Browsing by Author "Solas, Maribel"

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    Assessment of local adaptation and outbreeding risks in contrasting thermal environments of the giant kelp, Macrocystis pyrifera
    (2024) Solas, Maribel; Correa, Rodolfo A.; Barria, Fernanda; Garces, Cristobal; Camus, Carolina; Faugeron, Sylvain
    Understanding the scope of local adaptation is critical to the definition of restoration strategies as it may affect individuals used as breeders or transplants. The assessment of such risks is, however, challenging for large seaweeds such as kelps, because their experimental manipulation is difficult in marine coastal environments. We investigated the consequences of local adaptation on reproductive traits of gametophytes, and growth and survival of sporophytes of the giant kelp, Macrocystis pyrifera. Over a thousand juvenile sporophytes were obtained from controlled crosses using 2 to 3 parental sporophytes from each of 18 populations from 5 different regions (i.e. Magellanes. Southern Chile, Atacama, Peru and California), to assess fertility and fecundity of female gametophytes when exposed to males of different habitats, and to produce juvenile sporophytes that were used to test for local adaptation sensu stricto in common garden experiments. By comparing sympatric and allopatric combinations of source populations and the average temperature of the sampled regions, we detected a significant pattern of local adaptation. We quantified the risks associated with different combinations of population/habitat for the performance of juvenile sporophytes typically used as transplants in kelp restoration actions. We found evidence of reduced reproductive success associated with outbreeding for high latitude populations, while low latitude populations favored hybrid crosses, suggesting a shift between outbreeding depression and hybrid vigor across different habitats (i.e., temperature). We also showed that a heatwave equally increased mortality of sporophytes across all regions except for Peruvian inbred crosses, suggesting these low latitude populations hold key genetic resources for future actions under ocean warming. Altogether, these experiments provide a framework for assessing risks associated with the choice of source populations in any kelp species.
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    Factores que favorecen y/o restringen la adaptación local en el huiro gigante Macrocystis Pyrifera
    (2023) Solas, Maribel; Faugeron, Sylvain Wielfrid; Pontificia Universidad Católica de Chile. Facultad de Ciencias Biológicas
    Comprender el alcance de la adaptación local en macroalgas es esencial para estrategias de restauración y cultivo de especies, porque afecta a individuos utilizados como reproductores o trasplantes. Investigamos las consecuencias de la adaptación local en una especie de kelp, comparando combinaciones locales y no locales de poblaciones, siguiendo un criterio de metapoblación, para evaluar además la importancia relativa de otros procesos evolutivos distintos a la adaptación local. Detectamos un patrón significativo de adaptación local en la fase esporofítica. Detectamos que los límites de tolerancia ecológica pueden afectar negativamente el desempeño de los individuos en ciertas regiones extremas, ya que además pueden sufrir más los efectos de endogamia, lo que afecta el desempeño de los individuos incluso en condiciones óptimas. Esperábamos restricciones entre individuos muy relacionados genéticamente para evitar depresión por endogamia y restricciones entre individuos de poblaciones más distantes para evitar depresión por exogamia. No obstante, los resultados muestran un efecto significativo en la reproducción de los gametofitos femeninos en presencia de machos emparentados. Así como un éxito reproductivo reducido en poblaciones de latitudes altas. En contraste, las poblaciones de bajas latitudes favorecieron cruces híbridos. Esto sugiere un cambio entre depresión por exogamia y vigor híbrido en diferentes hábitats. La ola de calor afectó a los esporofitos en todas las regiones, exceptuando los cruzamientos peruanos. Esto indica que estas poblaciones contienen recursos genéticos esenciales para acciones futuras frente al cambio climático.
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    Mates Matter: Gametophyte Kinship Recognition and Inbreeding in the Giant Kelp, Macrocystis pyrifera (Laminariales, Phaeophyceae)
    (2021) Camus, Carolina; Solas, Maribel; Martinez, Camila; Vargas, Jaime; Garces, Cristobal; Gil-Kodaka, Patricia; Ladah, Lydia B.; Serrao, Ester A.; Faugeron, Sylvain
    Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male-female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male-female kinship effect was stronger in high-latitude populations, suggesting that females from low-latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.