Diversity patterns and speciation processes in a two-island system with continuous migration

Author(s)

Princepe, Debora ; Czarnobai, Simone ; Pradella, Thiago M. ; Caetano, Rodrigo A. ; Marquitti, Flavia M. D. ; de Aguiar, Marcus A. M. ; Araujo, Sabrina B. L.

• Document type: Journal article
• Source: Evolution; v. 76, n. 10, p. 12-pg., 2022-09-06.

Abstract

Geographic isolation is a central mechanism of speciation, but perfect isolation of populations is rare. Although speciation can be hindered if gene flow is large, intermediate levels of migration can enhance speciation by introducing genetic novelty in the semi-isolated populations or founding small communities of migrants. Here, we consider a two-island neutral model of speciation with continuous migration and study diversity patterns as a function of the migration probability, population size, and number of genes involved in reproductive isolation (dubbed as genome size). For small genomes, low levels of migration induce speciation on the islands that otherwise would not occur. Diversity, however, drops sharply to a single species inhabiting both islands as the migration probability increases. For large genomes, sympatric speciation occurs even when the islands are strictly isolated. Then species richness per island increases with the probability of migration, but the total number of species decreases as they become cosmopolitan. For each genome size, there is an optimal migration intensity for each population size that maximizes the number of species. We discuss the observed modes of speciation induced by migration and how they increase species richness in the insular system while promoting asymmetry between the islands and hindering endemism. (AU)

• FAPESP's process: 19/20271-5 - Evolutionary models in population dynamics
• Grantee: Marcus Aloizio Martinez de Aguiar
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/11187-8 - Mitochondrial inheritance in phylogenetic trees
• Grantee: Débora Princepe
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/01343-7 - ICTP South American Institute for Fundamental Research: a regional center for theoretical physics
• Grantee: Nathan Jacob Berkovits
• Support Opportunities: Special Projects
• FAPESP's process: 19/24449-3 - Evolution of the mitonuclear genetic interaction
• Grantee: Débora Princepe
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor