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| Author(s): |
Vítor Marquioni Monteiro
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2024-02-23 |
| Examining board members: |
Marcus Aloizio Martinez de Aguiar;
Alex Antonelli;
Jacopo Grilli;
Maurice de Koning;
Sabrina Borges Lino Araújo
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| Advisor: | Marcus Aloizio Martinez de Aguiar |
| Abstract | |
Sympatric speciation is a process where species emerge in a community in the presence of gene flow. Although already proposed by Darwin in 1859, it remains a very contentious diversification process to which strong evidence is not easy to find. Notwithstanding, in 1991, Derrida and Higgs showed that haploid individuals evolving in sympatry could form reproductively isolated groups under neutral evolutionary forces. Their model considers the evolution of a panmictic finite population, with sexual reproduction and a fixed mutation rate, in which individuals are described by binary sequences representing their genomes. In the limit of infinitely large genomes, a transition between low and high diversity regimes can be observed if mating restrictions based on genetic similarity are included. However, the same transition shows a different behavior when the genome is finite. This thesis presents a theoretical analysis of the distinct regimes of the finite Derrida-Higgs model displays, i.e., the low and high diversity regimes, including a heuristic approximation of the transition between the two. Furthermore, applications of the model and the theory are subsequently presented. The Princepe-Aguiar model for mitochondrial and nuclear genetic material coevolution is analyzed for the case of sympatric communities and our results corroborate the author's conclusions, stating that the barcode property of the mitochondrial DNA does not emerge in the absence of spatial structures. We finish this text with a model of viral evolution during epidemics in which we have studied the genetic variability in a neutral spread for different contact networks, and also the effects of quarantine regimes in such outbreaks spreading over scalefree networks. We, therefore, have introduced the first complete theory for the Derrida-Higgs dynamics which, albeit including heuristic approximations, can be extended to other studies (e.g. the mito-nuclear DNA coevolution model). Moreover, we advocate that our epidemic model provides a general framework to study the evolutionary patterns of a pathogen if the contact network structure is considered (AU) | |
| FAPESP's process: | 19/13341-7 - Phase transitions in finite Derrida-Higgs models |
| Grantee: | Vitor Marquioni Monteiro |
| Support Opportunities: | Scholarships in Brazil - Doctorate |