Relationship between genetic, bacterial and chemical diversity of the mediterranean sponge spongia - agaricina (relación entre la diversidad genética, bacteriana y química de la esponja mediterránea sp.)

• Autores: Charlotte Noyer
• Directores de la Tesis: MIkel A. Becerro (dir. tes.), Cruz Palacín Cabañas (tut. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2010
• Idioma: español
• Tribunal Calificador de la Tesis: María Jesús Uriz Lespe (presid.), Rocío Pérez Portela (secret.), Bernard Banaigs (voc.)
• Materias:
  • Ciencias de la vida
    • Biología animal (zoología)
      • Ecología animal
      • Zoología marina
    • Biología molecular
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• Resumen

  • Understanding diversity is a major ecological goal that has expanded to other social fields. The term biodiversity commonly refers to ecosystem, species and genetic diversity and the complex set of interactions within and between those levels. Diversity is linked to variability in and of life and it is a dynamic concept. However, little efforts have focused on the connections between multiple levels of diversity. Understanding the relationships between multiple levels of diversity may shed light on the mechanisms that generate and maintain biodiversity. In this study, we investigated the genetic, bacterial, and chemical diversity of the endangered Mediterranean sponge Spongia lamella (previously Spongia agaricina). These levels of diversity are intrinsically related to sponge evolution and could have strong conservation implications. We developed microsatellite markers and used multi-locus-heterozygosity and gene diversity to assess genetic diversity. We used denaturing gel gradient electrophoresis (DGGE) and quantitative PCR to compare, identify, and quantify main bacterial clades in the sponge. We used HPLC chromatograms to obtain chemical profiles. Then, we applied the Shannon index of diversity to calculate bacterial and chemical diversity. We calculated these three diversity indexes in multiple populations across the western Mediterranean and tested whether the three diversity levels investigated in this study were associated at a population level. Genetic analyses revealed that sponge populations were highly and significantly differentiated. The population from Ceuta presented the highest genetic diversity. We also observed bottlenecks for many populations, Ceuta being the least affected. DGGE revealed semi-quantitative intra- and interpopulation variation and significant differences in bacterial fingerprints between sponge populations. Quantitative PCR performed on Chloroflexi, Acidobacteria, and Actinobacteria (which are found in high abundance in this species) also differed significantly between populations. The Atlantic population (Berlangas, Portugal) presented the greatest differences for all the bacterial clades amplified. Comparison of chemical profiles showed that only nine compounds out of 22 differed between sponge populations. Chemical diversity was quite low, because of the presence of 2 major compounds (nitenin and an unidentified compound), but differed significantly between sponge populations. We found higher dissimilarities in genetic, bacterial, and chemical diversity with increasing geographic distance between populations. However, we failed to detect significant correlation between those three levels of diversity at a population level. This suggests that multiple geographically variable factors could regulate the genetic, bacterial, and chemical diversities investigated in this study, highlighting the complex nature of the mechanisms behind biodiversity.