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Kunwar CB, Chapagain RH, Subba B, Shrestha M, Jha B, Subedi J, Blangero J, Williams-Blangero S, Towne B. Occurrence of soil-transmitted helminths in women at the Himalayan region of Nepal. Kathmandu Univ Med J (KUMJ) 2006; 4:444-447. [PMID: 18603951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To find the occurrence pattern and prevalence of the soil transmitted helminths in women of child bearing age group. METHODS AND MATERIALS The study was conducted in Jiri , an area of Dolakha district at the altitude of 2100 meter from sea level. The faecal sample of 478 women of childbearing age (15 to 45 years) were taken randomly and examined for the ova of soil transmitted helianthus. RESULT The occurrence pattern was 53.0%, 20.0% and 2.7% for Hookworms, Ascaries lumbricoids and Trichuris Trichuria respectively. Both Ascaries and Hookworm prevalence rates noticeably increased with increasing age, with the highest infection rate between the age of 36-45 years while trichuris infection reached the highest in women of 15-25 years of age. CONCLUSION There is a high prevalence of hookworm and ascaries in women of childbearing age and necessary intervention is needed according to WHO guidelines.
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Williams-Blangero S, Blangero J. Collection of pedigree data for genetic analysis in isolate populations. Hum Biol 2006; 78:89-101. [PMID: 16900884 DOI: 10.1353/hub.2006.0023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pedigree data are useful for a wealth of research purposes in human population biology and genetics. The collection of extended pedigrees represents the most powerful sampling design for quantitative genetic and linkage studies of both normal and disease-related quantitative traits. In this paper we outline an approach for collecting pedigree data in stable isolate populations. As an example, the pedigree for the Jirel population, which was obtained using the methods presented, is described. The Jirel pedigree contains 2,000 study participants and more than 62,000 pairwise relationships that are informative for genetic analysis. Once such pedigrees are genetically characterized by a genome scan for a given trait, they become an invaluable resource for future genetic studies of any quantitative trait.
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Cardoso GM, Morato MJF, Gomes JAS, Rocha MOC, Bonfim IP, Williams-Blangero S, VandeBerg JL, Reis MR, Magalhães EFL, Correa-Oliveira R. Comparative analysis of cell phenotypes in different severe clinical forms of Chagas' disease. FRONT BIOSCI-LANDMRK 2006; 11:1158-63. [PMID: 16146804 DOI: 10.2741/1870] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The understanding of the role of the immune response in the development of gastrointestinal and cardio-digestive (CD) forms of Chagas disease has received little attention. In this paper, the commitment of each leukocyte population of peripheral blood to the production of IFN-gamma, TNF-alpha, IL-12, IL-4, IL-5 and IL-10 was studied in patients with the CD form of Chagas disease. The data show that cells from patients with the CD form of the disease have distinct cytokine profiles when compared with the other clinical forms of Chagas disease and suggest that eosinophils are the major source of cytokine production in this clinical entity. The data presented in this paper demonstrate that patients with CD form can be distinguished from patients with gastrointestinal or cardiac forms of the disease by the distinct cytokine profile of peripheral blood cells.
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Howard BV, Devereux RB, Cole SA, Davidson M, Dyke B, Ebbesson SOE, Epstein SE, Robinson DR, Jarvis B, Kaufman DJ, Laston S, MacCluer JW, Okin PM, Roman MJ, Romenesko T, Ruotolo G, Swenson M, Wenger CR, Williams-Blangero S, Zhu J, Saccheus C, Fabsitz RR, Robbins DC. A genetic and epidemiologic study of cardiovascular disease in Alaska natives (GOCADAN): design and methods. Int J Circumpolar Health 2005; 64:206-21. [PMID: 16050315 DOI: 10.3402/ijch.v64i3.17985] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This article is a report of the design and methods of the Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) Study. This longitudinal, population-based study was initiated to investigate the genetic determinants of cardiovascular disease and its risk factors. Between October 2000 and April 2004, this family study enrolled 1,214 Eskimos from several coastal villages in the Norton Sound region of Western Alaska. Examinations included a physical, laboratory determinations, and measures of subclinical disease. This study will generate a genome-wide scan for loci influencing cardiovascular disease-related traits. Relations between subclinical atherosclerosis and markers of inflammation will be examined using historic and newly drawn samples. The study will provide data on CVD prevalence, risk factors and the relative contribution of genetic and environmental determinants in Alaska Native peoples. Data from this study will contribute to the delivery of health-care and prevention of CVD in Alaska Eskimos and other populations.
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Williams-Blangero S. Recent trends in genetic research on captive and wild nonhuman primate populations. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2005. [DOI: 10.1002/ajpa.1330340606] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Williams-Blangero S, Corrêa-Oliveira R, Vandeberg JL, Subedi J, Upadhayay RP, Rai DR, Jha B, Blangero J. Genetic influences on plasma cytokine variation in a parasitized population. Hum Biol 2005; 76:515-25. [PMID: 15754969 DOI: 10.1353/hub.2004.0062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The soil-transmitted helminths are the most common helminthic infections, affecting about one-fourth of the world's population. There is a significant genetic component to susceptibility to infection with these organisms. Substantial changes in plasma cytokine levels are associated with helminthic infections, and there may be significant genetic components to this cytokine variation. Six plasma cytokine levels were assessed for 367 members of a single pedigree from the Jirel population of eastern Nepal. This population experiences moderate rates of infection with geohelminths. Sex, age, helminthic infection, infection with Giardia, and presence of a household latrine were considered as covariates in all analyses of the cytokine data. The analyses of the single Jirel pedigree revealed significant heritabilities for IFN-gamma (h2 = 0.654+/-0.096), TNF-alpha (h2 = 0.458+/-0.101), IL-2 (h2 = 0.583+/-0.101), IL-4 (h2 = 0.700+/-0.095), IL-5 (h2 = 0.676+/-0.087), and IL-10 (h2 = 0.597+/-0.093). The ratios of IL-4 to IFN-gamma and of IL-10 to IFN-gamma were used as indicators of the degree of type 2 bias in immunological response; analyses of these variables indicated that approximately 40-60% of the variation (h2 = 0.400-0.577) in these derived measures of relative type 2/type 1 response is due to genetic factors.
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Anderson JD, Williams-Blangero S, Anderson TJC. Spurious genotypes in female nematodes resulting from contamination with male DNA. J Parasitol 2004; 89:1232-4. [PMID: 14740915 DOI: 10.1645/ge-99r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Females of many invertebrates contain stored sperm or fertilized eggs or both, causing potential genotyping errors. We investigated errors caused by male DNA contamination by amplifying 5 microsatellites in DNA isolated from various tissue types in the nematode Ascaris lumbricoides. We observed additional alleles in 30/135 uterus-derived samples when compared with muscle controls, resulting in 20/135 (15%) incorrect genotypes and an underestimation of inbreeding. In contrast, we observed additional alleles in only 5/143 ovary-derived samples, resulting in 4/143 (3%) incorrect genotypes and no significant influence on inbreeding estimates. Because uterus constitutes approximately 17% of a female's organ weight, a substantial proportion of samples isolated from female tissue may contain male-derived DNA. Male contamination is easily avoided when using large nematodes such as A. lumbricoides. However, we urge caution for studies using DNA isolated from small invertebrates that store sperm or fertilized eggs or both.
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Tausig M, Subedi S, Subedi J, Broughton CL, Williams-Blangero S. THE PSYCHOLOGICAL DISEASE BURDEN IN NEPAL AND ITS RELATIONSHIP TO PHYSICAL HEALTH PROBLEMS. SOCIAL BEHAVIOR AND PERSONALITY 2004. [DOI: 10.2224/sbp.2004.32.5.419] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Psychological disorders are a substantial part of the disease burden in many developing countries, yet few health services are directed toward the detection and treatment of these disorders. The relationship between psychological disorders and physical health problems was investigated
by means of a community survey (N =653) in a small village in Nepal, using a shortened version of the DSM-III-R Checklist to estimate the prevalence of several psychological disorders and a version of the Cornell Medical Index to assess physical illness symptoms. Results indicate that
approximately 18.4 percent of this rural population has had a diagnosable mental illness. Moreover, there is substantial overlap between physical health problems and psychological disorder for those with a psychological disorder (32.5%). The findings indicate that health providers in
developing countries need to screen for psychological disorders as a standard part of health assessments.
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Williams-Blangero S. The Human Genome Project and Advances in Anthropological Genetics. Hum Biol 2004; 76:801-4. [PMID: 15974294 DOI: 10.1353/hub.2005.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tausig M, Subedi S, Broughton CL, Subedi J, Williams-Blangero S. Measuring community mental health in developing societies: evaluation of a checklist format in Nepal. Int J Soc Psychiatry 2003; 49:269-86. [PMID: 14727694 DOI: 10.1177/0020764003494005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND There is growing recognition of the importance of mental health problems in developing countries. In large part, however, we have very limited epidemiological data at national and/or community levels about the prevalence of mental illnesses. AIMS The purpose of this paper is to describe the reliability and validity characteristics of an assessment tool that may be useful for conducting community-level surveys (particularly in rural communities of developing countries) to obtain prevalence rates of mental illnesses. METHODS We used a sample of adults residing in a rural village in Nepal to assess disorders with a modified version of the DSM-III-R Checklist. We evaluated construct validity, scale reliability, convergent validity and discriminant validity. RESULTS There is strong evidence for the construct validity of generalized anxiety and depression in our sample. By contrast, the symptoms associated with mania and schizophrenia were not empirically distinct. Convergent validity is acceptable. As a test of validity characteristics, the pattern of sociodemographic correlations suggests that the specific social origins of disorder in Nepal will require further investigation. CONCLUSION The first step in obtaining high quality information on the distribution of mental illness in developing countries is to establish some reliable and valid indicators of disorder. The checklist format for assessing disorder appears to meet this objective and offers the possibility that community-level prevalence studies can be reasonably conducted.
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Williams-Blangero S, VandeBerg JL, Blangero J, Corrêa-Oliveira R. Genetic epidemiology of Trypanosoma cruzi infection and Chagas' disease. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2003; 8:e337-45. [PMID: 12700060 DOI: 10.2741/1058] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chagas' disease is a leading cause of heart disease throughout Latin America, affecting an estimated 16 to 18 million individuals. Given the large pool of primary hosts for this zoonotic disease, complete eradication of Chagas' disease through control of the arthropod vector is unlikely. Research with both humans and animal models indicates that there is considerable variation in susceptibility to infection and disease outcome, and that this variation may be due in part to genetic factors. This paper summarizes the evidence for genetic control of susceptibility to Trypanosoma cruzi infection and severity of disease outcome in Chagas' disease. The lack of an effective treatment or prevention for Chagas' disease indicates the great potential for genetic studies, and particularly for genome scans of extended human pedigrees, to improve our understanding of the determinants of this complex disease, and ultimately to suggest new pathways to be targeted in drug development efforts.
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Bethony J, Williams JT, Blangero J, Kloos H, Gazzinelli A, Soares-Filho B, Coelho L, Alves-Fraga L, Williams-Blangero S, Loverde PT, Correa-Oliveira R. Additive host genetic factors influence fecal egg excretion rates during Schistosoma mansoni infection in a rural area in Brazil. Am J Trop Med Hyg 2002; 67:336-43. [PMID: 12452486 DOI: 10.4269/ajtmh.2002.67.336] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
This study quantifies the influence of shared household and kinship on egg counts during Schistosoma mansoni infection in a sample from rural Brazil. Detailed genealogic information allowed assignment of 597 individuals to 6 multihousehold pedigrees residing in 145 households. A variance component method was used to partition egg counts into shared household, additive genetic, and individual-specific environmental effects. Host additive genetic effects consistently accounted for a large proportion of the variation in egg counts: 43% in an unadjusted model and 40% in model adjusted for covariates. In a model that examined the confounding of shared household with kinship, additive genetic effects still accounted for 27% of the variation in egg counts and shared household only 12%. The consistently important role for host additive genetic factors on the variation in egg counts points to new ways of modeling and understanding the mechanisms that contribute to trait variation during infection with S. mansoni.
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Bethony J, Williams JT, Almasy L, Corrêa-Oliveira R, Blangero JC, Williams-Blangero S. Genetic analysis of quantitative traits in highly ascertained samples: total serum IgE in families with asthma. Genet Epidemiol 2002; 21 Suppl 1:S174-9. [PMID: 11793664 DOI: 10.1002/gepi.2001.21.s1.s174] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The objective of this study was to compare the effect of an approximate ascertainment correction using proband phenotypes with heuristic corrections based on sample trait means and on published "standard" population values. Data were from the Collaborative Study on the Genetics of Asthma, which comprises 225 families ascertained through sib pairs affected with asthma. In variance component linkage analysis of IgE no lod scores greater than 3.0 were observed, either with or without several attempted corrections for ascertainment. The ascertained nature of the sample may have compromised the power to detect linkage to a quantitative trait (IgE) associated with the focal phenotype (asthma).
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Williams-Blangero S, VandeBerg JL, Subedi J, Aivaliotis MJ, Rai DR, Upadhayay RP, Jha B, Blangero J. Genes on chromosomes 1 and 13 have significant effects on Ascaris infection. Proc Natl Acad Sci U S A 2002; 99:5533-8. [PMID: 11960011 PMCID: PMC122804 DOI: 10.1073/pnas.082115999] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2001] [Accepted: 02/27/2002] [Indexed: 11/18/2022] Open
Abstract
Nematode parasites show a characteristic aggregated distribution among hosts. This observation has important implications for pathogenesis, immunology, and control of these infections, but the relative roles of environment and genetics in determining these patterns have remained uncertain. This paper presents the results of the first genome scan for susceptibility to infection with roundworm (Ascaris lumbricoides). Data on 375 genetic markers were generated for each of 444 members of a genetically isolated Nepalese population, the Jirels. Ascaris worm burden as assessed by egg counts was measured in these same individuals by using the Kato Katz thick smear method. The extensive genealogical data available for the population allowed assignment of all 444 individuals to a single pedigree that contained 6,209 pairs of relatives that were informative for genetic analysis. A variance components linkage analysis resulted in the unequivocal localization of two genes (one on chromosome 1 and another on chromosome 13) with clear, significant effects on susceptibility to Ascaris infection. This is the first evidence that individual quantitative trait loci influence variation in Ascaris burden in humans.
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Williams-Blangero S, McGarvey ST, Subedi J, Wiest PM, Upadhayay RP, Rai DR, Jha B, Olds GR, Guanling W, Blangero J. Genetic component to susceptibility to Trichuris trichiura: evidence from two Asian populations. Genet Epidemiol 2002; 22:254-64. [PMID: 11921085 DOI: 10.1002/gepi.0187] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Trichuris trichiura is an helminthic infection with potentially severe health consequences. The hypothesis that host genetic factors can account for the distribution of Trichuris was tested using familial data on egg counts available for two populations, the Jirels of Nepal and the population of Jishan Island in Jiangxi Province of the People's Republic of China. Whipworm is highly prevalent in the Jishan Island population (86%), but occurs at a low rate in the Jirel population (14%). A quantitative genetic analysis was performed on each data set, using a variance component approach. Approximately 28% of the variation in Trichuris trichiura loads was attributable to genetic factors in both populations. Common household effects accounted for only 4% of the variation in the Jirels and none of the variation in the Jishan Island population. These concordant results from two separate populations provide strong evidence of the important role of genetics in determining differential susceptibility to whipworm infection.
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Abstract
Genetic management is widely recognized as a critical component of the overall management of captive nonhuman primate colonies which produce animals for biomedical research. In this paper, we review the roles of conservation-oriented genetic management, research-oriented genetic management, genetic management at the level of taxomomic class, genetic management at the level of the population, and quantitative genetic analysis in comprehensive genetic management programs for nonhuman primate colonies. We conclude that genetic management is crucial for maintaining nonhuman primate populations suitable for genetic research on normal and disease-related phenotypes. In addition, for research programs that do not have specific genetic objectives, genetic management is essential to facilitate the selection of samples of well-matched unrelated animals for experimental purposes.
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Russow LM, Donnelley S, Dresser R, VandeBerg JL, Williams-Blangero S, Wolfle TL. Bioethics, Animal Research, and Ethical Theory. ILAR J 2001; 40:15-21. [PMID: 11533512 DOI: 10.1093/ilar.40.1.15] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Dyke B, Williams-Blangero S, Mamelka PM, Goodwin WJ. Future Costs of Chimpanzees in U.S. Research Institutions. ILAR J 2001; 37:193-198. [PMID: 11528040 DOI: 10.1093/ilar.37.4.193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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69
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Bethony J, Williams JT, Kloos H, Blangero J, Alves-Fraga L, Buck G, Michalek A, Williams-Blangero S, Loverde PT, Corréa-Oliveira R, Gazzinelli A. Exposure to Schistosoma mansoni infection in a rural area in Brazil. II: household risk factors. Trop Med Int Health 2001; 6:136-45. [PMID: 11251910 DOI: 10.1046/j.1365-3156.2001.00685.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A number of studies have pointed out the potential importance of the household in the transmission of schistosomiasis. The clustering of domestic activities associated with water collection, storage, and usage can result in the sharing of transmission sites and infective water contact behaviours. In this study, we employed a variance component method to estimate effects due to individual risk factors and shared residence on the variance in faecal egg counts during Schistosoma mansoni infection. A suite of covariates, which included demographic, socioeconomic, water supply, and water contact behaviour terms, contributed 15% to the variance in faecal egg counts. Shared residence alone accounted for 28% of the variance in faecal egg excretion. When both the suite of covariates and shared residence were considered in the same model, shared residence still contributed 22% to the variance in infection intensity. These results point to the importance of shared residence as a means of capturing the complex interrelationship between shared demographic, socioeconomic, physical environmental, and behavioural factors that influence transmission of schistosomiasis at the household level.
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VandeBerg JL, Williams-Blangero S, Dyke B, Rogers J. Examining priorities for a primate genome project. Science 2000; 290:1504-5. [PMID: 11185504 DOI: 10.1126/science.290.5496.1504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Jaquish CE, Dyer T, Williams-Blangero S, Dyke B, Leland M, Blangero J. Genetics of adult body mass and maintenance of adult body mass in captive baboons (Papio hamadryas subspecies). Am J Primatol 2000; 42:281-8. [PMID: 9261509 DOI: 10.1002/(sici)1098-2345(1997)42:4<281::aid-ajp3>3.0.co;2-t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Adult body mass and changes in mass during an individual's life are important indicators of general health and reproductive fitness. Therefore, characterization of the factors that influence normal variation in body mass has important implications for colony management and husbandry. The main objective of this study was to quantify the genetic contribution to adult body mass and its maintenance in baboons. Intra-individual mean and variance in body mass were calculated from multiple weight measures available for each of 1,614 animals at least 10 years of age. Heritabilities were estimated using maximum likelihood methods. Mean adult body mass had a significant heritability (50%) as did variance in adult body mass (12%). The sexes differed in several respects: on average females were smaller than males and had greater variability in adult body mass; mean and variance in body mass increased with age in females only; and number of offspring showed a significant positive relationship with body mass in females only. There were significant differences between subspecies in body mass as well as ability to maintain body mass. These results indicate that there is a significant genetic influence on body mass and its maintenance, and suggest that different factors influence changes in body mass with age as well as body mass maintenance in male and female baboons.
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Duggirala R, Williams JT, Williams-Blangero S, Blangero J. A variance component approach to dichotomous trait linkage analysis using a threshold model. Genet Epidemiol 2000; 14:987-92. [PMID: 9433612 DOI: 10.1002/(sici)1098-2272(1997)14:6<987::aid-gepi71>3.0.co;2-g] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We developed and utilized a multipoint variance components method to test for linkage between a disease trait and markers on chromosome 5 in the simulated data provided in GAW10 Problem 2. We demonstrated that the discrete trait variance components method recovers unbiased estimates of quantitative trait locus (QTL) location and reasonable estimates of effect size. We also showed that dichotomization of (a continuous trait such as) Q1 diminished the power to detect linkage compared to direct analysis of Q1, and that extended pedigree analyses provided superior power to detect linkage compared to those in nuclear families.
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Williams-Blangero S, Subedi J, Upadhayay RP, Manral DB, Rai DR, Jha B, Robinson ES, Blangero J. Genetic analysis of susceptibility to infection with Ascaris lumbricoides. Am J Trop Med Hyg 1999; 60:921-6. [PMID: 10403321 DOI: 10.4269/ajtmh.1999.60.921] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Epidemiologic studies of helminthic infections have shown that susceptibility to these parasites frequently aggregates in families, suggesting the possible involvement of genetic factors. This paper presents a genetic epidemiologic analysis of Ascaris lumbricoides infection in the Jirel population of eastern Nepal. A total of 1,261 individuals belonging to a single pedigree were assessed for intensity of Ascaris infection at two time points. Following an initial assessment in which all individuals were treated with albendazole, a follow-up examination was performed one year later to evaluate reinfection patterns. Three measures of worm burden were analyzed, including eggs per gram of feces, direct worm counts, and worm biomass (weight). For all traits, variance component analysis of the familial data provided unequivocal evidence for a strong genetic component accounting for between 30% and 50% of the variation in worm burden. Shared environmental (i.e., common household) effects account for between 3% and 13% of the total phenotypic variance.
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Beall CM, Almasy LA, Blangero J, Williams-Blangero S, Brittenham GM, Strohl KP, Decker MJ, Vargas E, Villena M, Soria R, Alarcon AM, Gonzales C. Percent of oxygen saturation of arterial hemoglobin among Bolivian Aymara at 3,900-4,000 m. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1999; 108:41-51. [PMID: 9915300 DOI: 10.1002/(sici)1096-8644(199901)108:1<41::aid-ajpa2>3.0.co;2-k] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A range of variation in percent of oxygen saturation of arterial hemoglobin (SaO2) among healthy individuals at a given high altitude indicates differences in physiological hypoxemia despite uniform ambient hypoxic stress. In populations native to the Tibetan plateau, a significant portion of the variance is attributable to additive genetic factors, and there is a major gene influencing SaO2. To determine whether there is genetic variance in other high-altitude populations, we designed a study to test the hypothesis that additive genetic factors contribute to phenotypic variation in SaO2 among Aymara natives of the Andean plateau, a population geographically distant from the Tibetan plateau and with a long, separate history of high-altitude residence. The average SaO2 of 381 Aymara at 3,900-4,000 m was 92+/-0.15% (SEM) with a range of 84-99%. The average was 2.6% higher than the average SaO2 of a sample of Tibetans at 3,800-4,065 m measured with the same techniques. Quantitative genetic analyses of the Aymara sample detected no significant variance attributable to genetic factors. The presence of genetic variance in SaO2 in the Tibetan sample and its absence in the Aymara sample indicate there is potential for natural selection on this trait in the Tibetan but not the Aymara population.
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VandeBerg JL, Williams-Blangero S, Wolfle TL. US Laws and Norms Related to Laboratory Animals. ILAR J 1999. [DOI: 10.1093/ilar.40.1.34] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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