| 21. |
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| 22. |
- Chang, Dan, et al.
(författare)
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The evolutionary and phylogeographic history of woolly mammoths : a comprehensive mitogenomic analysis
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Near the end of the Pleistocene epoch, populations of the woolly mammoth (Mammuthus primigenius) were distributed across parts of three continents, from western Europe and northern Asia through Beringia to the Atlantic seaboard of North America. Nonetheless, questions about the connectivity and temporal continuity of mammoth populations and species remain unanswered. We use a combination of targeted enrichment and high-throughput sequencing to assemble and interpret a data set of 143 mammoth mitochondrial genomes, sampled from fossils recovered from across their Holarctic range. Our dataset includes 54 previously unpublished mitochondrial genomes and significantly increases the coverage of the Eurasian range of the species. The resulting global phylogeny confirms that the Late Pleistocene mammoth population comprised three distinct mitochondrial lineages that began to diverge ~1.0–2.0 million years ago (Ma). We also find that mammoth mitochondrial lineages were strongly geographically partitioned throughout the Pleistocene. In combination, our genetic results and the pattern of morphological variation in time and space suggest that male-mediated gene flow, rather than large-scale dispersals, was important in the Pleistocene evolutionary history of mammoths.
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| 23. |
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| 24. |
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| 25. |
- Edwards, Ceiridwen J., et al.
(författare)
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Ancient Hybridization and an Irish Origin for the Modern Polar Bear Matriline
- 2011
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 21:15, s. 1251-1258
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Tidskriftsartikel (refereegranskat)abstract
- Background: Polar bears (Ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. Despite this, little is known about polar bear species history. Future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the timing and conditions of their initial divergence from brown bears (U. arctos) or their response to previous environmental change. Results: We used a spatially explicit phylogeographic model to estimate the dynamics of 242 brown bear and polar bear matrilines sampled throughout the last 120,000 years and across their present and past geographic ranges. Our results show that the present distribution of these matrilines was shaped by a combination of regional stability and rapid, long-distance dispersal from ice-age refugia. In addition, hybridization between polar bears and brown bears may have occurred multiple times throughout the Late Pleistocene. Conclusions: The reconstructed matrilineal history of brown and polar bears has two striking features. First, it is punctuated by dramatic and discrete climate-driven dispersal events. Second, opportunistic mating between these two species as their ranges overlapped has left a strong genetic imprint. In particular, a likely genetic exchange with extinct Irish brown bears forms the origin of the modern polar bear matriline. This suggests that interspecific hybridization not only may be more common than previously considered but may be a mechanism by which species deal with marginal habitats during periods of environmental deterioration.
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| 26. |
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| 27. |
- Ersmark, Erik, et al.
(författare)
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Population demography and genetic diversity in the Pleistocene cave lion
- 2015
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Ingår i: Open Quaternary. - : Ubiquity Press, Ltd.. - 2055-298X. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- With a range that covered most of northern Eurasia and parts of North America, the cave lion (Panthera spelaea) was one of the most widespread carnivores of the Late Pleistocene. Earlier ancient DNA analyses have shown that it is distinct from modern lions, and have suggested a demographic decline in Beringia during marine isotope stage 3 (MIS 3). Here, we further investigate the Late Pleistocene population dynamics in more detail by combining a powerful algorithm that couples MCMC with coalescent simulations under an approximate Bayesian computation framework. We use an ancient DNA dataset of previously published (n = 34) and new radiocarbon dated specimens (n = 14). Phylogenetic and network analyses based on the mitochondrial control region and the ATP8 gene identified two major haplogroups, one of which appears to vanish around 41,000 cal a BP. The approximate Bayesian computation analysis suggested a decline in effective population size (Ne) in Beringia of at least a 2-fold magnitude that began approximately 47,000 cal a BP, followed by an increase in Ne, most likely around 18,000 cal a BP. The cave lion went through a demographic bottleneck during MIS 3, which may have lasted for several tens of thousands of years, and only recovered shortly before the species' extinction. Several other large mammal species display similar declines in genetic diversity in Beringia during MIS 3, suggesting that major environmental changes might have affected megafaunal populations during this time period.
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| 28. |
- Evangelou, Evangelos, et al.
(författare)
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Genetic analysis of over 1 million people identifies 535 new loci associated with blood pressure traits.
- 2018
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:10, s. 1412-1425
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Tidskriftsartikel (refereegranskat)abstract
- High blood pressure is a highly heritable and modifiable risk factor for cardiovascular disease. We report the largest genetic association study of blood pressure traits (systolic, diastolic and pulse pressure) to date in over 1 million people of European ancestry. We identify 535 novel blood pressure loci that not only offer new biological insights into blood pressure regulation but also highlight shared genetic architecture between blood pressure and lifestyle exposures. Our findings identify new biological pathways for blood pressure regulation with potential for improved cardiovascular disease prevention in the future.
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| 29. |
- Fauchez, Thomas J. J., et al.
(författare)
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TRAPPIST Habitable Atmosphere Intercomparison (THAI) Workshop Report
- 2021
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Ingår i: The Planetary Science Journal. - : Institute of Physics Publishing (IOPP). - 2632-3338. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- The era of atmospheric characterization of terrestrial exoplanets is just around the corner. Modeling prior to observations is crucial in order to predict the observational challenges and to prepare for the data interpretation. This paper presents the report of the TRAPPIST Habitable Atmosphere Intercomparison workshop (2020 September 14-16). A review of the climate models and parameterizations of the atmospheric processes on terrestrial exoplanets, model advancements, and limitations, as well as direction for future model development, was discussed. We hope that this report will be used as a roadmap for future numerical simulations of exoplanet atmospheres and maintaining strong connections to the astronomical community.
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| 30. |
- Ivanova, Elena P, et al.
(författare)
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Impact of Nanoscale Roughness of Titanium Thin Film Surfaces on Bacterial Retention
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:3, s. 1973-1982
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Tidskriftsartikel (refereegranskat)abstract
- Two human pathogenic bacteria, Staphylococcus aureus CIP 68.5 and Pseudomonas aeruginosa ATCC 9025, were adsorbed onto surfaces containing Ti. thin films of varying thickness to determine the extent to which nanoscale surface roughness influences the extent of bacterial attachment. A magnetron sputter thin film system was used to deposit titanium films with thicknesses of 3,12, and 150 nm on glass substrata with corresponding surface roughness parameters of Rq 1.6, 1.2, and 0.7 nm (on a 4 μm x 4 μm scanning area). The chemical composition, wettability, and surface architecture of titanium thin films were characterized using X-ray photoelectron spectroscopy, contact angle measurements, atomic force microscopy, three-dimensional interactive visualization, and statistical approximation of the topographic profiles. Investigation of the dynamic evolution of the Ti. thin film, topographic parameters indicated that three commonly used parameters, Ra. Rq, and Rmax, were insufficient to effectively characterize the nanoscale rough/smooth surfaces. Two additional parameters, Rskw and Rkur: which describe the statistical distributions of roughness character, were found to be useful for evaluating the surface architecture. Analysis of bacterial retention profiles indicated that bacteria responded, differently to the surfaces on a scale of less than 1 nm change in the Ra and Rq Ti thin film surface roughness parameters by (i) an increased, number of retained cells by a factor of 2-3, and (ii) an elevated level of secretion of extracellular polymeric substances.
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