Inferring the contribution of sexual reproduction, migration and off-season survival to the temporal maintenance of microbial populations: a case study on the wheat fungal pathogenPuccinia striiformisf.sp.tritici

2014 ◽  
Vol 23 (3) ◽  
pp. 603-617 ◽  
Author(s):  
Sajid Ali ◽  
Pierre Gladieux ◽  
Hidayatur Rahman ◽  
Muhammad S. Saqib ◽  
Muhammad Fiaz ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Microbial Populations

Wide spread invasion without sexual reproduction? A case study on European willows in Patagonia, Argentina

2010 ◽  
Vol 13 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Katharina B. Budde ◽  
Leonardo Gallo ◽  
Paula Marchelli ◽  
Eva Mosner ◽  
Sascha Liepelt ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Wide Spread

The prevalence and evolution of sex in microorganisms

Genome ◽  
2004 ◽  
Vol 47 (5) ◽  
pp. 775-780 ◽  
Author(s):  
Jianping Xu
Keyword(s):  
Sexual Reproduction ◽  
Recent Progress ◽  
Natural Populations ◽  
Microbial Populations ◽  
Model Organisms ◽  
Costs And Benefits ◽  
Evolution Of Sex ◽  
Excellent Model ◽  
Maintenance Of Sex ◽  
Eukaryotic Microbes

The origin of sex and how sex is maintained are among the biggest puzzles in biology. Most investigations into this problem have focused on complex eukaryotes like animals and plants. This mini-review summarizes recent progress in our understanding of the evolution of sex, highlighting results from studies of experimental and natural populations of microorganisms. Increasing evidence indicates that sexual reproduction in natural populations of viruses, bacteria, and eukaryotic microbes is much more prevalent than previously thought. In addition, investigations using experimental microbial populations are providing important parameters relevant to our understanding of the origin and maintenance of sex. It is argued that microbes are excellent model organisms to explore the mechanisms responsible for the evolution of sex.Key words: costs and benefits of sex, natural populations, experimental populations, Müller's Ratchet, interaction among mutations, loss of sex.

scholarly journals First report of the sexual stage of the flax pathogen Mycosphaerella linicola in France and its impact on pasmo epidemiology

2020 ◽  
Author(s):  
Delphine Paumier ◽  
Blandine Bammé ◽  
Annette Penaud ◽  
Romain Valade ◽  
Frédéric Suffert
Keyword(s):  
Sexual Reproduction ◽  
Late Summer ◽  
Sexual Stage ◽  
Plant Host ◽  
Temporal Shift ◽  
Developmental Dynamics ◽  
Autumn And Winter ◽  
Quantitative Impact ◽  
First Time

AbstractWe performed a three-year field survey in France to characterize the dynamics of sexual reproduction in Mycosphaerella linicola, the causal agent of pasmo, during the interepidemic period. Cohorts of fruiting bodies were sampled from linseed straw during the autumn and winter and carefully observed, focusing on pseudothecia, asci and ascospores. A sequence of experimental steps corresponding to Koch’s postulates confirmed in July 2014, for the first time in France and continental Europe, the widespread presence of the sexual stage of M. linicola in plant host tissues. The developmental dynamics of pseudothecia on straw, expressed as the change over time in the percentage of mature pseudothecia, was similar in all three years. Pseudothecia appeared in late summer, with peak maturity reached in October. A temporal shift, thought to be due to early autumn rainfall, was highlighted in one of the three years. These observations suggest that sexual reproduction plays a significant role in the epidemiology of pasmo in France. A resurgence of M. linicola infections in spring flax is thought to have occurred in recent years, due to the increase in the area under flax. The presence of the sexual stage of this pathogen probably increased the quantitative impact of residues of winter linseed (used for oil) and flax straw (left on the soil for retting and used for fibers) as an interepidemic ‘brown bridge’. This case study highlights how certain parts of a disease cycle, in this case the sexual phase, can become crucial due to changes in production conditions.

scholarly journals The extended Price equation: migration and sex

2021 ◽  
Author(s):  
Jake Brown ◽  
Jared M Field
Keyword(s):  
Natural Selection ◽  
Sexual Reproduction ◽  
Evolutionary Change ◽  
Price Equation ◽  
Hamilton’S Rule ◽  
Population Structures ◽  
Biological Interpretation ◽  
Hamilton's Rule

The Price equation provides a general partition of evolutionary change into two components. The first is usually thought to represent natural selection and the second, transmission bias. Here, we provide a new derivation of the generalised equation, which contains a largely ignored third term. Unlike the original Price equation, this extension can account for migration and mixed asexual and sexual reproduction. The derivation here expresses the generalised equation explicitly in terms of fitness, rendering this otherwise difficult third term more open to biological interpretation and use. This re-derivation also permits fundamental results, derived from the Price equation, to be more easily generalised. We take Hamilton's rule as a case study, and provide an exact, total expression that allows for population structures like haplodiploidy. Our analysis, more generally, makes clear the previously hidden assumptions in similar fundamental results, highlighting the caution that must be taken when interpreting them.

scholarly journals Sexual reproduction vs. clonal propagation in the recovery of a seagrass meadow after an extreme weather event

2019 ◽  
Vol 83 (4) ◽  
pp. 357 ◽  
Author(s):  
Diogo Paulo ◽  
Onno Diekmann ◽  
Ana Alexandra Ramos ◽  
Filipe Alberto ◽  
Ester Alvares Serrão
Keyword(s):  
Sexual Reproduction ◽  
Clonal Propagation ◽  
Seagrass Meadow ◽  
Genotypic Diversity ◽  
Weather Event ◽  
Winter Storms ◽  
Relative Contribution ◽  
Sexual Propagation ◽  
Seedling Germination

Marine flowering plants can reproduce sexually and clonally, and the relative contribution of these two modes can be dependent on the environmental conditions. Zostera marina, a seagrass widely distributed in the northern hemisphere, can form annual and perennial meadows with different proportions of sexual versus clonal propagation depending on the environmental disturbance regime. We study the hypothesis that the contribution of sexual propagation varies during the recovery of a seagrass meadow. In this case study, we compare the proportion of sexual versus clonal propagation of a perennial Z. marina meadow before its disappearance due to winter storms and after recovery. Before disturbance, genotypic diversity was high, indicating frequent sexual reproduction events likely to create an abundant seed bank. Seedling germination allowed the population to recover after the extreme disturbance. As months passed, seedlings became rare and finally absent, giving place to adult shoots. In an advanced stage of colonization, the shoots colonized the area by vegetative growth, which lowered the genotypic diversity. Despite this reduction over time, the genotypic diversity of the new meadow is still high, demonstrating the importance of sexual reproduction in meadow recovery and persistence.

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

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