Genetic And Environmental Correlations
Mostrando 49-60 de 69 artigos, teses e dissertações.
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49. Genetics of Life History in DROSOPHILA MELANOGASTER. I. Sib Analysis of Adult Females
A sib analysis of adult life-history characters was performed on about twelve hundred females from a laboratory Drosophila melanogaster population that had been sampled from nature and cultured so as to preserve its genetic variability. The following results were found. There was no detectable trend with age in additive or dominance genetic variances for age
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50. Gene–environment interaction and the genetics of depression
Depression is a group of brain disorders with varied origins, complex genetics and obscure neurobiology. Definitions of clinical phenotypes are not rooted in their neurobiology, and animal models of behavioural despair have considerable limitations. Nevertheless, investigation of subtle alterations in gene expression, of correlations between genotype and bra
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51. Venezuelan kindreds reveal that genetic and environmental factors modulate Huntington's disease age of onset
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by a triplet (CAG) expansion mutation. The length of the triplet repeat is the most important factor in determining age of onset of HD, although substantial variability remains after controlling for repeat length. The Venezuelan HD kindreds encompass 18,149 individuals spanni
National Academy of Sciences.
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52. Ethnohistory, genetics, and cancer mortality in Europeans
Geographic variation in cancer rates is thought to be the result of two major factors: environmental agents varying spatially and the attributes, genetic or cultural, of the populations inhabiting the areas studied. These attributes in turn result from the history of the populations in question. We had previously constructed an ethnohistorical database for E
The National Academy of Sciences of the USA.
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53. P-Element-Induced Variation in Metabolic Regulation in Drosophila
Movement of transposable elements has been demonstrated to be a cause of genetic variation that is relevant to quantitative characters in Drosophila. Here a particular class of P-element-induced variation known to be mediated through changes in expression of targeted enzyme-encoding genes is examined. Balancer chromosomes and the ``jumpstarter'' modified P-e
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54. Brain size does not predict general cognitive ability within families
Hominid brain size increased dramatically in the face of apparently severe associated evolutionary costs. This suggests that increasing brain size must have provided some sort of counterbalancing adaptive benefit. Several recent studies using magnetic resonance imaging (MRI) have indicated that a substantial correlation (mean r = ≈0.4) exists between brain
The National Academy of Sciences.
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55. Genetic and Environmental Effects on the Expression of Peptidases and Larval Viability in Drosophila Melanogaster
The peptidase system in Drosophila melanogaster, consisting of dipeptidase-A, dipeptidase-B, dipeptidase-C and the leucine aminopeptidases, was used as a model to study the adaptive significance of enzyme activity variation. The involvement of the peptidases in osmoregulation has been suggested from the ubiquitous distribution of peptidase activities in near
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56. Population Genetics of Euphydryas Butterflies. I. Genetic Variation and the Neutrality Hypothesis
Twenty-one populations of the checkerspot butterfly, Euphydryas editha, and ten populations of Euphydryas chalcedona were sampled for genetic variation at eight polymorphic enzyme loci. Both species possessed loci that were highly variable from population to population and loci that were virtually identical across all populations sampled. Our data indicate t
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57. Genetic and environmental components of interindividual variation in circulating levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3.
We assessed the magnitude of the genetic component in the variation of circulating levels of insulin-like growth factors I and II (IGF-I and IGF-II), and their binding proteins IGFBP-1 and IGFBP-3 by measuring their serum concentrations in 32 monozygotic and 47 dizygotic adult twin pairs of the same sex. The intrapair correlation for the IGF-I levels was r =
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58. Measurements of age-related changes of physiological processes that predict lifespan of Caenorhabditis elegans
Aging is characterized by progressive, degenerative changes in many tissues. To elucidate the relationships among degenerative changes in Caenorhabditis elegans, we developed methods to measure age-related changes quantitatively and analyzed correlations among these changes by using a longitudinal study. The age-related declines of pharyngeal pumping and bod
National Academy of Sciences.
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59. Polymorphism of theophylline metabolism in man.
To determine whether genetic mechanisms control large interindividual variations in theophylline elimination in normal uninduced human subjects, and, if so, to test the possibility that these genetic factors are transmitted as a simple Mendelian trait, theophylline was administered to 79 unrelated adults, six sets of monozygotic twins, six sets of dizygotic
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60. Genetic Variability of Flight Metabolism in DROSOPHILA MELANOGASTER . II. Relationship between Power Output and Enzyme Activity Levels
The major goal of the studies reported here was to determine the extent to which genetic variation in the activities of the enzymes participating in flight metabolism contributes to variation in the mechanical power output of the flight muscles in Drosophila melanogaster. Isogenic chromosome substitution lines were used to partition the variance of both type