Project description:While safety of fasting therapy is debated in humans, extended fasting occurs routinely and safely in wild animals. To do so, food deprived animals like breeding penguins anticipate the critical limit of fasting by resuming feeding. To date, however, no molecular indices of the physiological state that links spontaneous refeeding behaviour with fasting limits had been identified. Blood proteomics and physiological data reveal here that fasting-induced body protein depletion is not unsafe “per se”. Indeed, incubating penguins only abandon their chick/egg to refeed when this state is associated with metabolic defects in glucose homeostasis/fatty acid utilization, insulin production and action, and possible renal dysfunctions. Our data illustrate how the field investigation of “exotic” models can be a unique source of information, with possible biomedical interest.
Project description:In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries.
Project description:This paper reports on human burials and dietary reconstructions using a combination of mortuary, isotopic data and new 14C dates, recorded on mortuary contexts excavated at Aniwa, Futuna, and Tanna islands in 1964 during Shutlers pioneering archaeological work and more recently in the course of our South Vanuatu Archaeological Survey (SVAS) project. The earliest burials date to the first millennium AD, with subsequent changes and continuities of practice into the 19th century. Isotopic results suggest an influence of geographic and environmental characteristics of each islands on their diet. Diachronic comparisons suggest a decrease in diet breadth over time without significant change in food trophic level. These variations are discussed in relation to the complex history of island settlement, adaptation, and interaction in the region and beyond. In this paper, we analyse carbon and nitrogen isotopic data measured in individuals from Aniwa, Tanna and Futuna in relation to ecological and cultural features of the islands, and discuss their variation in relation to the islands’ complex history of settlement, adaptation, and interaction within the South Vanuatu region and beyond.
Project description:In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries. Data from NI and SA penguin juveniles are already on GEO n°GSE17725
Project description:In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries. We compared muscle sample biopsy from 4 penguin juveniles captured just before they undergone their first immersion to cold water (named NI for Never Immersed) and 3 penguin juveniles that had completly accomplished their acclimation to marine life (named SA for Sea Acclimated).
Project description:Changes in penguin populations on the Antarctic Peninsula have been linked to several environmental factors, but the potentially devastating impact of volcanic activity has not been considered. Here we use detailed biogeochemical analyses to track past penguin colony change over the last 8,500 years on Ardley Island, home to one of the Antarctic Peninsula's largest breeding populations of gentoo penguins. The first sustained penguin colony was established on Ardley Island c. 6,700 years ago, pre-dating sub-fossil evidence of Peninsula-wide occupation by c. 1,000 years. The colony experienced five population maxima during the Holocene. Overall, we find no consistent relationships with local-regional atmospheric and ocean temperatures or sea-ice conditions, although the colony population maximum, c. 4,000-3,000 years ago, corresponds with regionally elevated temperatures. Instead, at least three of the five phases of penguin colony expansion were abruptly ended by large eruptions from the Deception Island volcano, resulting in near-complete local extinction of the colony, with, on average, 400-800 years required for sustainable recovery.
Project description:Circoviruses infect a variety of animal species and have small (~1.8-2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adélie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adélie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015-2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adélie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adélie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.
Project description:BackgroundPenguins are flightless aquatic birds widely distributed in the Southern Hemisphere. The distinctive morphological and physiological features of penguins allow them to live an aquatic life, and some of them have successfully adapted to the hostile environments in Antarctica. To study the phylogenetic and population history of penguins and the molecular basis of their adaptations to Antarctica, we sequenced the genomes of the two Antarctic dwelling penguin species, the Adélie penguin [Pygoscelis adeliae] and emperor penguin [Aptenodytes forsteri].ResultsPhylogenetic dating suggests that early penguins arose ~60 million years ago, coinciding with a period of global warming. Analysis of effective population sizes reveals that the two penguin species experienced population expansions from ~1 million years ago to ~100 thousand years ago, but responded differently to the climatic cooling of the last glacial period. Comparative genomic analyses with other available avian genomes identified molecular changes in genes related to epidermal structure, phototransduction, lipid metabolism, and forelimb morphology.ConclusionsOur sequencing and initial analyses of the first two penguin genomes provide insights into the timing of penguin origin, fluctuations in effective population sizes of the two penguin species over the past 10 million years, and the potential associations between these biological patterns and global climate change. The molecular changes compared with other avian genomes reflect both shared and diverse adaptations of the two penguin species to the Antarctic environment.
Project description:The eco-evolutionary history of penguins is characterised by shifting from temperate to cold environments. Breeding in Antarctica, the Emperor penguin appears as an extreme outcome of this process, with unique features related to insulation, heat production and energy management. However, whether this species actually diverged from a less cold-adapted ancestor, more ecologically similar to its sister species, the King penguin, is still an open question. As the Antarctic colonisation likely resulted in vast changes in selective pressure experienced by the Emperor penguin, the relative quantification of the genomic signatures of selection, unique to each sister species, could answer this question. Applying phylogeny-based selection tests on 7651 orthologous genes, we identified a more pervasive selection shift in the Emperor penguin than in the King penguin, supporting the hypothesis that its extreme cold adaptation is a derived state. Furthermore, among candidate genes under selection, four (TRPM8, LEPR, CRB1, and SFI1) were identified before in other cold-adapted homeotherms, like the woolly Mammoth, while other 161 genes can be assigned to biological functions relevant to cold adaptation identified in previous studies. Location and structural effects of TRPM8 substitutions in Emperor and King penguin lineages support their functional role with putative divergent effects on thermal adaptation. We conclude that extreme cold adaptation in the Emperor penguin largely involved unique genetic options which, however, affect metabolic and physiological traits common to other cold-adapted homeotherms.