Population structure of Heterobasidion annosum as determined by somatic incompatibility, sexual incompatibility, and isoenzyme patterns

1985 ◽  
Vol 63 (12) ◽  
pp. 2268-2273 ◽  
Author(s):  
Jan Stenlid

Pure cultures of Heterobasidion annosum were isolated from diseased trees in a 120-year-old Norway spruce stand. Clones of the fungus were identified by three different methods: studies of somatic incompatibility, identification of mating factors, and comparative studies of isoenzyme patterns. All of these methods yielded similar results. The study of somatic incompatibility was found to be the easiest and most reliable method for future investigations of population structures of Heterobasidion annosum. Nine clones were identified within a 60 × 60 m area. The number of trees infected by one clone varied from 1 to 13. The largest area occupied by one single clone was 30 m in diameter. Altogether, 10 different mating alleles were found, of which 2 occurred in four different clones and 2 occurred in two different clones. The vegetative spread of H. annosum between trees within the area occupied by a particular clone was confirmed by excavating root systems.

2004 ◽  
Vol 34 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Vaidotas Lygis ◽  
Rimvydas Vasiliauskas ◽  
Jan Stenlid

Persistence of the root rot pathogen Heterobasidion annosum (Fr.) Bref. s.s. on infested areas and its transfer to a forest regeneration was studied in three forest sites in eastern Lithuania. The sites represented H. annosum disease centres in Pinus sylvestris L. stands, which were clear-felled and replanted with Betula pendula Roth 25 years prior to our study. Fungal isolation from trees and stumps on each site was performed on both replanted B. pendula and surrounding P. sylvestris from the previous generation. Low productivity of B. pendula stands (45.0–76.1 m3·ha–1), high mortality rates, and comparatively low vigor of trees (measured as crown densities) indicated a strong impact of root rot. Based on somatic incompatibility tests, we detected large spreading areas of clones of H. annosum (up to 48 m across) and old (35- to 40-year-old) clonal individuals. Territorial clones covered areas that encompassed both previous stands of P. sylvestris and current stands of B. pendula. Our results showed that H. annosum is able to persist in root systems of diseased trees for decades and readily attack birch replanted on infested sites. In addition, a total of 83 fungal species (out of 398 isolates) was found as a result of sampling 508 B. pendula, 49 P. sylvestris, 21 Juniperus communis L., and 1 Salix cinerea L. trees.


2001 ◽  
Vol 79 (5) ◽  
pp. 600-611 ◽  
Author(s):  
Jeremy R Dettman ◽  
Bart J van der Kamp

The population structures of Armillaria ostoyae (Romagn.) Herink and Armillaria sinapina Bérubé & Dessureault were investigated at a study site near Williams Lake in the central interior of British Columbia. One hundred and twenty eight fungal isolates were examined from nine infection centers and individual genets were delineated using random amplified polymorphic DNA (RAPD) analysis and somatic incompatibility tests. Six A. ostoyae genets ranging in size from 0.70 to >15 ha were detected. The population structure of A. ostoyae was consistent with a clonal reproductive strategy, and infection centers were occupied by single A. ostoyae genets or ramets thereof. Eighteen relatively small A. sinapina genets were detected, with infection centers being occupied by multiple genets. Armillaria sinapina appears to be more pathogenic to coniferous hosts than previously reported in the region. Armillaria ostoyae appears to initiate new infections of available substrate via airborne basidiospores at a lower frequency than A. sinapina. However once established, A. ostoyae can spread quite aggressively and capture significant amounts of secondary resources, while A. sinapina is unable to do so. The results of somatic incompatibility tests used to differentiate genets corresponded with the results of RAPD analysis, with only one minor discrepancy.Key words: Armillaria, RAPD, population structure, genet, ramet, clone.


2021 ◽  
pp. 1-13
Author(s):  
Emma Alfaro ◽  
Xochitl Inostroza ◽  
José E. Dipierri ◽  
Daniela Peña Aguilera ◽  
Jorge Hidalgo ◽  
...  

Abstract The analysis of multiple population structures (biodemographic, genetic and socio-cultural) and their inter-relations contribute to a deeper understanding of population structure and population dynamics. Genetically, the population structure corresponds to the deviation of random mating conditioned by a limited number of ancestors, by restricted migration in the social or geographic space, or by preference for certain consanguineous unions. Through the isonymic method, surname frequency and distribution across the population can supply quantitative information on the structure of a human population, as they constitute universal socio-cultural variables. Using documentary sources to undertake the Doctrine of Belén’s (Altos de Arica, Chile) historical demography reconstruction between 1763 and 1820, this study identified an indigenous population with stable patronymics. The availability of complete marriage, baptism and death records, low rates of migration and the significant percentage of individuals registered and constantly present in this population favoured the application of the isonymic method. The aim of this work was to use given names and surnames recorded in these documentary sources to reconstruct the population structure and migration pattern of the Doctrine of Belén between 1750 and 1813 through the isonymic method. The results of the study were consistent with the ethno-historical data of this ethnic space, where social cohesion was, in multiple ways, related to the regulation of daily life in colonial Andean societies.


Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 471
Author(s):  
P.-C.G. Vassiliou

A more realistic way to describe a model is the use of intervals which contain the required values of the parameters. In practice we estimate the parameters from a set of data and it is natural that they will be in confidence intervals. In the present study, we study Non-Homogeneous Markov Systems (NHMS) processes for which the required basic parameters are in intervals. We call such processes Non-Homogeneous Markov Set Systems (NHMSS). First we study the set of the relative expected population structure of memberships and we prove that under certain conditions of convexity of the intervals of the parameters the set is compact and convex. Next, we establish that if the NHMSS starts with two different initial distributions sets and allocation probability sets under certain conditions, asymptotically the two expected relative population structures coincide geometrically fast. We continue proving a series of theorems on the asymptotic behavior of the expected relative population structure of a NHMSS and the properties of their limit set. Finally, we present an application for geriatric and stroke patients in a hospital and through it we solve problems that surface in an application.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Guang Yao Fan ◽  
Yi Ye ◽  
Yi Ping Hou

Abstract Detecting population structure and estimating individual biogeographical ancestry are very important in population genetics studies, biomedical research and forensics. Single-nucleotide polymorphism (SNP) has long been considered to be a primary ancestry-informative marker (AIM), but it is constrained by complex and time-consuming genotyping protocols. Following up on our previous study, we propose that a multi-insertion-deletion polymorphism (Multi-InDel) with multiple haplotypes can be useful in ancestry inference and hierarchical genetic population structures. A validation study for the X chromosome Multi-InDel marker (X-Multi-InDel) as a novel AIM was conducted. Genetic polymorphisms and genetic distances among three Chinese populations and 14 worldwide populations obtained from the 1000 Genomes database were analyzed. A Bayesian clustering method (STRUCTURE) was used to discern the continental origins of Europe, East Asia, and Africa. A minimal panel of ten X-Multi-InDels was verified to be sufficient to distinguish human ancestries from three major continental regions with nearly the same efficiency of the earlier panel with 21 insertion-deletion AIMs. Along with the development of more X-Multi-InDels, an approach using this novel marker has the potential for broad applicability as a cost-effective tool toward more accurate determinations of individual biogeographical ancestry and population stratification.


2010 ◽  
Vol 192 (24) ◽  
pp. 6465-6476 ◽  
Author(s):  
Vartul Sangal ◽  
Heather Harbottle ◽  
Camila J. Mazzoni ◽  
Reiner Helmuth ◽  
Beatriz Guerra ◽  
...  

ABSTRACT Salmonellosis caused by Salmonella enterica serovar Newport is a major global public health concern, particularly because S. Newport isolates that are resistant to multiple drugs (MDR), including third-generation cephalosporins (MDR-AmpC phenotype), have been commonly isolated from food animals. We analyzed 384 S. Newport isolates from various sources by a multilocus sequence typing (MLST) scheme to study the evolution and population structure of the serovar. These were compared to the population structure of S. enterica serovars Enteritidis, Kentucky, Paratyphi B, and Typhimurium. Our S. Newport collection fell into three lineages, Newport-I, Newport-II, and Newport-III, each of which contained multiple sequence types (STs). Newport-I has only a few STs, unlike Newport-II or Newport-III, and has possibly emerged recently. Newport-I is more prevalent among humans in Europe than in North America, whereas Newport-II is preferentially associated with animals. Two STs of Newport-II encompassed all MDR-AmpC isolates, suggesting recent global spread after the acquisition of the bla CMY-2 gene. In contrast, most Newport-III isolates were from humans in North America and were pansusceptible to antibiotics. Newport was intermediate in population structure to the other serovars, which varied from a single monophyletic lineage in S. Enteritidis or S. Typhimurium to four discrete lineages within S. Paratyphi B. Both mutation and homologous recombination are responsible for diversification within each of these lineages, but the relative frequencies differed with the lineage. We conclude that serovars of S. enterica provide a variety of different population structures.


2008 ◽  
Vol 51 (6) ◽  
pp. 601-610
Author(s):  
A. P. Kominakis

Abstract. Empirical estimations of heritability, systematic effects and predictions of sires’ breeding values (BVs) were obtained under various population structures for simulated populations consisted of n = 400 animals in 5 herds for a trait of medium heritability (h2 = 0.30). An infinitesimal additive genetic animal model was assumed while simulating data. Population structure was varied to allow for good and poor connectedness across herds and (non)random association between the genetic and the environmental effects. The impact of the various population structures on the parameter estimation(s) was assessed using Mean Squared Error (MSE) and Pearson’s correlations. Allowing sires to have progenies in more than one herd (good herd connectedness) and random use of sires across herds generally resulted in good parameter estimations. Poor connectedness significantly affected herd effects estimation and BV prediction but not heritability estimation as long as random usage of sires across environments was guaranteed. Selective use of the best sires in the best herds along with poor connectedness resulted in poorest estimations of all parameters examined. In the latter case, heritability was seriously underestimated (h2 = 0.06) while highest error, lowest accuracies for the BVs and a remarkable underestimation of the genetic gain were observed. Use of reference sires on a natural mating basis to create genetic links between herds has served a good solution for both heritability and BVs estimation under unfavorable structure. Mating 0.25 of the herd ewes with reference sires resulted in a heritability estimate close to the simulated one. Significantly better estimates of systematic effects and BVs were, however, obtained when 0.5 of the herd ewes were mated by reference sires.


2015 ◽  
Author(s):  
Jorge Peña ◽  
Bin Wu ◽  
Arne Traulsen

AbstractSpatial structure greatly affects the evolution of cooperation. While in two-player games the condition for cooperation to evolve depends on a single structure coefficient, in multiplayer games the condition might depend on several structure coefficients, making it difficult to compare different population structures. We propose a solution to this issue by introducing two simple ways of ordering population structures: the containment order and the volume order. If population structure 𝒮1 is greater than population structure 𝒮2 in the containment or the volume order, then 𝒮1 can be considered a stronger promoter of cooperation. We provide conditions for establishing the containment order, give general results on the volume order, and illustrate our theory by comparing different models of spatial games and associated update rules. Our results hold for a large class of population structures and can be easily applied to specific cases once the structure coefficients have been calculated or estimated.


2016 ◽  
Vol 24 (2) ◽  
pp. 85-97 ◽  
Author(s):  
Sylvanus A. Nwafili ◽  
Tian-Xiang Gao

Abstract The genetic diversity and population structure of Chrysichthys nigrodigitatus were evaluated using a 443 base pair fragment of the mitochondrial control region. Among the eight populations collected comprising 129 individuals, a total of 89 polymorphic sites defined 57 distinct haplotypes. The mean haplotype diversity and nucleotide diversity of the eight populations were 0.966±0.006 and 0.0359±0.004, respectively. Analysis of molecular variance showed significant genetic differentiation among the eight populations (FST =0.34; P < 0.01). The present results revealed that C. nigrodigitatus populations had a high level of genetic diversity and distinct population structures. We report the existence of two monophyletic matrilineal lineages with mean genetic distance of 10.5% between them. Non-significant negative Tajima’s D and Fu’s Fs for more than half the populations suggests that the wild populations of C. nigrodigitatus underwent a recent population expansion, although a weak one since the late Pleistocene.


1993 ◽  
Vol 97 (10) ◽  
pp. 1223-1228 ◽  
Author(s):  
E.M. Hansen ◽  
J. Stenlid ◽  
M. Johansson

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