| 1. |
- Muhlemann, B., et al.
(författare)
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Ancient hepatitis B viruses from the Bronze Age to the Medieval period
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 557:7705, s. 418-423
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis B virus (HBV) is a major cause of human hepatitis. There is considerable uncertainty about the timescale of its evolution and its association with humans. Here we present 12 full or partial ancient HBV genomes that are between approximately 0.8 and 4.5 thousand years old. The ancient sequences group either within or in a sister relationship with extant human or other ape HBV clades. Generally, the genome properties follow those of modern HBV. The root of the HBV tree is projected to between 8.6 and 20.9 thousand years ago, and we estimate a substitution rate of 8.04 x 10(-6-)1.51 x 10(-5) nucleotide substitutions per site per year. In several cases, the geographical locations of the ancient genotypes do not match present-day distributions. Genotypes that today are typical of Africa and Asia, and a subgenotype from India, are shown to have an early Eurasian presence. The geographical and temporal patterns that we observe in ancient and modern HBV genotypes are compatible with well-documented human migrations during the Bronze and Iron Ages(1,2). We provide evidence for the creation of HBV genotype A via recombination, and for a long-term association of modern HBV genotypes with humans, including the discovery of a human genotype that is now extinct. These data expose a complexity of HBV evolution that is not evident when considering modern sequences alone.
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| 2. |
- Lennartsson, T, et al.
(författare)
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'The Meadow is the Mother of the Field.' Comparing Transformations in Hay Production in Three European Agroecosystems
- 2016
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Ingår i: Martor. - 1224-6271. ; 21, s. 103-126
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Tidskriftsartikel (refereegranskat)abstract
- This research compares the production of hay in three historical European agroecological systems: in northern Romania, central Sweden and eastern central France. We analyse hay production in relation to the entire production system, the local natural conditions, and the variety of ways by which hay production was transformed over time. We found broad commonalities, but also discovered significant differences in each of three historical trajectories. Introduction of fodder crops, crop rotations and mechanization are important drivers of changes in all three areas, although the timing, sequence and causation vary from place to place. There are signifcant differences in the organization of farm labour, in the role of beef and dairy production, the role of political reforms and the climatic constraints of outdoor grazing which affected the transformation of fodder production. This paper highlights the potential of an integrated, interdisciplinary approach for better understanding the complex interaction of people, their social and economic contexts, and their environment.
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