Browsing by Author "Noll, Daly"

Now showing 1 - 8 of 8
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    Comparative genome-wide polymorphic microsatellite markers in Antarctic penguins through next generation sequencing
    (2017) Abreu Vianna, Juliana de; Noll, Daly; Mura Jornet, Isidora; Valenzuela Guerra, Paulina; González Acuña, Daniel; Navarro, Cristel; Loyola, David E.; Dantas, Gisele P. M.
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    Comparative Genomics Supports Ecologically Induced Selection as a Putative Driver of Banded Penguin Diversification
    (2024) Leon, Fabiola; Pizarro, Eduardo; Noll, Daly; Pertierra, Luis R.; Parker, Patricia; Espinaze, Marcela P. A.; Luna-Jorquera, Guillermo; Simeone, Alejandro; Frere, Esteban; Dantas, Gisele P. M.; Cristofari, Robin; Cornejo, Omar E.; Bowie, Rauri C. K.; Vianna, Juliana A.
    The relative importance of genetic drift and local adaptation in facilitating speciation remains unclear. This is particularly true for seabirds, which can disperse over large geographic distances, providing opportunities for intermittent gene flow among distant colonies that span the temperature and salinity gradients of the oceans. Here, we delve into the genomic basis of adaptation and speciation of banded penguins, Gal & aacute;pagos (Spheniscus mendiculus), Humboldt (Spheniscus humboldti), Magellanic (Spheniscus magellanicus), and African penguins (Spheniscus demersus), by analyzing 114 genomes from the main 16 breeding colonies. We aim to identify the molecular mechanism and genomic adaptive traits that have facilitated their diversifications. Through positive selection and gene family expansion analyses, we identified candidate genes that may be related to reproductive isolation processes mediated by ecological thermal niche divergence. We recover signals of positive selection on key loci associated with spermatogenesis, especially during the recent peripatric divergence of the Gal & aacute;pagos penguin from the Humboldt penguin. High temperatures in tropical habitats may have favored selection on loci associated with spermatogenesis to maintain sperm viability, leading to reproductive isolation among young species. Our results suggest that genome-wide selection on loci associated with molecular pathways that underpin thermoregulation, osmoregulation, hypoxia, and social behavior appears to have been crucial in local adaptation of banded penguins. Overall, these results contribute to our understanding of how the complexity of biotic, but especially abiotic, factors, along with the high dispersal capabilities of these marine species, may promote both neutral and adaptive lineage divergence even in the presence of gene flow.
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    Cryptic speciation in gentoo penguins is driven by geographic isolation and regional marine conditions: Unforeseen vulnerabilities to global change
    (2020) Pertierra, Luis R.; Segovia, Nicolás I.; Noll, Daly; Martínez, Pablo A.; Pliscoff, Patricio; Barbosa, Andrés; Vianna, Juliana; Aragón, Pedro; Raya Rey, Andrea; Pistorius, Pierre; Trathan, Phil; Polanowski, Andrea; Bonadonna, Francesco; Le Bohec, Célin; Bi, Ke; Wang-Claypool, Cynthia Y.; González Acuña, Daniel; Dantas, Gisele P. M.; Bowie, Rauri C. K.; Poulin, Elie
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    Genetic structure of introduced American mink (Neovison vison) in Patagonia : colonisation insights and implications for control and management strategies
    (2018) Mora, Mónica; Medina-Vogel, Gonzalo; Sepúlveda, Maximiliano A.; Noll, Daly; Álvarez Varas, Rocío; De Abreu, Vianna Juliana
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    Genomic Introgression and Adaptation of Southern Seabird Species Facilitate Recent Polar Colonization
    (2025) Jorquera Faundez, Maria Josefina; Morales, Lucina; Ng, Elize Y.X.; Noll, Daly; Pertierra, Luis R.; Pliscoff, Patricio; Balza, Ulises; Boulinier, Thierry; Gamble, Amandine; Kasinsky, Tatiana; McInnes, Julie C.; Marin, Juan Carlos; Olmastroni, Silvia; Pistorius, Pierre; Phillips, Richard A.; Gonzalez-Solis, Jacob; Emmerson, Louise; Poulin, Elie; Bowie, Rauri C.K.; Burridge, Christopher P.; Vianna, Juliana
    Genomic adaptation and introgression can occur during the speciation process, enabling species to diverge in their frequencies of adaptive alleles or acquire new alleles that may promote adaptation to environmental changes. There is limited information on introgression in organisms from extreme environments and their responses to climate change. To address these questions, we focused on the 3 southern skua species, selected for their widespread distribution across the Southern Hemisphere and their complex history of speciation and introgression events. Our genomic data reveal that these skuas underwent diversification around the Penultimate Glacial Period, followed by subsequent demographic expansion. We identified a geographic region of introgression among species that followed a directional pattern sourced from the Antarctic continent, South America, and east to west in subantarctic islands, all converging towards the Antarctic Peninsula. The 3 skua species and admixed individuals exhibited a unique pattern of putative genes under selection, allowing adaptation to extreme conditions. Individuals with a higher proportion of Brown Skua ancestry showed signs of selection on genes related to reproductive isolation, while admixed individuals with a higher proportion of South Polar Skua ancestry displayed patterns resembling those of the South Polar Skua. Introgression may be a key mechanism of adaptation for many species that may help buffer against the ongoing climate change.
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    History of Diversification and Adaptation from North to South Revealed by Genomic Data: Guanacos from the Desert to Sub-Antarctica
    (2024) Leon, Fabiola; Pizarro, Eduardo J.; Noll, Daly; Pertierra, Luis R.; Gonzalez, Benito A.; Johnson, Warren E.; Marin, Juan Carlos; Vianna, Juliana A.
    The increased availability of quality genomic data has greatly improved the scope and resolution of our understanding of the recent evolutionary history of wild species adapted to extreme environments and their susceptibility to anthropogenic impacts. The guanaco (Lama guanicoe), the largest wild ungulate in South America, is a good example. The guanaco is well adapted to a wide range of habitats, including the Sechura Desert, the high Andes Mountains to the north, and the extreme temperatures and conditions of Navarino Island to the south. Guanacos also have a long history of overexploitation by humans. To assess the evolutionary impact of these challenging habitats on the genomic diversity, we analyzed 38 genomes (similar to 10 to 16x) throughout their extensive latitudinal distribution from the Sechura and Atacama Desert to southward into Tierra del Fuego Island. These included analyses of patterns of unique differentiation in the north and geographic region further south with admixture among L. g. cacsilensis and L. g. guanicoe. Our findings provide new insights on the divergence of the subspecies similar to 800,000 yr BP and document two divergent demographic trajectories and to the initial expansion of guanaco into the more southern portions of the Atacama Desert. Patagonian guanacos have experienced contemporary reductions in effective population sizes, likely the consequence of anthropogenic impacts. The lowest levels of genetic diversity corresponded to their northern and western limits of distribution and some varying degrees of genetic differentiation. Adaptive genomic diversity was strongly linked with environmental variables and was linked with colonization toward the south followed by adaptation.
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    Record of an alleged extinct rodent: molecular analyses of the endemic Octodon pacificus from Chile
    (2017) Abreu Vianna, Juliana de; Noll, Daly; Moreno, Lucila; Silva, Carolina; Muñoz Leal, Sebastián; Najle, María; González Acuña, Daniel
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    Shifting Perspectives in Polar Research: Global Lessons on the Barriers and Drivers for Securing Academic Careers in Natural Sciences
    (2021) Figuerola, Blanca; Valiente, Nicolas; Barbosa, Andres; Brasier, Madeleine J.; Colominas-Ciuro, Roger; Convey, Peter; Liggett, Daniela; Fernandez-Martinez, Miguel Angel; Gonzalez, Sergi; Griffiths, Huw J.; Jawak, Shridhar D.; Merican, Faradina; Noll, Daly; Prudencio, Janire; Quaglio, Fernanda; Pertierra, Luis R.
    The polar regions provide valuable insights into the functioning of the Earth's regulating systems. Conducting field research in such harsh and remote environments requires strong international cooperation, extended planning horizons, sizable budgets and long-term investment. Consequently, polar research is particularly vulnerable to societal and economic pressures during periods of austerity. The global financial crisis of 2008, and the ensuing decade of economic slowdown, have already adversely affected polar research, and the current COVID-19 pandemic has added further pressure. In this article we present the outcomes of a community survey that aimed to assess the main barriers and success factors identified by academic researchers at all career stages in response to these global crises. The survey results indicate that the primary barriers faced by polar early and mid-career researchers (EMCRs) act at institutional level, while mitigating factors are developed at individual and group levels. Later career scientists report pressure toward taking early retirement as a means of institutions saving money, reducing both academic leadership and the often unrecognized but vital mentor roles that many play. Gender and social inequalities are also perceived as important barriers. Reorganization of institutional operations and more effective strategies for long-term capacity building and retaining of talent, along with reduction in non-research duties shouldered by EMCRs, would make important contributions toward ensuring continued vitality and innovation in the polar research community.