Journal of Experimental Marine Biology and Ecology, 2012
Marine ecosystems involve relationships between genomic interactions of marine populations with s... more Marine ecosystems involve relationships between genomic interactions of marine populations with shared biogeographic ranges and the environmental conditions. These relationships, studied mainly through neutral DNA markers, are not always consistent with actual biogeographic patterns or the evolutionary history of marine species. In addition, increased information at functional genomic level from non-model species allows the study of adaptive responses in marine populations. This work reports local transcriptomic patterns in populations of the mussel Mytilus chilensis and their correspondence with oceanographic variability in southern Chile. Analysis of gene expression patterns was conducted through qPCR of seven candidate genes involved in the response to environmental stress (HSP70, HSP90), iron metabolism (Ferritin), pathogens (Mytilin B, Defensin) and oxidative stress (SOD-CuZn, Catalase) in at five study sites located in southern Chile, from Valdivia (39°56′S-73°36′W) to Melinka (43°52′S-73°44′W). Multivariate and correlation analyses were used to assess the relationship between levels of individual gene expression and site features characterized using satellite data on surface temperature, chlorophyll concentration and total suspended sediments. Two main groups of sites with differential patterns of gene expression were identified. Individuals exposed to higher temperatures showed an overexpression of HSP70, HSP90 and Ferritin genes. The expression of SOD-CuZn and Catalase was correlated with local chlorophyll-a (i.e. food availability for mussels), although with opposite correlations. In addition, Mytilin B showed higher levels of expression in areas with higher freshwater influence. Patterns of gene expression across the region of interest suggest that spatial variability in environmental conditions induce phenotypic changes in different populations of the same mussel species. In addition, the analysis of expression patterns in candidate genes can reveal local patterns in populations where other molecular markers show no genetic structure.
This study describes the results from transcriptomes sequenced by illumina technology from four p... more This study describes the results from transcriptomes sequenced by illumina technology from four populations in the marine snail Tegula atra along central-northern Chile (28-31°S) during summer and winter 2014. In silico differential expression of transcripts annotated to known proteins revealed several local patterns associated to the environmental thermal variability. Herein, northern populations evidenced lower number of genes highly regulated, while southern populations displayed opposite patterns. This relationship could suggest that northern snail populations are more adapted to high temperature variations, enabling specific genes (e.g. HSPs and antioxidant system) to maintain high transcriptional activity under controlled physiological conditions. This transcriptome response or "frontloading" strategy can significantly increase the speed of response to thermal stress, and also be a relevant molecular underpinning to explain the genomic diversity along the Chilean coast.
Journal of Experimental Marine Biology and Ecology, 2012
Marine ecosystems involve relationships between genomic interactions of marine populations with s... more Marine ecosystems involve relationships between genomic interactions of marine populations with shared biogeographic ranges and the environmental conditions. These relationships, studied mainly through neutral DNA markers, are not always consistent with actual biogeographic patterns or the evolutionary history of marine species. In addition, increased information at functional genomic level from non-model species allows the study of adaptive responses in marine populations. This work reports local transcriptomic patterns in populations of the mussel Mytilus chilensis and their correspondence with oceanographic variability in southern Chile. Analysis of gene expression patterns was conducted through qPCR of seven candidate genes involved in the response to environmental stress (HSP70, HSP90), iron metabolism (Ferritin), pathogens (Mytilin B, Defensin) and oxidative stress (SOD-CuZn, Catalase) in at five study sites located in southern Chile, from Valdivia (39°56′S-73°36′W) to Melinka (43°52′S-73°44′W). Multivariate and correlation analyses were used to assess the relationship between levels of individual gene expression and site features characterized using satellite data on surface temperature, chlorophyll concentration and total suspended sediments. Two main groups of sites with differential patterns of gene expression were identified. Individuals exposed to higher temperatures showed an overexpression of HSP70, HSP90 and Ferritin genes. The expression of SOD-CuZn and Catalase was correlated with local chlorophyll-a (i.e. food availability for mussels), although with opposite correlations. In addition, Mytilin B showed higher levels of expression in areas with higher freshwater influence. Patterns of gene expression across the region of interest suggest that spatial variability in environmental conditions induce phenotypic changes in different populations of the same mussel species. In addition, the analysis of expression patterns in candidate genes can reveal local patterns in populations where other molecular markers show no genetic structure.
This study describes the results from transcriptomes sequenced by illumina technology from four p... more This study describes the results from transcriptomes sequenced by illumina technology from four populations in the marine snail Tegula atra along central-northern Chile (28-31°S) during summer and winter 2014. In silico differential expression of transcripts annotated to known proteins revealed several local patterns associated to the environmental thermal variability. Herein, northern populations evidenced lower number of genes highly regulated, while southern populations displayed opposite patterns. This relationship could suggest that northern snail populations are more adapted to high temperature variations, enabling specific genes (e.g. HSPs and antioxidant system) to maintain high transcriptional activity under controlled physiological conditions. This transcriptome response or "frontloading" strategy can significantly increase the speed of response to thermal stress, and also be a relevant molecular underpinning to explain the genomic diversity along the Chilean coast.
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