Polymorphic microsatellite markers in the brown seaweed Fucus vesiculosus.

BACKGROUND: Fucus vesiculosus is a brown seaweed dominant on temperate rocky shores of the northern hemisphere and, is typically distributed in the mid-upper intertidal zone. It is an external fertilizer that reproduces sexually, providing an excellent model to address conflicting theories related to mating systems and sexual selection. Microsatellite markers have been reported for several Fucus species, however the genomic libraries from where these markers have been isolated, have originated from two or more species pooled together (F. vesiculosus and F. serratus in one library; F. vesiculosus, F. serratus and Ascophyllum nodosum in a second library), or when the genomic DNA originated from only one species it was from Fucus spiralis. Although these markers cross-amplify F. vesiculosus individuals, the level of polymorphism has been low for relatedness studies. FINDINGS: The microsatellite markers described here were obtained from an enriched genomic library, followed by 454 pyrosequencing. A total of 9 microsatellite markers were tested across 44 individuals from the North of Portugal. The mean number of alleles across loci was 8.7 and the gene diversity 0.67. CONCLUSIONS: The high variability displayed by these microsatellite loci should be useful for paternity analysis, assessing variance of reproductive success and in estimations of genetic variation within and between populations.

Phenological and morphological variations in the Mediterranean orange coral Astroides calycularis between two distant localities.

Studies of intraspecific variation in the presence of different environmental features are essential to improving the knowledge of species population dynamics and structure. Astroides calycularis is an azooxanthellate scleractinian coral commonly found in shallow rocky habitats of the southwestern Mediterranean Sea. This study compares the fertilization period of two coral populations located in distantly separated localities; one in an upwelling area off the southern coast of the Iberian Peninsula, and the other on the southwestern coasts of Italy. Colony morphology varied between localities, the former having massive-shaped morphology with densely crowded polyps, the latter having bush-shaped morphology and separated polyps. These differences are possibly due to the different hydrodynamic conditions of their respective habitats. Gonochorism and planula brooding as sexual patterns and conditions of the coral coincide at both sites, but a delay in the timing of fertilization and planulation of the southern Iberian Peninsula population was observed, probably linked to a shift in the time at which seawater reaches its maximum temperature at each site.

Development of microsatellite markers as a molecular tool for conservation studies of the Mediterranean reef builder coral Cladocora caespitosa (Anthozoa, Scleractinia).

Cladocora caespitosa is a reef-building zooxanthellate scleractinian coral in the Mediterranean Sea. Mortality events have recurrently affected this species during the last decade. Thus, knowledge of its genetic structure, population diversity, and connectivity is needed to accomplish suitable conservation plans. In order to obtain a better understanding of the population genetics of this species, 13 highly variable microsatellites markers were developed from a naturally bleached colony. The developed primers failed to amplify zooxanthella DNA, isolated from C. caespitosa, verifying that these markers were of the coral and not algal symbiont origin. The degree of polymorphism of these loci was tested on tissue samples from 28 colonies. The allele number for each loci ranged from 2 to 13 (mean N(a) = 5.4), with an average observed heterozygosity of 0.42 (H(e) = 0.43) and all loci were in Hardy-Weinberg equilibrium. These new markers should be useful in future conservation genetic studies and will help to improve the resolution of the individual identification within this coral species. Primers were also tested in Oculina patagonica, with successful amplifications of several loci.