Cover Image

Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity

Tradeoffs are one of the essential ingredients that shape the diversity of life on Earth. They are thought to create ecological niches and restrict the accessible evolutionary pathways in a nontrivial way. Nevertheless, much is still unknown about the way tradeoffs steer the course of evolution. Rec...

Full description

Main Author: AMADO, André da Conceição
Other Authors: CAMPOS, Paulo Roberto de Araújo
Format: doctoralThesis
Language: eng
Published: Universidade Federal de Pernambuco 2019
Subjects:
Física estatística
Dinâmica evolucionária
Tradeoffs
Multicelularidade
Online Access: https://repositorio.ufpe.br/handle/123456789/29704
Tags: Add Tag
No Tags, Be the first to tag this record!
id ir-123456789-29704
recordtype dspace
spelling ir-123456789-297042019-03-15T05:04:35Z Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity AMADO, André da Conceição CAMPOS, Paulo Roberto de Araújo http://lattes.cnpq.br/5460648232693565 http://lattes.cnpq.br/5468845680173423 Física estatística Dinâmica evolucionária Tradeoffs Multicelularidade Tradeoffs are one of the essential ingredients that shape the diversity of life on Earth. They are thought to create ecological niches and restrict the accessible evolutionary pathways in a nontrivial way. Nevertheless, much is still unknown about the way tradeoffs steer the course of evolution. Recent studies open a new venue to the empirical exploration of this subject. The access to the genetic content of life has been revolutionizing the knowledge across the whole Biology, bringing some answers and raising a lot of new questions. The whole concept of multicellular life has been extending from the beginning of the 1990’s with the recognition of multicellular bacteria and numerous behaviors in the now shadowy region between unicellular and multicellular life. The approach of experimental evolution recently provided the first experimental insights into the process of transition from unicellular to multicellular life, by evolving multicellular organisms under controlled conditions in the laboratory. This current work aims to provide a contribution to the theoretical understanding of the role of tradeoffs in the transition to multicellularity and complexity development. For that, we introduce and explore some models tailored to elucidate some of the aspects of these transitions. Each of those models is explored through a combination of analytical and simulational methods, which allows us to extract further information. A first approach deals with the establishment of an efficient mode of metabolism within the context of competition with a rapid and inefficient mode. Usually, high rate inefficient metabolisms tend to dominate, therefore extra mechanisms are necessary to counteract this. Within a resource-based formulation, we study the effect of group structure in the population and find that with groups the efficient mode outcompetes the inefficient one in a broad domain of the parameter space. In the sequel, we analyze the contribution of tradeoffs to the evolution of complexity. It is empirically known that complex networks of tradeoffs are established at the cellular and metabolic level. In this context, a system with an arbitrary number of tradeoffs over a given number of tasks is investigated. We carry out a statistical analysis over different sets of parameters in order to examine the dependence of cell specialization on the number and strength of the tradeoffs. A concrete application of the model to the carbon-nitrogen fixation tradeoff in cyanobacteria is provided. At last, we introduce a mechanistic model for the dynamics of multicellular aggregates. We consider the existence of different microscopic mechanisms shaping multicellular aggregates. Particularly, the model is applied to the study of the size-complexity rule and interesting results follows from that approach. Depending on the geometry of the aggregates the size-complexity rule can be followed or not. We found that more fragile aggregates violate the rule and more robust ones obey it. Each of the works addressed here provides some answers and raises new issues to be explored in the future. For instance, what is the effect of germ-soma tradeoffs for the outcomes predicted in our models? Or, if the size-complexity rule can be violated under some circumstances, there exist additional mechanisms that can also have the same effect? These and other questions are raised and briefly discussed in the conclusions. CNPq vida tem revolucionado o conhecimento em todas as áreas da Biologia, introduzindo algumas respostas e um sem-número de novas questões. O conceito de vida multicelular tem sido extendido desde o início dos anos 1990, com o reconhecimento de bactérias multicelulares e variados comportamentos ao longo do espectro que se abre entre vida unicelular e multicelular. A abordagem da evolução experimental providenciou recentemente os primeiros experimentos onde a transição de unicelular para multicelular pode ser observada directamente, sob condições controladas em laboratório. O trabalho aqui apresentado tem como objectivo contribuir para a compreensão teórica do papel dos tradeoffs na transição para a multicelularidade e desenvolvimento da complexidade. Para tal, nós introduzimos e exploramos alguns modelos desenhados para elucidar alguns aspectos destas transições. Os modelos são explorados utilizando uma combinação de métodos analíticos e simulações numéricas, o que nos permite obter mais informação dos modelos. Uma primeira abordagem lida com o estabelecimento de um modo eficiente de metabolismo no contexto de competição com um modo rápido e ineficiente. Geralmente metabolismos rápidos e ineficientes tendem a dominar, sendo necessária a introdução de outros mecanismos para o contrariar. No contexto de uma formulação baseada em recursos, nós estudamos o efeito da estruturação da população em grupos e obtemos agora que o metabolismo eficiente passa a dominar numa grande região do espaço de parâmetros. Em seguida, analisamos a contribuição dos tradeoffs para a evolução da complexidade. Empiricamente, sabe-se que redes complexas de tradeoffs são estabelecidas a nível celular e metabólico. Neste contexto, investigamos um sistema com um número arbitrário de tradeoffs incidentes sobre um dado número de tarefas. Realizamos uma análise estatística sobre diferentes conjuntos de parâmetros com o objectivo de examinar a forma como a especialização celular depende do número e intensidade dos tradeoffs. Apresentamos ainda uma aplicação concreta do modelo ao tradeoff existente entre os processos de fixação de carbono e nitrogênio nas cianobactérias. For fim, introduzimos um modelo mecanístico para a dinâmica dos agregados multicelulares. Consideramos a existência de diferentes mecanismos microscópicos que controlam a evolução dos agregados multicelulares. Em particular, aplicamos o modelo ao estudo da regra do tamanho-complexidade e obtemos resultados interessantes. Dependendo da geometria considerada, a regra do tamanho-complexidade pode ser respeitada ou não. Cada um dos trabalhos desenvolvidos respondem algumas questões e levantam outras a explorar no futuro. Por exemplo, qual é o efeito do tradeoff entre funções reprodutivas e somáticas nos resultados obtidos? Ou, se a regra do tamanho-complexidade pode ser violada sob certas condições, existirão mecanismos adicionais que produzem o mesmo efeito? Estas e outras questões são levantadas e discutidas brevemente nas conclusões. 2019-03-14T21:24:56Z 2019-03-14T21:24:56Z 2018-02-23 doctoralThesis https://repositorio.ufpe.br/handle/123456789/29704 eng openAccess Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ Universidade Federal de Pernambuco UFPE Brasil Programa de Pos Graduacao em Fisica
institution REPOSITORIO UFPE
collection REPOSITORIO UFPE
language eng
topic Física estatística
Dinâmica evolucionária
Tradeoffs
Multicelularidade
spellingShingle Física estatística
Dinâmica evolucionária
Tradeoffs
Multicelularidade
AMADO, André da Conceição
Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
description Tradeoffs are one of the essential ingredients that shape the diversity of life on Earth. They are thought to create ecological niches and restrict the accessible evolutionary pathways in a nontrivial way. Nevertheless, much is still unknown about the way tradeoffs steer the course of evolution. Recent studies open a new venue to the empirical exploration of this subject. The access to the genetic content of life has been revolutionizing the knowledge across the whole Biology, bringing some answers and raising a lot of new questions. The whole concept of multicellular life has been extending from the beginning of the 1990’s with the recognition of multicellular bacteria and numerous behaviors in the now shadowy region between unicellular and multicellular life. The approach of experimental evolution recently provided the first experimental insights into the process of transition from unicellular to multicellular life, by evolving multicellular organisms under controlled conditions in the laboratory. This current work aims to provide a contribution to the theoretical understanding of the role of tradeoffs in the transition to multicellularity and complexity development. For that, we introduce and explore some models tailored to elucidate some of the aspects of these transitions. Each of those models is explored through a combination of analytical and simulational methods, which allows us to extract further information. A first approach deals with the establishment of an efficient mode of metabolism within the context of competition with a rapid and inefficient mode. Usually, high rate inefficient metabolisms tend to dominate, therefore extra mechanisms are necessary to counteract this. Within a resource-based formulation, we study the effect of group structure in the population and find that with groups the efficient mode outcompetes the inefficient one in a broad domain of the parameter space. In the sequel, we analyze the contribution of tradeoffs to the evolution of complexity. It is empirically known that complex networks of tradeoffs are established at the cellular and metabolic level. In this context, a system with an arbitrary number of tradeoffs over a given number of tasks is investigated. We carry out a statistical analysis over different sets of parameters in order to examine the dependence of cell specialization on the number and strength of the tradeoffs. A concrete application of the model to the carbon-nitrogen fixation tradeoff in cyanobacteria is provided. At last, we introduce a mechanistic model for the dynamics of multicellular aggregates. We consider the existence of different microscopic mechanisms shaping multicellular aggregates. Particularly, the model is applied to the study of the size-complexity rule and interesting results follows from that approach. Depending on the geometry of the aggregates the size-complexity rule can be followed or not. We found that more fragile aggregates violate the rule and more robust ones obey it. Each of the works addressed here provides some answers and raises new issues to be explored in the future. For instance, what is the effect of germ-soma tradeoffs for the outcomes predicted in our models? Or, if the size-complexity rule can be violated under some circumstances, there exist additional mechanisms that can also have the same effect? These and other questions are raised and briefly discussed in the conclusions.
author2 CAMPOS, Paulo Roberto de Araújo
format doctoralThesis
author AMADO, André da Conceição
author_sort AMADO, André da Conceição
title Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
title_short Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
title_full Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
title_fullStr Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
title_full_unstemmed Fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
title_sort fitness tradeoffs in the evolutionary transition to multicellularity and the evolution of complexity
publisher Universidade Federal de Pernambuco
publishDate 2019
url https://repositorio.ufpe.br/handle/123456789/29704
_version_ 1641987419050868736
score 13.657419

Similar Items