While traits and trait plasticity are partly genetically based, investigating epigenetic mechanisms may provide more nuanced understanding of the mechanisms underlying response to environment. Using ...AFLP and methylation‐sensitive AFLP, we tested the hypothesis that differentiation to habitats along natural salt marsh environmental gradients occurs at epigenetic, but not genetic loci in two salt marsh perennials. We detected significant genetic and epigenetic structure among populations and among subpopulations, but we found multilocus patterns of differentiation to habitat type only in epigenetic variation for both species. In addition, more epigenetic than genetic loci were correlated with habitat in both species. When we analysed genetic and epigenetic variation simultaneously with partial Mantel, we found no correlation between genetic variation and habitat and a significant correlation between epigenetic variation and habitat in Spartina alterniflora. In Borrichia frutescens, we found significant correlations between epigenetic and/or genetic variation and habitat in four of five populations when populations were analysed individually, but there was no significant correlation between genetic or epigenetic variation and habitat when analysed jointly across the five populations. These analyses suggest that epigenetic mechanisms are involved in the response to salt marsh habitats, but also that the relationships among genetic and epigenetic variation and habitat vary by species. Site‐specific conditions may also cloud our ability to detect response in replicate populations with similar environmental gradients. Future studies analysing sequence data and the correlation between genetic variation and DNA methylation will be powerful to identify the contributions of genetic and epigenetic response to environmental gradients.
Individuals may delay dispersing from their natal habitat, even after maturation to adulthood. Such delays can have broad consequences from determining population structure to allowing an individual ...to gain indirect fitness by helping parents rear future offspring. Dispersal in species that use delayed dispersal is largely thought to be opportunistic; however, how individuals, particularly inexperienced juveniles, assess their environments to determine the appropriate time to disperse is unknown. One relatively unexplored possibility is that dispersal decisions are the result of epigenetic mechanisms interacting between a genome and environment during development to generate variable dispersive phenotypes. Here, we tested this using epiRADseq to compare genome-wide levels of DNA methylation of blood in cooperatively breeding chestnut-crowned babblers (Pomatostomus ruficeps). We measured dispersive and philopatric individuals at hatching, before fledging, and at 1 year (following when first year dispersal decisions would be made). We found that individuals that dispersed in their first year had a reduced proportion of methylated loci than philopatric individuals before fledging, but not at hatching or as adults. Further, individuals that dispersed in the first year had a greater number of loci change methylation state (i.e. gain or lose) between hatching and fledging. The existence and timing of these changes indicate some influence of development on epigenetic changes that may influence dispersal behavior. However, further work needs to be done to address exactly how developmental environments may be associated with dispersal decisions and which loci in particular are manipulated to generate such changes.
Environmentally induced phenotypic plasticity may be a critical component of response to changing environments. We examined local differentiation and adaptive phenotypic plasticity in response to ...elevated temperature in half‐sib lines collected across an elevation gradient for the alpine herb, Wahlenbergia ceracea. Using Amplified Fragment Length Polymorphism (AFLP), we found low but significant genetic differentiation between low‐ and high‐elevation seedlings, and seedlings originating from low elevations grew faster and showed stronger temperature responses (more plasticity) than those from medium and high elevations. Furthermore, plasticity was more often adaptive for plants of low‐elevation origin and maladaptive for plants of high elevation. With methylation sensitive‐AFLP (MS‐AFLP), we revealed an increase in epigenetic variation in response to temperature in low‐elevation seedlings. Although we did not find significant direct correlations between MS‐AFLP loci and phenotypes, our results demonstrate that adaptive plasticity in temperature response to warming varies over fine spatial scales and suggest the involvement of epigenetic mechanisms in this response.
Our work presents an exciting fusion of research on epigenetics (DNA methylation in particular) and adaptive phenotypic plasticity. The relationship between epigenetic mechanisms and phenotypic plasticity has been the subject of increasing speculation in ecological studies. Our results demonstrate that adaptive plasticity in temperature response of an alpine herb varies over remarkably fine geographic scales and indicates the involvement of epigenetic mechanisms in this response.
Introduced species are interesting systems for the study of contemporary evolution in new environments because of their spatial and temporal scales. For this study we had three aims: (i) to determine ...how genetic diversity and genetic differentiation of introduced populations of the house sparrow (Passer domesticus) in Brazil varies with range expansion, (ii) to determine how genetic diversity and differentiation in Brazil compares to ancestral European populations; and (iii) to determine whether selection or genetic drift has been more influential on phenotypic divergence. We used six microsatellite markers to genotype six populations from Brazil and four populations from Europe. We found slightly reduced levels of genetic diversity in Brazilian compared to native European populations. However, among introduced populations of Brazil, we found no association between genetic diversity and time since introduction. Moreover, overall genetic differentiation among introduced populations was low indicating that the expansion took place from large populations in which genetic drift effects would likely have been weak. We found significant phenotypic divergence among sites in Brazil. Given the absence of a spatial genetic pattern, divergent selection and not genetic drift seems to be the main force behind most of the phenotypic divergence encountered. Unravelling whether microevolution (e.g., allele frequency change), phenotypic plasticity, or both mediated phenotypic divergence is challenging and will require experimental work (e.g., common garden experiments or breeding programs).
Introduced species offer unique opportunities to study evolution in new environments, and some provide opportunities for understanding the mechanisms underlying macroecological patterns. We sought to ...determine how introduction history impacted genetic diversity and differentiation of the house sparrow (Passer domesticus), one of the most broadly distributed bird species. We screened eight microsatellite loci in 316 individuals from 16 locations in the native and introduced ranges. Significant population structure occurred between native than introduced house sparrows. Introduced house sparrows were distinguished into one North American group and a highly differentiated Kenyan group. Genetic differentiation estimates identified a high magnitude of differentiation between Kenya and all other populations, but demonstrated that European and North American samples were differentiated too. Our results support previous claims that introduced North American populations likely had few source populations, and indicate house sparrows established populations after introduction. Genetic diversity also differed among native, introduced North American, and Kenyan populations with Kenyan birds being least diverse. In some cases, house sparrow populations appeared to maintain or recover genetic diversity relatively rapidly after range expansion (<50 years; Mexico and Panama), but in others (Kenya) the effect of introduction persisted over the same period. In both native and introduced populations, genetic diversity exhibited large‐scale geographic patterns, increasing towards the equator. Such patterns of genetic diversity are concordant with two previously described models of genetic diversity, the latitudinal model and the species diversity model.
Atypical teratoid rhabdoid tumour (ATRT) is a malignant tumour of the central nervous system with a dismal prognosis. There is no consensus on optimal treatment and different multimodal strategies ...are currently being used in an attempt to improve outcomes. To evaluate the impact of high-dose chemotherapy followed by autologous stem-cell rescue (HD48 SCR), radiotherapy (RT) at first line, intrathecal chemotherapy (IT) and extent of surgical resection upon recurrence-free survival (RFS) and overall survival (OS). An online database search identified prospective and retrospective studies focused on the treatment of children and adolescents with newly diagnosed ATRT. Clinical, therapeutic and outcome data were extracted and an individual pooled data analysis was conducted. Out of 389 publications, 12 manuscripts were included in our review. Data from 332 patients were analysed. Median age at diagnosis was 37 months (range 1–231). HD-SCR, RT and IT had been administered to 28.6 % (58/203), 49.6 % (118/238) and 21 % (65/310) of the patients, respectively. Gross total resection (GTR) had been achieved in 46.5 % (152/327) of the cases. In the multivariate analysis, hazard ratios (95 % Confidence Interval) for HD-SCR were: RFS-HR = 0.570 (0.357–0.910) p = 0.019, and OS-HR = 0.388 (0.214–0.704) p = 0.002; and for RT: RFS-HR = 0.551 (0.351–0.866) p = 0.01, and OS-HR = 0.393 (0.216–0.712) p = 0.002. IT and GTR were not significantly associated with improved RFS or OS in the multivariate analysis. In our pooled data review, HD-SCR and RT at first line were associated with improved outcomes in children and adolescents with newly diagnosed ATRT.
GROND—a 7-Channel Imager Greiner, J.; Bornemann, W.; Clemens, C. ...
Publications of the Astronomical Society of the Pacific,
04/2008, Letnik:
120, Številka:
866
Journal Article
Recenzirano
Odprti dostop
We describe the construction of GROND, a 7-channel imager, primarily designed for rapid observations of gamma-ray burst afterglows. It allows simultaneous imaging in the Sloan
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bands. GROND was commissioned at the MPI/ESO 2.2 m telescope at La Silla (Chile) in April 2007, and first results of its performance and calibration are presented.
The GROWA model was applied to the entire Federal State of North Rhine-Westphalia (ca. 34,000
km
2) using a grid resolution of 100
m. It conceptually combines distributed meteorological data (winter ...and summer precipitation and potential evapotranspiration) with distributed site parameters (land use, soil properties, slope gradient, slope exposure, mean depth to groundwater) to facilitate the calculation of long-term annual averages of total runoff. In the GROWA model groundwater recharge is expressed as a constant proportion (baseflow indices) of the total runoff. This portion depends on certain characteristics of the investigated area, e.g. the slope gradient, soil and hydrogeological properties as well as the degree of surface sealing.
In this paper special emphasis is put on the influence of geology on groundwater recharge. In this respect, a new calibration procedure for the parameterization of geology-related parameters is described. In previous applications of the GROWA model baseflow indices have been identified on the basis of observed mean monthly low-water runoff values (MoMLR). Since the MoMLR-values significantly overestimate groundwater recharge in solid rock regions due to high interflow proportions, a more sophisticated hydrograph separation method has been applied. In this study runoff data from about 125 gauging stations within the Federal State of North Rhine-Westphalia were used to derive baseflow indices. The raster-based simulation was carried out using a grid resolution of 100
m.
The accuracy of the calculated groundwater recharge values for the period 1979–1999 was verified on the basis of data from gauging stations. A good agreement between observed runoff values from the sub-catchments and model results was achieved.
We present a scheme of adjusting the mid-infrared absorption properties to desired energy transitions in quantum dot-based photodetectors by combining band gap engineering with the self-organized ...growth of quantum dots. Embedding the self-organized InAs quantum dots into an AlAs/GaAs superlattice enables us to tune the optical transition energy by changing the superlattice period as well as by changing the growth conditions of the dots. Using a one-band envelope function framework, we are able, in a three-dimensional calculation, to predict the absorption spectra of these devices as well as their polarization properties. These calculations further predict a strong impact of the dots on the superlattice minibands. By comparing aligned, periodic dot stacks with nonperiodic dot arrangements within the superlattice, we can experimentally confirm this prediction.
Non-resuscitation fluids constitute the majority of fluid administered for septic shock patients in the intensive care unit (ICU). This multicentre, randomized, feasibility trial was conducted to ...test the hypothesis that a restrictive protocol targeting non-resuscitation fluids reduces the overall volume administered compared with usual care.
Adults with septic shock in six Swedish ICUs were randomized within 12 h of ICU admission to receive either protocolized reduction of non-resuscitation fluids or usual care. The primary outcome was the total volume of fluid administered within three days of inclusion.
Median (IQR) total volume of fluid in the first three days, was 6008 ml (interquartile range IQR 3960-8123) in the restrictive fluid group (n = 44), and 9765 ml (IQR 6804-12,401) in the control group (n = 48); corresponding to a Hodges-Lehmann median difference of 3560 ml 95% confidence interval 1614-5302; p < 0.001). Outcome data on all-cause mortality, days alive and free of mechanical ventilation and acute kidney injury or ischemic events in the ICU within 90 days of inclusion were recorded in 98/98 (100%), 95/98 (98%) and 95/98 (98%) of participants respectively. Cognition and health-related quality of life at six months were recorded in 39/52 (75%) and 41/52 (79%) of surviving participants, respectively. Ninety out of 134 patients (67%) of eligible patients were randomized, and 15/98 (15%) of the participants experienced at least one protocol violation.
Protocolized reduction of non-resuscitation fluids in patients with septic shock resulted in a large decrease in fluid administration compared with usual care. A trial using this design to test if reducing non-resuscitation fluids improves outcomes is feasible.
Clinicaltrials.gov, NCT05249088, 18 February 2022. https://clinicaltrials.gov/ct2/show/NCT05249088.
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