Adaptive genetic variation distinguishes Chilean blue mussels (Mytilus chilensis) from different marine environments.
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ABSTRACT:
SUBMITTER: Araneda C
PROVIDER: S-EPMC4851556 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Epigenetic variation affects gene expression without altering the underlying DNA sequence of genes controlling ecologically relevant phenotypes through different mechanisms, one of which is long non-coding RNAs (lncRNAs). This study identified and evaluated the gene expression of lncRNAs in the gill and mantle tissues of Mytilus chilensis individuals from two ecologically different sites: Cochamó (41°S) and Yaldad (43°S), southern Chile, both impacted by climatic-related conditions and by mussel farming given their use as seedbeds. Sequences identified as lncRNAs exhibited tissue-specific differences, mapping to 3.54 % of the gill transcriptome and 1.96 % of the mantle transcriptome, representing an average of 2.76 % of the whole transcriptome. Using a high fold change value (≥|100|), we identified 43 and 47 differentially expressed lncRNAs (DE-lncRNAs) in the gill and mantle tissue of individuals sampled from Cochamó and 21 and 17 in the gill and mantle tissue of individuals sampled from Yaldad. Location-specific DE-lncRNAs were also detected in Cochamó (65) and Yaldad (94) samples. Via analysis of the differential expression of neighboring protein-coding genes, we identified enriched GO terms related to metabolic, genetic, and environmental information processing and immune system functions, reflecting how the impact of local ecological conditions may influence the M. chilensis (epi)genome expression. These DE-lncRNAs represent complementary biomarkers to DNA sequence variation for maintaining adaptive differences and phenotypic plasticity to cope with natural and human-driven perturbations.
| S-EPMC10776947 | biostudies-literature
Project description:The study of adaptive population differences is relevant for evolutionary biology, as it evidences the power of selective local forces relative to gene flow in maintaining adaptive phenotypes and their underlying genetic determinants. However, human-mediated hybridization through habitat translocations, a common and recurrent aquaculture practice where hybrids could eventually replace local genotypes, risk populations' ability to cope with perturbations. The endemic marine mussel Mytilus chilensis supports a booming farming industry in the inner sea of Chiloé Island, southern Chile, which entirely relies on artificially collected seeds from natural beds that are translocated to ecologically different fattening centers. A matter of concern is how farm-impacted seedbeds will potentially cope with environmental shifts and anthropogenic perturbations. This study provides the first de novo transcriptome of M. chilensis; assembled from tissue samples of mantles and gills of individuals collected in ecologically different farm-impacted seedbeds, Cochamó (41°S) and Yaldad (43°S). Both locations and tissue samples differentially expressed transcripts (DETs) in candidate adaptive genes controlling multiple fitness traits, involved with metabolism, genetic and environmental information processing, and cellular processes. From 189,743 consensus contigs assembled: 1,716 (Bonferroni p value ≤ 0.05) were DETs detected in different tissues of samples from different locations, 210 of them (fold change ≥ | 100|) in the same tissue of samples from a different location, and 665 (fold change ≥ | 4|) regardless of the tissue in samples from a different location. Site-specific DETs in Cochamó (169) and Yaldad (150) in candidate genes controlling tolerance to temperature and salinity shifts, and biomineralization exhibit a high number of nucleotide genetic variants with regular occurrence (frequency > 99%). This novel M. chilensis transcriptome should help assessing and monitoring the impact of translocations in wild and farm-impacted mussel beds in Chiloé Island. At the same time, it would help designing effective managing practices for conservation, and translocation traceability.
| S-EPMC8174845 | biostudies-literature
Project description:The blue mussel Mytilus chilensis is an endemic and key socioeconomic species inhabiting the southern coast of Chile. This bivalve species supports a booming aquaculture industry, which entirely relies on artificially collected seeds from natural beds that are translocated to diverse physical-chemical ocean farming conditions. Furthermore, mussel production is threatened by a broad range of microorganisms, pollution, and environmental stressors that eventually impact its survival and growth. Herein, understanding the genomic basis of the local adaption is pivotal to developing sustainable shellfish aquaculture. We present a high-quality reference genome of M. chilensis, which is the first chromosome-level genome for a Mytilidae member in South America. The assembled genome size was 1.93 Gb, with a contig N50 of 134 Mb. Through Hi-C proximity ligation, 11,868 contigs were clustered, ordered, and assembled into 14 chromosomes in congruence with the karyological evidence. The M. chilensis genome comprises 34,530 genes and 4795 non-coding RNAs. A total of 57% of the genome contains repetitive sequences with predominancy of LTR-retrotransposons and unknown elements. Comparative genome analysis of M. chilensis and M. coruscus was conducted, revealing genic rearrangements distributed into the whole genome. Notably, transposable Steamer-like elements associated with horizontal transmissible cancer were explored in reference genomes, suggesting putative relationships at the chromosome level in Bivalvia. Genome expression analysis was also conducted, showing putative genomic differences between two ecologically different mussel populations. The evidence suggests that local genome adaptation and physiological plasticity can be analyzed to develop sustainable mussel production. The genome of M. chilensis provides pivotal molecular knowledge for the Mytilus complex.
| S-EPMC10137854 | biostudies-literature
Project description:Background biology: Global warming has accelerated in recent decades, with the Arctic warming 2–3 times faster than the global average. As a result boreal species are expanding into the Arctic, at a pace reflecting environmental warming. Nevertheless, the poleward expansion of boreal marine species is restricted by their ability to tolerate low water temperatures, and in the case of intertidal species, sub-zero air temperatures during winter. In Greenland, however, the number of days with extreme sub-zero air temperatures has decreased by more than 50% since the 1950’s, suggesting that the low air temperature constraint is weakening. Although boreal intertidal species could potentially benefit from this warmer climate to establish populations in the Arctic, recent work has shown that local intertidal summer air temperatures in Greenland can exceed 36°C. This temperature is above the thermoregulatory capacity of many boreal intertidal species, including the highly abundant blue mussel Mytilus edulis. Therefore will further colonisation of M. edulis in Greenland be inhibited by the increasingly warm summer temperatures. Aim of experiment: Intertidal animals (Greenland blue mussel M. edulis) were sampled in situ on the first warm days of the year from the inner (warmer) and outer (cooler) regions of the Godthåbsfjorden around Nuuk (64°N) to examine the fjord temperature gradient effect. In addition, subtidal M. edulis were also collected and subjected to two acute temperature shocks of 22 and 32°C, which represented common and extreme summer air temperatures for intertidal habitats near Nuuk.
2020-11-25 | E-MTAB-9786 | biostudies-arrayexpress
Project description:Azaspiracids are a class of recently discovered algae-derived shellfish toxins. Their distribution globally is on the increase with mussels being most widely implicated in azaspiracid-related food poisoning events. Evidence that these toxins were bound to proteins in contaminated mussels has been shown recently. In the present study characterization of these proteins in blue mussels, Mytilus edulis, was achieved using a range of advanced proteomics tools. Four proteins present only in the hepatopancreas of toxin-contaminated mussels sharing identity or homology with cathepsin D, superoxide dismutase, glutathione S-transferase Pi, and a bacterial flagellar protein have been characterized. Several of the proteins are known to be involved in self-defense mechanisms against xenobiotics or up-regulated in the presence of carcinogenic agents. These findings would suggest that azaspiracids should now be considered and evaluated as potential tumorigenic compounds. The presence of a bacterial protein only in contaminated mussels was an unexpected finding and requires further investigation. The proteins identified in this study should assist with development of urgently required processes for the rapid depuration of azaspiracid-contaminated shellfish. Moreover they may serve as early warning indicators of shellfish exposed to this family of toxins.
| S-EPMC2722768 | biostudies-literature
Project description:Smooth-shelled blue mussels, Mytilus spp., have a worldwide antitropical distribution and are ecologically and economically important. Mussels of the Mytilus edulis species complex have been the focus of numerous taxonomic and biogeographical studies, in particular in the Northern hemisphere, but the taxonomic classification of mussels from South America remains unclear. The present study analysed 348 mussels from 20 sites in Argentina, Chile, Uruguay and the Falkland Islands on the Atlantic and Pacific coasts of South America. We sequenced two mitochondrial locus, Cytochrome c Oxidase subunit I (625 bp) and 16S rDNA (443 bp), and one nuclear gene, ribosomal 18S rDNA (1770 bp). Mitochondrial and nuclear loci were analysed separately and in combination using maximum likelihood and Bayesian inference methods to identify the combination of the most informative dataset and model. Species delimitation using five different models (GMYC single, bGMYC, PTP, bPTP and BPP) revealed that the Mytilus edulis complex in South America is represented by three species: native M. chilensis, M. edulis, and introduced Northern Hemisphere M. galloprovincialis. However, all models failed to delimit the putative species Mytilus platensis. In contrast, however, broad spatial scale genetic structure in South America using Geneland software to analyse COI sequence variation revealed a group of native mussels (putatively M. platensis) in central Argentina and the Falkland Islands. We discuss the scope of species delimitation methods and the use of nuclear and mitochondrial genetic data to the recognition of species within the Mytilus edulis complex at regional and global scales.
| S-EPMC8412288 | biostudies-literature
Project description:The invasive marine mussel Mytilus galloprovincialis has displaced the native congener Mytilus trossulus from central and southern California, but the native species remains dominant at more northerly sites that have high levels of freshwater input. To determine the extent to which interspecific differences in physiological tolerance to low salinity might explain limits to the invasive species’ biogeography, we used an oligonucleotide microarray to compare the transcriptional responses of these two species to an acute decrease in salinity. Among 6,777 genes on the microarray, 117 genes showed significant changes that were similar between species, and 12 genes showed significant species-specific responses to salinity stress. Osmoregulation and cell cycle control were important aspects of the shared transcriptomic response to salinity stress, whereas the genes with species-specific expression patterns were involved in mRNA splicing, polyamine synthesis, exocytosis, translation, cell adhesion, and cell signaling. Forty-five genes that changed expression significantly during salinity stress also changed expression during heat stress, but the direction of change in expression was typically opposite for the two forms of stress. These results (i) provide insights into the role of changes in gene expression in establishing physiological tolerance to acute decreases in salinity, and (ii) indicate that transcriptomic differences between M. galloprovincialis and M. trossulus in response to salinity stress are subtle and involve only a minor fraction of the overall suite of gene regulatory responses.
2011-01-10 | GSE25111 | GEO
Project description:[original Title] Transcriptomic responses to heat-stress in invasive and native blue mussels (genus Mytilus): molecular correlates of invasive success. Invasive species are increasingly prevalent in marine ecosystems worldwide. Although many studies have examined the ecological effects of invasives, little is known about physiological mechanisms that might contribute to invasive success. The mussel Mytilus galloprovincialis, a native of the Mediterranean Sea, is a successful invader on the central and southern coasts of California, where it has largely displaced the native congener, Mytilus trossulus. It has been previously shown that thermal responses of several physiological traits may underlie the capacity of M. galloprovincialis to out-compete M. trossulus in warm habitats. To elucidate possible differences in stress-induced gene expression between these congeners, we developed an oligonucleotide microarray with 8,874 probes representing 4,488 different genes that recognized mRNAs of both species. In acute heat-stress experiments, 1,531 of these genes showed temperature-dependent changes in gene expression that were highly similar in the two congeners. In contrast, 96 genes showed species-specific responses to heat-stress, functionally characterized by their involvement in oxidative stress, proteolysis, energy metabolism, ion transport, cell signaling, and cytoskeletal reorganization. The gene that showed the biggest difference between the species was the gene for the molecular chaperone small heat shock protein 24, which was highly induced in M. galloprovincialis and showed only a small change in M. trossulus. These different responses to acute heat-stress may help to explain—and predict—the invasive success of M. galloprovincialis in a warming world.
2010-10-11 | GSE19031 | GEO
Project description:Marine mussels of the genus Mytilus have an unusual mode of mitochondrial DNA (mtDNA) transmission termed doubly uniparental inheritance (DUI). Female mussels are homoplasmic for the F mitotype, which is inherited maternally, while males are usually heteroplasmic, carrying a mixture of the maternal F mitotype and the paternally inherited M genome. Two classes of M genomes have been observed: "standard" M genomes and "recently masculinized" M genomes. The latter are more similar to F genomes at the sequence level but are transmitted paternally like standard M genomes. In this study we report the complete sequences of two standard male M. edulis and one recently masculinized male M. trossulus mitochondrial genome. A comparative analysis, including the previously sequenced M. edulis F and M. galloprovincialis F and M mtDNAs, reveals that these genomes are identical in gene order, but highly divergent in nucleotide and amino acid sequence. The large amount (>20%) of nucleotide substitutions that fall in coding regions implies that there are several amino acid replacements between the F and M genomes, which likely have an impact on the structural and functional properties of the mitochondrial proteome. Correlation of the divergence rate of different protein-coding genes indicates that mtDNA-encoded proteins of the M genome are still under selective constraints, although less highly than genes of the F genome. The mosaic F/M control region of the masculinized F genome provides evidence for lineage-specific sequences that may be responsible for the different mode of transmission genetics. This analysis shows the value of comparative genomics to better understand the mechanisms of maintenance and segregation of mtDNA sequence variants in mytilid mussels.
| S-EPMC1456209 | biostudies-literature
Project description:The effect of CO2-driven ocean acidification (OA) on marine biota has been extensively studied mostly on a single stage of the life cycle. However, the cumulative and population-level response to this global stressor may be biased due to transgenerational effects and their impacts on physiological plasticity. In this study, we exposed adult mussels Mytilus chilensis undergoing gametogenesis to two pCO2 levels (550 and 1200 ?atm) for 16 weeks, aiming to understand if prolonged exposure of reproductive individuals to OA can affect the performance of their offspring, which, in turn, were reared under multiple stressors (pCO2, temperature, and dissolved cadmium). Our results indicate dependence between the level of pCO2 of the broodstock (i.e., parental effect) and the performance of larval stages in terms of growth and physiological rates, as a single effect of temperature. While main effects of pCO2 and cadmium were observed for larval growth and ingestion rates, respectively, the combined exposure to stressors had antagonistic effects. Moreover, we found a suppression of feeding activity in post-spawning broodstock upon high pCO2 conditions. Nevertheless, this observation was not reflected in the final weight of the broodstock and oocyte diameter. Due to the ecological and socioeconomic importance of mussels' species around the globe, the potential implications of maternal effects for the physiology, survival, and recruitment of larvae under combined global-change stressors warrant further investigation.
| S-EPMC6196759 | biostudies-literature