| 1. |
- Lorenzen, Eline D., et al.
(författare)
-
Species-specific responses of Late Quaternary megafauna to climate and humans
- 2011
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 479:7373, s. 359-364
-
Tidskriftsartikel (refereegranskat)abstract
- Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, emphasizing the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.
|
|
| 2. |
- Raghavan, Maanasa, et al.
(författare)
-
The genetic prehistory of the New World Arctic
- 2014
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 345:6200, s. 1020-
-
Tidskriftsartikel (refereegranskat)abstract
- The New World Arctic, the last region of the Americas to be populated by humans, has a relatively well-researched archaeology, but an understanding of its genetic history is lacking. We present genome-wide sequence data from ancient and present-day humans from Greenland, Arctic Canada, Alaska, Aleutian Islands, and Siberia. We show that Paleo-Eskimos (similar to 3000 BCE to 1300 CE) represent a migration pulse into the Americas independent of both Native American and Inuit expansions. Furthermore, the genetic continuity characterizing the Paleo-Eskimo period was interrupted by the arrival of a new population, representing the ancestors of present-day Inuit, with evidence of past gene flow between these lineages. Despite periodic abandonment of major Arctic regions, a single Paleo-Eskimo metapopulation likely survived in near-isolation for more than 4000 years, only to vanish around 700 years ago.
|
|
| 3. |
- Rasmussen, Morten, et al.
(författare)
-
Ancient human genome sequence of an extinct Palaeo-Eskimo
- 2010
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 463:7282, s. 757-762
-
Tidskriftsartikel (refereegranskat)abstract
- We report here the genome sequence of an ancient human. Obtained from ∼4,000-year-old permafrost-preserved hair, the genome represents a male individual from the first known culture to settle in Greenland. Sequenced to an average depth of 20×, we recover 79% of the diploid genome, an amount close to the practical limit of current sequencing technologies. We identify 353,151 high-confidence single-nucleotide polymorphisms (SNPs), of which 6.8% have not been reported previously. We estimate raw read contamination to be no higher than 0.8%. We use functional SNP assessment to assign possible phenotypic characteristics of the individual that belonged to a culture whose location has yielded only trace human remains. We compare the high-confidence SNPs to those of contemporary populations to find the populations most closely related to the individual. This provides evidence for a migration from Siberia into the New World some 5,500 years ago, independent of that giving rise to the modern Native Americans and Inuit.
|
|
| 4. |
- Clausen, Bettina Hjelm, et al.
(författare)
-
Cell therapy centered on IL-1Ra is neuroprotective in experimental stroke.
- 2016
-
Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 1432-0533 .- 0001-6322. ; 131:5, s. 91-775
-
Tidskriftsartikel (refereegranskat)abstract
- Cell-based therapies are emerging as new promising treatments in stroke. However, their functional mechanism and therapeutic potential during early infarct maturation has so far received little attention. Here, we asked if cell-based delivery of the interleukin-1 receptor antagonist (IL-1Ra), a known neuroprotectant in stroke, can promote neuroprotection, by modulating the detrimental inflammatory response in the tissue at risk. We show by the use of IL-1Ra-overexpressing and IL-1Ra-deficient mice that IL-1Ra is neuroprotective in stroke. Characterization of the cellular and spatiotemporal production of IL-1Ra and IL-1α/β identifies microglia, not infiltrating leukocytes, as the major sources of IL-1Ra after experimental stroke, and shows IL-1Ra and IL-1β to be produced by segregated subsets of microglia with a small proportion of these cells co-expressing IL-1α. Reconstitution of whole body irradiated mice with IL-1Ra-producing bone marrow cells is associated with neuroprotection and recruitment of IL-1Ra-producing leukocytes after stroke. Neuroprotection is also achieved by therapeutic injection of IL-1Ra-producing bone marrow cells 30 min after stroke onset, additionally improving the functional outcome in two different stroke models. The IL-1Ra-producing bone marrow cells increase the number of IL-1Ra-producing microglia, reduce the availability of IL-1β, and modulate mitogen-activated protein kinase (MAPK) signaling in the ischemic cortex. The importance of these results is underlined by demonstration of IL-1Ra-producing cells in the human cortex early after ischemic stroke. Taken together, our results attribute distinct neuroprotective or neurotoxic functions to segregated subsets of microglia and suggest that treatment strategies increasing the production of IL-1Ra by infiltrating leukocytes or microglia may also be neuroprotective if applied early after stroke onset in patients.
|
|
| 5. |
- Gahoonia, Simy Kaur, et al.
(författare)
-
Upon Not Opening The Black Box
- 2020
-
Ingår i: CHI EA '20: Extended Abstracts of the 2020 CHI Conference on Human Factors in Computing Systems. - New York, NY, USA : ACM Digital Library. - 9781450368193
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- On the eve of the General Data Protection Regulation (GDPR) coming into effect we, a university laboratory, marked the occasion with an interactive installation called Compliance. Data traces from Compliance were subsequently processed by the lab, here enacted in the form of a play. While much discussion has centered around modern 'black-boxed' processing of data, less attention has been paid to the value of the data itself, and whether it merits use. We draw on dramaturgical methods for both analysis and presentation [15], allowing for readers to imagine staging their own, different, versions of the event. Drawing on the ambiguous ontological status of (yet unexamined) data, we offer a discussion on the value of data, its use and non-use, as well as how to live with this ambivalence, continuously negotiating social contracts about our further conduct with the data.
|
|
| 6. |
- Lambertsen, Kate Lykke, et al.
(författare)
-
Microglia Protect Neurons against Ischemia by Synthesis of Tumor Necrosis Factor
- 2009
-
Ingår i: The Journal of Neuroscience. - 1529-2401. ; 29:5, s. 1319-1330
-
Tidskriftsartikel (refereegranskat)abstract
- Microglia and infiltrating leukocytes are considered major producers of tumor necrosis factor (TNF), which is a crucial player in cerebral ischemia and brain inflammation. We have identified a neuroprotective role for microglial-derived TNF in cerebral ischemia in mice. We show that cortical infarction and behavioral deficit are significantly exacerbated in TNF-knock-out (KO) mice compared with wild-type mice. By using in situ hybridization, immunohistochemistry, and green fluorescent protein bone marrow (BM)-chimeric mice, TNF was shown to be produced by microglia and infiltrating leukocytes. Additional analysis demonstrating that BM-chimeric TNF-KO mice grafted with wild-type BM cells developed larger infarcts than BM-chimeric wild-type mice grafted with TNF-KO BM cells provided evidence that the neuroprotective effect of TNF was attributable to microglial-not leukocyte-derived TNF. In addition, observation of increased infarction in TNF-p55 receptor (TNF-p55R)-KO mice compared with TNF-p75R and wild-type mice suggested that microglial-derived TNF exerts neuroprotective effects through TNF-p55R. We finally report that TNF deficiency is associated with reduced microglial population size and Toll-like receptor 2 expression in unmanipulated brain, which might also influence the neuronal response to injury. Our results identify microglia and microglial-derived TNF as playing a key role in determining the survival of endangered neurons in cerebral ischemia.
|
|
