Cloning humans, cloning literature: genetics and the imagination deficit

After the birth of Dolly, media stories on cloning were replete with references to well-known science fiction plots. This essay criticizes the 'imagination deficit' of scientists and journalists, first by problematizing the uncritical adoption of attentuated science fiction plots in the media coverage of Dolly, and second, by proposing to look at more expansive science fiction novels that carefully examine issues such as uniqueness and identity in relation to the new genetics.     

Abortion rhetoric in American news coverage of the human cloning debate

Abstract

The issue of human cloning has received intense media and political attention since the cloning of Dolly the sheep was announced in 1997. This research explores the discursive basis for support and opposition to human cloning by examining the role of abortion-related rhetoric in constructing the concept of human cloning within the American press. An in-depth content analysis of human cloning news coverage was conducted on a sample of articles collected from the mainstream press as well as advocacy publications with either a pro-science or Christian fundamentalist orientation. Statistically significant differences were found indicating an important role for abortion rhetoric in the human cloning debate. This expansion of abortion rhetoric into the domain of science policy portends a unique and growing problem for resolving bioethical debates within American politics over the future development of biomedical technologies such as human cloning.     

Microsatellite genetic variation of Asian populations of Dolly Varden char

Genetic variation at eight microsatellite loci was examined in 21 populations of Dolly Varden charrs, Salvelinus malma, representing five geographical regions (Kamchatka Peninsula, Sea of Okhotsk coast, Sea of Japan coast, Sakhalin Island, and Kuril islands). Hierarchical analysis of molecular variance showed that 11% (58% in terms of R-statistics) of the variation was distributed among of northern subspecies of Dolly Varden, Salvelinus malma malma and southern Asian Dolly Varden, S. m. krascheninnikovi while similar values were attributed to the among-regional level within northern Dolly Varden 9% (7%) and southern Asian Dolly Varden 11% (14%). Permutation-based tests indicated a mutational component to genetic differentiation based on allelic size variance and suggested that divergence of the two subspecies had occurred at least 3,000 generations ago. On large spatial scales (within the Asian range of the species), populations clustered according to their geographical location. On smaller scales (within regions and subregions) correlation between genetic and geographic distances was not significant. Northern Dolly Varden has higher allelic diversity and more private alleles than southern subspecies, this probably indicating differences in demographic history.     

The Divergence of the Dolly Varden Char Salvelinus malma in the Asian Northern Pacific Populations Inferred from the PCR–RFLP Analysis of Mitochondrial DNA

Genetic differentiation of the Dolly Varden char Salvelinus malmaWalbaum was studied in five populations from the western part of the Northern Pacific. Using restriction analysis (RFLP), we examined polymorphism of three mitochondrial DNA (mtDNA) fragments amplified in polymerase chain reaction (PCR). MtDNA haplotypes were shown to fall into two phylogenetic groups, which probably reflect the existence of two previously described subspecies of Asian Dolly Varden,S. malma malma and S. malma krascheninnikovi. The divergence of mtDNA nucleotide sequences in the Dolly Varden subspecies (about 4%) corresponds to the differences between the valid char species from the genus Salvelinus.     

Karyological Differences between Northern Dolly Varden Salvelinus malma malma and White Char Salvelinus albusfrom the Kamchatka River Basin

The karyotypes of northern Dolly Varden and white char, sympatrically inhabiting the Kamchatka River basin, were studied. The karyotype of Dolly Varden was stable: 2n= 78 andNF= 98 + 2, while in white char, polymorphism and mosaicism for the chromosome number were revealed: 2n= 76–79, NF= 98 + 2. Using a routine chromosome staining technique, the karyotype of white char (2n= 78) was shown to be identical to that of Dolly Varden. In both karyotypes, similar sets of marker chromosomes were present: two pairs of submetacentric (SM), one pair of submeta-subtelocentric (SM-ST), one pair of large acrocentric (A), and one pair of large subtelocentric (ST) chromosomes. However, the karyotypes of Dolly Varden and white char differed in the number and location of nucleolus organizer regions (NORs). In Dolly Varden, single NORs located in the telomeric regions of the marker SM-ST chromosomes were observed. In white char, NORs were multiple and located both in the telomeric regions of the marker SM-ST chromosomes and on the short and long arms of large ST chromosomes. The identical marker chromosomes indicate considerable phylogenetic relatedness between Dolly Varden and white char from the Kamchatka River basin. Variation in NORs provides evidence for the reproductive isolation of these chars and their species status.     

Redd superimposition by introduced rainbow trout,oncorhynchus mykiss, on native charrs in a japanese stream

Spawning redd superimposition of introduced, spring-spawning rainbow trout,Oncorhynchus mykiss, on native, fall-spawning Dolly varden,Salvelinus malma, and white-spotted charr,S. leucomaenis, were examined in a small stream in Hokkaido, Japan. The stream reaches in which Dolly Varden and white-sported charr redds were observed in fall 1997 greatly overlapped with the reaches in which rainbow trout redds were recorded in spring 1998. Spawning microhabitats were also similar between trout and the two charr species. Thirteen and 3% of Dolly Varden and white-spotted charr redds, respectively, were superimposed by rainbow trout redds. The eggs or alevins in the disturbed charr redds were potentially damaged because charrs were not likely to have emerged from the redds before the superimposition occurred. In sufficiently great abundance, introduced rainbow trout may negatively impact native charr populations by dislodging the latter’s spawning redds.     

Differentiation of Dolly Varden Char <Emphasis Type="Italic">Salvelinus malma</Emphasis> from Asia and North America Inferred from PCR-RFLP Analysis of Mitochondrial DNA

Genetic differentiation of Dolly Varden char Salvelinus malma Walbaum from the Asian and North American Pacific coasts was studied. We examined restriction fragment length polymorphism of three mitochondrial DNA (mtDNA) fragments amplified in polymerase chain reaction, which encoded four NADH dehydrogenase subunits, the cytochrome b gene, and a D-loop segment. The mtDNA haplotypes were shown to form three phylogenetic groups, whose geographic distribution corresponded to three Dolly Varden subspecies: S. malma malma, S. malma krascheninnikovi, and S. malma lordi. The nucleotide sequence divergence between S. malma malma and S. malma krascheninnikovi was 3.8%; between S. malma malma and S. malma lordi, 3.1%; and between S. malma krascheninnikovi and S. malma lordi, 2.5%. The northern Dolly Varden S. malma malma from Asia was shown to be genetically identical to that from North America.__________Translated from Genetika, Vol. 41, No. 5, 2005, pp. 626–634.Original Russian Text Copyright © 2005 by Oleinik, Skurikhina, Brykov, Crane, Wenburg.     

Allozyme Diversity and Genetic Divergence of the Dolly Varden Salvelinus malma Walbaum from the Kuril Islands

Genetic variation was studied in the southern subspecies of the Asian Dolly Varden Salvelinus malma krascheninnikovi from the Kuril Islands. Thirty-six genetic loci controlling 19 enzyme systems were analyzed in 13 Dolly Varden populations from the Shumshu, Paramushir, Onekotan, Rasshua, Simushir, Urup, Iturup, and Kunashir islands. In the studied populations, the proportion of polymorphic loci was 35 to 85% and the mean heterozygosity was 0.104 to 0.173; populations from the Kunashir Island were characterized by maximum heterozygosity. In the island populations examined, significant interpopulation heterogeneity of allele frequencies was found for all studied population pairs. For the all island populations, the interpopulation diversity (G _ST = 0.188) was comparable to this parameter for the populations from the Kunashir Island only (G _ST = 0.170). Genetic distances between populations did not correlate with the corresponding geographical distances, which indicates the lack of a pronounced gene exchange between the island populations. Cluster analysis and multidimensional scaling based on genetic distances did not reveal clear groups among the studied populations but indicated greater similarity within the Iturup–Simushir–Urup–Paramushir group and a greater genetic divergence of the Kunashir, Onekotan, Rasshua, and especially Shumshu populations. In the Shumshu population, allele frequencies indicate the admixture of genes of the northern Dolly Varden. The observed pattern of genetic differentiation was probably caused largely by genetic drift under the conditions of a limited gene flow because of homing (which is typical of the Dolly Varden) and the presence of isolated nonanadromous populations. The population–genetic analysis of the Dolly Varden from the Kuril Islands does not give grounds to distinguish any other isolated char species in this region than S. malma, which is represented by the southern form S. m. krascheninnikovi with an admixture of the northern form S. m. malma in the Shumshu Island.     

Contributions to the Flora of Spitsbergen,especially of Red bay,from the Collections of W. S. Bruce,F.R.S.G.S., Naturalist to the Prince of Monaco's Expeditions of 1898 and 1899

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce.

Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns.

Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence F_v/F_m ratio (an estimate of photosynthetic capacity) up to 36 months post-fire.

Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium F_v/F_m 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, F_v/F_m in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis.

Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function.     

Offshore Dolly Varden charr (<Emphasis Type="Italic">Salvelinus malma</Emphasis>) in the North Pacific

Many studies have investigated the ecology of charrs in freshwater, however, little is known about charrs in the ocean. This study examined the distribution, seasonal abundance, and some biological features of Dolly Varden (Salvelinus malma) in the Pacific Ocean. An analysis of by-catch data of Japanese offshore salmon monitoring showed that Dolly Varden were distributed across a wide range in the offshore waters of the Pacific Ocean, including the Japan Sea, Bering Sea, and Okhotsk Sea. The catch per unit effort showed a sharp increase from May to August, followed by a sharp decrease in September. Offshore areas served as an important summer habitat for anadromous Dolly Varden.     

Effects of forestry on the thermal habitat of Dolly Varden (<Emphasis Type="Italic">Salvelinus malma</Emphasis>)

Forestry activities in riparian areas are known to affect stream communities considerably. Not only do riparian deforestation resulting from agriculture or urbanization developments affect stream communities but extensive commercial plantation and forestry practices can alter stream environments adjacent to remaining, intact or secondary forests. Because forestry often includes the construction of logging roads through the riparian zone, this can directly degrade stream environments. Twelve streams in the Shiretoko Peninsula, Hokkaido were investigated so as to determine the effects of forestry practices on stream temperature, periphyton biomass, grazer (benthic invertebrates) biomass and Dolly Varden (Salvelinus malma Walbaum) biomass. The greater the proportion of planted area in the catchment, the higher the stream temperature. Stream temperature directly affects periphyton biomass and Dolly Varden biomass negatively. Neither stream temperature nor periphyton biomass predicted grazer biomass, whereas a positive correlation was found between grazer biomass and Dolly Varden biomass that forage on invertebrates. The overall results indicated that Dolly Varden in the Shiretoko streams were negatively affected by forestry practices and the resultant stream temperature increases. Without effective future riparian forest management, the complex effects of both riparian disturbance and ongoing global warming could further reduce Dolly Varden populations in the region.     

Seed–seedling conflict in conifers as a result of plant–plant interactions at the forest-tundra ecotone

Background: As the climate warms, plant interactions between shrubs and conifer seedlings may affect migration of boreal trees into alpine areas; however these interactions have not been widely tested across conifer life stages.

Aims: Determine the role of shading by Betula glandulosa shrubs on early Picea mariana recruitment in the forest-tundra ecotone of the Mealy Mountains, Labrador (Canada).

Methods: Four shrub treatments were established with varying degrees of shade (unaltered, trimmed, cleared, shaded). Emergence and growth of P. mariana in treatment plots were compared to control plots without shrubs.

Results: Seedling emergence was facilitated; seedlings beneath shrubs emerged at greater levels (16% ± 5.1%) than in the control (0.5% ± 0.3%); however, evidence of facilitation post-emergence was weak, likely due to stronger interactions with seedbed species at this stage. Vertical growth of young seedlings was greatest in control and shaded plots, but needle production significantly decreased with increased shade suggesting that seedlings may compete with shrubs for light early in life.

Conclusions: Although facilitation has been previously implicated as an important mechanism in stressful environments, our study indicates that the early life stages of some conifers at the tree line are not strongly facilitated by shrubs as has been previously suggested for adults.     

Stand- and plot-level changes in a boreal forest understory community following wildfire

Background: Boreal forest understory plant communities are known to be resilient to fire – the species composition of stands after a fire is quite similar to the pre-fire composition. However, we know little about recovery of individual plants within particular locations in forest stands (i.e. plot-level changes) since we usually do not have pre-fire data for plots.

Aims: We wanted to determine whether species recruited into the same or different locations in a Pinus banksiana stand that experienced a severe wildfire.

Methods: We used pre-existing permanent plots to evaluate the cover of understory after an unplanned wildfire.

Results: Across the entire stand nine of 47 species showed a significant change in cover. The largest change in a plant functional group was in the mosses, with all species present before fire being eliminated. There was no change in species diversity or total cover. At the plot level, species composition showed a much greater change. An average of 47% of the species present in a plot before the fire were absent in the same plot after the fire, and the total species turnover in plots was 88% of the species present before the fire. The plots showed a similar shift in species composition.

Conclusions: These results confirm that boreal forest communities show a high degree of resilience to fire, but within a forest stand species will be found in different locations following fire, potentially exposing them to a different set of biotic and abiotic conditions in these new locations.     

Low levels of hybridization between sympatric Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation

Understanding the extent of interspecific hybridization and how ecological segregation may influence hybridization requires comprehensively sampling different habitats over a range of life history stages. Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) are recently diverged salmonid fishes that come into contact in several areas of the North Pacific where they occasionally hybridize. To better quantify the degree of hybridization and ecological segregation between these taxa, we sampled over 700 fish from multiple lake (littoral and profundal) and stream sites in two large, interconnected southwestern Alaskan lakes. Individuals were genotyped at 12 microsatellite markers, and genetic admixture (Q) values generated through Bayesian‐based clustering revealed hybridization levels generally lower than reported in a previous study (<0.6% to 5% of samples classified as late‐generation hybrids). Dolly Varden and Arctic char tended to make different use of stream habitats with the latter apparently abandoning streams for lake habitats after 2–3 years of age. Our results support the distinct biological species status of Dolly Varden and Arctic char and suggest that ecological segregation may be an important factor limiting opportunities for hybridization and/or the ecological performance of hybrid char.     

Erythrocyte orientational and cell volume effects on NMR <Emphasis Type="Italic">q</Emphasis>-space analysis: simulations of restricted diffusion

Pulsed field-gradient spin echo nuclear magnetic resonance spectroscopy of water diffusing in erythrocytes leads to diffusion interference and diffraction effects, which are visualised in q-space plots of signal intensity versus the magnitude of the spatial wave-number vector q. Interpretation of the features of these q-space plots has been aided by Monte Carlo random walk simulations of diffusion in lattices of virtual erythrocytes. Here, the effect of varying the orientation of the cells with respect to the direction in which diffusion is measured, on the appearance of q-space plots, was investigated, together with the effect of changing the cell volume. We show that these changes are reflected in the appearance of the plots in a way that is diagnostic of the microscopic geometry of the sample.     

Experimental evidence from Cantabrian mountain heathlands suggests new recommendations for management of Vaccinium myrtillus L

Background: Management actions in mountain heathlands oriented to increasing the cover of Vaccinium myrtillus promote mowing of Calluna vulgaris to avoid competition. However, such action ignores the fact that plant–plant interactions range from competition to facilitation under different stress conditions.

Aims: To test whether the interactions between these two species are related to competition or facilitation, which would change the perspective for their management in mountain heathlands.

Methods: A total of 40 experimental plots located in a montane heathland (northern Spain) were selected. Calluna or Vaccinium plants were either cut at ground level or not cut, and plots were fertilized with nitrogen or not in a three-factorial design. Vegetative and reproductive shoot mass and length of the current year’s shoots were estimated in two consecutive years for both species. Herbivory on Vaccinium by browsing ungulates was compared in control plots and plots where Calluna had been cut 2 yrs ago.

Results: The two study species co-occurred in 72.4% of the sampled plots, although Calluna was more abundant. Vaccinium growth was greater in plots with Calluna than in plots where Calluna had been cut. Browsing on Vaccinium was also higher in plots were Calluna had been cut, and the effect of fertilization was only significant on the reproductive biomass of Calluna.

Conclusions: Contrary to initial proposals, our results suggest that Vaccinium does not always benefit from the cutting of Calluna in heathlands. Thus, the management of Cantabrian mountain heathlands should consider maintaining Calluna in order to facilitate the growth of Vaccinium.     

Effect of Sky Lark plots and additional tramlines on territory densities of the Sky Lark Alauda arvensis in an intensively managed agricultural landscape

Capsule: Sky Lark plots and additional tramlines increase Sky Lark Alauda arvensis territory densities in winter crops.

Aims: To analyse the effects on Sky Lark territory density of Sky Lark plots and additional tramlines in winter cereals and oilseed rape.

Methods: We mapped Sky Lark territories on fields with Sky Lark plots or additional tramlines as well as on adjacent control sites, from 2010 to 2013 in Saxony, Germany, where agricultural land use is intensive, dominated by winter-sown crops and takes place in large fields.

Results: In test sites with Sky Lark plots, 5.6 and 3.1 territories per 10?ha were found in the early (April/May) and late periods (June/July) respectively, compared to 3.3 and 1.4 territories per 10?ha in control sites. Sky Lark territory densities in fields with additional tramlines were 1.6 times higher in the early period (4.2 versus 2.6 territories per 10?ha) and 2.2 times higher in the late period (3.6 versus 1.6 territories per 10?ha).

Conclusion: Sky Lark plots and additional tramlines improve large fields for the Sky Lark and have the potential to increase the Sky Lark population.     

Crop presence,but not genetic diversity,impacts on the rare arable plant Valerianella rimosa

Background: Intensive farming affects farmland biodiversity, and some arable plants in particular. Increasing crop genetic diversity can increase crop productivity or resilience and could also benefit rare arable plants.

Aims: We examined whether barley presence, sowing density and genetic diversity impacted the rare plant Valerianella rimosa and explored possible underlying mechanisms.

Methods: In a field study near Dundee, Scotland, we sowed plots of five single barley genotypes, and all five genotypes combined, at three densities; we also had barley-free plots. Valerianella seeds were sown into half of all plots. Measured responses included early-season cover and harvest biomass of barley and common weeds, abiotic parameters (soil moisture, light) and establishment, biomass and seed production by V. rimosa.

Results: Barley presence promoted V. rimosa establishment early in the growing season, but without barley density or genetic diversity effects. By harvest, the impact of barley presence on V. rimosa abundance was lost; there were no effects on Valerianella seed production. Barley negatively impacted common weeds, but V. rimosa did not benefit from any indirect facilitation by barley, being bigger without barley.

Conclusions: Early beneficial effects of barley on V. rimosa abundance appear offset by late-season competition. However, limited impacts of barley on V. rimosa reproductive success, and negative impacts on common weeds, indicate crops might play a role in conservation management of rare arable plants by creating space in the weed community.     

Variation of plant diversity components in different scales in relation to grazing and climatic conditions

Background: Understanding the role of livestock grazing on plant diversity can be improved by an accurate measurement of diversity at all hierarchical scales due to the changeability of diversity components in space.

Aims: We evaluated the effects of grazing on plant species diversity at different scales of all common and rare species in two regions that have different climatic conditions (arid vs. semi-arid).

Methods: In each region, we collected abundant data of plant species from a nested sampling design that consisted of local (80 plots) and regional (16 sites) scales. We partitioned total species diversity (γ) into within plots (α_l), among plots (β_l) and among sites (β₂) using the additive partitioning.

Results: Diversity among sites contributed the most to total diversity for all and rare plant species in both regions. In addition, α₁ and β₁ diversities in ungrazed areas were greater than those in grazed areas for all and common species in both climates.

Conclusion: Abandonment of grazing after 10 years resulted in significant regeneration of common species at the local scale, with no change in rare species. We conclude that low grazing intensity is likely to be an important tool for conservation of plant diversity in which all scales should be considered.     

Differentiation of the Dolly Varden Char (Salvelinus malma) and the Taranetz Char (Salvelinus taranetzi) Inferred from the PCR–RFLP Analysis of Mitochondrial DNA

Genetic differentiation of two sympatric char species, the Dolly Varden char (Salvelinus malma Walbaum) and the Taranetz char (S. taranetzi Kaganovski), has been studied. Restriction fragment length polymorphism (RFLP) analysis has been used to compare three mitochondrial DNA (mtDNA) fragments (ND1/ND2, ND5/ND6, and Cytb/D-loop) amplified via polymerase chain reaction (PCR). The divergence between S. malma and S. taranetzi inferred from mtDNA nucleotide sequences is 2.8%; between S. leucomaenis and S. taranetzi, 7.1%; and between S. malma and S. leucomaenis, 7.5%. The absence of common haplotypes and the degree of divergence indicate that the Dolly Varden char and the Taranetz char are genetically isolated and confirm that S. taranetzimay be regarded as a separate species.