Adaptation and gene flow in Neotropical amphibians (ADAPTFLOW)
Adaptación y flujo genético en anfibios neotropicales (ADAPTFLOW)
Principal investigator
Carles Vilà
Financial institution
MIN ECONOMÍA Y COMPETITIVIDAD
Fecha de inicio
Fecha de fin
Code
CGL2016-75227-P
Department
Ecology and Evolution
Researchers
Pontifícia Universidade Católica do Rio Grande do Sul (Porto Alegre, Brasil), Uppsala University (Uppsala, Suecia), Carnegie Museum of Natural History (Pittsburgh, USA), Universidad Nacional Autónoma de México (México DF, Méjico)
Brief description
La adaptación y el flujo genético son normalmente vistos como fuerzas opuestas. Mientras que la adaptación a diferentes hábitats (junto con la deriva genética y mutaciones) tiende aumentar la diferenciación en linajes, el flujo genético los tiende a homogeneizar y a reducir su diferenciación. Por tanto, el flujo genético comúnmente ha sido visto como un mecanismo que reduce las posibilidades de especiación. Sin embargo, durante los últimos años se ha acumulado evidencia que sugiere la posibilidad de divergencia aunque no haya aislamiento reproductivo y se siga produciendo intercambio genético entre los linajes. De hecho, algunos estudios han mostrado que la introgresión de genes procedentes de poblaciones divergentes incluso podría aumentar la diversidad fenotípica y el potencial evolutivo. Esta propuesta tiene como objetivo investigar la interacción entre el flujo genético y la adaptación en dos grupos de ranas neotropicales. En primer lugar, vamos a estudiar la radiación adaptativa de ranas de desarrollo directo del género Eleutherodactylus en el Caribe. Las especies de este género se han diversificado ampliamente en este sistema de islas, ocupando nichos ecológicos muy diferentes. Por ejemplo, algunas especies viven dentro de bromelias arbóreas, mientras que otras viven en cuevas o fuertemente asociadas a cursos de agua. Ranas que utilizan el mismo nicho han evolucionado de forma independiente en diferentes islas, pero muestran signos claros de convergencia morfológica. Para entender mejor esta radiación adaptativa vamos a completar las bases de datos morfológicos y genéticos existentes con información de las especies de América Central para así reconstruir la biogeografía del grupo y para estimar de manera más precisa el número de eventos de dispersión entre islas y la diversificación dentro de ellas. En este contexto, también vamos a investigar la evolución del dimorfismo sexual y su asociación con la ecomorfología de las especies utilizando métodos filogenéticos comparativos. A continuación, vamos a comparar los transcriptomas de unas 40 especies para investigar la base genética de esta convergencia mediante la estima de cuántos genes y qué genes están involucrados en la adaptación a un microhábitat determinado. Además, vamos a estudiar el flujo genético entre especies estrechamente relacionadas y simpátricas durante su divergencia, así como entre taxones más distantes pero que explotan el mismo microhábitat en la misma isla ¿Podría el flujo genético haber facilitado la convergencia dentro de las islas? En segundo lugar, vamos a estudiar el flujo genético a una escala mucho más grande, en un panel de 20-30 especies de ranas ampliamente distribuidas por toda la cuenca del Amazonas y adaptadas a diferentes nichos. Esto mostrará el impacto de la adaptación en el flujo de genes y los factores ambientales que lo limitan en cada caso. Sin embargo, para estimar el flujo genético es preciso utilizar un enfoque multilocus y los paneles de marcadores que son útiles para estudiar variación intra-específica (como los microsatélites o SNP) rara vez proporcionan datos comparables entre especies. Vamos a utilizar tecnologías de secuenciación masiva para secuenciar simultáneamente un gran número de loci que han demostrado ser útiles en comparaciones intra e interespecíficas en anfibios. Estos datos podrían facilitar las comparaciones de la estructura poblacional, flujo de genes y dinámica demográfica entre las diferentes especies.
Adaptation and gene flow are normally seen as opposing forces. While adaptation to different habitats (together with random genetic drift and novel mutations) tends to accumulate nucleotide differences in diverging lineages, gene flow tends to homogenize them and reduce differentiation. Thus, gene flow has commonly been seen as a mechanism reducing the chances of speciation. However, during recent years the scientific community has become more aware of divergence with gene flow. In fact, some studies have shown that introgression of genes from diverging populations could even increase the evolutionary potential and phenotypic diversity. This proposal aims at investigating the interplay between gene flow and adaptation in two multi-species systems of Neotropical frogs. First, we will study the adaptive radiation of the direct developing Eleutherodactylus frogs in the Caribbean. Species from this genus have extensively diversified in this island system, occupying very different ecological niches. For example, some species live within arboreal bromeliads while others live in caves or tightly associated to streams. Frogs using the same niche have independently evolved on different islands, but show clear signs of morphological convergence. To better understand this adaptive radiation we will complete existing morphological and genetic databases with information from species from Central America to reconstruct the biogeography of the group and properly assess the number of inter-island dispersal and within-island radiation events. In this context, we will also investigate the evolution of sexual dimorphism and its association with microhabitat specialization using phylogenetic comparative methods. In addition, we will use transcriptome capture of about 40 species to investigate the genetic basis of this convergence by assessing how many genes and what genes are involved in the adaptation to a given microhabitat. Also, we will study gene flow between sympatric closely related species during their divergence, and between more distantly related taxa exploiting the same microhabitat. Could gene flow have facilitated convergence within islands? Second, we will study intra-species gene flow at a much larger scale between a panel of 20-30 frog species widely distributed across the Amazonian basin and adapted to different niches. This will illustrate the role of adaptation on the long distance gene flow and which environmental factors limit this gene flow in each case. However, we need to use a multi-locus approach to reliably estimate gene flow, and the panels of markers that are useful within species (such as microsatellites or SNPs) rarely provide data that is comparable across species. We will use next generation sequencing technologies to simultaneously sequence a large number of loci that have shown to be useful in intra- and inter-specific comparisons. These data could facilitate comparisons of population structure, gene flow and also population dynamics.
Adaptation and gene flow are normally seen as opposing forces. While adaptation to different habitats (together with random genetic drift and novel mutations) tends to accumulate nucleotide differences in diverging lineages, gene flow tends to homogenize them and reduce differentiation. Thus, gene flow has commonly been seen as a mechanism reducing the chances of speciation. However, during recent years the scientific community has become more aware of divergence with gene flow. In fact, some studies have shown that introgression of genes from diverging populations could even increase the evolutionary potential and phenotypic diversity. This proposal aims at investigating the interplay between gene flow and adaptation in two multi-species systems of Neotropical frogs. First, we will study the adaptive radiation of the direct developing Eleutherodactylus frogs in the Caribbean. Species from this genus have extensively diversified in this island system, occupying very different ecological niches. For example, some species live within arboreal bromeliads while others live in caves or tightly associated to streams. Frogs using the same niche have independently evolved on different islands, but show clear signs of morphological convergence. To better understand this adaptive radiation we will complete existing morphological and genetic databases with information from species from Central America to reconstruct the biogeography of the group and properly assess the number of inter-island dispersal and within-island radiation events. In this context, we will also investigate the evolution of sexual dimorphism and its association with microhabitat specialization using phylogenetic comparative methods. In addition, we will use transcriptome capture of about 40 species to investigate the genetic basis of this convergence by assessing how many genes and what genes are involved in the adaptation to a given microhabitat. Also, we will study gene flow between sympatric closely related species during their divergence, and between more distantly related taxa exploiting the same microhabitat. Could gene flow have facilitated convergence within islands? Second, we will study intra-species gene flow at a much larger scale between a panel of 20-30 frog species widely distributed across the Amazonian basin and adapted to different niches. This will illustrate the role of adaptation on the long distance gene flow and which environmental factors limit this gene flow in each case. However, we need to use a multi-locus approach to reliably estimate gene flow, and the panels of markers that are useful within species (such as microsatellites or SNPs) rarely provide data that is comparable across species. We will use next generation sequencing technologies to simultaneously sequence a large number of loci that have shown to be useful in intra- and inter-specific comparisons. These data could facilitate comparisons of population structure, gene flow and also population dynamics.