| 1. |
- Dumanski, Jan P., et al.
(författare)
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Smoking is associated with mosaic loss of chromosome Y
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 347:6217, s. 81-83
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Tidskriftsartikel (refereegranskat)abstract
- Tobacco smoking is a risk factor for numerous disorders, including cancers affecting organs outside the respiratory tract. Epidemiological data suggest that smoking is a greater risk factor for these cancers in males compared to females. This observation, together with the fact that males have a higher incidence of and mortality from most non-sex-specific cancers, remains unexplained. Loss of chromosome Y (LOY) in blood cells is associated with increased risk of nonhematological tumors. We demonstrate here that smoking is associated with LOY in blood cells in three independent cohorts [TwinGene: odds ratio (OR) = 4.3, 95% CI = 2.8-6.7; ULSAM: OR = 2.4, 95% CI = 1.6-3.6; and PIVUS: OR = 3.5, 95% CI = 1.4-8.4] encompassing a total of 6014 men. The data also suggest that smoking has a transient and dose-dependent mutagenic effect on LOY status. The finding that smoking induces LOY thus links a preventable risk factor with the most common acquired human mutation.
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| 2. |
- Grandin, Ulf, et al.
(författare)
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Allozyme variation at a PGI locus in differently aged populations of Moehringia trinervia (Caryophyllaceae) in a successional area
- 2002
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 22:3, s. 303-311
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Tidskriftsartikel (refereegranskat)abstract
- We studied genetic effects of the colonisation process during primary succession by analysing allozyme variation at a PGI locus in differently aged populations of Moehringia trinervia, which is a selfing annual with low dispersal ability. The populations studied come from islands and shores created in the 1880s by a drop in the water table of a Swedish lake and from old parts of a large island and of the mainland. The population age is known from five vegetation analyses over a century. We have also analysed the genetic composition of M. trinervia derived from seeds in the soil. Mainland populations had a higher genetic diversity than island populations that were little differentiated and differed genetically from the mainland populations. There was no temporal trend in the distribution of genetic variation on the new islands. The presence of alleles in the extant populations was associated with the proportion of that allele in the seed bank, indicating a main recruitment from the seed bank and not by repeated immigrations. We suggest that some of the new islands were colonised by a few early founders from the mainland. Later colonisation has occurred between adjacent islands, which preserves the founder effect and could explain the uniform, low genetic variation in the island populations
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| 3. |
- Gunnarsson, Urban, et al.
(författare)
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Local-scale genetic structure in the peatmoss Sphagnum fuscum
- 2007
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Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 16:2, s. 305-312
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Tidskriftsartikel (refereegranskat)abstract
- Sphagnum (peatmoss) dominates huge areas of the Northern Hemisphere and acts as a significant carbon sink on a global scale, yet little is known about the genetic structure of Sphagnum populations. We investigated genetic structure within a population of the common peatmoss Sphagnum fuscum, to assess local patterns of genetic diversity and the spatial extent of clones. One hundred seventeen shoots were sampled from five transects in Fuglmyra, central Norway, and sequenced for three anonymous DNA regions. Five neighbourhood patches were marked along each transect, and from each patch, five stems were sampled for molecular analyses. Seventeen haplotypes could be distinguished and two major groups of haplotypes differed by 12 mutational steps. The two major haplotype groups differed significantly in microhabitat association along the distance to groundwater table and the pH gradients, indicating microhabitat differentiation. The haplotypes within these groups were all genetically similar, differing by one or two mutations. The most common haplotype occurred in four transects separated by 250-m distance. Most of the molecular variation in the population was found among transects, and within patches. Large dominating clones within each transect resulted in low variation explained by the among-patch-within-transect component of spatial structure. Mutation appears to account for a larger proportion of the population variation than recombination. Within the population, vegetative growth and asexual reproduction from gametophyte fragments dominate as the main reproductive mode.
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| 4. |
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| 5. |
- Lönn, Mikael, et al.
(författare)
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Hybrids and fruit set in a mixed flowering-time population of Gymnadenia conopsea (Orchidaceae)
- 2006
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 143:1, s. 222-228
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Tidskriftsartikel (refereegranskat)abstract
- We have recently found that the morphologically determined subspecies Gymnadenia conopsea ssp conopsea in Sweden includes early and late flowering individuals. We were interested in the interactions between the flowering time groups; if there were gene flow between them and if so this was detrimental or advantageous. A spatially mixed population of early and late flowering individuals was studied using three microsatellite loci. We measured patterns in genetic differentiation and inferred occurrence of hybridisation and introgression. Variation in flowering time, fertility and relative and absolute fruit set was measured. The pattern of introgression between flowering-time groups differed between loci. In two of the three investigated loci, allele separation was distinct between early and late flowering plants and one genetically obvious hybrid was infertile. In the third locus, several alleles were shared between the two flowering time variants. The degree of introgression was associated to fruit set failure, which was higher in the late flowering plants and lower in early flowering plants. A small group of early flowering individuals with somewhat delayed flowering compared to the main group was genetically distinct and had lower relative and absolute fruit set. This group was not genetically intermediate, but rather constituting an independent group, with lower fruit set possibly caused by absence of pollinators. There seem to be a strong barrier against introgression into the late flowering group which is kept genetically distinct and less diverse. The early flowering group is diverse, includes two subgroups and seems to benefit from gene flow.
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| 6. |
- Wallin, Lotta, et al.
(författare)
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Artificial dispersal as a restoration tool in meadows : sowing or planting?
- 2009
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Ingår i: Restoration Ecology. - 1061-2971 .- 1526-100X. ; 17:2, s. 270-279
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Tidskriftsartikel (refereegranskat)abstract
- Habitat fragmentation and the abandonment of former agricultural practices have led to extremely low dispersal rates for plant species growing in traditionally managed hay meadows in Sweden. Historically, seed dispersal between populations was maintained by hay movement, grazing animals, and farmers sharing their equipment. Because these means of dispersal typically are no longer occurring, artificial dispersal using seeds and plug-plants is tested here as a restoration tool. In this study, we chose two perennial herbs commonly occurring in meadows as test species, viz, Hypochoeris maculata L. (Asteraceae) and Succisa pratensis Moench. (Dipsacaceae). We found that plug-plant transplants were twice as effective as seed sowing for both species. The seed collection site was found to be important for seed-based establishment and survival; consequently, the choice of donor meadow is important when acquiring seeds used for restoration. We also found that survival of plants introduced as seeds was generally lower at sites harboring species favored by nitrogen as well as at sites in later successional phases. Both methods of introducing meadow species worked well, even though long-term establishment may well be more successful with the plug-plant method due to higher plug-plant establishment 2 years after introduction in the field.
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