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Inheritance Mode (inheritance + mode)
Selected AbstractsInheritance mode and realized heritability of resistance to imidacloprid in the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2009Yan Hua Wang Abstract BACKGROUND: The brown planthopper, Nilaparvata lugens (Stål), is a serious pest that causes enormous losses to the rice crop in Asia. The genetic basis of imidacloprid resistance was investigated in N. lugens. RESULTS: The resistant strain, selected for imidacloprid resistance from a field population of N. lugens collected from Nanjing, Jiangsu Province, China, showed a 964-fold resistance compared with the laboratory strain. Progenies of reciprocal crosses (F1 and F1,) showed similar dose,mortality responses (LC50) to imidacloprid, and also exhibited a similar degree of dominance (D), 0.58 for F1 and 0.63 for F1,. Chi-square analyses of self-bred and backcross progenies (F2, F2, and BC respectively) rejected the hypothesis for a single gene control of the resistance. The estimated realized heritability (h2) of imidacloprid resistance was 0.1141 in the resistant strain of N. lugens. CONCLUSION: The results showed that imidacloprid resistance in N. lugens was autosomal and was expressed as an incompletely dominant trait, probably controlled by multiple genes. Copyright © 2009 Society of Chemical Industry [source] Aggressive periodontitis is likely influenced by a few small effect genesJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2009Flavia M. De Carvalho Abstract Aim: To evaluate the inheritance mode of aggressive periodontitis in a collection of families with a similar geographic origin. Materials and Methods: Segregation analysis was performed in pedigree data from 74 families by the use of the SEGREG program of SAGE v.5.4.2. Homogeneous no transmission, homogeneous Mendelian transmission, homogeneous general transmission, semi-general transmission and heterogeneous general transmission models were tested assuming the prevalence of aggressive periodontitis as 1% and no deviations from Hardy,Weinberg equilibrium. The parameters of the model were estimated by the method of maximum likelihood, which provides the overall ln (likelihood), -2ln and the AIC (Akaike's score) for each model. The likelihood ratio test (LRT) was used to compare each model against a fully general model (p>0.05). Results: The most parsimonious mode of inheritance was the semi-general transmission model that allows the heterozygote transmission probability to vary. Conclusion: This result provides strong support for the hypothesis that genetic factors play a role in aggressive periodontitis and that a few loci, each with relatively small effects, contribute to aggressive periodontitis, with or without interaction with environmental factors. [source] Reproductive barriers between two sympatric beetle species specialized on different host plantsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 11 2009H.-J. XUE Abstract Knowledge on interspecific pre- and post-zygotic isolation mechanisms provides insights into speciation patterns. Using crosses (F1 and backcrosses) of two closely related flea beetles species, Altica fragariae and A. viridicyanea, specialized on different hosts in sympatry, we measured: (a) the type of reproductive isolation and (b) the inheritance mode of preference and host-specific performance, using a joint-scaling test. Each species preferred almost exclusively its host plant, creating strong prezygotic isolation between them, and suggesting that speciation may occur at least partly in sympatry. Reproductive isolation was intrinsic between females of A. fragariae and either A. viridicyanea or F1 males, whereas the other crosses showed ecologically dependent reproductive isolation, suggesting ecological speciation. The genetic basis of preference and performance was at least partially independent, and several loci coded for preference, which limits the possibility of sympatric speciation. Hence, both ecological and intrinsic factors may contribute to speciation between these species. [source] Isolation, Characterization and Preliminary Genetic Analysis of Laboratory Tricyclazole-resistant Mutants of the Rice Blast Fungus, Magnaporthe griseaJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2006C. Q. Zhang Abstract The minimum inhibitory concentration of tricyclazole for hyphal melanization (MIC-H) was adopted to detect the sensitivity of 129 Magnaporthe grisea isolates collected in China in 2000. Results showed that the mean MIC-H was 0.2 ,g/ml and no isolate with a MIC-H ,1 ,g/ml was detected. Therefore, 1 ,g/ml was chosen as a discriminatory dose to identify resistant mutants generated by ultraviolet (UV) radiation. Only three low-level resistant (R) mutants derived from the sensitive (S) isolate TH16 were obtained. In addition, fitness decrease was observed for all mutants, with lower sporulation ability and pathogenicity to rice than that of the wild strain TH16. Four crosses between S × R and S × S were tested to determine the inheritance mode of resistance during the process of sexual recombination by analysing the sensitivity of hybrid F1 progeny to tricyclazole. Progeny of crosses between a tricyclazole-sensitive strain and tricyclazole-resistant mutants segregated in a 1 : 1 (R : S) ratio and no segregation was found in the cross of S × S, indicating that each mutant contained a single gene for resistance. No nucleotide differences leading to amino acid changes in the coding sequences for 1,3,6,8-tetrahydroxynaphthalene reductase (4HNR) and 1,3,8-trihydroxynaphthalene reductase (3HNR) were found between resistant mutants and sensitive strains. Therefore, it is preliminarily concluded that tricyclazole resistance in M. grisea was conferred by a one-locus mutation in a single Mendelian gene other than those encoding for 4HNR or 3HNR. [source] Rapid genetic analysis of oculocutaneous albinism (OCA1) using denaturing high performance liquid chromatography (DHPLC) systemPRENATAL DIAGNOSIS, Issue 5 2006Shin-Yu Lin Abstract Objectives To present the prenatal genetic diagnoses and counseling for two cases of oculocutaneous albinism (OCA) type I family by detection of mutations in the OCA1 gene by denaturing high performance liquid chromatography (DHPLC) system and a review of the literature. Methods All DNA samples were extracted from peripheral whole blood and amniocentesis-derived cells. Mutation analysis was performed for all five coding exons of the TYR gene, which were amplified by PCR. DHPLC was used for heteroduplex detection and sequence analysis was performed to demonstrate the mutation loci. Results Case 1: After sampling of blood from the family members and performing amniocentesis of the fetus, it was demonstrated that the affected boy and the female fetus were shown to be compound heterozygotes for mutations in the TYR gene. In addition, it was shown that the parents were carriers of the two mutations. However, the couple chose to keep the baby. Case 2: Mutation analysis of the DNA of the siblings revealed two heterozygous mutations in the TYR gene. Her husband is free of the disease. According to the principles of autosomal recessive inheritance, the incidence of affected offspring is very low. Conclusions Herein we introduce a novel application for molecular diagnostic of DHPLC coupled with direct sequencing, which can provide an effective and exact diagnosis in patients with albinism. Clinicians should be cognizant of the risk of OCA inheritance by the offspring through careful identification of genetic mutations and the inheritance mode, both important to ensure comprehensive genetic counseling. Copyright © 2006 John Wiley & Sons, Ltd. [source] Familial essential tremor with apparent autosomal dominant inheritance: Should we also consider other inheritance modes?MOVEMENT DISORDERS, Issue 9 2006Shaochun Ma MD Abstract A positive family history is present in many patients with essential tremor (ET), but twin studies and segregation analysis have suggested that ET is not entirely a genetic disorder. Two genetic loci have been identified in autosomal dominant (AD) ET and polymorphisms in the DRD3 and HS1-BP3 genes have been proposed as the possible susceptibility factors for ET. There is also evidence for further genetic heterogeneity. We evaluated 4 unrelated large kindreds with ET with an apparent AD mode of transmission. Each kindred spanned at least 3 generations and contained at least 13 living affected subjects who met criteria for definitive ET. None of the pedigrees had evidence for inheritance of ET from both parents. Known genetic ET loci were excluded in these families. We detected a preferential transmission of ET in every kindred and the proportion of affected offspring varied from 75% to 90% (P < 0.05) in the generations with complete ascertainment. Our data indicate that non-Mendelian preferential transmission of an affected allele is a feature in many ET kindreds with multiple affected members and an apparent AD mode of inheritance. ET may have a complex etiology. Additional genetic models need to be considered, including an interaction of susceptibility genes and environmental risk factors. © 2006 Movement Disorder Society [source] | |||||||||||||