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View Article and Find Full Text PDFIn bluefin tuna aquaculture, high mortalities of hatchery-reared juveniles occur in sea cages owing to wall collisions that are caused by high-speed swimming in panic due to changes in illuminance. Here, we report that targeted gene mutagenesis of the ryanodine receptor (RyR1b), which allows the sarcoplasmic reticulum to release Ca in fast skeletal muscle, using highly active Platinum TALENs caused slow swimming behaviour in response to external stimuli in Pacific bluefin tuna (PBT) larvae. This characteristic would be a useful trait to prevent wall collisions in aquaculture production.
View Article and Find Full Text PDFPredicting antigens that would be protective is crucial for the development of recombinant vaccine using genome based vaccine development, also known as reverse vaccinology. High-throughput antigen screening is effective for identifying vaccine target genes, particularly for pathogens for which minimal antigenicity data exist. Using red sea bream iridovirus (RSIV) as a research model, we developed enzyme-linked immune sorbent assay (ELISA) based RSIV-derived 72 recombinant antigen array to profile antiviral antibody responses in convalescent Japanese amberjack (Seriola quinqueradiata).
View Article and Find Full Text PDFPopulations of widespread marine organisms are typically characterized by a low degree of genetic differentiation in neutral genetic markers, but much less is known about differentiation in genes whose functional roles are associated with specific selection regimes. To uncover possible adaptive population divergence and heterogeneous genomic differentiation in marine three-spined sticklebacks (Gasterosteus aculeatus), we used a candidate gene-based genome-scan approach to analyse variability in 138 microsatellite loci located within/close to (<6 kb) functionally important genes in samples collected from ten geographic locations. The degree of genetic differentiation in markers classified as neutral or under balancing selection-as determined with several outlier detection methods-was low (F(ST) = 0.
View Article and Find Full Text PDFDue to its influence on body size, timing of maturation is an important life-history trait in ectotherms with indeterminate growth. Comparison of patterns of growth and maturation within and between two populations (giant vs. normal sized) of nine-spined sticklebacks (Pungitius pungitius) in a breeding experiment revealed that the difference in mean adult body size between the populations is caused by differences in timing of maturation, and not by differential growth rates.
View Article and Find Full Text PDFBackground: Studies of closely related species with different sex chromosome systems can provide insights into the processes of sex chromosome differentiation and evolution. To investigate the potential utility of molecular markers in studying sex chromosome differentiation at early stages of their divergence, we examined the levels and patterns of genetic differentiation between sex chromosomes in nine-spined (Pungitius pungitius) and three-spined sticklebacks (Gasterosteus aculeatus) using microsatellite markers.
Results: A set of novel microsatellite markers spanning the entire length of the sex chromosomes were developed for nine-spined sticklebacks using the sequenced genomes of other fish species.
Examples of parallel evolution of phenotypic traits have been repeatedly demonstrated in threespine sticklebacks (Gasterosteus aculeatus) across their global distribution. Using these as a model, we performed a targeted genome scan--focusing on physiologically important genes potentially related to freshwater adaptation--to identify genetic signatures of parallel physiological evolution on a global scale. To this end, 50 microsatellite loci, including 26 loci within or close to (<6 kb) physiologically important genes, were screened in paired marine and freshwater populations from six locations across the Northern Hemisphere.
View Article and Find Full Text PDFGenome scan approaches to detect footprints of directional selection in the genomes of wild animal and plant populations have become popular tools to study local adaptation and speciation at the molecular level. Most studies thus far have used random molecular markers and found footprints of directional selection at, on average, 5% (range: 1-15%) of the examined loci. We focused on physiologically important genes that exhibit transcriptional responses to specific environmental or developmental conditions and assessed if these genes have been subject to directional selection and are responsible for local adaptation in the three-spined stickleback (Gasterosteus aculeatus).
View Article and Find Full Text PDFBackground: Identification of genes involved in adaptation and speciation by targeting specific genes of interest has become a plausible strategy also for non-model organisms. We investigated the potential utility of available sequenced fish genomes to develop microsatellite (cf. simple sequence repeat, SSR) markers for functionally important genes in nine-spined sticklebacks (Pungitius pungitius), as well as cross-species transferability of SSR primers from three-spined (Gasterosteus aculeatus) to nine-spined sticklebacks.
View Article and Find Full Text PDFThe genetic structure of contemporary populations can be shaped by both their history and current ecological conditions. We assessed the relative importance of postglacial colonization history and habitat type in the patterns and degree of genetic diversity and differentiation in northern European nine-spined sticklebacks (Pungitius pungitius), using mitochondrial DNA (mtDNA) sequences and 12 nuclear microsatellite and insertion/deletion loci. The mtDNA analyses identified - and microsatellite analyses supported - the existence of two historically distinct lineages (eastern and western).
View Article and Find Full Text PDFAlbinism with a large variation in body color was found in a hatchery population of Japanese flounder. In addition to albinism, ambicoloration and pseudo-albinism were simultaneously observed in some individuals. Albinos had a remarkably lower number of melanophores on the scales of ocular side than wild-type individuals did, although no significant difference was observed in the numbers of xanthophores and iridophores.
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