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PubMed1992

Human population genetic studies using hypervariable loci. I. Analysis of Assamese, Australian, Cambodian, Caucasian, Chinese and Melanesian populations.

Population genetic studies, in Australian, Assamese, Cambodian, Chinese, Caucasian and Melanesian populations, were performed with several highly polymorphic DNA loci. Results showed that the Caucasian and Chinese had the highest level of heterozygosity. The size range of the majority of the polymorphic DNA fragments of a locus was the same in the different populations. The distinguishing feature of each ethnic group was the relative frequency of a particular set or group of alleles. For example, alleles greater than 9.0 kb in size, in D14S13, or from 4.5 to 4.7 kb, in D18S27, were less than half as frequent in Caucasians than in the other populations. Overall, there were groups of alleles, at one or more loci, whose frequencies were different among some of the ethnic groups and therefore could be used to differentiate one group from the other.

Alleles↗
PubMed1979

The use of restriction endonucleases to measure mitochondrial DNA sequence relatedness in natural populations. I. Population structure and evolution in the genus Peromyscus.

In this study we introduce to natural population analysis a molecular technique that involves the use of restriction endonucleases to compare mitochondrial DNA (mtDNA) sequences. We have examined the fragment patterns produced by six restriction endonucleases acting upon mtDNA isolated from 23 samples of three species of the rodent Peromyscus. Our observations confirm the following conclusions derived from previous experiments with laboratory animals: (1) mtDNA within an individual homogeneous; (2) at least the majority of mtDNA present in an individual is inherited from the female parent. Our experiments demonstrate for the first time that there is detectable heterogeneity in mtDNA sequences within and among natural geographic populations of a species and that this heterogeneity can readily be used to estimate relatedness between individuals and populations. Individuals collected within a single locale show less than 0.5% sequence divergence, while those collected from conspecific populations separated by 50 ti 500 miles differ by approximately 1.5%. The mtDNAs of the closely related sibling species P. polionotus and P. maniculatus differ from each other by 13 to 17%; nonsibling species differ by more than 20%. Qualitative and quantitative approaches to analysis of digestion patterns are suggested. The results indicate that restriction analysis of mtNDA may become the most sensitive and powerful technique yet available for reconstructing evolutionary relationships among conspecific organisms.

Animals↗
PubMed2004

Microalbuminuria independently predicts all-cause and cardiovascular mortality in a British population: The European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk) population study.

BACKGROUND: In patients with diabetes or hypertension, raised albuminuria is independently associated with an increased risk of all mortality, cardiovascular morbidity and mortality, and renal insufficiency. The role of albuminuria in the general population is still controversial. We therefore undertook this study to examine the relationship between albuminuria and all-cause, cardiovascular disease (CVD) and non-CVD mortality in the general population. METHODS: Prospective population-based cohort study of 20 911 individuals aged 40-79 years recruited in 1993-1997 for the EPIC-Norfolk Study (UK) and followed-up for an average of 6.3 years. Random spot urine specimens were collected at baseline and the albumin-to-creatinine ratio measured. Participants were categorized into normoalbuminuria, microalbuminuria, and macroalbuminuria ordered groups. At follow-up, vital status and cause of death were obtained from the UK Office for National Statistics. RESULTS: During follow-up, 934 deaths were registered. Age-adjusted all-cause mortality rate increased significantly across categories of baseline albuminuria (5.3, 5.2, and 6.3/1000 person years (pyrs) across tertiles of normoalbuminuria, 8.7/1000 pyrs for microalbuminuria, and 18.4/1000 pyrs for macroalbuminuria, P < 0.001 for trend); CVD, 1.6, 1.7, 2.1, 4.3, 12.6/1000 pyrs (P < 0.001); and non-CVD, 3.7, 3.5, 4.2, 4.4, 5.8/1000 pyrs (P = 0.052) respectively. The multivariate hazard ratio for all-cause mortality associated with microalbuminuria was 1.48 (95% CI: 1.20, 1.79), and CVD 2.03 (95% CI: 1.55, 2.67). The association with non-CVD mortality was only significant in men. CONCLUSIONS: The significant increased risk of all-cause mortality especially from CVD associated with microalbuminuria, suggest that this may be a useful indicator in identifying those in the population at greatest absolute risk of fatal CVD events alongside conventional CVD risk factors.

Adult↗
PubMed1992

Gonococcal infection, infertility, and population growth: I. Endemic states in behaviourally homogeneous growing populations.

Sexually transmitted diseases such as gonorrhoea are a significant cause of infertility in women when the infection is untreated. They have the potential to alter human population growth rates in many developing countries where sexually transmitted diseases are prevalent due to limited public health facilities for diagnosis and treatment. The authors develop a simple model describing the conditions under which such a disease can exist in a growing population in which sexual partners are chosen at random by proportionate mixing. Using the model, the impact that such a disease could have for a range of possible parameters is examined. Then a full parameter set for gonorrhoea in a developing country is estimated. Analysis demonstrates the significant influence gonococcal infection may have in reducing population growth rate in some communities. For example, the simple model predicts that a prevalence of 20% in sexually active adults results in a 50% reduction in the population growth rate. Finally, the authors discuss how potential control initiatives may change the parameter values that determine transmission and alter the demographic impact of gonorrhoea.

Africa↗
PubMed2005

Colony social organization and population genetic structure of an introduced population of formosan subterranean termite from New Orleans, Louisiana.

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is an invasive species in many parts of the world, including the U.S. mainland. The reasons for its invasive success may have to do with the flexible social and spatial organization of colonies. We investigated the population and breeding structure of 14 C. formosanus colonies in Louis Armstrong Park, New Orleans, LA. This population has been the focus of extensive study for many years, providing the opportunity to relate aspects of colony breeding structure to previous findings on colony characteristics such as body weight and number of workers, wood consumption, and intercolony aggression. Eight colonies were headed by a single pair of outbred reproductives (simple families), whereas six colonies were headed by low numbers of multiple kings and/or queens that were likely the neotenic descendants of the original colony (extended families). Within the foraging area of one large extended family colony, we found genetic differentiation among different collection sites, suggesting the presence of separate reproductive centers. No significant difference between simple family colonies and extended family colonies was found in worker body weight, soldier body weight, foraging area, population size, or wood consumption. However, level of inbreeding within colonies was negatively correlated with worker body weight and positively correlated with wood consumption. Also, genetic distance between colonies was positively correlated with aggression levels, suggesting a genetic basis to nestmate discrimination cues in this termite population. No obvious trait associated with colony reproductive structure was found that could account for the invasion success of this species.

Animals↗
PubMed2005

A method to determine if consenters to population surveys are representative of the target study population.

BACKGROUND: Searching medical records of study non-responders to investigate selection bias is no longer acceptable. We explore an alternative by comparing consultation rates in survey responders who consented to medical record review, with anonymized consultation rates for the total practice populations. METHODS: Anonymized aggregated consultation rates for the year following a population-based survey were calculated for headache and a number of other conditions (chosen to reflect a mixture of chronic and episodic conditions). These rates were compared across two groups of adults: (i) responders to the survey who consented to medical record review and (ii) a 'population group' created from records of the general practices participating in the survey to represent all patients aged 18 years and over at the mid-point in the study year. The consultation rates for the conditions were compared across the two groups using direct standardization. RESULTS: Adjusted consultation rates were similar but generally higher in the responders. CONCLUSIONS: This alternative method applied here offers one potential approach to determine whether study respondents are representative of the population from which they were sampled with respect to general practice consultations.

Adolescent↗
PubMed2003

Population genetics of accessory gland proteins and sexual behavior in Drosophila melanogaster populations from Evolution Canyon.

Evolution Canyon in Lower Nahal Oren, Mount Carmel, Israel has been identified as a location promoting sympatric speciation. Several previous studies on Drosophila melanogaster populations from the two disparate slopes of the canyon suggest that these two populations are experiencing incipient speciation. However, recent microsatellite data did not reveal the expected level of population differentiation. Given the importance of this system for studying speciation, we set out to test two predictions of the incipient speciation hypothesis--genetic differentiation and sexual isolation. We sequenced six different Acp genes from isofemale lines from the south-facing slope (11 lines) and north-facing slope (nine lines) of Evolution Canyon. We found no evidence of genetic differentiation between the two slopes (F(ST) = -0.03). We also conducted mate choice tests, using intraslope F1 hybrids between different isofemale lines. There was no significant departure from random mating in mixtures of flies from the two slopes. Our results provide further indication that it is unlikely these two populations are experiencing incipient speciation. We discuss our results in light of the discrepancies that have been published on this enigmatic D. melanogaster system from Evolution Canyon.

Animals↗
PubMed1997

HLA-B44 subtyping in a Spanish population: further evidence of Caucasian population diversity.

HLA-B44 is the most frequent HLA-B allele in Caucasian populations. Several B44 subtypes, B*4402-B*4406, have been identified in individuals with this ethnic origin. Mismatches among B44 subtypes have been described as major targets for allogeneic responses in bone marrow transplantation. We have developed a PCR-SSO method, based on a B12- specific DNA amplification of exon 2 through exon 3 and subsequent non radioactive hybridization with eight probes, which allow us to discriminate all B12 homozygous combinations. We applied this method to determine the frequency of B44 subtypes in a Spanish population, as well as their HLA-A,-C,-DRB1,-DRB3/DRB4/ DRB5,-DQA1 and -DQB1 associated haplotypes. A total of 141 healthy unrelated Spanish individuals and 31 B44-bearing haplotypes were investigated. Four B44 alleles were identified, B*4402 (33%), B*4403 (66%), B*4404 (0.7%), and B*4405 (0.7%). Haplotype analysis showed a clear differentiated distribution pattern for the two major B44 subtypes. B*4402 is associated with Cw5 (11/13) and A2 antigens (10/13). In contrast, B*4403 is mainly found together with DRB1*0701 (14/16). An inverted B*4402/B*4403 frequency in comparison with other European and North American Caucasian populations, revealed the existence of an extended haplotype diversity between populations of the same ethnic origin. Apart from anthropological studies, high resolution typing for HLA class I antigens presenting molecular polymorphism will be of great relevance in unrelated bone marrow transplantation.

HLA-B Antigens↗
PubMed1995

Nuclear DNA polymorphism in a Mandenka population from Senegal: comparison with eight other human populations.

A large and ethnically well defined Mandenka sample from Senegal is analysed for 80 nuclear DNA RFLPs, and compared with eight previously studied human populations. A high level of genetic diversity is found in this sample, comparable to that observed in two African Pygmy samples, but lower than that of a European sample. High population variation is observed for most markers. A neutrality test reveals that the markers used in this study can be considered as neutral. A high correlation is found between genetic and geographic distances (r = 0.62), suggesting that geography does also affect long range population genetic relationships and is an important factor behind differentiation among human populations.

Alleles↗
PubMed2000

Genetic erosion in northern marginal population of the common wild rice Oryza rufipogon Griff. and its conservation, revealed by the change of population genetic structure.

In order to monitor genetic erosion within the northern marginal population of common wild rice Oryza rufipogon Griff. from Dongxiang, Jiangxi Province, China, allozyme diversity encoded by 22 loci was analyzed electrophoretically from all the existing subpopulations in 1980, 1985 and 1994. The sample collected from the nine large subpopulations in 1980 showed the highest levels of genetic diversity (A = 1.27, P = 18.20%, Ho = 0.042 and He = 0.049) and a slight deviation from Hardy-Weinberg expectation (F = 0.143), the sample from five moderate ones in 1985 displayed medium levels of genetic diversity (A = 1.14, P = 13.60%, Ho = 0.008 and He = 0.049) and a great deviation from Hardy-Weinberg expectation (F = 0.837), and the sample from two small ones in 1994 demonstrated the lowest levels of genetic diversity (A = 1.09, P = 9.10%, Ho = 0.000 and He = 0.043) and the largest deviation from Hardy-Weinberg expectation (F = 1.000). The results not only documented the genetic erosion stemmed from the extinction of the subpopulations, but also revealed the drastic change of the population genetic structure due to the reduction of the population. Finally, some conservation strategies for the population are proposed.

DNA, Plant↗
PubMed2026

Recovering the precolonial population structure of Khoe-San descendant populations.

San populations from Botswana and Namibia retain exceptional linguistic, cultural, and genetic diversity, but few Khoisan-speaking groups remain south of the Kalahari Desert. However, historically, far southern Africa was home to many San and Khoekhoe groups. Popular opinion often implies that such populations do not contribute to the ancestry of contemporary South Africans. Here, we characterize the genetic ancestry of self-identified South African Coloured groups and reconstruct precolonial and colonial population structures from 620 newly sampled individuals. These groups retain the majority of Khoe-San genetic ancestry (>48%), suggesting the persistence of Khoe-San ancestry to the present day. By isolating the Khoe-San ancestry component, we show that it is intermediate between the &#x2260;Khomani San and Nama and distinct from Kalahari Khoe-San populations. We also find that signatures of the Indian Ocean slave trade can be traced to Indonesian islands such as Sulawesi, Java, and Flores, while the South Asian ancestry is regionally nonspecific.

Humans↗
PubMed1989

Effect of cage population density on plasma corticosterone and peripheral lymphocyte populations of laboratory mice.

The effect of different population densities of mice per cage on plasma corticosterone, peripheral lymphocytes and specific lymphocyte subpopulations was investigated. The animals were housed in groups of 2, 4 or 8 mice per cage and the blood samples were taken from each animal of these groups on days one, 7 and 14. A significant elevation (P less than 0.05) in plasma corticosterone concentration was observed in the group of 8 mice per cage on days one and 7 as compared with those of 2 or 4 mice per cage. The number of peripheral lymphocytes was significantly decreased in the groups of 2 (P less than 0.01) and 8 (P less than 0.05) mice per cage as compared with the group of 4 mice per cage on day one. A significantly decreased number of lymphocytes (P less than 0.01) in the group of 8 mice per cage continued to day 7. There were no significant differences in specific lymphocyte subpopulations observed among these groups. The results of this study suggest that a population density of 4 mice per cage induced minimal stress compared to that induced by the population densities of 2 or 8 mice per cage. Since stress is known to induce alteration in a variety of biological functions, the population density of mice per cage should be considered in the interpretation of research data.

Animals↗
PubMed2004

Chlamydia trachomatis genital infection in apparently healthy adult population of Tamil Nadu, India: a population-based study.

Since the epidemiology of Chlamydia trachomatis infection in apparently healthy population has not been studied in India, a population-based study was conducted in the state of Tamil Nadu, India in order to analyse the prevalence of genital chlamydial infections in the community and to implement control programmes. A representative sample was taken from three randomly selected districts by using the 'probability proportional to size' cluster survey method. Households were the basic units of clusters. Adults aged 15-45 years, pre-identified from the selected households were enrolled during the medical camps conducted for a major study on community prevalence of sexually transmitted diseases in Tamil Nadu. Blood and urine samples collected from the study subjects were tested by enzyme-linked immunosorbent assay (ELISA) for anti-chlamydial IgM antibodies and by the commercial Amplicor polymerase chain reaction (PCR) test for chlamydial DNA. The prevalence of anti-C. trachomatis antibodies determined by IgM-ELISA was 2.4% (95% CI 1.6%-3.2%). The prevalence of genital chlamydial infection determined by PCR was 1.1% (95% CI 0.5%-1.7%). Majority of the detected infections (68.8%) were asymptomatic. This is the first Indian report on the prevalence of genital chlamydial infections in the general population. It is concluded that this study provides evidence for a substantial burden of approximately 10 million asymptomatic genital chlamydial infection cases in the sexually active age groups in the general population of India.

Adolescent↗
PubMed2000

Prevalence and risk factors of peripheral vascular disease in a selected South Indian population: the Chennai Urban Population Study.

OBJECTIVE: The epidemiology of peripheral vascular disease has rarely been studied in non-European populations. The purpose of this study was to determine the prevalence and risk factors of peripheral vascular disease (PVD) among South Indians. RESEARCH DESIGN AND METHODS: The Chennai Urban Population Study is an epidemiological study involving 2 residential areas in Chennai in South India. Of the 1,399 eligible subjects (> or =20 years of age), 1,262 (90.2%) participated in the study. All of the study subjects underwent an oral glucose tolerance test and were categorized as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or diabetes. Peripheral Doppler studies were performed on 50% of the study subjects, and PVD was defined as an ankle-brachial index (ABI) <0.9. RESULTS: The prevalence rates of PVD were 2.7, 2.9, and 6.3% in individuals with NGT, IGT, and diabetes, respectively The overall prevalence rate was 3.2%. Known diabetic subjects had a higher prevalence of PVD (7.8%) compared with newly diagnosed diabetic subjects (3.5%). PVD was uncommon until middle-age and then the prevalence rate increased dramatically. Univariate regression analysis showed age >50 years (odds ratio [OR] 6.3, 95% CI 2.1-20.6, P<0.001) and hypertension (OR 2.7, 0.9-7.3, P = 0.08) to be associated with PVD, whereas smoking and serum lipid levels showed no association. Multivariate regression analysis identified age as the most significant risk factor for PVD. Of the 90 subjects who had coronary artery disease (CAD), only 6 had PVD, and the positive predictive value of the ABI for CAD was only 30%. CONCLUSIONS: The prevalence of PVD in this urban South Indian population is considerably lower than that reported in European and U.S. studies and is in marked contrast to the high prevalence rate of CAD reported in this population.

Adult↗
PubMed2000

Aedes aegypti in Tahiti and Moorea (French Polynesia): isoenzyme differentiation in the mosquito population according to human population density.

Genetic differences at five polymorphic isoenzyme loci were analyzed by starch gel electrophoresis for 28 Aedes aegypti samples. Considerable (i.e., high Fst values) and significant (i.e., P values >10(-4)) geographic differences were found. Differences in Ae. aegypti genetic structure were related to human population densities and to particularities in mosquito ecotopes in both Tahiti and Moorea islands. In highly urbanized areas (i.e., the Papeete agglomeration), mosquitoes were highly structured. Recurrent extinction events consecutive to insecticidal treatments during dengue outbreaks tend to differentiate mosquito populations. In less populated zones (i.e., the east coast of Moorea and Tahiti), differences in ecotope characteristics could explain the lack of differentiation among mosquitoes from rural environments such as the east coast of Tahiti where natural breeding sites predominate. When the lowest populated zones such as Tahiti Iti and the west coast of Moorea are compared, mosquito are less differentiated in Moorea. These results will be discussed in relation to the recent findings of variation in mosquito infection rates for dengue-2 virus.

Aedes↗
PubMed2000

[Genetic demographic processes in Ukrainian population in 1990. The marriage structure of the Donetsk population].

Analysis of records of the marriages that were contracted in the city of Donetsk revealed that, between 1960 and 1992, the marriage rate in the city decreased from 14.8 to 4.7 per 1000 people, the migration rate (m) decreased from 0.71 to 0.34, and the endogamy index increased from 0.123 to 0.458. Between 1960 and 1985, outbreeding in the Donetsk population increased, which was expressed in an increase in the frequency of interethnic marriages, migration range, and the average marital distance, as well as a decrease in the proportion of the indigenous ethnic group (Ukrainians). By 1992, outbreeding decreased: the population became more homogeneous ethnically (93% Slavic), the proportion of Ukrainians and the frequency of monoethnic marriages increased, and the average marital distance decreased. In 1960 and 1992, the coefficients of marriage contingency (K) with respect to ethnicity were 0.34 and 0.22, respectively. Regarding birthplaces, the population became almost panmictic (in 1960 and 1992, the K values were 0.15 and 0.10, respectively). Marriage structure with respect to occupation remained almost unchanged (the K values were 0.22 and 0.23, respectively). Throughout the entire period studied, the most pronounced population subdivision was that with respect to the education level (the K values were 0.36 and 0.39, respectively).

Adult↗
PubMed2001

Allergy test results of a rural and small-city population compared with those of an urban population.

The frequency of sensitization to environmental antigens changes in different regions. As such, the pattern of sensitivity to common allergens was studied at multiple sites across central Pennsylvania, an area composed of small cities and rural communities, to determine uniqueness of allergies in populations from this area in contrast to allergies as determined by skin testing in large urban centers. The study reported was undertaken to determine allergen variation from an urban population compared with a rural population of a Northeastern state so that environmental avoidance and immunotherapy can be more precisely prescribed. Patient charts were retrospectively reviewed to determine sensitivity to house dust mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae), cockroach, Penicillium, Aspergillus spp, dog, cat, timothy grass, ragweed, oak, and Alternaria tenuis at five sites in Pennsylvania. All of these sites were classified as "small city" or "rural" for the study. One hundred patient records were examined at each site for the results of allergy testing by the prick puncture, radioallergosorbent test (RAST), or intradermal methods. These small-city and rural data were pooled and compared with that of the National Cooperative Inner-City Asthma Study (NCI-CAS), which included 1286 patients from urban environments. The prevalence of allergy to both species of dust mites, dog, timothy grass, and ragweed was significantly greater in the pooled rural group than in the NCICAS inner-city patients (P < .05). In contrast, sensitivity to cockroach antigens and Alternaria was significantly greater in the NCICAS urban population than in the pooled rural group (P < .05). No statistically significant difference was found between the NCICAS and the pooled rural patients in reference to Penicillium, cat, and oak (P > .05).

Animals↗
PubMed1977

[Medico-genetic study of the population of the Samarkand region. II. Population-genetic description of 4 kishlaks of the Urgut district].

This report is a second one in a series of works devoted to the medico-genetical screening of Uzbekistan populations. The paper comprises the results of the analysis of the populational structure of one of the village councils (soviets) of the Urgut District of the Samarkand Region. The main parameters of the population studied were as follows: total number 1529 persons, the average number of inhabitants of one village--328. The proportion of the inhabitants studied--56%, the average number of persons per family--5.22; the average period between subsequent generations--30-35 years, the gametic index--0.8, the inbreeding coefficient inferred from pedigrees--0.018899--0.00781, Fst = 0.03577, the average genetic distanse according to Edwards--0.0231-0.0671. The distribution of Mendelian markers (ABO, Rh, Hp and Ptc) was studied. The observed ratio between a high degree of inbreeding and a relatively low extent of isolation of populations permits to explain satisfactorily the distribution and frequencies of hereditary pathology in the Urgut District of the Samarkand Region pointed out in the previous report.

Adolescent↗