutionary patterns in the evolution of complex multicellularity.
Proc Natl Acad Sci U S A
; 121(7): e2319840121, 2024 Feb 13.
Article
em En
| MEDLINE
| ID: mdl-38315855
ABSTRACT
"Complex multicellularity," conventionally defined as large organisms with many specialized cell types, has evolved five times independently in eukaryotes, but never within prokaryotes. A number of hypotheses have been proposed to explain this phenomenon, most of which posit that eukaryotes evolved key traits (e.g., dynamic cytoskeletons, alternative mechanisms of gene regulation, or subcellular compartments) which were a necessary prerequisite for the evolution of complex multicellularity. Here, we propose an alternative, nonadaptive hypothesis for this broad macroevolutionary pattern. By binning cells into groups with finite genetic bottlenecks between generations, the evolution of multicellularity greatly reduces the effective population size (Ne) of cellular populations, increasing the role of genetic drift in evolutionary change. While both prokaryotes and eukaryotes experience this phenomenon, they have opposite responses to drift eukaryotes tend to undergo genomic expansion, providing additional raw genetic material for subsequent multicellular innovation, while prokaryotes generally face genomic erosion. Taken together, we hypothesize that these idiosyncratic lineage-specific evolutionary dynamics play a fundamental role in the long-term divergent evolution of complex multicellularity across the tree of life.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Deriva Genética
/
Evolução Biológica
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article