Significant levels of self-fertilization in natural populations of tamarack

1987 ◽  
Vol 65 (6) ◽  
pp. 1087-1091 ◽  
Author(s):  
Peggy Knowles ◽  
Glenn R. Furnier ◽  
Mary A. Aleksiuk ◽  
Daniel J. Perry
Keyword(s):  
Adult Stage ◽  
Natural Populations ◽  
Stand Density ◽  
Outcrossing Rate ◽  
Larix Laricina ◽  
Northern Ontario ◽  
Marker Loci ◽  
Self Fertilization ◽  
The Mean ◽  
The One

The mating system in five northern Ontario populations of tamarack (Larix laricina (Du Roi) K. Koch) was investigated using five allozyme marker loci (Aat3, G6p, Mdh3, Pgi2, and 6pg2). The mean multilocus outcrossing rate was 0.729, lower than estimates reported for most other conifers. The one population with a much higher stand density than the others had the highest outcrossing rate (0.908). Significant heterozygote deficiencies, relative to Hardy – Weinberg expectations, were observed at most loci in all five embryo populations. In contrast, there appeared to be few cases of heterozygote deficiencies in the adult populations, indicating that many inbred seedlings do not survive to the adult stage.

The mating system in natural populations of Thujaorientalis

1991 ◽  
Vol 21 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Chang Yi Xie ◽  
Bruce P. Dancik ◽  
Francis C. Yeh
Keyword(s):  
Mating System ◽  
Expectation Maximization ◽  
Natural Populations ◽  
Expectation Maximization Algorithm ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
System Parameters ◽  
Marker Loci ◽  
Self Fertilization ◽  
The Mean

EM (expectation–maximization) algorithm procedures were used to estimate mating-system parameters in four natural populations of Thujaorientalis L. from China using seven allozyme marker loci (Fest1, Idh1, Idh2, Mr, Pgi2, Skdh1, and 6Pg2). The mean single-locus outcrossing rate was 0.70 for the species, but estimates showed that there was significant heterogeneity among loci within populations. Multilocus estimates of the outcrossing rate showed that there was significant heterogeneity among populations and among trees within populations. The mean multilocus outcrossing rate (0.75) was higher than the outcrossing rate (0.63) observed in a closely related conifer, Thujaoccidentalis L., but lower than estimates that have been reported for most other conifers. Significant heterozygote deficiencies, relative to Hardy–Weinberg and mating-system equilibria, were observed in all filial populations. In contrast, the maternal populations conformed to Hardy–Weinberg and mating-system equilibria at most loci. Self-fertilization and other forms of inbreeding (e.g., sibling mating) within the sampled populations are important contributors to the low outcrossing estimates in this conifer.

Evidence of high self-fertilization in natural populations of eastern white cedar (Thuja occidentalis)

1990 ◽  
Vol 68 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Daniel J. Perry ◽  
Peggy Knowles
Keyword(s):  
Natural Populations ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
Embryo Survival ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Northwestern Ontario ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Eastern White Cedar

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at four loci (Mdh-1, Me, 6Pg-2, and Pgm) to obtain estimates of outcrossing rates for three eastern white cedar populations in northwestern Ontario, Canada. Multilocus population outcrossing rate estimates were low, ranging from 0.507 to 0.745, with significant heterogeneity among populations. Low stand densities and relatively high selfed embryo survival may have contributed to the low effective outcrossing rates observed. Single-tree multilocus outcrossing rate estimates were obtained for nine trees from one population. When estimated jointly with outcross pollen pool allele frequencies, these outcrossing rate estimates ranged from 0.253 to 1.023 with significant heterogeneity among trees. Key words: mating system, outcrossing rate, Thuja occidentalis L.

Effects of stand density on outcrossing rate in two Norway spruce (Picea abies) populations

1991 ◽  
Vol 69 (12) ◽  
pp. 2704-2708 ◽  
Author(s):  
M. Morgante ◽  
G. G. Vendramin ◽  
P. Rossi
Keyword(s):  
Picea Abies ◽  
Mating System ◽  
Norway Spruce ◽  
Stand Density ◽  
Major Effect ◽  
Outcrossing Rate ◽  
High Density ◽  
Low Density ◽  
The Mean ◽  
Key Words Mating System

The mating system was investigated in two neighbouring Norway spruce (Picea abies (L.) Karst.) populations with markedly different stand densities. The amount of outcrossing was estimated using open-pollinated array data at four enzyme loci. Multilocus estimates of the proportion of viable progeny owing to outcrossing were 0.956 and 0.955 for the low- and high-density stand, respectively, indicating that the large reduction in stand density had no impact on outcrossing rates. The multilocus estimate was higher than the mean single-locus estimate only for the low-density stand. The lowering of the mean estimate in the low-density stand is probably a consequence of the clustering of related individuals. The regression of pollen allele frequencies on ovule genotype, which is a direct measure of the effective selfing caused by consanguineous matings, had a significant coefficient for the low-density stand and a nonsignificant one for the high-density stand. This obvservation confirms that the major effect of low-stand density in Norway spruce is the occurrence of consanguineous matings. Key words: mating system, outcrossing rate, inbreeding, Norway spruce, stand density.

Mating system in natural populations of eastern white pine in Quebec

1995 ◽  
Vol 25 (10) ◽  
pp. 1697-1703 ◽  
Author(s):  
J. Beaulieu ◽  
J.-P. Simon
Keyword(s):  
Family Structure ◽  
Mating System ◽  
Natural Populations ◽  
Outcrossing Rate ◽  
The Other ◽  
Single Locus ◽  
White Pine ◽  
Eastern White Pine ◽  
Gene Frequencies ◽  
Self Fertilization

The mating system in two natural eastern white pine (Pinusstrobus L.) populations in Quebec was investigated. These populations contrasted in density and age. The single-locus as well as multilocus outcrossing rate estimates were obtained from four polymorphic enzyme loci using open-pollinated progeny data. The single-locus outcrossing rates ranged from 0.934 to 1.110 with a mean of 1.026 in one population and varied from 0.862 to 1.186 with a mean of 1.007 in the other population. Multilocus estimates exceeded 1.0 in both populations, suggesting the possible absence of self-fertilization. Pollen pool gene frequencies were homogeneous in one population and heterogeneous in the other. The positive or less negative F-values found in the filial populations compared with those observed in the parental populations suggest the presence of a family structure favouring consanguineous matings.

Evaluation of Road Utilisation as Space For Holding Social Ceremonies in Indigenous Residential Area of Ogbomoso, Nigeria

2018 ◽  
Vol 1 (March 2018) ◽  
Author(s):  
S.A Okanlawon ◽  
O.O Odunjo ◽  
S.A Olaniyan
Keyword(s):  
Transport Infrastructure ◽  
Noisy Environment ◽  
Policy Makers ◽  
The Core ◽  
Local Roads ◽  
Strict Enforcement ◽  
The Mean ◽  
The One ◽  
The City ◽  
The Town

This study examined Residents’ evaluation of turning transport infrastructure (road) to spaces for holding social ceremonies in the indigenous residential zone of Ogbomoso, Oyo State, Nigeria. Upon stratifying the city into the three identifiable zones, the core, otherwise known as the indigenous residential zone was isolated for study. Of the twenty (20) political wards in the two local government areas of the town, fifteen (15) wards that were located in the indigenous zone constituted the study area. Respondents were selected along one out of every three (33.3%) of the Trunk — C (local) roads being the one mostly used for the purpose in the study area. The respondents were the residents, commercial motorists, commercial motorcyclists, and celebrants. Six hundred and forty-two (642) copies of questionnaire were administered and harvested on the spot. The Mean Analysis generated from the respondents’ rating of twelve perceived hazards listed in the questionnaire were then used to determine respondents’ most highly rated perceived consequences of the practice. These were noisy environment, Blockage of drainage by waste, and Endangering the life of the sick on the way to hospital; the most highly rated reasons why the practice came into being; and level of acceptability of the practice which was found to be very unacceptable in the study area. Policy makers should therefore focus their attention on strict enforcement of the law prohibiting the practice in order to ensure more cordial relationship among the citizenry, seeing citizens’ unacceptability of the practice in the study area.

Growth table for Corsican pine in Flanders (Belgium)

1991 ◽  
Vol 56 ◽  
Author(s):  
B. Meuleman
Keyword(s):  
Insect Pests ◽  
Sandy Loam ◽  
Stand Density ◽  
Forest Tree ◽  
Permanent Plots ◽  
New Findings ◽  
Volume Increment ◽  
The Mean ◽  
Annual Volume ◽  
Very High

After  its introduction at the start of this century, the Corsican pine has become  an important forest tree in Flanders (Belgium). The total area covered by  Corsican pine is about 11.000 ha. Due to climatological factors it is  virtually absent from the Walloon part of Belgium. Despite the crisis in 1984  - 1986, practical experiences with its vitality and disease resistance are  generally positive. Compared to Scots pine which is native to Belgium, its  productivity and insensitivity for insect pests is large.     To quantify the productivity of Corsican pine, a growth table was  constructed using a method developed by PALM and DAGNELIE. It was based on  data from 321 temporarily and 80 permanent plots distributed over Flanders.  Five yield classes were distinguished according to dominant height at 50  years. For each yield class, a series of tables as a function of treatment  was constructed. Treatments were characterized by the mean annual  circumference increment.     These tables allow to predict the growth of Corsican pines. Such  predictions for the whole range of species are necessary for the development  of a good forestry policy and for timber industries. The tables also provide  information for any given Corsican pine stand that is helpful in practice:  expected productivity, stand density, determination of the felling quantum.      The data show that the productivity of Corsican pine is very high. The very  early culmination of the current annual volume increment and the rather  constant level of the mean annual volume increment after culmination are  interesting new findings. It is also shown that it is possible to work with  long rotation periods. This offers good opportunities for the production of  high quality wood and is also important for the social and ecological role of  the forest.     Productivity is lowest on very dry and sandy soils. A high productivity on  moderately dry sand and loamy sand soils and loamy soils make the Corsican  pine one of the most valuable tree species for the Kempen in Flanders.  Although productivity is very high on well drained sandy loam and loam soils,  plantation of Corsican pine on these locations is not advised.

scholarly journals SAT0267 ROLE OF AGGRESSIVE IMMUNOSUPPRESSION ON SUBGLOTTIC STENOSIS IN GRANULOMATOSIS WITH POLYANGIITIS: RETROSPECTIVE ANALYSIS OF A MONOCENTRIC COHORT

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1076.1-1077
Author(s):  
L. Moroni ◽  
L. Giudice ◽  
G. A. Ramirez ◽  
S. Sartorelli ◽  
A. Cariddi ◽  
...  
Keyword(s):  
Medical Treatment ◽  
Clinical Characteristics ◽  
Granulomatosis With Polyangiitis ◽  
Balloon Catheter ◽  
Subglottic Stenosis ◽  
Damage Accrual ◽  
The Mean ◽  
The One

Background:Subglottic stenosis (SGS) is defined as airway narrowing below the vocal cords and is a common and potentially life-threatening manifestation of Granulomatosis with Polyangiitis (GPA), with an estimated prevalence of 16-23% (1). Balloon catheter dilation is effective in GPA-related SGS, but relapses are frequent. Little is known about the role of immunosuppression in this setting.Objectives:to analyse the clinical characteristics of a monocentric GPA cohort, describe phenotype differences among patients with and without SGS and investigate the role of surgical and medical treatments on relapse risk and general outcome.Methods:Biopsy-proven patients with SGS were identified by review of medical charts among a cohort of patients with GPA, classified according to the algorithm of the European Medicine Agency (2). The clinical characteristics of patients with SGS were retrospectively collected over a median follow-up time of 15.9 years and compared to those of patients without SGS.Results:Fourteen patients with SGS-GPA were identified, with a female to male ratio of 1:1 and a prevalence of 29.2% among the cohort. The mean ± SD age at GPA onset was 30.8 ± 14.4 years, with a mean time from GPA diagnosis to SGS onset of 4.7 ± 4.2 years. ANCA were positive in 78.6% (54.0% anti-PR3, 18.1% anti-MPO and 27.9% IFI only). The mean Birmingham Vasculitis Activity Score (BVAS) at onset was 10.0 ± 5.6. The main clinical manifestations associated with SGS were crusty rhinitis (100%), sinusitis (78%), pulmonary disease (72.7%), otitis/mastoiditis (50%), glomerulonephritis (42.9%), orbital pseudotumor (28.6%). Six patients (42.9%) received medical treatment only, other six (42.9%) had one to three balloon dilations and two (14.2%) underwent four or more procedures. Eight patients had no SGS relapse (maximum one dilation) and they all received immunosuppression with rituximab (RTX), cyclophosphamide (CYC) or azathioprine (AZA). All patients who received no immunosuppression, methotrexate (MTX) or mycophenolate (MMF) had at least one relapse. Patients treated with MTX or MMF had a mean relapse-free survival of 13.1 months, which was comparable to the one of patients not receiving medical treatment (40.2 months; p=NS) and shorter than the one of patients receiving CYC or RTX (153.2 months; p=0.032). CYC use also inversely correlated with the number of surgical procedures (r=-0.691, p=0.006). Compared to patients without SGS (31 consecutive patients with at least 4 years of follow-up), patients with SGS-GPA had an earlier disease onset (mean age 30.8 vs 50.4 years; p<0.001), but with lower BVAS (mean 10.0 vs 15.3; p=0.013) and showed a higher prevalence of crusty rhinitis (100% vs 67.7%; p=0.019). No difference was observed in damage accrual over time between the two groups.Conclusion:Subglottic stenosis is highly prevalent in patients with GPA and may define a milder disease subset occurring more frequently in younger patients. MTX and MMF might be insufficient to prevent SGS relapses requiring balloon dilation. Aggressive immunosuppression (CYC or RTX) might have a non-redundant role in this setting and reduce the risk of relapses.References:[1]Quinn KA, et al. Subglottic stenosis and endobronchial disease in granulomatosis with polyangiitis. Rheumatology 2019; 58 (12), 2203-2211.[2]Watts R, et al. Development and validation of a consensus methodology for the classification of the ANCA associated vasculitides and polyarteritis nodosa for epidemiological studies. Ann Rheum Dis 2007; 66: 222-7.Disclosure of Interests:Luca Moroni: None declared, Laura Giudice: None declared, Giuseppe Alvise Ramirez: None declared, Silvia Sartorelli: None declared, adriana cariddi: None declared, Angelo Carretta: None declared, Enrica Bozzolo: None declared, Lorenzo Dagna Grant/research support from: The Unit of Immunology, Rheumatology, Allergy and Rare Diseases (UnIRAR) received unresctricted research/educational grants from Abbvie, Bristol-Myers Squibb, Celgene, Janssen, Merk Sharp & Dohme, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, Sanofi-Genzyme, and SOBI., Consultant of: Prof Lorenzo Dagna received consultation honoraria from Abbvie, Amgen, Biogen, Bristol-Myers Squibb, Celltrion, Novartis, Pfizer, Roche, Sanofi-Genzyme, and SOBI.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

scholarly journals Two-term expansion of the ground state one-body density matrix of a mean-field Bose gas

2021 ◽  
Vol 60 (3) ◽  
Author(s):  
Phan Thành Nam ◽  
Marcin Napiórkowski
Keyword(s):  
Density Matrix ◽  
Ground State ◽  
Mean Field ◽  
Interaction Strength ◽  
Bose Gas ◽  
Body Density ◽  
The Mean ◽  
The One ◽  
Mean Field Regime ◽  
Number Of Particles

AbstractWe consider the homogeneous Bose gas on a unit torus in the mean-field regime when the interaction strength is proportional to the inverse of the particle number. In the limit when the number of particles becomes large, we derive a two-term expansion of the one-body density matrix of the ground state. The proof is based on a cubic correction to Bogoliubov’s approximation of the ground state energy and the ground state.

scholarly journals Acute bilateral foot drop with or without cauda equina syndrome—a case series

2021 ◽  
Vol 163 (4) ◽  
pp. 1191-1198
Author(s):  
Andreas K. Demetriades ◽  
Marco Mancuso-Marcello ◽  
Asfand Baig Mirza ◽  
Joseph Frantzias ◽  
David A. Bell ◽  
...  
Keyword(s):  
Cauda Equina Syndrome ◽  
Cauda Equina ◽  
Case Series ◽  
Foot Drop ◽  
Spinal Disease ◽  
Full Resolution ◽  
Degenerative Spinal Disease ◽  
The Mean ◽  
The One

Abstract Introduction Isolated acute bilateral foot drop due to degenerative spine disease is an extremely rare neurosurgical presentation, whilst the literature is rich with accounts of chronic bilateral foot drop occurring as a sequela of systemic illnesses. We present, to our knowledge, the largest case series of acute bilateral foot drop, with trauma and relevant systemic illness excluded. Methods Data from three different centres had been collected at the time of historic treatment, and records were subsequently reviewed retrospectively, documenting the clinical presentation, radiological level of compression, timing of surgery, and degree of neurological recovery. Results Seven patients are presented. The mean age at presentation was 52.1 years (range 41–66). All patients but one were male. All had a painful radiculopathic presentation. Relevant discopathy was observed from L2/3 to L5/S1, the commonest level being L3/4. Five were treated within 24 h of presentation, and two within 48 h. Three had concomitant cauda equina syndrome; of these, the first two made a full motor recovery, one by 6 weeks follow-up and the second on the same-day post-op evaluation. Overall, five out of seven cases had full resolution of their ankle dorsiflexion pareses. One patient with 1/5 power has not improved. Another with 1/5 weakness improved to normal on the one side and to 3/5 on the other. Conclusion When bilateral foot drop occurs acutely, we encourage the consideration of degenerative spinal disease. Relevant discopathy was observed from L2/3 to L5/S1; aberrant innervation may be at play. Cauda equina syndrome is not necessarily associated with acute bilateral foot drop. The prognosis seems to be pretty good with respect to recovery of the foot drop, especially if partial at presentation and if treated within 48 h.

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