University of Iceland

About: University of Iceland is a education organization based out in Reykjavik, Suðurnes, Iceland. It is known for research contribution in the topics: Population & Genome-wide association study. The organization has 5423 authors who have published 16199 publications receiving 694762 citations. The organization is also known as: Háskóli Íslands.

The Artiodactyl APOBEC3 Innate Immune Repertoire Shows Evidence for a Multi-Functional Domain Organization that Existed in the Ancestor of Placental Mammals

Abstract: Background: APOBEC3 (A3) proteins deaminate DNA cytosines and block the replication of retroviruses and retrotransposons. Each A3 gene encodes a protein with one or two conserved zinccoordinating motifs (Z1, Z2 or Z3). The presence of one A3 gene in mice (Z2–Z3) and seven in humans, A3A-H (Z1a, Z2a-Z1b, Z2b, Z2c-Z2d, Z2e-Z2f, Z2g-Z1c, Z3), suggests extraordinary evolutionary flexibility. To gain insights into the mechanism and timing of A3 gene expansion and into the functional modularity of these genes, we analyzed the genomic sequences, expressed cDNAs and activities of the full A3 repertoire of three artiodactyl lineages: sheep, cattle and pigs. Results: Sheep and cattle have three A3 genes, A3Z1, A3Z2 and A3Z3, whereas pigs only have two, A3Z2 and A3Z3. A comparison between domestic and wild pigs indicated that A3Z1 was deleted in the pig lineage. In all three species, read-through transcription and alternative splicing also produced a catalytically active double domain A3Z2-Z3 protein that had a distinct cytoplasmic localization. Thus, the three A3 genes of sheep and cattle encode four conserved and active proteins. These data, together with phylogenetic analyses, indicated that a similar, functionally modular A3 repertoire existed in the common ancestor of artiodactyls and primates (i.e., the ancestor of placental mammals). This mammalian ancestor therefore possessed the minimal A3 gene set, Z1-Z2-Z3, required to evolve through a remarkable series of eight recombination events into the present day eleven Z domain human repertoire. Conclusion: The dynamic recombination-filled history of the mammalian A3 genes is consistent with the modular nature of the locus and a model in which most of these events (especially the expansions) were selected by ancient pathogenic retrovirus infections.

Effect of glacier loading/deloading on volcanism: postglacial volcanic production rate of the Dyngjufjöll area, central Iceland

Abstract: Tephrochronological dating of postglacial volcanism in the Dyngjufjoll volcanic complex, a major spreading center in the Icelandic Rift Zone, indicates a high production rate in the millennia following deglaciation as compared to the present low productivity. The visible and implied evidence indicates that lava production in the period 10 000–4500 bp was at least 20 to 30 times higher than that in the period after 2900 bp but the results are biased towards lower values for lava volumes during the earlier age periods since multiple lava layers are buried beneath younger flows. The higher production rate during the earlier period coincides with the disappearance of glaciers of the last glaciation. Decreasing lithostatic pressure as the glacier melts and vigorous crustal movements caused by rapid isostatic rebound may trigger intense volcanism until a new pressure equilibrium has been established.

Genome-wide analyses using UK Biobank data provide insights into the genetic architecture of osteoarthritis

Abstract: Osteoarthritis is a common complex disease imposing a large public-health burden. Here, we performed a genome-wide association study for osteoarthritis, using data across 16.5 million variants from the UK Biobank resource. After performing replication and meta-analysis in up to 30,727 cases and 297,191 controls, we identified nine new osteoarthritis loci, in all of which the most likely causal variant was noncoding. For three loci, we detected association with biologically relevant radiographic endophenotypes, and in five signals we identified genes that were differentially expressed in degraded compared with intact articular cartilage from patients with osteoarthritis. We established causal effects on osteoarthritis for higher body mass index but not for triglyceride levels or genetic predisposition to type 2 diabetes.

A meta-analysis of genome-wide association studies identifies multiple longevity genes

Abstract: Human longevity is heritable, but genome-wide association (GWA) studies have had limited success. Here, we perform two meta-analyses of GWA studies of a rigorous longevity phenotype definition including 11,262/3484 cases surviving at or beyond the age corresponding to the 90th/99th survival percentile, respectively, and 25,483 controls whose age at death or at last contact was at or below the age corresponding to the 60th survival percentile. Consistent with previous reports, rs429358 (apolipoprotein E (ApoE) e4) is associated with lower odds of surviving to the 90th and 99th percentile age, while rs7412 (ApoE e2) shows the opposite. Moreover, rs7676745, located near GPR78, associates with lower odds of surviving to the 90th percentile age. Gene-level association analysis reveals a role for tissue-specific expression of multiple genes in longevity. Finally, genetic correlation of the longevity GWA results with that of several disease-related phenotypes points to a shared genetic architecture between health and longevity.

International variation in the incidence of hip fractures: Cross-national project on osteoporosis for the world health organization program for research on aging

Abstract: A cross-national study of hip fracture incidence was carried out in five geographic areas – Beijing, China; Budapest, Hungary; Hong Kong; Porto Alegre, Brazil; and Reykjavik, Iceland – during the years 1990–1992 Cases of hip fracture among women and men of age 20 years and older were identified using hospital discharge data in conjunction with medical records, operating room logs, and radiology logs Estimated incidence rates varied widely, with Beijing reporting the lowest rates (age-adjusted rate per 100 000 population for men 20 years and older = 454; women = 396) and Reykjavik the highest rates (men = 1413; women = 2741) Rates were higher for women than for men in every area except Beijing In every area except Budapest, review of the operating room or radiology logs identified additional cases that were not reported in the discharge list, increasing the estimated number of hip fractures by 11% to 62%, depending on the area Review of medical records identified miscoding of hip fractures (ICD9 820) as ‘shaft of femur and other femur fractures’ (ICD9 821) in the discharge lists of every area except Budapest, increasing the estimated number of hip fractures by 1% to 30% The final estimates of hip fracture incidence taking into account all investigated sources of undercount and overcount ranged from 15% lower to 89% higher than an estimate based on the discharge diagnoses alone Although these results indicate substantial limitations in relying on hospital discharge data alone to estimate hip fracture incidence rates, the extent of errors found in the discharge lists is smaller than the large international variation found here and previously reported in incidence rates The findings support the conclusion that the differences reported among countries mainly reflect genuine variation in the hip fracture incidence rates