Samuel Veilleux, Armelle Decaulne, Najat Bhiry. (2021). (Vol. 7).
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Dimas Sianipar, Bor-Shouh Huang, Kuo-Fong Ma, Ming-Che Hsieh, Po-Fei Chen, D. Daryono. (2022). (Vol. 229).
Keywords: Asperities Finite-fault Flores Thrust Rupture Source-time-functions
Programme: 133
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. (2021). Seabird population changes following mammal eradication at oceanic Saint-Paul Island, Indian Ocean (Vol. 63).
Keywords: Island restoration Petrels Population growth rate Rats Shearwaters Terns
Programme: 109
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Piero Poli, Nikolai M. Shapiro. (2022). (Vol. 49).
Keywords: backprojection seismology source surface waves Tonga volcanology
Programme: 133
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D. Noll, F. Leon, D. Brandt, P. Pistorius, C. Le Bohec, F. Bonadonna, P. N. Trathan, A. Barbosa, A. Raya Rey, G. P. M. Dantas, R. C. K. Bowie, E. Poulin, J. A. Vianna. (2022). Positive selection over the mitochondrial genome and its role in the diversification of gentoo penguins in response to adaptation in isolation (Vol. 12). Bachelor's thesis, , .
Abstract: Although mitochondrial DNA has been widely used in phylogeography, evidence has emerged that factors such as climate, food availability, and environmental pressures that produce high levels of stress can exert a strong influence on mitochondrial genomes, to the point of promoting the persistence of certain genotypes in order to compensate for the metabolic requirements of the local environment. As recently discovered, the gentoo penguins (Pygoscelis papua) comprise four highly divergent lineages across their distribution spanning the Antarctic and sub-Antarctic regions. Gentoo penguins therefore represent a suitable animal model to study adaptive processes across divergent environments. Based on 62 mitogenomes that we obtained from nine locations spanning all four gentoo penguin lineages, we demonstrated lineage-specific nucleotide substitutions for various genes, but only lineage-specific amino acid replacements for the ND1 and ND5 protein-coding genes. Purifying selection (dN/dS?1) is the main driving force in the protein-coding genes that shape the diversity of mitogenomes in gentoo penguins. Positive selection (dN/dS?>?1) was mostly present in codons of the Complex I (NADH genes), supported by two different codon-based methods at the ND1 and ND4 in the most divergent lineages, the eastern gentoo penguin from Crozet and Marion Islands and the southern gentoo penguin from Antarctica respectively. Additionally, ND5 and ATP6 were under selection in the branches of the phylogeny involving all gentoo penguins except the eastern lineage. Our study suggests that local adaptation of gentoo penguins has emerged as a response to environmental variability promoting the fixation of mitochondrial haplotypes in a non-random manner. Mitogenome adaptation is thus likely to have been associated with gentoo penguin diversification across the Southern Ocean and to have promoted their survival in extreme environments such as Antarctica. Such selective processes on the mitochondrial genome may also be responsible for the discordance detected between nuclear- and mitochondrial-based phylogenies of gentoo penguin lineages.
Keywords: Evolution Evolutionary genetics
Programme: 137,354
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. (2022). Rapid radiation of Southern Ocean shags in response to receding sea ice (Vol. 49).
Keywords: biogeography climate cycles cormorant Leucocarbo Southern Ocean speciation sub-Antarctic
Programme: 394
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Yanzhi Cao, Zhuang Jiang, Becky Alexander, Jihong Cole-Dai, Joel Savarino, Joseph Erbland, Lei Geng. (2022). On the potential fingerprint of the Antarctic ozone hole in ice-core nitrate isotopes: a case study based on a South Pole ice core (Vol. 22).
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Garcin N, Viblanc VA, Schull Q, Michaux D, Reichert S, Robin JP, Bize P, Stier A. (2021). Naturally equipped to resist stress.
Abstract: Stress exposure and stress response are likely to vary according to life history strategies and environmental contexts. Although the acute release of glucocorticoids in response to unpredictable environmental conditions may lead to adaptative behavioral and physiological responses, exposure to high glucocorticoid levels on the long-term usually leads to deleterious cascading effects on animal’s physiology, behavior and fitness. Yet, some species may be more adapted to cope with challenging events than others and might naturally possess protective mechanisms limiting the adverse consequences of prolonged exposure to high glucocorticoid levels. King penguin chicks being naturally exposed to harsh weather, prolonged fasting and constant predation pressure, we investigated the life-history, behavioral and physiological consequences of an experimental increase in corticosterone levels on the medium and long-term (after removing implants), predicting to find relatively few costs associated with such treatment. Although non-significant, CORT-treated chicks were slightly larger, fledged slightly earlier and had slightly higher survival chances than placebo chicks. CORT-treated chicks were significantly more aggressive and displayed lower corticosterone response to acute stress on the medium term, while their physical activity and whole-body energetics were not significantly affected. While mitochondrial density was not significantly affected by the CORT treatment, CORT-treated chicks had lower oxidative stress levels on the long-term than placebo ones, and no significant impact was observed on telomere shortening. Finally, the expression of several genes (i.e. CORT receptor, HSP90, mTOR, NRF2 and TERF2) was up regulated in treated chicks, which could potentially mediate the apparent ‘stress’ resistance we observed at the phenotypic level.
Programme: 119
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Roman Dubreucque. (2022). Modifications du fonctionnement écologique de systèmes aquatiques aux Iles Kerguelen..
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Oihana Boudreau. (2022).
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