Narum, S. R., Di Genova, A., Micheletti, S. J., & Maass, A. (2018). Genomic variation underlying complex life-history traits revealed by genome sequencing in Chinook salmon. Proc. R. Soc. B-Biol. Sci., 285(1883), 9 pp.
Abstract: A broad portfolio of phenotypic diversity in natural organisms can buffer against exploitation and increase species persistence in disturbed ecosystems. The study of genomic variation that accounts for ecological and evolutionary adaptation can represent a powerful approach to extend understanding of phenotypic variation in nature. Here we present a chromosome-level reference genome assembly for Chinook salmon (Oncorhynchus tshawytscha; 2.36 Gb) that enabled association mapping of life-history variation and phenotypic traits for this species. Whole-genome re-sequencing of populations with distinct life-history traits provided evidence that divergent selection was extensive throughout the genome within and among phylogenetic lineages, indicating that a broad portfolio of phenotypic diversity exists in this species that is related to local adaptation and life-history variation. Association mapping with millions of genome-wide SNPs revealed that a genomic region of major effect on chromosome 28 was associated with phenotypes for premature and mature arrival to spawning grounds and was consistent across three distinct phylogenetic lineages. Our results demonstrate how genomic resources can enlighten the genetic basis of known phenotypes in exploited species and assist in clarifying phenotypic variation that may be difficult to observe in naturally occurring organisms.
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Navarrete, S. A., Barahona, M., Weidberg, N., & Broitman, B. R. (2022). Climate change in the coastal ocean: shifts in pelagic productivity and regionally diverging dynamics of coastal ecosystems. Proc. R. Soc. B-Biol. Sci., 289(1970).
Abstract: Climate change has led to intensification and poleward migration of the Southeastern Pacific Anticyclone, forcing diverging regions of increasing, equatorward and decreasing, poleward coastal phytoplankton productivity along the Humboldt Upwelling Ecosystem, and a transition zone around 31 degrees S. Using a 20-year dataset of barnacle larval recruitment and adult abundances, we show that striking increases in larval arrival have occurred since 1999 in the region of higher productivity, while slower but significantly negative trends dominate poleward of 30 degrees S, where years of recruitment failure are now common. Rapid increases in benthic adults result from fast recruitment-stock feedbacks following increased recruitment. Slower population declines in the decreased productivity region may result from aging but still reproducing adults that provide temporary insurance against population collapses. Thus, in this region of the ocean where surface waters have been cooling down, climate change is transforming coastal pelagic and benthic ecosystems through altering primary productivity, which seems to propagate up the food web at rates modulated by stock-recruitment feedbacks and storage effects. Slower effects of downward productivity warn us that poleward stocks may be closer to collapse than current abundances may suggest.
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