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Homozygous Genotypes (homozygous + genotype)
Selected AbstractsThe haematology of gynogenic tench, Tinca tinca L., and of recessively homozygous colour tench strainsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2003M. Flaj Summary Two wild-coloured strains of tench (the first meiotic gynogenic generation MeiG1, and their control diploid half siblings) and three recessively homozygous colour strains (golden, blue and alampic) were examined for the determination of basic haematological indices. The MeiG1 strain had higher erythrocyte counts than diploid controls or the blue and alampic strains (P < 0.001), and had a higher blood haemoglobin content than all three colour strains (P < 0.001). No differences were detected among strains for haematocrit, mean corpuscular haemoglobin, or mean corpuscular volume. Both the lowest leucocyte count (P < 0.001) and leucocrit value (P < 0.001) were found in the alampic tench, and may result from a negative pleiotropic effect of this recessive homozygous genotype (bbgg). In agreement with previous findings in tench, the differential leucocyte count revealed lymphocytes to be the dominating white blood cells; their rate was about 90% in both the wild-coloured and blue strains, and less in the other two strains (83,84%). Neutrophil granulocytes were most abundant in the MeiG1 strain. Eosinophil granulocytes were detected only in the golden strain, and were not common (0.2%). [source] Investigation of Quantitative Trait Loci in the CCKAR Gene With Susceptibility to AlcoholismALCOHOLISM, Issue 2002Takehito Okubo Background Cholecystokinin (CCK) plays an important role in the function of the central nervous system by interacting with dopamine and other neurotransmitters. We previously reported genetic variations in the promoter and coding regions of the CCKA receptor (CCKAR), CCKBR, and CCK genes and a possible association between polymorphisms of the CCKAR gene and alcoholism. In this study, association analyses were re-examined between the polymorphisms of the promoter region of the CCKAR gene and patients with alcohol withdrawal symptoms, in addition to patients with alcoholic liver injury. Methods A total of 131 Japanese male patients with alcohol withdrawal symptoms, 70 Japanese patients with alcoholic liver injury, and 98 age-matched Japanese male controls (nonhabitual drinkers) were examined using polymerase chain reaction-based single strand conformational polymorphism and sequencing analyses. Results Significant differences between patients with hallucination and controls were found in the allele frequencies at the ,388 and ,85 loci of the CCKAR gene (p= 0.0095, p= 0.0087, respectively), but these differences were not significant after Bonferroni correction for multiple testing. In contrast, the frequency of the homozygous genotype ,85 CC was significantly higher in hallucination-positive patients than in controls (p= 0.0031) and in patients with hallucination accompanying delirium tremens than in controls (p= 0.0022), and these differences were significant after Bonferroni correction. Conclusions The data from the case control suggest that polymorphisms of the promoter region of the CCKAR gene do not play a major role in the pathogenesis of alcohol withdrawal symptoms or alcoholic liver injury. However, a significant association was found between polymorphism at the ,85 locus of the CCKAR gene and patients with hallucination, and especially patients with hallucination accompanying delirium tremens. [source] A novel mutation of the ,-globin gene promoter (,102 C>A) and pitfalls in family screeningAMERICAN JOURNAL OF HEMATOLOGY, Issue 12 2007Patricia Aguilar-Martinez We describe a family with ,-thalassemia in which several pitfalls of genetic diagnoses were present. These include coherent family phenotypes with discrepancies in molecular findings because of nonpaternity, and a false ,-globin gene homozygous genotype due to a large deletion in the second locus. These findings underline the difficulties of family genetic studies and the need for tight relationship between professionals involved in laboratory studies and those in-charge of the clinical follow-up and genetic counselling. In this family, we also report a new silent ,-thalassemia mutation, ,102 (C>A), in the distal CACCC box of the ,-globin gene promoter. Am. J. Hematol., 2007. © 2007 Wiley-Liss, Inc. [source] No association between polymorphism in tyrosine hydroxylase and personality traits in healthy Japanese subjectsPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 2 2010Shoko Tsuchimine MSc The aim of the present study was to investigate whether there is an association between the (TCAT)n repeat polymorphism in the tyrosine hydroxylase (TH) gene and personality. The (TCAT)n repeat polymorphism in the TH gene was genotyped in 898 healthy Japanese subjects. Personality traits were evaluated using the Temperament and Character Inventory (TCI). There was no significant difference in the TCI scores of subjects with and without the T9 allele. Furthermore, no significant association was found between each genotype and the TCI scores, even when the TCI scores were compared with the homozygous genotype. These findings suggest that the (TCAT)n repeat polymorphism in the TH gene does not contribute to the personality traits evaluated on the TCI in healthy Japanese subjects. [source] Rheumatoid arthritis association with the FCRL3 ,169C polymorphism is restricted to PTPN22 1858T,homozygous individuals in a Canadian populationARTHRITIS & RHEUMATISM, Issue 12 2006William G. Newman Objective Variants in genes encoding the Fc receptor,like 3 (FcRL-3) and the class II major histocompatibility complex (MHC) transactivator proteins have been associated with an increased risk of rheumatoid arthritis (RA) in Japanese and Nordic populations, respectively. The aim of this study was to investigate these associations in a Canadian Caucasian cohort of RA cases and healthy controls. Methods A total of 1,187 RA patients and 462 healthy controls were genotyped for FCRL3 and MHC2TA gene variants associated with RA. Epistasis between the FCRL3 ,169C and the PTPN22 1858T variants was also examined. Results An association was detected between RA and both the FCRL3 ,169C allele (OR 1.19, P = 0.023) and the homozygous genotype (OR 1.41, P = 0.027), but association of the MHC2TA promoter region variant (,168G) with RA was not replicated. Stratification of the RA cohort by PTPN22 genotypes revealed the FCRL3 risk variant and RA association was stronger in the patient subgroup lacking PTPN22 1858T variants (P = 0.004) and was not detectable in the subgroup with PTPN22 1858T variants (P = 0.52). The PTPN22 association with RA was greater in the absence than in the presence of the FCRL3 ,169C allele (P = 0.0008 versus P = 0.001). The PTPN22 1858T variant also increased the risk of autoimmune thyroid disease (AITD) in the RA patients, whereas the FCRL3 risk variant was protective against AITD. Conclusion Our findings support an association of RA with an FCRL3 functional polymorphism and reveal that this association is stronger in the absence of PTPN22 risk genotypes. These findings support a genetic heterogeneity across RA populations, suggesting that both the FCRL3 and PTPN22 genes play roles in RA susceptibility, but in different individuals. [source] Linkage and mapping analysis of a non-susceptibility gene to densovirus (nsd-2) in the silkworm, Bombyx moriINSECT MOLECULAR BIOLOGY, Issue 2 2003D. O. Ogoyi Abstract Nonsusceptibility to Bombyx mori densovirus type 2 (BmDNV-2) is controlled by a recessive non-susceptibility gene, nsd-2 (non-susceptibility to DNV-2) in B. mori. Taking advantage of a lack of crossing over in females, reciprocal backcrossed F1 (BF1) progeny were used for linkage analysis and mapping of nsd-2 using silkworm strains C124 and 902, which are classified as being highly susceptible and non-susceptible to DNV-2, respectively. BF1 larvae were inoculated twice with DNV-2 virus at the first and second instar stages. DNA was extracted from each of the surviving fifth instar larvae and analysed by RFLP inheritance patterns using probes specific to each of the 28 linkage groups of B. mori. Our results indicated that the non-susceptibility gene was linked to linkage group 17, since all surviving larvae showed the homozygous profile of strain 902 in their genotype. The other linkage groups showed mixtures of heterozygous and homozygous genotypes, indicating an independent assortment. A linkage map of 30.6 cM was constructed for linkage group 17 with nsd-2 mapped at 24.5 cM and three closely linked cDNA markers were identified. [source] Tissue histopathology, clinical chemistry and behaviour of adult comt -gene-disrupted miceJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2003Kristiina Haasio Abstract Catechol- O -methyltransferase (COMT) enzyme is a widely distributed enzyme that catalyses O -methylation of catecholamines and other compounds having a catechol structure. Because there has been some concern about the consequences of a low COMT activity in the development of oestrogen-dependent cancers and because one of the COMT inhibitors, tolcapone, has caused serious liver injuries in Parkinsonian patients, the histopathology and clinical chemistry of Comt -gene-disrupted mice were studied at the age of 12 months. Owing to the high COMT activities in liver and kidney and the role of COMT in the metabolism of catechol oestrogens, special emphasis was given to the histology of the liver, kidney and oestrogen-dependent organs such as mammary glands and uterus. The mice of both heterozygous and homozygous genotypes appear to be physically healthy and fertile. Diurnal motility rhythm and behaviour in measuring anxiety and depression were equal in all genotypes. At the age of 12 months, the body weight of homozygous mice was 7,9% lower than that of the other groups. This was re,ected in histology as a diminished incidence of vacuolation of liver cells (fatty change). Macroscopic pathology and histopathology revealed no abnormal ,ndings in any COMT genotype. The values of some clinical chemistry parameters, such as alkaline phosphatase, alanine aminotransferase, urea, glucose, calcium and proteins, were at a higher level in homozygous animals compared with the wild-type mice. However, all the values remained within the normal physiological range, and the differences in enzyme levels between genotypes were not re,ected as histopathological ,ndings in the relevant organs. No changes in haematological parameters or plasma catecholamine concentrations were noted but plasma 3,4-dihydroxyphenylethylene glycol levels were high in COMT null mice. The results suggest that the full or 50% lack of Comt gene as such is not associated with any toxic consequences. Copyright © 2003 John Wiley & Sons, Ltd. [source] Analysis of a chalcone synthase mutant in Ipomoea purpurea reveals a novel function for flavonoids: amelioration of heat stressMOLECULAR ECOLOGY, Issue 5 2003L. C. Coberly Abstract Flavonoids are thought to function in the plant stress response and male fertility in some, but not all, species. We examined the effects of a self-fertile chalcone synthase null allele, a, for the effects of heat and light stress on fertilization success and flower production in Ipomoea purpurea. Pollen recipients and pollen donors of both homozygous genotypes exhibit reduced fertilization success at high temperatures, indicating that high temperature acts as a stress-lowering fertilization success. Homozygous aa individuals exhibit reduced male and female fertilization success, compared to AA individuals, at high temperatures but not at low temperatures. In addition, aa individuals produce fewer flowers than AA individuals at low temperatures, but not at high temperatures. These results suggest that flavonoids alleviate heat stress on fertilization success. They also suggest that pleiotropic effects at the A locus may explain the low frequency of the a allele in natural populations. [source] Pyramiding of Xa7 and Xa21 for the improvement of disease resistance to bacterial blight in hybrid ricePLANT BREEDING, Issue 6 2006J. Zhang Abstract ,Minghui 63' is a restorer line widely used in hybrid rice production in China for the last two decades. This line and its derived hybrids, including ,Shanyou 63', are susceptible to bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo). To improve the bacterial blight resistance of hybrid rice, two resistance genes Xa21 and Xa7, have been introgressed into ,Minghui 63' by marker-assisted selection and conventional backcrossing, respectively. The single resistance gene-introgressed lines, Minghui 63 (Xa21) and Minghui 63 (Xa7) had higher levels of resistance to bacterial blight than their derived hybrids, Shanyou 63 (Xa21) or Shanyou 63 (Xa7). Both Xa21 and Xa7 showed incomplete dominance in the heterozygous background of rice hybrids by infection with GX325 and KS-1-21. The improved restorer lines, with the homozygous genotypes, Xa21Xa21 or Xa7Xa7, were more resistant than their hybrids with the heterozygous genotypes Xa21xa21 or Xa7xa7. To further enhance the bacterial blight resistance of ,Minghui 63' and its hybrids, Xa21 and Xa7 were pyramided into the same background using molecular marker-aided selection. The restorer lines developed with the resistance genes Xa21 and Xa7, and their derived hybrids were evaluated for resistance after inoculation with 10 isolates of pathogens from China, Japan and the Philippines, and showed a higher level of resistance to BB than the restorer lines and derived hybrids having only one of the resistance genes. The pyramided double resistance lines and their derived hybrids have the same high level of resistance to BB. These results clearly indicate that pyramiding of dominant genes is a useful approach for improving BB resistance in hybrid rice. [source] Limited application of homozygous genotypes in apple breedingPLANT BREEDING, Issue 4 2005L. Vanwynsberghe Abstract Apple is a temperate fruit species with several breeding disadvantages such as the highly heterozygous nature of the genome and a long reproductive cycle. It is expected that homozygous apple genotypes can increase breeding efficiency, but inbreeding is prevented by the gametophytic self-incompatibility mechanism. In this paper, the production and characterization of homozygous genotypes, generated from anther culture in Malus × domestica cv. ,Braeburn', is described as well as their potential for use in breeding programmes. After determination of large scale anther culture efficiency, anther culture-derived genotypes were simple sequence repeat (SSR)-fingerprinted to determine their homozygous nature and confirm their androgenic origin. Their value for breeding was estimated based on growth and fertility measurements. The use of homozygous androgenic genotypes from ,Braeburn' in apple breeding programmes is currently not a realistic approach, partly because of the low efficiency of anther culture, but mainly because of the reduced vigour and severe sterility of the androgenic genotypes produced. [source] | |||||||||||||