Resumen de Challenges in marine ecology: genomic investigations of dispersal patterns and phenotypic plasticity in Mediterranean Fishes = Desafíos en ecología marina: investigaciones genómicas de los patrones de dispersión y de la plasticidad fenotípica en peces del Mediterráneo
One of the most important challenges in marine ecology is understanding the dispersal capabilities of species. Connectivity, if from en evolutionary perspective or a more current ecological perspective, is highly important in determining the natural regulation of populations. By considering both time scales, it is possible to estimate the persistence of a species and its populations. Hence, correct management decisions on conservation issues should include genetic population data combined with oceanographic processes as well as direct measurements of larval dispersal for the full understanding of the population dynamics of species. Therefore, in this thesis I evaluated the population structure, larval dispersal and gene expression in several fish species from the Mediterranean Sea. In this thesis, I approach a variety of ecological and evolutionary challenges from different angles. In chapter 3.1 I analyze the genetic population structure of two different Mediterranean fish species. The first analysis focuses on the conservation of the endangered species Epinephelus marginatus and attempts to give indications on the status of the species as well as population genetic information for the correct design of management strategies. As it becomes clear that oceanographic processes, such as fronts and currents, are important factors in influencing genetic population structure, I proceed with a more multi-disciplinary analysis of the genetic structuring of Serranus cabrilla, a common Mediterranean fish species. The approach includes the comparison of genetic data with oceanographic particle simulations and can give indications on the degree of influence that the physical environment can have on a species genetic distribution. In chapter 3.2 I move from a population approach to the individual level approach. The development, physiology and behavior of an organism determine the life history traits as well as the adaptability to changing conditions. I investigate this by evaluating the differences in gene expression and function for males displaying alternative reproductive tactics as well as females. This is the first genome-wide study for a non-molecular model species in the context of alternative mating strategies and provides essential information on the molecular basis of social dominance. With the production of a de novo transcriptome assembly in chapter 3.2, it can be possible to identify in silico single nucleotide polymorphism markers from this type of data. I start in chapter 3.3 with the development of such markers in Tripterygion delaisi exploring for an optimal protocol allowing future SNP developments in non-model species. This type of genetic markers permits a more time and resource-efficient genotyping for a large amount of samples. Therefore, I used SNPs to explore connectivity patterns by using paternity analysis. The direct evidence of dispersal requires a large amount of individuals, but can provide very important insights and is essential to understanding current connectivity patterns in different marine habitats. This study especially complements the investigations in chapter 3.1 granting a wholesome understanding of population connectivity on evolutionary as well as ecological time scales.
