UCN-CEAZA
Gene expression analysis in Mytilus chilensis populations reveals local patterns associated with ocean environmental conditions.
Núñez-Acuña, G., Tapia, F., Haye, P., & Gallardo-Escárate, C.
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.
Año: 2012
Palabras claves: Gene expression; Mytilus chilensis; Adaptative response; Environmental stress; Thermal tolerance; Sea surface temperature
Referencia APA: Núñez-Acuña, G., Tapia, F., Haye, P., & Gallardo-Escárate, C. (2012). Gene expression analysis in Mytilus chilensis populations reveals local patterns associated with ocean environmental conditions. Journal Of Experimental Marine Biology And Ecology, 420-421, 56-64.
Testing sustainable management in Northern Chile: harvesting Macrocystis pyrifera (Phaeophyceae, Laminariales). A case study.
Borras-Chavez, R., Edwards, M., & Vásquez, J.
Kelp harvesting in northern Chile is managed by local fishermen and is part of an organized industry. However, the lack of standardized harvesting protocols has made regulation difficult. This, in combination with the impacts of oceanographic disturbances has resulted in some kelp populations being considerably reduced during the last decade. Consequently, harvest methods that maintain kelp resources are sorely needed if harvesting is to remain a viable industry in Chile. Here, experiments were done to identify sustainable methods for harvesting Macrocystis pyrifera along the coast of northern Chile. Three methods were compared with regard to their impacts on kelp populations; one that involves extracting half of the fronds from each individual in a population, one that involves extracting all the fronds from half of the individuals in a population, and a third that involves extracting all the fronds from all of the individuals in a population (i.e., the method currently used). Following this, populations were evaluated over a 2-month period to monitor re-growth of the remaining individuals and recruitment of new individuals, as well as changes in understory algal diversity and herbivore abundance. Our results indicate that removing half of the fronds from each individual in a population was the best method for maintaining the resource for future harvest because, it (1) maintains rapid growth of new fronds on the harvested individuals, (2) promotes recruitment of new individuals, and (3) reduces herbivore densities through physical abrasion. Consequently, this method is recommended for future harvesting of M. pyrifera in Northern Chile.
Año: 2012
Palabras claves: EcologyKelp, harvesting, Macrocystis, Phaeophyta, Sustainability
Referencia APA: Borras-Chavez, R., Edwards, M., & Vásquez, J. (2012). Testing sustainable management in Northern Chile: harvesting Macrocystis pyrifera (Phaeophyceae, Laminariales). A case study. J Appl Phycol, 24(6), 1655-1665.
Asociacion del color de la concha de reproductores de Argopecten purpuratus (Lamarck, 1819) con la supervivencia, crecimiento y desarrollo larval de sus progenies.
Garcia, R. & Winkler, F.
Las conchas de moluscos bivalvos marinos son extremadamente diversas en sus patrones de pigmentación y riqueza de colores. Tal diversidad se debe a factores ambientales y genéticos. En bivalvos marinos adultos, individuos con coloraciones de concha poco comunes en las poblaciones silvestres suelen presentar tasas de crecimiento y supervivencia menores que aquellos con colores de concha más frecuentes. Conociendo que la variación del color de la concha en Argopecten purpuratus está bajo control genético, en este trabajo se pone a prueba la hipótesis de que los loci responsables de dicha variación pueden afectar el crecimiento, la supervivencia y la tasa de desarrollo de las larvas de esta especie. Se estimó la supervivencia y el crecimiento en progenies de cruzamientos dirigidos entre individuos de A. purpuratus con colores de concha blanco, naranja y marrón, y se verificó la existencia de diferencias en las tasas de desarrollo. El crecimiento de las larvas producidas en cruzamientos que incluyeron individuos marrones o blancos con naranja no mostraron diferencias entre sí. En cambio, las progenies producto de autofecundaciones de individuos naranja y blancos presentaron tasas de crecimiento significativamente menores que las anteriores y distintas entre sí. Las tasas de desarrollo y de supervivencia, en cambio, no mostraron diferencias entre las progenies de los distintos tipos de cruzamientos. Los resultados sugieren que los genes que controlan la variación del color en las conchas de juveniles y adultos de A. purpuratus afectarían la tasa de crecimiento de sus larvas, pero no la tasa de desarrollo ni su supervivencia.
Año: 2012
Palabras claves: Argopecten purpuratus, ostión del norte, pectinidos, cultivo, desarrollo larval, color, Chile.
Referencia APA: Garcia, R. & Winkler, F. (2012). Asociacion del color de la concha de reproductores de Argopecten purpuratus (Lamarck, 1819) con la supervivencia, crecimiento y desarrollo larval de sus progenies. Latin American Journal Of Aquatic Research, 40(2), 367-375.