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Genetic Inheritance (genetic + inheritance)
Selected AbstractsAn interstitial deletion of the long arm of chromosome 21 in a case of a first episode of psychosisACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2002J. Takhar Objective:,Case of an interstitial deletion of the long arm of chromosome 21 presenting with first episode of psychosis. Method:,A case report. Results:,A 16-year-high school student of Somalian origin presented with a first episode of psychosis, mild mental retardation and dysmorphic features. Chromosome analysis revealed an interstitial deletion in the long arm of chromosome 21, described as 46, XX del (21) (q21q22.1). Conclusion:,First episode of psychosis occurred in combination with neurobiological vulnerability and a complex genetic inheritance. The occurrence of psychosis in our case may be attributable to genes located within the region 21q21q22.1. The possibility that other loci exist on chromosome 21, which predispose to schizophrenia has to be considered. Identification of susceptibility genes will greatly facilitate investigation of factors that contribute to the disease process and may lead to early intervention and prevention. [source] LEAKY PREZYGOTIC ISOLATION AND POROUS GENOMES: RAPID INTROGRESSION OF MATERNALLY INHERITED DNAEVOLUTION, Issue 4 2005Kai M. A. Chan Abstract Accurate phylogenies are crucial for understanding evolutionary processes, especially species diversification. It is commonly assumed that "good" species are sufficiently isolated genetically that gene genealogies represent accurate phylogenies. However, it is increasingly clear that good species may continue to exchange genetic material through hybridization (introgression). Many studies of closely related species reveal introgression of some genes without others, often with more rapid introgression of maternally inherited chloroplast or mitochondrial DNA (cpDNA, mtDNA). We seek a general explanation for this biased introgression using simple models of common reproductive isolating barriers (RIBs). We compare empirically informed models of prezygotic isolation (for pre- and postinsemination mechanisms of both female choice and male competition) with postzygotic isolation and demonstrate that rate of introgression depends critically upon type of RIB and mode of genetic inheritance (maternal versus biparental versus paternal). Our frequency-dependent prezygotic RIBs allow much more rapid introgression of biparentally and maternally inherited genes than do commonly modeled postzygotic RIBs (especially maternally inherited DNA). After considering the specific predictions in the context of empirical observations, we conclude that our model of prezygotic RIBs is a general explanation for biased introgression of maternally inherited genomic components. These findings suggest that we should use extreme caution when interpreting single gene genealogies as species phylogenies, especially for cpDNA and mtDNA. [source] Cell cycle mechanisms of sister chromatid separation; Roles of Cut1/separin and Cut2/securinGENES TO CELLS, Issue 1 2000Mitsuhiro Yanagida The correct transmission of chromosomes from mother to daughter cells is fundamental for genetic inheritance. Separation and segregation of sister chromatids in growing cells occurs in the cell cycle stage called ,anaphase'. The basic process of sister chromatid separation is similar in all eukaryotes: many gene products required are conserved. In this review, the roles of two proteins essential for the onset of anaphase in fission yeast, Cut2/securin and Cut1/separin, are discussed with regard to cell cycle regulation, and compared with the postulated roles of homologous proteins in other organisms. Securin, like mitotic cyclins, is the target of the anaphase promoting complex (APC)/cyclosome and is polyubiquitinated before destruction in a manner dependent upon the destruction sequence. The anaphase never occurs properly in the absence of securin destruction. In human cells, securin is an oncogene. Separin is a large protein (MW ,180 kDa), the C-terminus of which is conserved, and is thought to be inhibited by association with securin at the nonconserved N-terminus. In the budding yeast, Esp1/separin is thought to be a component of proteolysis against Scc1, an essential subunit of cohesin which is thought to link duplicated sister chromatids up to the anaphase. Whether fission yeast Cut1/separin is also implicated in proteolysis of cohesin is discussed. [source] Bivariate combined linkage and association mapping of quantitative trait lociGENETIC EPIDEMIOLOGY, Issue 5 2008Jeesun Jung Abstract In this paper, bivariate/multivariate variance component models are proposed for high-resolution combined linkage and association mapping of quantitative trait loci (QTL), based on combinations of pedigree and population data. Suppose that a quantitative trait locus is located in a chromosome region that exerts pleiotropic effects on multiple quantitative traits. In the region, multiple markers such as single nucleotide polymorphisms are typed. Two regression models, "genotype effect model" and "additive effect model", are proposed to model the association between the markers and the trait locus. The linkage information, i.e., recombination fractions between the QTL and the markers, is modeled in the variance and covariance matrix. By analytical formulae, we show that the "genotype effect model" can be used to model the additive and dominant effects simultaneously; the "additive effect model" only takes care of additive effect. Based on the two models, F -test statistics are proposed to test association between the QTL and markers. By analytical power analysis, we show that bivariate models can be more powerful than univariate models. For moderate-sized samples, the proposed models lead to correct type I error rates; and so the models are reasonably robust. As a practical example, the method is applied to analyze the genetic inheritance of rheumatoid arthritis for the data of The North American Rheumatoid Arthritis Consortium, Problem 2, Genetic Analysis Workshop 15, which confirms the advantage of the proposed bivariate models. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source] Short and Prolonged Periods of Maternal Separation and Voluntary Ethanol Intake in Male and Female Ethanol-Preferring AA and Ethanol-Avoiding ANA RatsALCOHOLISM, Issue 4 2005Erika Roman Background: Genetic as well as environmental factors can affect the propensity for psychopathology and/or drug dependence. Maternal separation represents an animal experimental model that is useful in studies of effects of early life experiences. The authors have established a protocol for short and prolonged periods of maternal separation to study adult neurochemistry, behavior, and ethanol intake and have previously reported alterations in ethanol intake in Wistar rats and ethanol-preferring rats. The aim of the current study was to more thoroughly study how early life experiences affect an inherited propensity for high and low ethanol intake, respectively, in male and female ethanol-preferring AA (Alko alcohol) and ethanol-avoiding ANA (Alko, Non-Alcohol) rats. Methods: AA and ANA pups were assigned to one of three different rearing conditions: 15 min (MS15) or 360 min (MS360) of daily maternal separation in litters or normal animal facility rearing (AFR) during postnatal days 1 to 21. In adulthood, voluntary ethanol intake was investigated using the two-bottle free choice paradigm. Results: In male ethanol-preferring AA rats, MS15 resulted in a lower intake and fewer high-preferring animals at 8% and 10% ethanol compared with MS360 rats. The male MS360 rats had a higher ethanol intake at 8% and 10% ethanol in comparison with AFR rats. In contrast, the female AA MS15 and MS360 rats had a lower ethanol intake and a lower preference for the 10% ethanol solution compared with the female AA AFR rats. In male and female ANA rats, no major separation-induced effects were found. Conclusions: The current results show that genetic inheritance can be affected by environmental manipulations in AA rats with an inherent high ethanol intake. The findings in female ethanol-preferring AA rats give further evidence of a differential outcome of maternal separation in male and female rats, as previously shown. [source] Practitioner Review: Early adversity and developmental disordersTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 5 2005Eric Taylor Background:, Knowledge of genetic influences, on developmental disorders such as autism spectrum, attention deficit/hyperactivity disorder and learning disabilities, has increased the opportunities for understanding the influences of the early environment. Methods:, This paper provides a selective, narrative review for clinicians of the effects of factors such as exposure to toxins and stresses in utero and in postnatal life; brain injuries and perinatal compromise; neglect, malnutrition and selective food deficiencies. It also considers what is known about the mechanisms through which early adversities operate. Results:, Gaps in the research are identified and suggestions made about clinical investigations. Several types of environmental adversity have associations with later disorders that suggest a causal role. The effects are often on a broad range of psychological processes, and are not always quickly reversible. Several adversities often coexist, calling for skilled judgement about priorities in treatment. Conclusions:, Individuals vary considerably in their exposure to adversity and their vulnerability to its effects, and genetic inheritance can influence both. [source] Fetal nutrition: A reviewACTA PAEDIATRICA, Issue 2005Irene Cetin Abstract Knowledge of fetal nutrient supply has greatly increased in the last decade due to the availability of fetal blood samples obtained under relatively steady-state conditions. These studies, together with studies utilizing stable isotope methodologies, have clarified some aspects of the supply of the major nutrients for the fetus such as glucose, amino acids and fatty acids. At the same time, the relevance of intrauterine growth has been recognized not only for the well-being of the neonate and child, but also for later health in adulthood. The major determinants of fetal nutrient availability are maternal nutrition and metabolism together with placental function and metabolism. The regulation of the rate of intrauterine growth is the result of complex interactions between genetic inheritance, endocrine environment and availability of nutrients to the fetus. [source] | |||||||||||||