scholarly journals POPULATION BOTTLENECKS AND NONEQUILIBRIUM MODELS IN POPULATION GENETICS. I. ALLELE NUMBERS WHEN POPULATIONS EVOLVE FROM ZERO VARIABILITY

Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 745-763
Author(s):  
Takeo Maruyama ◽  
Paul A Fuerst
Keyword(s):  
Gene Diversity ◽  
Population Expansion ◽  
Allele Frequency Distribution ◽  
Population Bottlenecks ◽  
Rare Alleles ◽  
The Mean ◽  
Low Levels ◽  
Short Time ◽  
Initial Distributions ◽  
Sudden Population Expansion

ABSTRACT A simple numerical method was developed for the mean number and average age of alleles in a population that was initiated with no genetic variation following a sudden population expansion. The methods are used to examine the question of whether allele numbers are elevated compared with values seen in equilibrium populations having equivalent gene diversity. Excess allele numbers in expanding populations were found to be the rule. This was true whether the population began with zero variation or with low levels of variation in either of two initial distributions (initially an equilibrium allele frequency distribution or initially with loci occurring in only two classes of variation). Although the increase of alleles may persist for only a short time, when compared with the time which is required for approach to final equilibrium, the increase may be long when measured in absolute generation numbers. The pattern of increase in very rare alleles (those present only once in a sample) and the persistence of the original allele were also investigated.

scholarly journals POPULATION BOTTLENECKS AND NONEQUILIBRIUM MODELS IN POPULATION GENETICS. II. NUMBER OF ALLELES IN A SMALL POPULATION THAT WAS FORMED BY A RECENT BOTTLENECK

Genetics ◽  
1985 ◽  
Vol 111 (3) ◽  
pp. 675-689
Author(s):  
Takeo Maruyama ◽  
Paul A Fuerst
Keyword(s):  
Gene Diversity ◽  
Large Population ◽  
Population Expansion ◽  
Small Population ◽  
Allelic Loss ◽  
Population Bottlenecks ◽  
Sufficient Statistic ◽  
Allele Number ◽  
Excess Number ◽  
Recent Bottleneck

ABSTRACT A model is presented in which a large population in mutation/drift equilibrium undergoes a severe restriction in size and subsequently remains at the small size. The rate of loss of genetic variability has been studied. Allelic loss occurs more rapidly than loss of genic heterozygosity. Rare alleles are lost especially rapidly. The result is a transient deficiency in the total number of alleles observed in samples taken from the reduced population when compared with the number expected in a sample from a steady-state population having the same observed heterozygosity. Alternatively, the population can be considered to posses excess gene diversity if the number of alleles is used as the statistical estimator of mutation rate. The deficit in allele number arises principally from a lack of those alleles that are expected to appear only once or twice in the sample. The magnitude of the allelic deficiency is less, however, than the excess that an earlier study predicted to follow a rapid population expansion. This suggests that populations that have undergone a single bottleneck event, followed by rapid population growth, should have an apparent excess number of alleles, given the observed level of genic heterozygosity and provided that the bottleneck has not occurred very recently. Conversely, such populations will be deficient for observed heterozygosity if allele number is used as the sufficient statistic for the estimation of 4Nev. Populations that have undergone very recent restrictions in size should show the opposite tendencies.

Population Genetics ofCaenorhabditis elegans: The Paradox of Low Polymorphism in a Widespread Species

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Arjun Sivasundar ◽  
Jody Hey
Keyword(s):  
Genetic Variation ◽  
Microsatellite Loci ◽  
Population Expansion ◽  
Widespread Species ◽  
C Elegans ◽  
Model Research ◽  
The World ◽  
Natural Isolates ◽  
History Of ◽  
Low Levels

AbstractCaenorhabditis elegans has become one of the most widely used model research organisms, yet we have little information on evolutionary processes and recent evolutionary history of this widespread species. We examined patterns of variation at 20 microsatellite loci in a sample of 23 natural isolates of C. elegans from various parts of the world. One-half of the loci were monomorphic among all strains, and overall genetic variation at microsatellite loci was low, relative to most other species. Some population structure was detected, but there was no association between the genetic and geographic distances among different natural isolates. Thus, despite the nearly worldwide occurrence of C. elegans, little evidence was found for local adaptation in strains derived from different parts of the world. The low levels of genetic variation within and among populations suggest that recent colonization and population expansion might have occurred. However, the patterns of variation are not consistent with population expansion. A possible explanation for the observed patterns is the action of background selection to reduce polymorphism, coupled with ongoing gene flow among populations worldwide.

Pattern of plasma progesterone, oestradiol-17β, luteinizing hormone and androgen in non-pregnant buffalo (Bubalus bubalis)

1982 ◽  
Vol 100 (2) ◽  
pp. 279-284 ◽  
Author(s):  
R. C. Arora ◽  
R. S. Pandey
Keyword(s):  
Luteinizing Hormone ◽  
Peak Level ◽  
Systemic Circulation ◽  
Bubalus Bubalis ◽  
High Concentration ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Androgen Level ◽  
The Mean ◽  
Low Levels

Abstract. Domestic buffaloes were used to characterize the pattern of progesterone, oestradiol-17β, LH and androgen in the systemic circulation following infertile insemination. Concentrations of hormones were measured by RIA in blood samples collected daily or at alternate days following insemination. The concentration of progesterone was lowest on the day of insemination, and increased significantly to a peak level of 4.00 ± 0.60 ng/ml by day 13 post insemination. After day 17, it declined significantly (P < 0.01) to reach low levels by day 21. The concentration of oestradiol-17β was high at the time of insemination and declined significantly (P < 0.01) by day 2 after insemination. It was maintained around the basal level till day 18 with minor peaks in between this period. It again rose significantly (P < 0.01) at subsequent oestrus. The mean level of LH was highest at the time of insemination, and declined significantly (P < 0.01) by day 1 post insemination. It did not vary appreciably till the animal returned to oestrus. The oestrous value of LH and progesterone were negatively correlated (r = −0.77). The androgen level was observed to be high at insemination in 3 out of 5 animals, but the overall pattern of this steroid was inconsistent during the period studied. A high concentration of androgen was recorded in all the animals from day 2–5 before the onset of oestrus.

Genetic Diversity among Calamus brandisii Becc. (Arecaceae) Populations in Kerala Part of Western Ghats

2021 ◽  
Vol 43 (1) ◽  
pp. 38-42
Author(s):  
Kavungal Priya ◽  
◽  
Indira . ◽  
Vadakkethil Balakrishnan Sreekumar ◽  
Renuka . ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Western Ghats ◽  
Rapd Markers ◽  
Gene Diversity ◽  
Issr Markers ◽  
High Genetic Diversity ◽  
Western Ghats Of India ◽  
The Mean ◽  
Two Parameters ◽  
Two Populations

Calamus brandisii Becc. is one of the endemic slender rattans found in the Western Ghats of India. The genetic diversity of two main populations available in Kerala was investigated using 20 RAPD and 9 ISSR markers. Two parameters viz., gene diversity and genetic diversity within and among populations were analyzed. ISSR analysis showed quite high genetic diversity in Pandimotta compared to Bonacaud population whereas in RAPD markers both these populations were moderately diverse. The percentage of total genetic differentiation (Gst) among two populations is relatively higher than the mean Gst value indicating high genetic diversity within the populations. The genetic distance between these two populations was 0.1739 with ISSR markers and 0.1971 with RAPD markers. Because of its high genetic diversity, Pandimotta population can be treated as an important population of gene diversity with potentially useful genes. This may be included in the high priority reservoir for genetic conservation also.

scholarly journals Distribution-Free Model for Ambulance Location Problem with Ambiguous Demand

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Chu ◽  
Lu Wang ◽  
Xin Liu ◽  
Chengbin Chu ◽  
Yang Sui
Keyword(s):  
Probability Distribution ◽  
Location Problem ◽  
Service Level ◽  
Mixed Integer ◽  
Distribution Free ◽  
Demand Information ◽  
The Mean ◽  
Constrained Model ◽  
Short Time ◽  
Ambulance Location

Ambulance location problem is a key issue in Emergency Medical Service (EMS) system, which is to determine where to locate ambulances such that the emergency calls can be responded efficiently. Most related researches focus on deterministic problems or assume that the probability distribution of demand can be estimated. In practice, however, it is difficult to obtain perfect information on probability distribution. This paper investigates the ambulance location problem with partial demand information; i.e., only the mean and covariance matrix of the demands are known. The problem consists of determining base locations and the employment of ambulances, to minimize the total cost. A new distribution-free chance constrained model is proposed. Then two approximated mixed integer programming (MIP) formulations are developed to solve it. Finally, numerical experiments on benchmarks (Nickel et al., 2016) and 120 randomly generated instances are conducted, and computational results show that our proposed two formulations can ensure a high service level in a short time. Specifically, the second formulation takes less cost while guaranteeing an appropriate service level.

scholarly journals PSYCHOLOGICAL PROFILE OF PATIENTS ELIGIBLE FOR BARIATRIC SURGERY

2016 ◽  
Vol 29 (suppl 1) ◽  
pp. 27-30 ◽  
Author(s):  
Graziela Aparecida Nogueira de Almeida RIBEIRO ◽  
Helenice Brizolla GIAMPIETRO ◽  
Lídia Barbieri BELARMINO ◽  
Wilson SALGADO-JÚNIOR
Keyword(s):  
Bariatric Surgery ◽  
Binge Eating ◽  
Average Score ◽  
Psychological Profile ◽  
Psychosocial Characteristics ◽  
The Mean ◽  
Low Levels ◽  
Using Data ◽  
Binge Eating Scale ◽  
To Receive

Abstract Background: The psychologist who works in bariatric surgery has a role to receive, evaluate, prepare and educate the patient who will undergo the surgical procedure. Psychological evaluation becomes important in so far as allows us to obtain data on personal and familiar history and allow tracing of possible psychopathology. Aim: To collect data on psychological evaluations of patients in a bariatric surgery service of a public hospital in order to describe the psychological profile of patients in this service. Method: Data were collected from 827 patients between 2001 and 2015, using data from an interview, Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Binge Eating Scale (BES). Results: The mean age of patients before surgery was 39 years+/- 10, the mean BMI was 51 kg/m²+7, and most patients (81%) were female. The average score on the BDI was 14.8+8 and women had significantly higher scores than men. On the BAI the average score was 11+8 and on the ECAP was 14+8, both with no difference between groups. Conclusions: Psychosocial characteristics of the patients points to the significant presence of indicators of depression, with low levels of anxiety and binge eating.

Pyridoxine Deficiency After Solid Organ Transplant

2017 ◽  
Vol 27 (3) ◽  
pp. 251-256
Author(s):  
Summer Van Arsdale ◽  
Sarah E. Yost ◽  
Chiu-Hsieh Hsu ◽  
Mary Meer ◽  
Shari Schoentag ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Solid Organ Transplantation ◽  
Organ Transplant ◽  
Multivariate Logistic Regression Analysis ◽  
Study Cohort ◽  
Solid Organ ◽  
Immune Functions ◽  
Pyridoxine Deficiency ◽  
The Mean ◽  
Low Levels

Objective: Pyridoxine is 1 of 8 B vitamins that assist in a variety of essential functions including immune functions. The purpose of this study was to assess the risk factors associated with low pyridoxine levels in solid organ transplantation recipients. Design: The study cohort was divided into 2 groups: (a) patients with normal pyridoxine levels or (b) patients with low pyridoxine levels. Dietary evaluation and clinical characteristics of all patients, rejection episodes, and immunosuppression were collected. Simple descriptive statistics were used to analyze the overall cohort. Results: Of the 48 patients, 29 (60%) in the study cohort were identified to have low pyridoxine levels. The mean interval between transplantation and pyridoxine level check was 910 days (standard deviation [SD] 456). The mean weight at the time of dietary consultation was 80 kg (SD 20.7). More patients in the deficient group received thymoglobulin for rejection treatment (56% vs 0%; P = .01) and were thymoglobulin recipients (78% vs 10%; odds ratio [OR] = 31.5; 95% confidence interval [CI], 2.35-422.30; P < .01). A strong correlation was identified between thymoglobulin treatment for induction and a low level of pyridoxine (correlation coefficient R = 0.6, P = .004) and between thymoglobulin treatment for rejection and a low pyridoxine level (correlation coefficient R = 0.5, P = .05). Based on multivariate logistic regression analysis, only thymoglobulin treatment (induction or rejection treatment) was significantly associated with low pyridoxine levels (OR = 19.5, 95% CI, 1.01-375.24; P < .05). Conclusions: Low levels of pyridoxine appear to be relatively common, and thymoglobulin treatments are associated with low pyridoxine levels. Prospective studies are needed to confirm and valuate the significance of these findings.

scholarly journals Main features of Poaceae pollen season in Madeira region (Portugal)

2015 ◽  
Vol 68 (4) ◽  
pp. 367-372
Author(s):  
Irene Câmara Camacho ◽  
Rita Câmara ◽  
Roberto Camacho
Keyword(s):  
Pollen Season ◽  
Airborne Pollen ◽  
Growing Season ◽  
Onset Date ◽  
Critical Levels ◽  
Pollen Monitoring ◽  
Madeira Island ◽  
Poaceae Pollen ◽  
The Mean ◽  
Low Levels

<p>The pollinic spectrum of the Madeira region is dominated by grass pollen, which also represents an important aeroallergen in Europe. The present work aims to analyze the main features of the Poaceae pollen season in the Madeira region to determine the allergic risk. The study took place in Funchal city, the capital of Madeira Island, over a period of 10 years (2003–2012). The airborne pollen monitoring was carried out with a Hirst type volumetric trap, following well-established guidelines.</p><p>In the atmosphere of Funchal, the mean annual Poaceae pollen index was 229. The mean Poaceae pollen season lasts 275 days, with an onset date in January/March and an end date in November/December. Poaceae counts showed a seasonal variation with 2 distinct peaks: a higher peak between March and June, and the second one in autumn. The peak values occurred mainly between April and June, and the highest peak was 93 grains/m<sup>3</sup>, detected on the 27th May of 2010. The Poaceae pollen remaining at low levels during the whole growing season, presenting a nil to low allergenic risk during most of the study period. Higher critical levels of allergens have been revealed after 2006. In general, the pollen risk from Poaceae lasted only a few days per year, despite the very long pollen season and the abundance of grasses in the landscape of Madeira Island.</p>

scholarly journals Genetic studies revealed differences between European and North American populations of Calypogeia azurea

2016 ◽  
Vol 42 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Katarzyna Buczkowska ◽  
Alina Bączkiewicz ◽  
Patrycja Gonera
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Oil Bodies ◽  
Genetic Studies ◽  
Isozyme Loci ◽  
The Mean ◽  
Different Parts ◽  
Nei's Genetic Distance

Abstract Calypogeia azurea, a widespread, subboreal-montane liverwort species, is one of a few representatives of the Calypogeia genus that are characterized by the occurrence of blue oil bodies. The aim of the study was to investigate the genetic variation and population structure of C. azurea originating from different parts of its distribution range (Europe and North America). Plants of C. azurea were compared with C. peruviana, another Calypogeia species with blue oil bodies. In general, 339 gametophytes from 15 populations of C. azurea were examined. Total gene diversity (HT) estimated on the basis of nine isozyme loci of C. azurea at the species level was 0.201. The mean Nei’s genetic distance between European populations was equal to 0.083, whereas the mean genetic distance between populations originating from Europe and North America was 0.413. The analysis of molecular variance (AMOVA) showed that 69% of C. azurea genetic variation was distributed among regions (Europe and North America), 15% - among populations within regions, and 16% - within populations. Our study revealed that C. azurea showed genetic diversity within its geographic distribution. All examined samples classified as C. azurea differed in respect of isozyme patterns from C. peruviana.

EFFECTS OF CONTINUOUS DAILY ADMINISTRATION OF 0.5 mg OF CHLORMADINONE ACETATE ON THE PLASMA LEVELS OF PROGESTERONE AND ON THE URINARY EXCRETION OF LUTEINIZING HORMONE AND TOTAL OESTROGENS

1970 ◽  
Vol 63 (4) ◽  
pp. 705-716 ◽  
Author(s):  
U. Larsson-Cohn ◽  
E. D. B. Johansson ◽  
L. Wide ◽  
C. Gemzell
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Level ◽  
Urinary Excretion ◽  
Corpus Luteum ◽  
Plasma Levels ◽  
Chlormadinone Acetate ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
All Treatment

ABSTRACT Daily determinations of the plasma level of progesterone and the urinary excretion of luteinizing hormone (LH) and total oestrogens were performed in 6 subjects during one control cycle, immediately followed by three cycles of daily treatment with 0.5 mg of chlormadinone acetate continuously. The control cycles were ovulatory according to the parameters investigated. Two of the women showed a normal LH excretion pattern in all treatment cycles. The four other subjects also had periodical variations in the LH excretion but no distinct midcycle peaks occurred. The mean oestrogen excretion was increased in all three treatment cycles but the difference was satistically significant only in the last two cycles. Compared with the treatment cycles, the sum of progesterone values was significantly decreased in the first two cycles. Chlormadinone acetate in this dose had no thermogenic effect. Three of the subjects showed bleeding irregularities which had no clear connection with the hormone variations measured in the study. It is suggested that the low levels of progesterone might be due to a defective corpus luteum function.

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