Linking local movement and molecular analysis to explore philopatry and population connectivity of the southern stingray Hypanus americanus

Peer reviewedPublisher PD

Analyses of genetic variation in reef-building corals

Die vorliegende Dissertation untersucht die genetischer Variation in unterschiedlichen riffbildenden Korallen mit Hilfe molekularbiologischer Methoden. Hierzu wurden verschiedene Korallenarten (Anthozoa/Hydrozoa) mit Mikrosatelliten Markern auf das Vorkommen von intrakolonialer genetischer Variabilität (IGV) analysiert. IGV beschreibt einen Prozess bei welchem genetisch unterschiedlichen Einheiten in einer einzelnen Korallenkolonie existieren können. Im Zuge der Arbeit wurde untersucht, in welchen Arten, Altersklassen und Wuchsformen IGV auftritt und ob das Phänomen Auswirkungen auf die genetische Variation von Korallen hat. Die Ergebnisse der Dissertation zeigen auf, dass IGV in allen analysierten Korallenarten auftritt. Des Weiteren war es möglich zwischen IGV verursachenden Prozessen (Mosaizismus/Chimärismus) zu differenzieren. Zusammengefasst verdeutlicht die vorliegende Dissertation das IGV ein häufiges Phänomen in Korallen ist und hohe genetische Variation existieren kann

Isolation, characterization and cross amplification of eleven novel microsatellite loci for the hydrozoan coral Millepora

Milleporidae are of high ecological and economic importance, as, together with the scleractinian corals, they belong to the main reef builders of tropical coral reefs. Coral reefs face severe threats mainly due to anthropogenic disturbance. Understanding their population structure and dynamics is crucial for any conservation effort. Here we report the first microsatellite loci for the Milleporidae. Eleven polymorphic markers were developed for the hydrozoan corals Millepora dichotoma from the Great Barrier Reef (Australia) and tested for amplification in M. dichotoma from the Red Sea (Egypt), as well as for Millepora platyphylla from the Pacific Ocean (Moorea, French Polynesia). All loci were variable with 4–15 alleles per locus. Nine loci were transferable between geographic regions and species. These are the first microsatellites for hydrozoan corals. They will provide valuable tools for characterizing the population structure and genetic diversity of the group thereby benefitting coral reef conservation

Data from: More than one genotype: How common is intracolonial genetic variability in scleractinian corals?

In recent years, a few colonial marine invertebrates have shown intracolonial genetic variability, a previously unreported phenomenon. Intracolonial genetic variability describes the occurrence of more than a single genotype within an individual colony. This variability can be traced back to two underlying processes: chimerism and mosaicism. Chimerism is the fusion of two or more individuals, whereas mosaicism mostly derives from somatic cell mutations. Until now, it remained unclear to what degree the ecologically important group of hermatypic (reef building) corals might be affected. We investigate the occurrence of intracolonial genetic variability in five scleractinian corals: Acropora florida, Acropora hyacinthus, Acropora sarmentosa, Pocillopora species complex and Porites australiensis. The main focus was to test different genera for the phenomenon via microsatellite markers and to distinguish which underlying process caused the genetic heterogeneity. Our results show that intracolonial genetic variability was common (between 46.6% for A. sarmentosa and 23.8% for P. species complex) in all tested corals. The main process was mosaicism (69 cases of 222 tested colonies), but at least one chimera existed in every species. This suggests that intracolonial genetic variability is widespread in scleractinian corals and could challenge the view of a coral colony as an individual and therefore a unit of selection. However, it might also hold potential for colony survival under rapidly changing environmental conditions

The history, biological relevance, and potential applications for polyp bailout in corals

Corals have evolved a variety of stress responses to changing conditions, many of which have been the subject of scientific research. However, polyp bailout has not received widespread scientific attention, despite being described more than 80 years ago. Polyp bailout is a drastic response to acute stress in which coral colonies break down, with individual and patches of polyps detaching from the colony and the calcareous skeleton Polyps retain their symbiotic partners, have dispersal ability, and may undergo secondary settlement and calcification. Polyp bailout has been described worldwide in a variety of anthozoan species, especially in Scleractinia. It can be induced by multiple natural stressors, but also artificially. Little is known about the evolutionary and ecological potential and consequences of breaking down modularity, the dispersal ability, and reattachment of polyps resulting from polyp bailout. It has been shown that polyp bailout can be used as a model system, with promise for implementation in various research topics. To date, there has been no compilation of knowledge on polyp bailout, which prompted us to review this interesting stress response and provide a basis to discuss research topics and priorities for the future

Pocillopora_species_complex_dryad

Pocillopora_species_complex_drya

Porites_australiensis_dryad

Porites_australiensis_drya

Acropora_Hyacinthus_dryad

Acropora_Hyacinthus_drya

Acropora_Sarmentosa_dryad

Acropora_Sarmentosa_drya

Acropora-florida_dryad

Acropora-florida_drya