252 research outputs found
Defining management units for cetaceans by combining genetics, morphology, acoustics and satellite tracking
Managing animal units is essential in biological conservation and requires spatial and temporal identification of such units. Since even neighbouring populations often have different conservation status and face different levels of anthropogenic pressure, detailed knowledge of population structure, seasonal range and overlap with animals from neighbouring populations is required to manage each unit separately. Previous studies on genetic structure and morphologic separation suggests three distinct populations of harbour porpoises with limited geographic overlap in the North Sea (NS), the Belt Sea (BS) and the Baltic Proper (BP) region. In this study, we aim to identify a management unit for the BS population of harbour porpoises. We use Argos satellite data and genetics from biopsies of tagged harbour porpoises as well as acoustic data from 40 passive acoustic data loggers to determine management areas with the least overlap between populations and thus the least error when abundance and population status is estimated. Discriminant analysis of the satellite tracking data from the BS and NS populations showed that the best fit of the management unit border during the summer months was an eastâwest line from Denmark to Sweden at latitude 56.95°N. For the border between BS and BP, satellite tracking data indicate a sharp decline in population density at 13.5°E, with 90% of the locations being west of this line. This was supported by the acoustic data with the average daily detection rate being 27.5 times higher west of 13.5°E as compared to east of 13.5°E. By using this novel multidisciplinary approach, we defined a management unit for the BS harbour porpoise population. We recommend that these boundaries are used for future monitoring efforts of this population under the EU directives. The boundaries may also be used for conservation efforts during the summer months, while seasonal movements of harbour porpoises should be considered during winter
Complete Inactivation of Sebum-Producing Genes Parallels the Loss of Sebaceous Glands in Cetacea
Publisher's version (Ăștgefin grein)Genomes are dynamic biological units, with processes of gene duplication and loss triggering evolutionary novelty. The mammalian skin provides a remarkable case study on the occurrence of adaptive morphological innovations. Skin sebaceous glands (SGs), for instance, emerged in the ancestor of mammals serving pivotal roles, such as lubrication, waterproofing, immunity, and thermoregulation, through the secretion of sebum, a complex mixture of various neutral lipids such as triacylglycerol, free fatty acids, wax esters, cholesterol, and squalene. Remarkably, SGs are absent in a few mammalian lineages, including the iconic Cetacea. We investigated the evolution of the key molecular components responsible for skin sebum production: Dgat2l6, Awat1, Awat2, Elovl3, Mogat3, and Fabp9. We show that all analyzed genes have been rendered nonfunctional in Cetacea species (toothed and baleen whales). Transcriptomic analysis, including a novel skin transcriptome from blue whale, supports gene inactivation. The conserved mutational pattern found in most analyzed genes, indicates that pseudogenization events took place prior to the diversification of modern Cetacea lineages. Genome and skin transcriptome analysis of the common hippopotamus highlighted the convergent loss of a subset of sebum-producing genes, notably Awat1 and Mogat3. Partial loss profiles were also detected in non-Cetacea aquatic mammals, such as the Florida manatee, and in terrestrial mammals displaying specialized skin phenotypes such as the African elephant, white rhinoceros and pig. Our findings reveal a unique landscape of âgene vestigesâ in the Cetacea sebum-producing compartment, with limited gene loss observed in other mammalian lineages: suggestive of specific adaptations or specializations of skin lipids.This work was supported by Project No. 031342 cofinanced
by COMPETE 2020, Portugal 2020 and the European Union
through the ERDF, and by Fundacža~o para a Cie^ncia e a
Tecnologia through national funds. R.R.F. thanks the Danish
National Research Foundation for its support of the Center
for Macroecology, Evolution, and Climate (grant DNRF96).
We acknowledge the various Cetacea genome consortiums
for genome sequencing and assemblies. We also thank Gısli
Vikingsson at the Marine and Freshwater Research Institute in
Iceland for lending us the Larsen gun and to North Sailing
whale watching for the use of their zodiac.Peer Reviewe
Genomic insights into the conservation status of the worldâs last remaining Sumatran rhinoceros populations
Highly endangered species like the Sumatran rhinoceros are at risk from inbreeding. Five historical and 16 modern genomes from across the species range show mutational load, but little evidence for local adaptation, suggesting that future inbreeding depression could be mitigated by assisted gene flow among populations. Small populations are often exposed to high inbreeding and mutational load that can increase the risk of extinction. The Sumatran rhinoceros was widespread in Southeast Asia, but is now restricted to small and isolated populations on Sumatra and Borneo, and most likely extinct on the Malay Peninsula. Here, we analyse 5 historical and 16 modern genomes from these populations to investigate the genomic consequences of the recent decline, such as increased inbreeding and mutational load. We find that the Malay Peninsula population experienced increased inbreeding shortly before extirpation, which possibly was accompanied by purging. The populations on Sumatra and Borneo instead show low inbreeding, but high mutational load. The currently small population sizes may thus in the near future lead to inbreeding depression. Moreover, we find little evidence for differences in local adaptation among populations, suggesting that future inbreeding depression could potentially be mitigated by assisted gene flow among populations
Patients' perspectives on high-tech home care: a qualitative inquiry into the user-friendliness of four technologies
BACKGROUND: The delivery of technology-enhanced home care is growing in most industrialized countries. The objective of our study was to document, from the patient's perspective, how the level of user-friendliness of medical technology influences its integration into the private and social lives of patients. Understanding what makes a technology user-friendly should help improve the design of home care services. METHODS: Four home care interventions that are frequently used and vary in their technical and clinical features were selected: Antibiotic intravenous therapy, parenteral nutrition, peritoneal dialysis and oxygen therapy. Our qualitative study relied on the triangulation of three sources of data: 1) interviews with patients (n = 16); 2) interviews with carers (n = 6); and 3) direct observation of nursing visits of a different set of patients (n = 16). Participants of varying socioeconomic status were recruited through primary care organizations and hospitals that deliver home care within 100 km of Montreal, the largest urban area in the province of Quebec, Canada. RESULTS: The four interventions have both a negative and positive effect on patients' lives. These technologies were rarely perceived as user-friendly, and user-acceptance was closely linked to user-competence. Compared with acute I.V. patients, who tended to be passive, chronic patients seemed keener to master technical aspects. While some of the technical and human barriers were managed well in the home setting, engaging in the social world was more problematic. Most patients found it difficult to maintain a regular job because of the high frequency of treatment, while some carers found their autonomy and social lives restricted. Patients also tended to withdraw from social activities because of social stigmatization and technical barriers. CONCLUSIONS: While technology contributes to improving the patients' health, it also imposes significant constraints on their lives. Policies aimed at developing home care must clearly integrate principles and resources supporting the appropriate use of technology. Close monitoring of patients should be part of all technology-enhanced home care programs
Demographic reconstruction from ancient DNA supports rapid extinction of the great auk
The great auk was once abundant and distributed across the North Atlantic. It is now extinct, having been heavily exploited for its eggs, meat, and feathers. We investigated the impact of human hunting on its demise by integrating genetic data, GPS-based ocean current data, and analyses of population viability. We sequenced complete mitochondrial genomes of 41 individuals from across the speciesâ geographic range and reconstructed population structure and population dynamics throughout the Holocene. Taken together, our data do not provide any evidence that great auks were at risk of extinction prior to the onset of intensive human hunting in the early 16th century. In addition, our population viability analyses reveal that even if the great auk had not been under threat by environmental change, human hunting alone could have been sufficient to cause its extinction. Our results emphasise the vulnerability of even abundant and widespread species to intense and localised exploitation
Dense sampling of bird diversity increases power of comparative genomics
© 2020, The Author(s). Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity1â4. Sparse taxon sampling has previously been proposed to confound phylogenetic inference5, and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363 genomes from 92.4% of bird familiesâincluding 267 newly sequenced genomes produced for phase II of the Bird 10,000 Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater numbers than has previously been possible and to recognize genomic novelties in particular bird lineages. The densely sampled alignment provides a single-base-pair map of selection, has more than doubled the fraction of bases that are confidently predicted to be under conservation and reveals extensive patterns of weak selection in predominantly non-coding DNA. Our results demonstrate that increasing the diversity of genomes used in comparative studies can reveal more shared and lineage-specific variation, and improve the investigation of genomic characteristics. We anticipate that this genomic resource will offer new perspectives on evolutionary processes in cross-species comparative analyses and assist in efforts to conserve species
Potential Cost-Effectiveness of Universal Access to Modern Contraceptives in Uganda
<div><h3>Background</h3><p>Over two thirds of women who need contraception in Uganda lack access to modern effective methods. This study was conducted to estimate the potential cost-effectiveness of achieving universal access to modern contraceptives in Uganda by implementing a hypothetical new contraceptive program (NCP) from both societal and governmental (Ministry of Health (MoH)) perspectives.</p> <h3>Methodology/Principal Findings</h3><p>A Markov model was developed to compare the NCP to the status quo or current contraceptive program (CCP). The model followed a hypothetical cohort of 15-year old girls over a lifetime horizon. Data were obtained from the Uganda National Demographic and Health Survey and from published and unpublished sources. Costs, life expectancy, disability-adjusted life expectancy, pregnancies, fertility and incremental cost-effectiveness measured as cost per life-year (LY) gained, cost per disability-adjusted life-year (DALY) averted, cost per pregnancy averted and cost per unit of fertility reduction were calculated. Univariate and probabilistic sensitivity analyses were performed to examine the robustness of results. Mean discounted life expectancy and disability-adjusted life expectancy (DALE) were higher under the NCP vs. CCP (28.74 vs. 28.65 years and 27.38 vs. 27.01 respectively). Mean pregnancies and live births per woman were lower under the NCP (9.51 vs. 7.90 and 6.92 vs. 5.79 respectively). Mean lifetime societal costs per woman were lower for the NCP from the societal perspective (1,987) and the MoH perspective (685). In the incremental analysis, the NCP dominated the CCP, i.e. it was both less costly and more effective. The results were robust to univariate and probabilistic sensitivity analysis.</p> <h3>Conclusion/Significance</h3><p>Universal access to modern contraceptives in Uganda appears to be highly cost-effective. Increasing contraceptive coverage should be considered among Uganda's public health priorities.</p> </div
Early Pleistocene enamel proteome from Dmanisi resolves Stephanorhinus phylogeny
The sequencing of ancient DNA has enabled the reconstruction of speciation, migration and admixture events for extinct taxa. However, the irreversible post-mortem degradation2 of ancient DNA has so far limited its recoveryâoutside permafrost areasâto specimens that are not older than approximately 0.5 million years (Myr). By contrast, tandem mass spectrometry has enabled the sequencing of approximately 1.5-Myr-old collagen type I, and suggested the presence of protein residues in fossils of the Cretaceous periodâalthough with limited phylogenetic use. In the absence of molecular evidence, the speciation of several extinct species of the Early and Middle Pleistocene epoch remains contentious. Here we address the phylogenetic relationships of the Eurasian Rhinocerotidae of the Pleistocene epoch, using the proteome of dental enamel from a Stephanorhinus tooth that is approximately 1.77-Myr old, recovered from the archaeological site of Dmanisi (South Caucasus, Georgia). Molecular phylogenetic analyses place this Stephanorhinus as a sister group to the clade formed by the woolly rhinoceros (Coelodonta antiquitatis) and Merckâs rhinoceros (Stephanorhinus kirchbergensis). We show that Coelodonta evolved from an early Stephanorhinus lineage, and that this latter genus includes at least two distinct evolutionary lines. The genus Stephanorhinus is therefore currently paraphyletic, and its systematic revision is needed. We demonstrate that sequencing the proteome of Early Pleistocene dental enamel overcomes the limitations of phylogenetic inference based on ancient collagen or DNA. Our approach also provides additional information about the sex and taxonomic assignment of other specimens from Dmanisi. Our findings reveal that proteomic investigation of ancient dental enamelâwhich is the hardest tissue in vertebrates, and is highly abundant in the fossil recordâcan push the reconstruction of molecular evolution further back into the Early Pleistocene epoch, beyond the currently known limits of ancient DNA preservation
Experience shapes our odor perception but depends on the initial perceptual processing of the stimulus
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