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101.
Phenological shifts in North American red squirrels: disentangling the roles of phenotypic plasticity and microevolution 下载免费PDF全文
Jeffrey E. Lane Andrew G. McAdam S. Eryn McFarlane Cory T. Williams Murray M. Humphries David W. Coltman Jamieson C. Gorrell Stan Boutin 《Journal of evolutionary biology》2018,31(6):810-821
Phenological shifts are the most widely reported ecological responses to climate change, but the requirements to distinguish their causes (i.e. phenotypic plasticity vs. microevolution) are rarely met. To do so, we analysed almost two decades of parturition data from a wild population of North American red squirrels (Tamiasciurus hudsonicus). Although an observed advance in parturition date during the first decade provided putative support for climate change‐driven microevolution, a closer look revealed a more complex pattern. Parturition date was heritable [h2 = 0.14 (0.07–0.21 (HPD interval)] and under phenotypic selection [β = ?0.14 ± 0.06 (SE)] across the full study duration. However, the early advance reversed in the second decade. Further, selection did not act on the genetic contribution to variation in parturition date, and observed changes in predicted breeding values did not exceed those expected due to genetic drift. Instead, individuals responded plastically to environmental variation, and high food [white spruce (Picea glauca) seed] production in the first decade appears to have produced a plastic advance. In addition, there was little evidence of climate change affecting the advance, as there was neither a significant influence of spring temperature on parturition date or evidence of a change in spring temperatures across the study duration. Heritable traits not responding to selection in accordance with quantitative genetic predictions have long presented a puzzle to evolutionary ecologists. Our results on red squirrels provide empirical support for one potential solution: phenotypic selection arising from an environmental, as opposed to genetic, covariance between the phenotypic trait and annual fitness. 相似文献
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Spectral karyotyping refines cytogenetic diagnostics of constitutional chromosomal abnormalities 总被引:12,自引:0,他引:12
E. Schröck T. Veldman Hesed Padilla-Nash Y. Ning Jack Spurbeck Syed Jalal Lisa G. Shaffer Peter Papenhausen Chahira Kozma Mary C. Phelan Eigil Kjeldsen Stephen A. Schonberg Patricia O’Brien Les Biesecker Stan du Manoir Thomas Ried 《Human genetics》1997,101(3):255-262
Karyotype analysis by chromosome banding is the standard method for identifying numerical and structural chromosomal aberrations
in pre- and postnatal cytogenetics laboratories. However, the chromosomal origins of markers, subtle translocations, or complex
chromosomal rearrangements are often difficult to identify with certainty. We have developed a novel karyotyping technique,
termed spectral karyotyping (SKY), which is based on the simultaneous hybridization of 24 chromosome-specific painting probes
labeled with different fluorochromes or fluorochrome combinations. The measurement of defined emission spectra by means of
interferometer-based spectral imaging allows for the definitive discernment of all human chromosomes in different colors.
Here, we report the comprehensive karyotype analysis of 16 samples from different cytogenetic laboratories by merging conventional
cytogenetic methodology and spectral karyotyping. This approach could become a powerful tool for the cytogeneticists, because
it results in a considerable improvement of karyotype analysis by identifying chromosomal aberrations not previously detected
by G-banding alone. Advantages, limitations, and future directions of spectral karyotyping are discussed.
Received: 4 August 1997 / Accepted: 8 September 1997 相似文献
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Luigi F Agnati Kjell Fuxe Maria Torvinen Susanna Genedani Rafael Franco Stan Watson Gastone G Nussdorfer Giuseppina Leo Diego Guidolin 《The journal of histochemistry and cytochemistry》2005,53(8):941-953
An important aspect of the image analysis of immunocytochemical preparations is the evaluation of colocalization of different molecules. The aim of the present study is to introduce image analysis methods to identify double-labeled locations exhibiting the highest association of two fluorophores and to characterize their pattern of distribution. These methods will be applied to the analysis of the cotrafficking of adenosine A2A and dopamine D2 receptors belonging to the G protein-coupled receptor family and visualized by means of fluorescence immunocytochemistry in Chinese hamster ovary cells after agonist treatment. The present procedures for colocalization have the great advantage that they are, to a large extent, insensitive to the need for a balanced staining with the two fluorophores. Thus, these procedures involve image processing, visualization, and analysis of colocalized events, using a covariance method and a multiply method and the evaluation of the identified colocalization patterns. Moreover, the covariance method offers the possibility of detecting and quantitatively characterizing anticorrelated patterns of intensities, whereas the immediate detection of colocalized clusters with a high concentration of labeling is a possibility offered by the multiply method. The present methods offer a new and sensitive approach to detecting and quantitatively characterizing strongly associated fluorescence events, such as those generated by receptor-receptor interaction, and their distribution patterns in dual-color confocal laser microscopy. 相似文献
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K. S. Jasper Kanes Stan E. Dosso Tania Lado Insua Xavier Mouy Andrew Bateman 《Marine Mammal Science》2024,40(1):73-88
Evaluation of temporal patterns in offshore marine mammal activity through visual data collection can be impaired by light and weather conditions and the cost of ship time. The conditions-independence and cost-efficacy of acoustic data collection make it popular for researching the temporal patterns of wild dolphins. However, Pacific white-sided dolphins (PWSDs) north of Southern California remain under-researched. This study evaluates diel and seasonal patterns in PWSD communication signals detected in 480 days of near-continuous passive acoustic data collected over 20 months from the Barkley Canyon node of Ocean Networks Canada's NEPTUNE observatory, offshore Vancouver Island, British Columbia, Canada. In this study, a random forest classifier is used to identify PWSD pulsed calls and false positives are manually removed. The resulting acoustic presence-absence data set is evaluated for seasonal and diel patterns using generalized additive mixed models, considering masking effects from ambient noise. PWSDs are found to be vocally active during all diel periods year-round, with high summer and low spring activity. Seasonally dependent diel patterns are identified, with PWSD pulsed calls exhibiting no diel pattern in spring, a slight increase in vocal activity during dusk and night in fall and winter, and a notable increase during night and dawn in summer. 相似文献
109.
Machielsen R Leferink NG Hendriks A Brouns SJ Hennemann HG Daussmann T van der Oost J 《Extremophiles : life under extreme conditions》2008,12(4):587-594
There is considerable interest in the use of enantioselective alcohol dehydrogenases for the production of enantio- and diastereomerically
pure diols, which are important building blocks for pharmaceuticals, agrochemicals and fine chemicals. Due to the need for
a stable alcohol dehydrogenase with activity at low-temperature process conditions (30°C) for the production of (2S,5S)-hexanediol,
we have improved an alcohol dehydrogenase from the hyperthermophilic archaeon Pyrococcus furiosus (AdhA). A stable S-selective alcohol dehydrogenase with increased activity at 30°C on the substrate 2,5-hexanedione was generated
by laboratory evolution on the thermostable alcohol dehydrogenase AdhA. One round of error-prone PCR and screening of ∼1,500
mutants was performed. The maximum specific activity of the best performing mutant with 2,5-hexanedione at 30°C was tenfold
higher compared to the activity of the wild-type enzyme. A 3D-model of AdhA revealed that this mutant has one mutation in
the well-conserved NADP(H)-binding site (R11L), and a second mutation (A180V) near the catalytic and highly conserved threonine
at position 183. 相似文献
110.
Jon Olav Vik Christian N. Brinch Stan Boutin Nils Christian Stenseth 《Population Ecology》2008,50(3):267-274
The classic fur trade records on Canadian lynx (Lynx canadensis) have rarely been analysed in direct conjunction with data on its principal prey, the snowshoe hare (Lepus americanus). Comparable long-term data for hare exist only for a region south of Hudson Bay. We fitted a bivariate log-linear time-series
model to this hare and lynx data to disentangle the within- and between-population interactions of these species. To reduce
problems with fur returns being non-normal and non-linearly related to abundance, we transformed the fur returns to a normal
distribution based on sample quantiles. The estimated effect on next year’s lynx abundance of a 1% increase in current hare
abundance was a 0.23% (SE = 0.05) increase in lynx. Conversely, a 1% increase in current lynx abundance corresponded to a
0.46% (SE = 0.12) decrease in next year’s hare abundance. This contrasts with some earlier studies. However, these studies
mixed hare data from south of Hudson Bay with lynx totals for all of Canada. Despite this asymmetry of interaction strengths,
coefficients of determination were similar for hare versus lynx and lynx versus hare, because hare abundance varies more than
lynx. Both species showed clear intraspecific density-dependence of about equal strength. A 1% increase in current abundance
increased next year’s abundance by about 0.75%.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献