Nascent life cycles and the emergence of higher-level individuality.
| Autor: | Ratcliff WC; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA william.ratcliff@biology.gatech.edu., Herron M; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA., Conlin PL; Department of Biology and BEACON Center for the Study of Evolution in Action, University of Washington, Seattle, WA 98195, USA., Libby E; Santa Fe Institute, Santa Fe, NM 87501, USA. |
|---|---|
| Jazyk: | angličtina |
| Zdroj: | Philosophical transactions of the Royal Society of London. Series B, Biological sciences [Philos Trans R Soc Lond B Biol Sci] 2017 Dec 05; Vol. 372 (1735). |
| DOI: | 10.1098/rstb.2016.0420 |
| Abstrakt: | Evolutionary transitions in individuality (ETIs) occur when formerly autonomous organisms evolve to become parts of a new, 'higher-level' organism. One of the first major hurdles that must be overcome during an ETI is the emergence of Darwinian evolvability in the higher-level entity (e.g. a multicellular group), and the loss of Darwinian autonomy in the lower-level units (e.g. individual cells). Here, we examine how simple higher-level life cycles are a key innovation during an ETI, allowing this transfer of fitness to occur 'for free'. Specifically, we show how novel life cycles can arise and lead to the origin of higher-level individuals by (i) mitigating conflicts between levels of selection, (ii) engendering the expression of heritable higher-level traits and (iii) allowing selection to efficiently act on these emergent higher-level traits. Further, we compute how canonical early life cycles vary in their ability to fix beneficial mutations via mathematical modelling. Life cycles that lack a persistent lower-level stage and develop clonally are far more likely to fix 'ratcheting' mutations that limit evolutionary reversion to the pre-ETI state. By stabilizing the fragile first steps of an evolutionary transition in individuality, nascent higher-level life cycles may play a crucial role in the origin of complex life.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'. (© 2017 The Author(s).) |
| Databáze: | MEDLINE |
| Externí odkaz: |
|