Browsing by Author "Dantas, Gisele P. M."

Now showing 1 - 8 of 8
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    Chinstrap penguin population genetic structure: one or more populations along the Southern Ocean?
    (2018) Mura-Jornet, Isidora; Pimentel, Carolina; Dantas, Gisele P. M.; Petry, Maria Virginia; Gonzalez-Acuna, Daniel; Barbosa, Andres; Lowther, Andrew D.; Kovacs, Kit M.; Poulin, Elie; Vianna, Juliana
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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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    Genome-wide analyses reveal drivers of penguin diversification
    (2020) Abreu Vianna, Juliana de; Fernandes, Flavia A. N.; Frugone, M. J.; Figueiro, H. V.; Pertierra, L. R.; Nolla, D.; Bi, K.; Wang Claypool, C. Y.; Lowther, A.; Parker, P.; Le Bohec, C.; Bonadonna, F.; Wienecke, B.; Pistorius, P.; Steinfurth, A.; Burridge, C. P.; Dantas, Gisele P. M.; Poulin, E.; Simison, W. B.; Henderson, J.; Eizirik, E.; Nery, M. F.; Bowie, Rauri C. K.
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    Have Historical Climate Changes Affected Gentoo Penguin (Pygoscelis papua) Populations in Antarctica?
    (2014) Pena M., Fabiola; Poulin, Elie; Dantas, Gisele P. M.; Gonzalez-Acuna, Daniel; Petry, Maria Virginia; Vianna, Juliana A.
    The West Antarctic Peninsula (WAP) has been suffering an increase in its atmospheric temperature during the last 50 years, mainly associated with global warming. This increment of temperature trend associated with changes in sea-ice dynamics has an impact on organisms, affecting their phenology, physiology and distribution range. For instance, rapid demographic changes in Pygoscelis penguins have been reported over the last 50 years in WAP, resulting in population expansion of sub-Antarctic Gentoo penguin (P. papua) and retreat of Antarctic Adelie penguin (P. adeliae). Current global warming has been mainly associated with human activities; however these climate trends are framed in a historical context of climate changes, particularly during the Pleistocene, characterized by an alternation between glacial and interglacial periods. During the last maximal glacial (LGM similar to 21,000 BP) the ice sheet cover reached its maximum extension on the West Antarctic Peninsula (WAP), causing local extinction of Antarctic taxa, migration to lower latitudes and/or survival in glacial refugia. We studied the HRVI of mtDNA and the nuclear intron beta fibint7 of 150 individuals of the WAP to understand the demographic history and population structure of P. papua. We found high genetic diversity, reduced population genetic structure and a signature of population expansion estimated around 13,000 BP, much before the first paleocolony fossil records (similar to 1,100 BP). Our results suggest that the species may have survived in peri-Antarctic refugia such as South Georgia and North Sandwich islands and recolonized the Antarctic Peninsula and South Shetland Islands after the ice sheet retreat.
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    Molecular Epidemiology of Avian Malaria in Wild Breeding Colonies of Humboldt and Magellanic Penguins in South America
    (2015) Sallaberry Pincheira, Nicole; Gonzalez Acuña, Daniel; Herrera Tello, Yeritza Romainne; Dantas, Gisele P. M.; Luna Jorquera, Guillermo; Frere, Esteban; Valdés Velásquez, Armando; Simeone, Alejandro; De Abreu, Vianna Juliana
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    Uncovering population structure in the Humboldt penguin (Spheniscus humboldti) along the Pacific coast at South America
    (2019) Dantas, Gisele P. M.; Oliveira, Larissa R.; Santos, Amanda M.; Flores, Mariana D.; de Melo, Daniella R.; Simeone, Alejandro; Gonzalez-Acuna, Daniel; Luna-Jorquera, Guillermo; Le Bohec, Celine; Valdes-Velasquez, Armando; Cardena, Marco; Morgante, Joao S.; Vianna, Juliana A.
    The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under genetic drift. High gene flow among populations, that can be constant or pulses of migration in a short period, may also decrease power of algorithms to detect genetic structure. Penguin species usually have large population sizes, high migratory ability but philopatric behavior, and recent investigations debate the existence of subtle population structure for some species not detected before. Previous study on Humboldt penguins found lack of population genetic structure for colonies of Punta San Juan and from South Chile. Here, we used mtDNA and nuclear markers (10 microsatellites and RAG1 intron) to evaluate population structure for 11 main breeding colonies of Humboldt penguins, covering the whole spatial distribution of this species. Although mtDNA failed to detect population structure, microsatellite loci and nuclear intron detected population structure along its latitudinal distribution. Microsatellite showed significant R-st values between most of pairwise locations (44 of 56 locations, R-st = 0.003 to 0.081) and 86% of individuals were assigned to their sampled colony, suggesting philopatry. STRUCTURE detected three main genetic clusters according to geographical locations: i) Peru; ii) North of Chile; and iii) Central-South of Chile. The Humboldt penguin shows signal population expansion after the Last Glacial Maximum (LGM), suggesting that the genetic structure of the species is a result of population dynamics and foraging colder water upwelling that favor gene flow and phylopatric rate. Our findings thus highlight that variable markers and wide sampling along the species distribution are crucial to better understand genetic population structure in animals with high dispersal ability.