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Context: Gilthead seabream (Sparus aurata) is a highly important farmed fish species specifically in the Mediterranean aquaculture industry. Infectious diseases present a significant threat to the sustainability of aquaculture with high economic losses due to mortalities, reduced productivity, and the necessity of additional treatments/vaccinations. Specific and sensitive methods for the detection of fish pathogens represent useful tools to investigate infection dynamics and enable early detection of the disease for better prevention. Selection and breeding for resistance against infectious diseases is also a highly valuable tool to help prevent or diminish disease outbreaks, and applying genomic information to the currently available advanced selection methods could accelerate the response to selection. The gram-negative bacteria Photobacterium damselae subsp. piscicida (Phdp) and the ectoparasite Sparicotyle chrisophrii (Sc) are two of the most important pathogens affecting seabream cultivation. Purpose of the study: The aims of this work are: (i) to investigate the genomic prediction of resistance to two highly problematic diseases in seabream through the application of 2b-RAD with the objective of achieving selective breeding goals and (ii) to design an effective assay for the detection and quantification of Phdp. Materials and methods: (i) 1233 and 1001 seabream individuals were challenged trough intramuscular injection with a virulent strain of Phdp and by co-habitation with naturally Sc-infected seabreams, respectively. Animals were monitored daily and data of dead/survived fish and number of parasites in the gills/body length were recorded. Genomic DNA was extracted from the finfish of all individuals and used to construct 2b-RAD libraries. Data were analyzed in order to find SNP based genotypes (GATK, SAMtools), perform Genome-Wide Association Studies, estimate breeding values (ASReml 4.0) and construct linkage-maps (Lep-Map v2). (ii) A primer set was designed from a partial sequence of the bamB gene (Primer3 web) considering two SNPs that discriminate between Phdp and its strictly correlated subspecies Phdd. The assay was tested for specificity/sensitivity on laboratory-generated samples as well as on previous experimentally infected seabream tissue samples. Results and discussion: (i) The reference catalogue contained 175,725 and 269,660 tags for the Phdp and the Sc challenge, respectively. The SNP detection process yielded genotypic data for 19,313 and 21,773 quality SNPs for Phdp and Sc, respectively, both grouped into 24 linkage groups (LG), which are consistent with the karyotype of this species. Genomic heritability for resistance to photobacteriosis was 0.31-0.33 and genomic heritability for tolerance to Sc was 0.11-0.22, suggesting potential to enhance both resistances through family-based selection. Estimated breeding values (EBV) using genomic (GBLUP) information presented 5-43% higher accuracy in comparison to those measured using the only pedigree information (PBLUP). GWAS revealed a quantitative trait locus (QTL) including 7 SNPs at LG17 which presented significant association with resistance to Phdp, while one SNP (LG17) was found affecting tolerance to Sc. (ii) The molecular method proposed for P. damselae diagnosis, with high specificity and sensitivity, proved to be suitable for detection, quantification and subspecies identification in one-step, overcoming the limitations of previous assays. Conclusions: The SNPs discovered through 2b-RAD genotyping could be used to implement new marker-assisted selection programs for the generation of more resistant fish, preventing important disease outbreaks in fish farms. In addition, the original molecular method proposed holds the potential to improve the current knowledge of Phdp infection dynamics and the development of better strategies to control this important fish disease.

Information on inflation of P-value, LD among significant SNPs, genes at QTL region and Manhattan plots. This file comprises supporting information which contains Q-Q plot, zoom in view of GWAS based P-values distributed at chromosome 2, information on genes around the highest significant SNP of chromsome2, LD values with heatmap for the top 5 significant markers of GWAS analysis, and Manhattan plots showing SNP positions corrected using linkage map information, and the shrinkage of p-values using model with the addition of top significant SNP used as fixed effect. Figure S2.1. Distribution of dead and alive sibs out of total sib count per full-sib family. Figure S2.2. Manhattan plot of –log10 P-values for P_D2D trait distributed across different LGs. Figure S2.3. (A-B): Manhattan plot of –log10 P-values for P_D2D trait distributed along the length (cM) of SA17. Figure S2.4. Q Q-Plot of –log10 P-values – days to death phenotype (P_D2D). Table S2.5. Variances explained by genome-wide significantly associated SNPs of P_D2D trait. Table S2.6. Summary for the functions of important candidate genes at QTL region (DOCX 718 kb).

A síndrome de Ascher (SA), um subtipo de0 anetodermia, é rara e caracterizada por apresentar em associação, com maior ou menor expressividade, relaxamento da pele das pálpebras, edema de lábio superior e aumento da tireóide. A etiologia é desconhecida, mas há evidências de defeito nas fibras elásticas, que se apresentam fragmentadas ou diminuídas. Relata-se o caso de paciente de 16 anos de idade, com queixa única: episódios recorrentes de edema bipalpebral. Ascher's Syndrome, a subtype of anetodermia, is a rare disease characterized by the association, in different degrees, of upper eyelid laxity, lip swelling and increase in thyroid size. Its etiology is unknown, but there is evidence for a defect in elastic fibers, which are either fragmented or decreased in number. A case is reported of a 16-year-old patient with a single complaint: recurrent episodes of bilateral eyelid edema.