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At least 397 records · Page 22Linked to original sources
PubMed2006

Genetic analysis and molecular mapping of the avirulence gene PRE1, a gene for host-species specificity in the blast fungus Magnaporthe grisea.

We analyzed host-species specificity of Magnaporthe grisea on rice using 110 F1 progeny derived from a cross between the Oryza isolate CH87 (pathogenic to rice) and the Digitaria isolate 6023 (pathogenic to crabgrass). To elucidate the genetic mechanisms controlling species specificity in M. grisea, we performed a genetic analysis of species-specific avirulence on this rice population. Avirulent and virulent progeny segregated in a 1:1 ratio on the 2 rice cultivars 'Lijiangxintuanheigu' (LTH) and 'Shin2', suggesting that a single locus, designated PRE1, was involved in the specificity. In a combination between 'Kusabue' and 'Tsuyuake', the segregation of the 4 possible phenotypes of F1 progeny was significantly different from the expected 3:1:3:1 and instead fit a ratio of 2:0:1:1. This indicated that 2 loci, PRE1 and AVR2, were involved in specific parasitism on rice. These results suggest that the species specificity of M. grisea on rice is governed by species-dependent genetic mechanisms that are similar to the gene-for-gene interactions controlling cultivar specificity. Pathogenicity tests with various plant species revealed that the Digitaria isolate 6023 was exclusively parasitic on crabgrass. Genetic linkage analysis showed that PRE1 was mapped on chromosome 3 with respect to RAPD and SSR markers. RAPD marker S361 was linked to the avirulence gene at a distance of ~6.4 cM. Two SSR markers, m677-678 and m77-78, were linked to the PRE1 gene on M. grisea chromosome 3 at distances of 5.9 and 7.1 cM, respectively. Our results will facilitate positional cloning and functional studies of this gene.

Base Sequence↗
PubMed2003

Population genetic analysis of white shrimp, Litopenaeus setiferus, using microsatellite genetic markers.

The white shrimp (Litopenaeus setiferus) is a commercially and recreationally valuable species, yet little is known of its population structure or genetic diversity. White shrimp are distributed along the Atlantic coast of the United States and from the west coast of Florida to the Bay of Campeche, Mexico. In this study, shrimp were collected from North Carolina, South Carolina (four separate collections were taken from 1995 to 1999), Georgia, the Atlantic and Gulf coasts of Florida, Louisiana, Texas and Mexico. DNA was isolated from these individuals, and genetic variation was assessed at six microsatellite loci. These loci were, for the most part, highly polymorphic with an average expected heterozygosity of 0.68. Deviations from Hardy-Weinberg proportions were observed over all samples, but experimental results suggested the presence of null alleles, which confounded a biological interpretation of this result. Pairwise tests of the similarity of allele frequency distributions and distance measure analyses showed broad-scale genetic homogeneity superimposed over occasional indications of random geographical and temporal differentiation. FST and RST estimates over all loci and samples were 0.002 or less and indicated little population structure. Weak but significant genetic differentiation was evident only between pooled western Atlantic and pooled Gulf of Mexico samples. Within the Gulf of Mexico or within the western Atlantic, the large-scale genetic homogeneity observed may be a consequence of genetic mixing resulting from pelagic larvae and adult migrations, while the random local genetic differentiation may be a result of genetic sampling or experimental sampling error. The weak differentiation between shrimp from the Gulf of Mexico and the western Atlantic can be explained by a relatively recent separation of these two populations and/or small amounts of ongoing gene flow.

Animals↗
PubMed1999

Should genetic analysis in newborn screening and a heterozygote test for hyperphenylalaninaemia be recommended? An Italian study.

OBJECTIVE: To determine whether the introduction of genetic analysis for phenylalanine hydroxylase (PAH) deficiency into regional screening programmes can be supported by the benefit-cost ratio. METHOD: Tests for the genetic PAH locus were carried out in 151 patients with hyperphenylalaninaemia originally from all of the Italian regions. PAH mutations were identified by extraction of genomic DNA from leucocytes (whole blood in EDTA), PAH exon amplification was determined by polymerase chain reaction, restriction enzyme analysis was carried out for some recognised mutations, and DNA sequence analysis for the other mutations. RESULTS: It was found that the eight most common mutations in the population accounted for 49% of the mutant alleles, which is well below the required standard for effective population screening (90%). CONCLUSIONS: Genetic screening for PAH deficiency in Italy does not increase the sensitivity of the methodology and the benefit-cost ratio, and thus provides no advantage, particularly as the correlation between genotype and the metabolic phenotype needed to optimise dietary intervention is still being studied.

Amino Acid Substitution↗
PubMed1999

Genetic analysis of HLA- and HPA-typing in idiopathic (autoimmune) thrombocytopenic purpura patients treated with cepharanthin.

We performed genetic analysis of human leukocyte antigen (HLA) and human platelet antigen (HPA) in 45 patients with cepharanthin-treated idiopathic thrombocytopenic purpura. HLA-typing was performed by the polymerase chain reaction-restriction fragment length polymorphism method, and HPA-typing by a polymerase chain reaction-sequence-specific primer method. There were 14 responders and 31 nonresponders. Responders included many patients who had already been treated with prednisolone. HLA-DRB1*0901 was significantly more common in responders than in nonresponders. In contrast, HLA-DRB1*0410 and DQB1*0401 were significantly more common in nonresponders. The a/b genotype of HPA-2a/2a (Ko(b)/Ko(b)) was significantly increased in responders. In contrast, HPA-2a/2b (Ko(b)/Ko(a)) and HPA-3a/3b (Bak(a)/Bak(b)) were significantly more common in nonresponders. These findings suggest that genetic studies of HLA and HPA can predict the response of idiopathic thrombocytopenic purpura to cepharanthin.

Adult↗
PubMedDate not supplied

A genetic analysis of type 2 (non-insulin-dependent) diabetes mellitus in Punjabi Sikhs and British Caucasoid patients.

A genetic analysis of diabetic and non-diabetic Punjabi Sikhs (n = 164) was made for markers of non-insulin-dependent diabetes mellitus using insulin receptor, insulin, and HLA-D alpha chain gene probes. Additionally British Caucasoids (n = 163) were studied using the insulin receptor probe. Insulin receptor gene restriction fragment length polymorphisms were defined using Southern blot techniques and the restriction enzyme Bgl II and BAm Hl. In Punjabi Sikhs and British Caucasoids neither of the restriction fragment length polymorphisms distinguished non-insulin-dependent diabetes mellitus subjects from controls. In the Sikhs no association with non-insulin-dependent diabetes mellitus was seen with the hypervariable region of the insulin gene or with HLA-DR/DQ/DX alpha chain restriction fragment length polymorphisms. We therefore conclude that despite the high prevalence of non-insulin-dependent diabetes mellitus in Asians we were unable to find any genetic markers for this disease using the available cloned gene probes.

Diabetes Mellitus, Type 2↗
PubMed2001

Genetic analysis of cholesterol accumulation in inbred mice.

Genetic linkage analysis in the laboratory mouse identified chromosomal regions containing genes that contribute to cholesterol accumulation in the liver and plasma. Comparisons between five inbred strains of mice obtained from the Jackson Laboratory (DBA/2, AKR, C57BL/6, SJL, and 129P3) revealed a direct correlation between intestinal cholesterol absorption and susceptibility to diet-induced hypercholesterolemia. This correlation was lost in the F1 generation arising from crosses between high- and low-absorbing strains. Linkage analyses in AKxD recombinant inbred strains and 129xSJL129F1 N2 backcross mice identified four quantitative trait loci (QTL) that influenced Liver cholesterol accumulation (Lcho1-4) and one locus that affected Plasma cholesterol accumulation (Pcho1). These loci map to five chromosomes and, with one exception, are different from the seven QTL identified previously that influence intestinal cholesterol absorption. We conclude that a large number of genes affects the amount of cholesterol absorbed in the small intestine and its accumulation in the liver and plasma of inbred mice.

Animals↗
PubMed2001

Comparison of three methods for obtaining principal components from family data in genetic analysis of complex disease.

Three multivariate techniques used to derive principal components (PCs) from family data were compared for their ability to model family data and power to detect linkage. Using the simulated data from Genetic Analysis Workshop 12, the five quantitative traits were first adjusted for age, sex, and environmental factors 1 and 2. Then, standard PCs, PCs obtained from between-family covariance, and PCs obtained from within-family genetic covariance were derived and subjected to multivariate sib pair linkage analysis. The standard PCs obtained from the overall correlation matrix allowed identification of key features of the true genetic model more readily than did the other methods. For detection of linkage, standard PCs and PCs obtained from the between-family genetic covariance performed similarly in terms of both power and type 1 error, and both methods performed better than the PCs obtained from within-family genetic covariance.

Chromosome Mapping↗
PubMed2003

Lasermicrodissection--an important prerequisite for the molecular-genetic analysis of bladder cancer.

The past 10 years have shown that a crucial point in the molecular-genetic analysis of malignant tumors is the exact histopathological definition and separation of the investigated lesions. Laser microdissection has become an important tool allowing for the study of specific histological entities and defined preneoplastic lesions. Reliable detection of tumor-specific alterations can be compromised by the presence of normal cells. This requires microdissection of pure tumor cell populations (>80%), necessary for detecting chromosomal alterations by loss of heterozygosity analysis (LOH) and fluorescence in situ hybridization (FISH). The combination of microdissection and molecular methods could also be useful for studying multifocal lesions of the urothelial tract. This article describes in detail the use of laser microdissection, whole genome amplification by Improved Primer Extension Preamplification (I-PEP)-PCR and subsequent LOH, FISH, and sequencing analyses for the investigation of urothelial tumors and their precursors, e.g. dysplasias and hyperplasias. The combination of the described methods allows for a wide spectrum of molecular investigations in lesions with a limited number of tumor cells, and might help to understand the fundamental alterations involved in urothelial carcinogenesis.

Chromosome Aberrations↗
PubMed1983

Genetic analysis of B2t, the structural gene for a testis-specific beta-tubulin subunit in Drosophila melanogaster.

Genetic analysis of the B2t locus has resulted in the recovery of four recessive mutations in the B2t structural gene and a deficiency that deletes the locus. Two of the mutations were recovered as suppressors of B2tD, a dominant male sterile mutation at the locus, and two were induced on wild-type chromosomes. All four mutant genes encode beta 2-tubulin subunits that are synthesized at normal rates but do not accumulate. All mutants are completely male sterile as homozygotes.

Animals↗
PubMed2002

Genetic analysis of tissue aging in Caenorhabditis elegans: a role for heat-shock factor and bacterial proliferation.

The genetic analysis of life span has revealed many interesting genes and pathways; however, our understanding of aging has been limited by the lack of a way to assay the aging process itself. Here we show that the tissues of aging worms have a characteristic appearance that is easy to recognize and quantify using Nomarski optics. We have used this assay to determine whether life-span mutations affect the rate of aging, to identify animals that age more rapidly than normal, and to infer the cause of death in C. elegans. Mutations that reduce insulin/IGF-1 signaling double the life span of C. elegans, and we find that tissue decline is slowed in these mutants. Thus this endocrine system appears to influence the rate at which tissues age. This effect extends even to the germline, which is the only mitotically active tissue in the adult. We find that Nomarski microscopy also allows a ready distinction between short-lived mutants that age more rapidly than normal and those that are simply sick, and we have identified an RNAi clone that confers a dramatic rapid-aging phenotype. This clone encodes the C. elegans heat-shock factor (HSF), a transcription factor that regulates the response to heat and oxidative stress. This suggests that heat-shock proteins, many of which act as chaperones, may function in normal animals to slow the rate of aging. Finally, we have identified a cause of death of C. elegans: namely, proliferating bacteria. This suggests that increased susceptibility to bacterial infections contributes to mortality in these animals, just as it does in humans.

Aging↗
PubMed2001

[Consequences of clinical genetic analysis of RET proto-oncogene].

Preliminary results of treatment of inherited medullary thyroid carcinoma, diagnosed primarily with genetic analysis of mutation of protooncogene RET are presented. Among 16 carriers of mutation identical with mutation diagnosed earlier in proband, there were 4 patients with clinically obvious medullary thyroid carcinoma and 12 asymptomatic carriers. In all patients, in whom calcitonin level was increased preoperatively, its normalization was obtained. The paper summarizes these aspects of cooperation between geneticians and physicians in which diagnostic results influence clinical decisions (indication and time of thyroid and lymph nodes surgery and it's spectrum, range of diagnostic procedures towards pheochromocytoma and parathyroid hyperplasia in relation to the found mutation).

Adolescent↗
PubMed2001

[Ethical issues in relation to genetic analysis research].

On April 2000, the so-called Millennium project which was launched by Japanese Government has started. Genetic research is one of the important subject in this project. Since there has been no official guideline for ethical issues in relation to genetic analysis research, Ministry of Health and Welfare arranged a special committee to prepare such a guideline. The process and key points of this guideline which has been published on April 2000 by Ministry of Health and Welfare was described.

Bioethics↗
PubMed2001

Complementation of the Magnaporthe grisea deltacpkA mutation by the Blumeria graminis PKA-c gene: functional genetic analysis of an obligate plant pathogen.

Obligate plant-pathogenic fungi have proved extremely difficult to characterize with molecular genetics because they cannot be cultured away from host plants and only can be manipulated experimentally in limited circumstances. Previously, in order to characterize signal transduction processes during infection-related development of the powdery mildew fungus Blumeria graminis (syn. Erysiphe graminis) f. sp. hordei, we described a gene similar to the catalytic subunit of cyclic AMP-dependent protein kinase A (here renamed Bka1). Functional characterization of this gene has been achieved by expression in a deltacpkA mutant of the nonobligate pathogen Magnaporthe grisea. This nonpathogenic M. grisea deltacpkA mutant displays delayed and incomplete appressorium development, suggesting a role for PKA-c in the signal transduction processes that control the maturation of infection cells. Transformation of the deltacpkA mutant with the mildew Bka1 open reading frame, controlled by the M. grisea MPG1 promoter, restored pathogenicity and appressorium maturation kinetics. The results provide, to our knowledge, the first functional genetic analysis of pathogenicity in an obligate pathogen and highlight the remarkable conservation of signaling components regulating infection-related development in pathogenic fungi.

Archaeal Proteins↗
PubMed1999

[Genetic analysis of anatomical and morphologic traits of the brain, determined by magnetic resonance imaging in families of schizophrenic patients].

Genetic analysis of clinical data and data obtained by magnetic resonance imaging (MRI) on 26 families of schizophrenic patients (26 probands who were patients with schizophrenia, 47 parents, and 15 siblings) revealed an enlargement of the ventricular brain system both in probands and their affected and healthy relatives. Most MRI parameters had high coefficients of inheritance and tended to be linked with positive and negative psychopathological symptoms. Our results confirm the hypothesis of genetic predisposition to the structural changes in the brains of schizophrenic patients and suggest that such MRI characteristics as the width of the anterior horn of the left lateral ventricle in the region of the caudate nucleus, the width of the central region of the left lateral ventricle, the width of the anterior horn of the right lateral ventricle in the region of the caudate nucleus, and the width of the central region of the right lateral ventricle may serve as a marker of predisposition to schizophrenia.

Adult↗
PubMed2001

[Genetic analysis in familial adenomatous polyposis].

BACKGROUND: Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited disorder caused by germline mutations in the APC gene. FAP is characterised by a variable, but normally large number of colorectal adenomas and variations in extracolonic manifestations. These variations are associated with specific mutations of the APC gene. MATERIAL AND METHODS: Representatives from 70 Norwegian families are under molecular investigation. Analyses have so far been concentrated on the part of the APC gene associated with classic FAP. RESULTS: Germline mutations causing FAP have been identified in 36 of the 70 families examined. All mutations identified are confined to the first half of the gene and correlate to classic FAP. INTERPRETATION: Because of the mutation heterogeneity in FAP, the size of the APC gene and variations in phenotype, it is a laborious task to identify the causative mutations. Better approaches to the analysis of the whole APC have now been established and will result in a higher degree of mutation detection independent of phenotype. Family history and phenotype-genotype correlations are still important guidelines for efficient molecular genetic analysis of the APC gene. Genetic surveillance, personal and socio-economic benefits from presymptomatic and predictive testing of members of FAP families are discussed.

Adenomatous Polyposis Coli↗
PubMed1993

Influencing the influenza virus: genetic analysis and engineering of the negative-sense RNA genome.

The genome of influenza virus has become amenable to genetic analysis as a result of newly developed methods for reconstitution of the ribonucleoprotein (RNP) complex. This allows a dissection of the regulatory signals and promoters required for transcription and replication of the viral genome. The ability to rescue chimeric viruses in vivo after transfection opens up a way to engineer viruses suitable for human immunization and carrying desirable antigenic determinants.

Base Sequence↗
PubMed1986

Genetic analysis workshop IV: insulin dependent diabetes mellitus--summary.

The Insulin Dependent Diabetes Mellitus (IDDM) study was one of the topics of Genetic Analysis Workshop IV (GAW IV) discussed October 7 - 8 at a pre-workshop meeting and presented October 9, 1985 at the American Society of Human Genetics meeting in Salt Lake City. The aim of the study was to have different groups analyze an identical body of real data in order to compare their analytical methods and the results based on their different approaches. This summary describes the available datasets and presents the main results of the nine participating groups. The detailed descriptions of analytical methods and results are presented in the individual papers following this overview. Although differing analytical methods were used there were no discrepancies regarding the interpretation of the data. Whereas the presented gametic associations were well established before, the real gain of this workshop was the unanimous result that the recessive 2-allele-model with incomplete penetrance had to be rejected and at least a 3-allele-model with differing susceptibility alleles and differing penetrances for heterozygotes and homozygotes had to be postulated for the transmission of IDDM.

Alleles↗