scholarly journals Estimating inbreeding and its effects in a long-term study of snapdragons (Antirrhinum majus)

2020 ◽  
Author(s):  
Louise Arathoon ◽  
Parvathy Surendranadh ◽  
Nicholas Barton ◽  
David L. Field ◽  
Melinda Pickup ◽  
...  
Keyword(s):  
Inbreeding Depression ◽  
Spatial Scales ◽  
Pollen Dispersal ◽  
Antirrhinum Majus ◽  
Fitness Components ◽  
Term Study ◽  
Long Term Study ◽  
In The Wild ◽  
Long Term Studies

AbstractInbreeding depression can be estimated by correlating heterozygosity with fitness components, but such heterozygosity-fitness correlations are typically weak. For over ten years, we studied a population of the self-incompatible plant, Antirrhinum majus, measuring heterozygosity and fitness proxies from 22,353 plants. Using a panel of 91 SNPs, we find that relatedness declines rapidly over short spatial scales. Individual heterozygosity varies more between individuals than expected, reflecting identity disequilibrium (g2) due to variation in inbreeding – a prerequisite for detecting inbreeding depression. We use two types of simulations to ask whether the heterozygosity distribution is consistent with spatially structured mating. First, we simulate offspring from matings with fathers at different distances and find that the distribution of heterozygosity in the field data is consistent with the measured pollen dispersal kernel. Second, we simulate a 1000-generation pedigree using the known spatial distribution, and find that identity disequilibrium, though highly variable between simulations, is consistent with that observed. Finally, we estimate inbreeding depression through the relationships between heterozygosity and six fitness proxies. Only the number of flowering stems is predicted by heterozygosity. Our approach provides a novel example of how long-term studies can elucidate population structure and fitness variation in the wild.

Senescence in the wild: Insights from a long-term study on Seychelles warblers

2015 ◽  
Vol 71 ◽  
pp. 69-79 ◽  
Author(s):  
Martijn Hammers ◽  
Sjouke A. Kingma ◽  
Kat Bebbington ◽  
Janske van de Crommenacker ◽  
Lewis G. Spurgin ◽  
...  
Keyword(s):  
Term Study ◽  
Long Term Study ◽  
In The Wild

scholarly journals Evaluation of the Switch From Amiodarone to Dronedarone in Patients With Atrial Fibrillation: Results of the ARTEMIS AF Studies

2020 ◽  
Vol 25 (5) ◽  
pp. 425-437
Author(s):  
Gerald V. Naccarelli ◽  
Deepak L. Bhatt ◽  
A. John Camm ◽  
Jean-Yves Le Heuzey ◽  
Federico Lombardi ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Antiarrhythmic Drugs ◽  
Adverse Reactions ◽  
Optimal Timing ◽  
Atrial Fibrillation Recurrence ◽  
Term Study ◽  
Long Term Study ◽  
Poor Recruitment ◽  
Long Term Studies

Background: Switching between antiarrhythmic drugs is timed to minimize arrhythmia recurrence and adverse reactions. Dronedarone and amiodarone have similar electrophysiological profiles; however, little is known about the optimal timing of switching, given the long half-life of amiodarone. Methods: The ARTEMIS atrial fibrillation (AF) Loading and Long-term studies evaluated switching patients with paroxysmal/persistent AF from amiodarone to dronedarone. Patients were randomized based on the timing of the switch: immediate, after a 2-week, or after a 4-week washout of amiodarone. Patients who did not convert to sinus rhythm after amiodarone loading underwent electrical cardioversion. The primary objectives were, for the Loading study, to evaluate recurrence of AF ≤60 days; and for the Long-term study, to profile the pharmacokinetics of dronedarone and its metabolite according to different timings of dronedarone initiation. Results: In ARTEMIS AF Loading, 176 were randomized (planned 768) after a 28 ± 2 days load of oral amiodarone. Atrial fibrillation recurrence trended less in the immediate switch versus 4-week washout group (hazard ratio [HR] = 0.65 [97.5% CI: 0.34-1.23]; P = .14) and in the 2-week washout versus the 4-week washout group (HR = 0.75 [97.5% CI: 0.41-1.37]; P = .32). In ARTEMIS AF Long-term, 108 patients were randomized (planned 105). Pharmacokinetic analyses (n = 97) showed no significant differences for dronedarone/SR35021 exposures in the 3 groups. Conclusion: The trial was terminated early due to poor recruitment and so our findings are limited by low numbers. However, immediate switching from amiodarone to dronedarone appeared to be well tolerated and safe.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus

1997 ◽  
Vol 21 ◽  
pp. 57-59
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
National Park ◽  
Climatic Factors ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study ◽  
Small Measure ◽  
Long Term Studies

Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue a long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus.

2003 ◽  
Vol 27 ◽  
pp. 42-44
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
National Park ◽  
Climatic Factors ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study ◽  
Small Measure ◽  
Long Term Studies

A variety of hypotheses have been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.

scholarly journals Spatio-Temporal Ecological and Evolutionary Dynamics in Natural Butterfly Populations (2015 Field Season)

2015 ◽  
Vol 38 ◽  
pp. 29-32
Author(s):  
Zachariah Gompert ◽  
Lauren Lucas
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Molecular Evolution ◽  
Natural Populations ◽  
Spatial And Temporal Variation ◽  
Long Term Study ◽  
Genome Wide ◽  
In The Wild ◽  
Long Term Studies

The study of evolution in natural populations has advanced our understanding of the origin and maintenance of biological diversity. For example, long term studies of wild populations indicate that natural selection can cause rapid and dramatic changes in traits, but that in some cases these evolutionary changes are quickly reversed when periodic variation in weather patterns or the biotic environment cause the optimal trait value to change (e.g., Reznick et al. 1997, Grant and Grant 2002). In fact, spatial and temporal variation in the strength and nature of natural selection could explain the high levels of genetic variation found in many natural populations (Gillespie 1994, Siepielski et al. 2009). Long term studies of evolution in the wild could also be informative for biodiversity conservation and resource management, because, for example, data on short term evolutionary responses to annual fluctuations in temperature or rainfall could be used to predict longer term evolution in response to directional climate change. Most previous research on evolution in the wild has considered one or a few observable traits or genes (e.g., Kapan 2001, Grant and Grant 2002, Barrett et al. 2008). We believe that more general conclusions regarding the rate and causes of evolutionary change in the wild and selection’s contribution to the maintenance of genetic variation could be obtained by studying genome-wide molecular evolution in a suite of natural populations. Thus, in 2012 we began a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area (GYA). This study will allow us to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations and determine whether selection consistently favors the same alleles across space and through time.

scholarly journals Spatio-Temporal Evolutionary Dynamics in Natural Butterfly Populations (2012 Field Season)

2012 ◽  
Vol 35 ◽  
pp. 73-76
Author(s):  
Zachariah Gompert ◽  
Lauren Lucas
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Molecular Evolution ◽  
Natural Populations ◽  
Spatial And Temporal Variation ◽  
Long Term Study ◽  
Genome Wide ◽  
In The Wild ◽  
Long Term Studies

The study of evolution in natural populations has advanced our understanding of the origin and maintenance of biological diversity. For example, long term studies of wild populations indicate that natural selection can cause rapid and dramatic changes in traits, but that in some cases these evolutionary changes are quickly reversed when periodic variation in weather patterns or the biotic environment cause the optimal trait value to change (e.g., Reznick et al. 1997; Grant and Grant 2002). In fact, spatial and temporal variation in the strength and nature of natural selection could explain the high levels of genetic variation found in many natural populations (Gillespie 1994; Siepielski et al. 2009). Long term studies of evolution in the wild could also be informative for biodiversity conservation and resource management, because, for example, data on short term evolutionary responses to annual fluctuations in temperature or rainfall could be used to predict longer term evolution in response to directional climate change. Most previous research on evolution in the wild has considered one or a few observable traits or genes (Kapan 2001; Grant and Grant 2002; Barrett et al. 2008). We believe that more general conclusions regarding the rate and causes of evolutionary change in the wild and selection’s contribution to the maintenance of genetic variation could be obtained by studying genome-wide molecular evolution in a suite of natural populations. Thus, we have begun a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area (GYA). This study will allow us to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations and determine whether selection consistently favors the same alleles across space and through time.

scholarly journals Distribution of natal dispersal distances and the genetic structure of Spruce Grouse (Falcipennis canadensis) populations

2016 ◽  
Vol 94 (6) ◽  
pp. 421-425 ◽  
Author(s):  
G.F. Barrowclough ◽  
M.A. Schroeder
Keyword(s):  
Genetic Structure ◽  
Natural Populations ◽  
Natal Dispersal ◽  
Term Study ◽  
Long Term Study ◽  
The Mean ◽  
Dispersal Distances ◽  
Breeding Seasons ◽  
Long Term Studies

Natal dispersal distances are difficult to measure, yet important for estimating the genetic structure and demographic connectedness of natural populations. Here we provide estimates of the distributions of male and female natal dispersal distances from a long-term study of Spruce Grouse (Falcipennis canadensis (L., 1758)) in southwestern Alberta, Canada, based on individuals marked as brood chicks and re-observed as adults during subsequent breeding seasons. The mean distance dispersed by females (2.33 km) was twice that of males (1.13 km), and both dispersal distributions were leptokurtic. Given estimates of population density and survivorship, we estimated the genetic effective neighborhood size of this population as approximately 541 individuals. We computed equivalent estimates for two additional long-term studies of this species, based on data available in the literature; mean natal dispersal distances, averaged across sexes, ranged from 1.73 to 2.73 km for the three populations; effective deme sizes ranged from 541 to 890. Consequently, three widespread populations of Spruce Grouse yielded roughly similar estimates of demographic and genetic structure.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus

2002 ◽  
Vol 26 ◽  
pp. 38-40
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
National Park ◽  
Climatic Factors ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study ◽  
Small Measure ◽  
Long Term Studies

Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.

Variation in the milk yield, endocrine and metabolic responses following bovine somatotropin administration to dairy cows

1992 ◽  
Vol 1992 ◽  
pp. 36-36
Author(s):  
M.T. Rose ◽  
T.E.C. Weekes ◽  
P. Rowlinson
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Subcutaneous Administration ◽  
Bovine Somatotropin ◽  
Yield Response ◽  
Term Study ◽  
Long Term Study ◽  
Genetic Potential ◽  
Long Term Studies

It is well established that the subcutaneous administration of bovine somatotropin (bst) to dairy cows results in an increased level of milk production. This effect occurs irrespective of the method of application, the duration of the treatment or the time after calving after which it commences. However, the reported extent of this galactopoietic effect in the published literature has been highly variable, with one long term study reporting an increase of over 11.5 kg/day (Bauman et al. 1985), whilst other long term studies have reported relatively small increases or no significant increase at all (Hof et al. 1991, Morbeck et al. 1991). As yet it is unknown what factors control the milk yield response to bst, though there is a clear effect of dose of the hormone and possibly of energy and protein balance. There are also confusing reports on the effect of the previous milk yield and genetic potential of the animal on the observed increase.

scholarly journals Natural recovery of a marine foundation species emerges decades after landscape-scale mortality

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Margaret O. Hall ◽  
Susan S. Bell ◽  
Bradley T. Furman ◽  
Michael J. Durako
Keyword(s):  
Anthropogenic Impacts ◽  
Foundation Species ◽  
Ecosystem Recovery ◽  
Term Study ◽  
Ecosystem Responses ◽  
Seagrass Community ◽  
Long Term Study ◽  
Seagrass Ecosystems ◽  
Long Term Studies

AbstractGlobally, the conditions and time scales underlying coastal ecosystem recovery following disturbance remain poorly understood, and post-disturbance examples of resilience based on long-term studies are particularly rare. Here, we documented the recovery of a marine foundation species (turtlegrass) following a hypersalinity-associated die-off in Florida Bay, USA, one of the most spatially extensive mortality events for seagrass ecosystems on record. Based upon annual sampling over two decades, foundation species recovery across the landscape was demonstrated by two ecosystem responses: the range of turtlegrass biomass met or exceeded levels present prior to the die-off, and turtlegrass regained dominance of seagrass community structure. Unlike reports for most marine taxa, recovery followed without human intervention or reduction to anthropogenic impacts. Our long-term study revealed previously uncharted resilience in subtropical seagrass landscapes but warns that future persistence of the foundation species in this iconic ecosystem will depend upon the frequency and severity of drought-associated perturbation.

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