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PubMed2002

Long-term effective population sizes, temporal stability of genetic composition and potential for local adaptation in anadromous brown trout (Salmo trutta) populations.

We examined the long-term temporal (1910s to 1990s) genetic variation at eight microsatellite DNA loci in brown trout (Salmo trutta L) collected from five anadromous populations in Denmark to assess the long-term stability of genetic composition and to estimate effective population sizes (Ne). Contemporary and historical samples consisted of tissue and archived scales, respectively. Pairwise thetaST estimates, a hierarchical analysis of molecular variance (amova) and multidimensional scaling analysis of pairwise genetic distances between samples revealed much closer genetic relationships among temporal samples from the same populations than among samples from different populations. Estimates of Ne, using a likelihood-based implementation of the temporal method, revealed Ne >or= 500 in two of three populations for which we have historical data. A third population in a small (3 km) river showed Ne >or= 300. Assuming a stepping-stone model of gene flow we considered the relative roles of gene flow, random genetic drift and selection to assess the possibilities for local adaptation. The requirements for local adaptation were fulfilled, but only adaptations resulting from strong selection were expected to occur at the level of individual populations. Adaptations resulting from weak selection were more likely to occur on a regional basis, i.e. encompassing several populations. Ne appears to have declined recently in at least one of the studied populations, and the documented recent declines of many other anadromous brown trout populations may affect the persistence of local adaptation.

Animals↗
PubMed2002

Does natural selection promote population divergence? A comparative analysis of population structure using amplified fragment length polymorphism markers and quantitative traits.

Divergent natural selection is considered an important force in plant evolution leading to phenotypic differentiation between populations exploiting different environments. Extending an earlier greenhouse study of population differentiation in the selfing annual plant Senecio vulgaris, we estimated the degree of population divergence in several quantitative traits related to growth and life history and compared these estimates with those based on presumably neutral molecular markers (amplified fragment length polymorphisms; AFLPs). This approach allowed us to disentangle the effects of divergent selection from that of other evolutionary forces (e.g. genetic drift). Five populations were examined from each of two habitat types (ruderal and agricultural habitats). We found a high proportion of total genetic variance to be among populations, both for AFLP markers (phiST = 0.49) and for quantitative traits (range of QST: 0.26-0.77). There was a strong correlation between molecular and quantitative genetic differentiation between pairs of populations (Mantel's r = 0.59). However, estimates of population differentiation in several quantitative traits exceeded the neutral expectation (estimated from AFLP data), suggesting that divergent selection contributed to phenotypic differentiation, especially between populations from ruderal and agricultural habitats. Estimates of within-population variation in AFLP markers and quantitative genetic were poorly correlated, indicating that molecular marker data may be of limited value to predict the evolutionary potential of populations of S. vulgaris.

DNA, Plant↗
PubMed2002

Loss of microsatellite diversity and low effective population size in an overexploited population of New Zealand snapper (Pagrus auratus).

Although the effects of overfishing on species diversity and abundance are well documented, threats to the genetic diversity of marine fish populations have so far been largely neglected. Indeed, there seems to be little cause for concern, as even "collapsed" stocks usually consist of several million individuals, whereas population genetics theory suggests that only very small populations suffer significant loss of genetic diversity. On the other hand, in many marine species the genetically effective population size (N(e)), which determines the genetic properties of a population, may be orders of magnitude smaller than the census population size (N). Here, microsatellite analyses of a time series of archived scales demonstrated a significant decline in genetic diversity in a New Zealand snapper population during its exploitation history. Effective population sizes estimated both from the decline in heterozygosity and from temporal fluctuations in allele frequency were five orders of magnitude smaller than census population sizes from fishery data. If such low N(e)/N ratios are commonplace in marine species, many exploited marine fish stocks may be in danger of losing genetic variability, potentially resulting in reduced adaptability, population persistence, and productivity.

Animals↗
PubMed2005

A comparison of linkage disequilibrium patterns and estimated population recombination rates across multiple populations.

Large-scale studies of linkage disequilibrium (LD) have shown considerable variation in the extent and distribution of pairwise LD within and between populations. Taken at face value, these results suggest that genomewide LD maps for one population may not be generalizable to other populations. However, at least part of this diversity is due to some undesirable features of pairwise LD measures, which are well documented for the D' and r2 measures. In this report, we compare patterns of LD derived from pairwise measures with statistical estimates of population recombination rates ( rho ) along a 10-Mb stretch of chromosome 20 in four population samples, comprising East Asians, African Americans, and U.K. and U.S. individuals of western European descent. The results reveal the expected variability of D' within and between populations but show better concordance in estimates of r2 for the same markers across the population samples. Estimates of rho correlate well across populations, but there is still evidence of population-specific spikes and troughs in rho values. We conclude that it is unlikely that a single haplotype map will provide a definitive guide for association studies of many populations; rather, multiple maps will need to be constructed to provide the best-possible guides for gene mapping.

Black or African American↗
PubMed2000

Monitoring of HIV-1 infection prevalence and trends in the general population using pregnant women as a sentinel population: 9 years experience from the Kagera region of Tanzania.

In the Kagera region of Tanzania, a population-based study was initiated in 1987 followed by the establishment of antenatal-clinic-based sentinel surveillance system in the town of Bukoba in 1990. Repeat studies in both populations in Bukoba in 1993 and 1996 made it possible to study the dynamics of HIV infection prevalence and incidence in the area. This study aims at comparing the findings from this sentinel surveillance system with those of cross-sectional studies in the general population to assess its validity in estimating HIV prevalence and their trends in the general population. A multistage cluster sampling technique was used in the population-based studies whereas the antenatal-clinic-based population was obtained by consecutively recruiting antenatal care attenders coming for the first time during a given pregnancy. Antibodies against HIV infection were tested using two independent enzyme-linked immunosorbent assay (ELISA) antibody detection tests. Unlinked anonymous testing strategy was adopted for the sentinel population. Age-adjusted prevalence among antenatal care attenders decreased from 22.4% (95% confidence interval [CI], 20.6-25.2) in 1990 to 16.1% (95% CI, 15.9-18.8) in 1993 and further to 13.7% (95% CI, 11.8-14.3) in 1996. These results closely resemble those of the general population of adult women in the clinic's catchment area (the town of Bukoba) where the age-adjusted prevalence of 29.1% (95% CI, 24.4-34.6) in 1987 showed a decrease in the studies in 1993 18.7% (95% CI, 15.1-23.0) and in 1996 14.9% (95% CI, 12.0-17.1). The study indicates that general population trend estimates can be generated using sentinel surveillance data based on pregnant women visiting an antenatal clinic for the first time during a given pregnancy. The benefits of using this group outweigh its limitations that are brought about by possible selection bias. Continued surveillance of the epidemic based on antenatal care patients as a sentinel population is therefore recommended.

Adolescent↗
PubMed2001

Evaluation of the efficacy of extrapolation population modeling to predict the dynamics of Americamysis bahia populations in the laboratory.

An age-classified projection matrix model has been developed to extrapolate the chronic (28-35 d) demographic responses of Americamysis bahia (formerly Mysidopsis bahia) to population-level response. This study was conducted to evaluate the efficacy of this model for predicting the population behavior of A. bahia held (for more than three generations) under controlled laboratory exposure conditions. The research involved the performance of a standard life-cycle test and a multigenerational (greater than three mysid generations, 55 d) assay using A. bahia to experimentally evaluate model predictions regarding population-level risks of chemical exposure. The organic compound para-nonylphenol was chosen as the chemical stressor in assays. This compound is a ubiquitous contaminant and suspected endocrine disruptor. Utilizing data obtained during the standard life-cycle test, aggregate estimates of population growth rate (lambda) and measured p-nonylphenol concentration were used to develop an exposure-response model of population-level effects. These estimates provided the basis of predictions for the long-term dynamics of mysid populations exposed to p-nonylphenol. The veracity of the mysid population model was evaluated through quantitative comparisons of model predictions based on the life-cycle test with dynamics of the experimental populations (multigenerational assay results). The results indicate that the population model was able to project within a few micrograms per liter the concentration where population-level effects would begin to occur (projected 16 micrograms/L from the model vs measured 19 micrograms/L from the multigenerational assay).

Aging↗
PubMed2005

[Polymorphism of Y-chromosomal microsatellites in Russian populations from the northern and southern Russia as exemplified by the populations of Kursk and Arkhangel'sk Oblast].

Allelic polymorphisms at five Y-chromosomal microsatellite loci (DYS19, DYS390, DYS391, DYS392, and DYS393) were typed in 87 individuals from male population samples from two geographically isolated regions (Arkhangelsk oblast and Kursk oblast) of the European part of Russia. The populations examined demonstrated substantial differences in the distribution of the DYS392 (P = 0.005) and DYS393 (P = 0.003) alleles. Estimates of genetic relationships between these populations and some other European populations (including Eastern-Slavic) showed that irrespectively of the measure of genetic distance chosen, Arkhangelsk population was closer to the populations belonging to the Finno-Ugric linguistic group (Saami and Estonians) and to the Estonian geographical neighbors, Latvians, while Kursk population was the member of a cluster formed by Eastern-Slavic populations (Russians of Novgorod oblast, Ukrainians, and Belarussians). Phylogenetic analysis of the most frequent haplotypes indicated that these differences between Kursk and Arkhangelsk populations were associated with high prevalence in the latter of major haplotypes characteristic primarily of the Finno-Ugric populations.

Alleles↗
PubMed2001

Low levels of genetic differentiation among populations of the freshwater fish Hypseleotris compressa (Gobiidae: Eleotridinae): implications for its biology, population connectivity and history.

The isolating nature of freshwater systems may lead to expectations of substantial genetic subdivision among populations of obligate freshwater species. We examined the genetic structure of populations of the freshwater fish Hypseleotris compressa (Gobiidae) using allozyme and mtDNA markers. Fifteen east coast Queensland populations and one Northern Territory population were sampled to examine levels of differentiation within and between drainages at near, medium and broad scales. Initial allozyme data suggested high levels of gene flow and connectivity among populations at broad spatial scales. However there was no significant relationship between geographical distance and gene flow among east coast populations which may indicate, among other possibilities, that these populations are not at equilibrium between gene flow and genetic drift. Analyses of a 567-bp fragment of the ATPase6 mtDNA gene revealed a star-shaped phylogeny, with many singleton, recently derived haplotypes. Tajima's test of neutrality was significantly negative. The allozyme and mtDNA data may be indicative of an historical demographic change that was reflected in the nonequilibrium pattern exhibited by contemporary populations. As estimating current levels of gene flow would violate basic assumptions of underlying models, approximations were not made. Nevertheless, patterns of genetic variation among populations of H. compressa do not match traditional expectations for a freshwater fish, and it would appear that there has been at least historical connectivity between populations now inhabiting different drainages.

Adenosine Triphosphatases↗
PubMed2005

Inter-population variations in concentrations, determinants of and correlations between 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE): a cross-sectional study of 3161 men and women from Inuit and European populations.

BACKGROUND: The study is part of a collaborative project (Inuendo), aiming to assess the impact of dietary persistent organochlorine pollutants (POPs) on human fertility. The aims with the present study are to analyze inter-population variations in serum concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE), to assess inter-population variations in biomarker correlations, and to evaluate the relative impact of different determinants for the inter-individual variations in POP-biomarkers. METHOD: In study populations of 3161 adults, comprising Greenlandic Inuits, Swedish fishermen and their wives, and inhabitants from Warsaw, Poland and Kharkiv, Ukraine, serum concentrations of CB-153 and p,p'-DDE, were analysed by gas chromatography-mass spectrometry. RESULTS: The median serum concentrations of CB-153 were for male and female Inuits 200 and 110, for Swedish fishermen 190 and their wives 84, for Kharkiv men and women 44 and 27, and for Warsaw men and women 17 and 11 ng/g lipids, respectively. The median serum concentrations of p,p'-DDE were for Kharkiv men and women 930 and 650, for male and female Inuits 560 and 300, for Warsaw men and women 530 and 380, and for Swedish fishermen 240 and their wives 140 ng/g lipids, respectively. The correlation coefficients between CB-153 and p,p'-DDE varied between 0.19 and 0.92, with the highest correlation among Inuits and the lowest among men from Warsaw. Men had averagely higher serum concentrations of CB-153 and p,p'-DDE, and there were positive associations between age and the POP-biomarkers, whereas the associations with BMI and smoking were inconsistent. Dietary seafood was of importance only in the Inuit and Swedish populations. CONCLUSION: CB-153 concentrations were much higher in Inuits and Swedish fishermen's populations than in the populations from Eastern Europe, whereas the pattern was different for p,p'-DDE showing highest concentrations in the Kharkiv population. The correlations between the POP-biomarkers varied considerably between the populations, underlining that exposure sources differ and that the choice of representative biomarkers of overall POP exposure has to be based on an analysis of the specific exposure situation for each population. Age and gender were consistent determinants of serum POPs; seafood was of importance only in the Inuit and Swedish populations.

Adult↗
PubMed2003

A novel method of estimating cost of therapy by using patient population characteristics: analysis of fluoroquinolones in various populations with different distributions of renal function.

INTRODUCTION: Formulary decisions regarding a given drug class are often made in the absence of patient outcome and/or sophisticated pharmacoeconomic data. Analyses that consider factors beyond simple acquisition costs may be useful in such situations. For example, the cost implications of using manufacturers' recommendations for dosing in patients with renal dysfunction may be important, depending on the distribution of various levels of renal function within a patient population. METHODS: Using four 1000-patient populations representing different renal function distributions and a fifth population of our medical center's distribution, we determined the costs of therapy for intravenous and oral levofloxacin, gatifloxacin, and moxifloxacin for a 10-day course of therapy for community-acquired pneumonia. Costs considered were average wholesale prices (AWPs), 50% of AWP, or same daily price, plus intravenous dose preparation and administration costs when applicable. Costs for each renal function distribution were examined for significant differences with an analysis-of-variance test. Also, costs of failing to adjust dosing regimens for decreased renal function were determined. RESULTS: Differences in fluoroquinolone costs (AWP, 50% AWP, or when matched as the same daily price) among the populations were found. When considering same daily prices, differences among populations ranged from about 35,000 dollars with intravenous gatifloxacin to more than 51,000 dollars for intravenous levofloxacin (all fluoroquinolones, p>0.05). Within a population, differences in costs among the intravenous fluoroquinolones ranged from 47,000-99,000 dollars. Rank orders of the drugs and population costs of therapy were affected by the pricing structure used and varied by the specific population and drug. Differences among the fluoroquinolones or populations were much smaller (<2100 dollars) when considering oral regimens. Costs potentially incurred by failing to adjust dosing for renal function were substantial. CONCLUSION: Formulary decisions can be facilitated by considering factors such as patient characteristics and related dosing in addition to simple acquisition costs. In our example, consideration of the distribution of renal function within a given patient population and related dosing for these fluoroquinolones revealed potentially important differences within the class.

Administration, Oral↗
PubMedDate not supplied

[Prevalence of anal incontinence in the elderly population: an epidemiological study of the elderly population served at the geriatric ambulatory service of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo].

The aim of the present work was to assess the prevalence of anal incontinence in the elderly population attended in the "Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo". The method employed was of individual interviews with patient attended in the Geriatric Ambulatory. As part of the assessment patients were classified as to sex, age, color, social-economical class and education, and compared to available data on the elderly population of the State and the City of São Paulo. Besides the question on signs and symptoms related to anal incontinence, associated factors such as bowel habit, sensation of incomplete evacuation, urgency to evacuate and soiling were also analysed, as well as, factors possibly related to anal incontinence such as urinary incontinence, use of medication as laxatives, associated diseases, such as neurological affections and diabetes mellitus, number of child births, and assistance received, previous anorectal or perineals operations, and locomotions limiting factor. The statistical method of test of proportion was used to analyse the proportions of the populations interviewed, as to sex and literacy compared to the elderly population of the State and City of São Paulo. To analyse the social-economical class of the population interviewed compared to the elderly population economically and non economically active, of the State of São Paulo, the test of qui-square adjusted was used. The test of qui-square was used to verify if the population of incontinent and continent, by sex; incontinent and continent in relation to bowel habit, by sex; incontinence sufferer of continuous and descontinuous anal incontinence, by sex; incontinent sufferer of anal incontinence to gas, liquid or solid, and the association of these manifestations, by sex; patients who complained of soiling, by sex; incontinent and continent, previously submitted to anorectal or perineal operations; and continent and incontinent with diabetes mellitus, are equal. To verify the proportions of women who had vaginal delivery in the continent and incontinent group, the test of Mann-Whitney was used. One hundred fourty six patients were interviewed, 43 men of an average 75 years old (62 to 91) and 103 women of an average 72 years old (60 to 88); as to colours, 69.9% were white, 18.5% were mullato, 9.6% were black and 2% were yellow. The comparative analysis with populational data indicated that the population interviewed was representative of the elderly population of the State and the City of São Paulo, as to age, color, social-economical class and education. The prevalence of anal incontinence was of 10.9% with no difference between the sexes, intestinal obstipation referred by 15.4% of the men and 28.1% of the women, sensation of incomplete evacuation referred by 21.2% of the patients, and the association of both referred by 13.7% were the most frequently observed functional gastrointestinal alterations. Soiling was referred by 10.3% of the patients with no difference related to sex. The use of medication or laxatives, the presence of diabetes mellitus, neurological affections, previews anorectal or perineal operations, or locomotion limiting factors, have no relation to anal incontinence. The prevalence of urinary incontinence was of 30.1%, and double continence of 6.3% with no statistical difference between sexes. There was statistical evidence of association between childbearing and anal incontinence.

Aged↗
PubMedDate not supplied

[Serum lipids and lipoproteins in a population from Oran. Comparison with a population from Lille].

Lipids, lipoproteins and apolipoproteins were analyzed in plasma of a city living Algerian population (Oran) free of obvious pathology. 129 individuals of this population were compared to a sample of subjects living in the surroundings of Lille (France). Several parameters were significantly different between the two populations. Cholesterol and phospholipids were lower in the population of Oran when compared with the population of Lille (4.90 mmol/l versus 5.47 mmol/l; 2.73 mmol/l versus 3.22 mmol/l respectively). Lipoproteins LpAI and LpAI:All were also lower in the population of Oran in comparison with the population of Lille (0.38 g/l versus 0.52 g/l; 0.68 g/l versus 1.00 g/l respectively), while LpCIII:B, LpE:B and Lp(a) were higher in the population of Oran when compared with the population of Lille (0.09 g/l versus 0.06 g/l; 0.28 g/l versus 0.16 g/l; 0.1 g/l versus 0.048 g/l) respectively. Several results argue in favor of the use of these lipoprotein parameters to better define the atherosclerotic risk. This was the main reason for characterizing the lipoprotein profile of such a population with a still unknown cardiovascular disease incidence.

Adult↗
PubMed2004

Gene flow, historical population dynamics and genetic diversity within French Guianan populations of a rainforest tree species, Vouacapoua americana.

Both gene flow and historical events influence the genetic diversity of natural populations. One way to understand their respective impact is to analyze population genetic structure at large spatial scales. We studied the distribution of genetic diversity of 17 populations of Vouacapoua americana (Caesalpiniaceae) in French Guiana, using nine microsatellite loci. Low genetic diversity was observed within populations, with a mean allelic richness and gene diversity of 4.1 and 0.506, respectively, which could be due to low effective population size and/or past bottlenecks. Using the regression between Fst/(1-Fst), estimated between pairs of populations, and the logarithm of the geographical distance, the spatial genetic structure can partly be explained by isolation-by-distance and limited gene flow among populations. This result is in agreement with the species' biology, including seed and pollen dispersal by rodents and insects, respectively. In contrast, no clear genetic signal of historical events was found when examining genetic differentiation among populations in relation to biogeographical hypotheses or by testing for bottlenecks within populations. Our conclusion is that nuclear spatial genetic structure of V. americana, at the geographic scale of French Guiana, is better explained by gene flow rather than by historical events.

DNA, Plant↗
PubMed2003

Disparate patterns of population genetic structure and population history in two sympatric penaeid shrimp species (Farfantepenaeus aztecus and Litopenaeus setiferus) in the eastern United States.

Analysing the population genetic structures of sympatric species provides opportunities to compare patterns of population genetic structure and phylogeography in order to gain insight into the factors that influence the development of the observed patterns. In this study, we compared the population genetic structures and phylogeographies of brown shrimp (Farfantepenaeus aztecus) and white shrimp (Litopenaeus setiferus), two sympatric penaeid shrimp species that inhabit the waters of the eastern USA, using sequence analysis of the mitochondrial DNA control region. Brown shrimp showed no significant phylogenetic structure or population subdivision, and closely related haplotypes were geographically dispersed. Mismatch analysis indicated that brown shrimp experienced a late-Pleistocene era sudden population expansion. In contrast, white shrimp had a complex haplotype phylogeny consisting of two distinct lineages and two less well-defined sublineages, and the haplotypes and lineages were geographically structured. Mismatch analysis for white shrimp also showed evidence of sudden population expansion, albeit for each lineage separately and more recently than in the brown shrimp. These disparate patterns may have developed as a result of species-specific differences in physiological tolerances and habitat preferences that caused greater fluctuations in white shrimp population sizes and reductions in long-term effective population size relative to that of the brown shrimp, and thereby increased the susceptibility of the white shrimp populations to stochastic genetic change.

Animals↗
PubMed2002

Effect of recombination in the parent populations on the means and combining ability variances in hybrid populations of maize ( Zea mays L.).

Recombination of selected genotypes plays a key role in plant breeding for generating new base populations. We investigated the influence of recombination in two parent populations on the means and combining ability variances of their hybrid population by (1) quantitative genetic theory and (2) experiments with maize. The two parent populations were founded by four early flint and four early dent inbred lines, respectively. Each population was studied in three generations: Syn-0, the four inbred lines themselves; Syn*-1, the six intrapool single crosses (SC); and Syn*-2, the three intrapool double crosses (DC). Four interpool hybrid populations were created: (1) all 16 SC and (2) all 36 DC were produced from generations Syn-0 and Syn*-1, respectively, (3) 168 biparental progenies (BIP) of type flint x dent (female x male), and (4) 168 BIP of type dent x flint were produced according to NC-design I with randomly sampled plants of generation Syn*-2. The half-sib and full-sib families obtained in this manner were evaluated for grain yield, dry matter concentration and plant height. According to theoretical results, differences in the population means of these hybrid populations indicate the presence of various types of epistasis. Changes in combining ability variances from SC to DC reflect different levels of parental inbreeding (F = 1 vs F = 0), whereas changes from DC to BIP only reflect the effects of recombination and are attributable to covariances between additive and dominance effects caused by linkage disequilibrium in the Syn-0 generations. The experimental results showed a significant decline in yield from DC to BIP due to a loss of gene combinations with favourable epistatic effects. Estimates of sigma(2)(GCA) attributable to flint or dent lines decreased or remained unchanged from SC to DC, but generally increased in the BIP populations. The consequences of these trends for developing improved interpool hybrids are discussed.

Chimera↗
PubMed2005

Population genetic study in two Transylvanian populations using forensically informative autosomal and Y-chromosomal STR markers.

Our study provides population genetic data on two population samples collected in a Hungarian speaking region of Transylvania, Romania. Allele frequency and profile databases were generated on 17 autosomal STR loci (D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, VWA, FGA, TH01, TPOX, CSF1PO, Penta E and Penta D) as well as at the 12 European Y-STR extended haplotype loci (DYS19, DYS389-I/II, DYS390, DYS391, DYS392, DYS393, DYS385 loci, DYS437, DYS438 and DYS439). Data were compared to a Central Hungarian (Budapest region) population sample [B. Egyed, S. Füredi, M. Angyal, L. Boutrand, A. Vandenberghe, J. Woller, Z. Padar, Analysis of eight STR loci in two Hungarian populations, Forensic Sci. Int. 113 (2000) 25-27] that was used as a reference group of the Hungarian population. Calculating the F(ST) indices and with the pairwise comparisons of interpopulation molecular variance (AMOVA) the two populations from Transylvania could be fit into the Hungarian population data showing less substructuring effects as compared to the previous findings in Hungary [B. Egyed, S. Füredi, M. Angyal, L. Boutrand, A. Vandenberghe, J. Woller, Z. Padar, Analysis of eight STR loci in two Hungarian populations, Forensic Sci. Int. 113 (2000) 25-27; B. Egyed, S. Füredi, M. Angyal, I. Balogh, L. Kalmar, Z. Padar, Analysis of the population heterogeneity in Hungary using fifteen forensically informative STR markers, Forensic Sci. Int. 158 (2005) 244-249].

Chromosomes, Human, Y↗
PubMed1998

Fast game theory coupled to slow population dynamics: the case of domestic cat populations.

We study a deterministic model of a population where individuals alternatively adopt hawk and dove tactics. It is assumed that the hawk and dove individuals compete for some resources at a fast time scale. This fast part of the model is coupled to a slow part that describes the growth of the population. It is shown that, in a constant game matrix, the population grows according to a logistic curve whose r and K parameters are related to the payoff of the tactics. Results show that the highest population density is obtained when all individuals are dove. We also study a density-dependent game matrix for which the gain is a function of the population density. In this case, we show that two stable equilibria can occur, a first one at low density with a high proportion of hawk individuals and a second one at large density with a low proportion of hawk individuals. Our model is applied to domestic cat populations for which the behavior of individuals in competition with one another can be modeled by two tactics: hawk and dove. Such tactics change with density of population. The results of the model agree well with observed data: high-density populations of domestic cats are mainly doves, whereas low-density populations are mainly hawks.

Animals↗
PubMed2004

Population-based surveillance for Yersinia enterocolitica infections in FoodNet sites, 1996-1999: higher risk of disease in infants and minority populations.

Active surveillance for laboratory-confirmed Yersinia enterocolitica (YE) infections was conducted at 5 Foodborne Diseases Active Surveillance Network (FoodNet) sites in the United States during 1996-1999. The annual incidence averaged 0.9 cases/100,000 population. After adjusting for missing data, the average annual incidence by race/ethnicity was 3.2 cases/100,000 population among black persons, 1.5 cases/100,000 population among Asian persons, 0.6 cases/100,000 population among Hispanic persons, and 0.4 cases/100,000 population among white persons. Incidence increased with decreasing age in all race/ethnicity groups. Black infants had the highest incidence (141.9 cases/100,000 population; range, 8.7 cases/100,000 population in Minnesota to 207.0 cases/100,000 population in Georgia). Seasonal variations in incidence, with a marked peak in December, were noted only among black persons. YE infections should be suspected in black children with gastroenteritis, particularly during November-February. Culturing for YE should be part of routine testing of stool specimens by clinical laboratories serving populations at risk, especially during the winter months.

Black or African American↗