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At least 955 records · Page 53Linked to original sources
PubMed1979

Restriction mapping of DNA of temperate Rhizobium meliloti phage 16-3: comparison of genetic and physical maps indicates a long, genetically silent chromosomal arm.

The complete restriction map of DNA (61.57 Kb) of temperate Rhizobium meliloti phage 16-3 has been constructed for enzymes BglII, HindIII, HpaI, KpnI, and a partial map for EcoRI. The strategy employed for mapping included the analysis of double, triple and partial digests; comparison of wild type and deletion mutants; and detailed analysis of subfragments, exploiting the presence of cohesive ends of the phage. Comparison of the genetic and physical maps indicates that one arm of the chromosome is genetically silent and/or contains nonessential genes.

Bacteriophages↗
PubMed1992

Comparison of glutamine synthetases from brains of genetically epilepsy prone and genetically epilepsy resistant rats.

Since glutamine synthetase (GS) has been proposed as the primary enzyme in the regulation of glutamate metabolism in the central nervous system and since inhibition of the activity of this enzyme in vivo leads to seizures, it has been proposed that an abnormality in the structure or function of this enzyme could be responsible for the induction of seizures in epilepsy prone rats. To test this hypothesis the glutamine synthetases were purified from the brains of both genetically epilepsy prone rats (GEPR) and their progenitors, genetically epilepsy resistant rats (GERR). The enzymes were compared using both SDS-PAGE and isoelectric focusing. The immunoreactivities of equal amounts of protein were determined using the ELISA technique, and the regulation of the glutamine synthetase activities by Mn2+/Mg2+ ratios were compared. The only difference found between the glutamine synthetases from the two strains was a slightly lower specific activity of the enzyme from the epilepsy prone animals.

Animals↗
PubMed2002

Analysis of genetic effects of major genes and polygenes on quantitative traits. II. Genetic models for seed traits of crops.

Genetic models for quantitative seed traits with effects of several major genes and polygenes, as well as their GE interaction, were proposed. Mixed linear model approaches were suggested for analyzing the genetic models. Monte Carlo simulations were conducted to evaluate unbiasedness and efficiency for estimating fixed effects and variance components of the embryo and the endosperm models, including effects of a major gene from an unbalanced modified diallel mating design with nine parents, respectively. Simulation results showed that estimates of generalized least squares (GLS) were unbiased and efficient, while those of ordinary least squares (OLS) were almost as good as GLS. Minimum norm quadratic unbiased estimation (MINQUE) could obtain unbiased estimates of the variance components. It was also suggested that precision of MINQUE estimation would be improved with augmentation of experimental size. Data from a modified diallel design in upland cotton ( Gossypium hirsutum L.) were used as a worked example to illustrate the parameter estimation.

Journal Article↗
PubMed2005

Isolation by genetic and physiological characteristics of a fuel-ethanol fermentative Saccharomyces cerevisiae strain with potential for genetic manipulation.

Fuel ethanol fermentation process is a complex environment with an intensive succession of yeast strains. The population stability depends on the use of a well-adapted strain that can fit to a particular industrial plant. This stability helps to keep high level of ethanol yield and it is absolutely required when intending to use recombinant strains. Yeast strains have been previously isolated from different distilleries in Northeast Brazil and clustered in genetic strains by PCR-fingerprinting. In this report we present the isolation and selection of a novel Saccharomyces cerevisiae strain by its high dominance in the yeast population. The new strain, JP1 strain, presented practically the same fermentative capacity and stress tolerance like the most used commercial strains, with advantages of being highly adapted to different industrial units in Northeast Brazil that used sugar cane juice as substrate. Moreover, it presented higher transformation efficiency that pointed out its potential for genetic manipulations. The importance of this strain selection programme for ethanol production is discussed.

Acids↗
PubMed1982

Psychogenic factors in some genetic and non-genetic forms of infertility.

Five categories of patients suffering from different genetic and non-genetic forms of infertility and three categories of similarly affected, but potentially fertile, clinically normal individuals were studied. The Eysenck's Personality Inventory (1964), Ryle's Marital Patterns Test (1966) and Leckie and Wither's Inventory for Depressive Illness (1967) were used to determine the role played by psychogenic factors in causing infertility. No significant quantitative or qualitative differences were observed in the various groups studied. The psychogenic disturbances present in these individuals appear to be the result of the effect of persisting infertility rather than the cause of it.

Anovulation↗
PubMed1985

Thermal preference behavior of genetically obese (ob/ob) and genetically lean (+/?) mice.

Chronically lower colonic temperatures (TcS) of genetically-obese (ob/ob) mice at ambient temperatures below thermoneutrality have led to speculation that these mutants regulate a lowered thermal setpoint relative to lean mice. Previous experiments, however, have not provided an opportunity for obese mice to exhibit compensatory thermoregulatory behaviors which might reinstate normal body temperature. In the present experiment, adult obese and lean (+/?) mice were tested at room temperature (25 degrees C) on a copper bar, thermal gradient to determine what temperatures they would select and what effect their selection would have on their TcS. The data revealed that ob/obs were more frequently observed within 25-35 degrees C locales than were lean controls, which spent more time in the below-25 degrees C zone (p less than 0.005). Ob/obs also raised their TcS to pretest values of leans' TcS, although ob/obs' TcS remained significantly lower than those of leans at the conclusion of testing. These data suggest that the hypothermia exhibited by the ob/ob may reflect both the absence of the opportunity to behaviorally thermoregulate and a genetic defect in thermogenesis.

Animals↗
PubMed1979

Aging, genetics, and the environment: potential of errors introduced into genetic information transfer by metal ions.

Metal ions, which are introduced into living organisms from the environment, are required in every aspect of genetic information transfer. However, the "wrong" metal ion, or even the "right" metal ion in the wrong concentration, can produce deleterious information transfer effects. Metal ions react with nucleic acids in many different ways, and virtually all of these reactions effect major changes in the structure of the nucleic acids. Cellular metal ion concentrations change with age. The effects of such concentration changes on genetic information transfer suggest the possibility that metal ions can influence the aging process. A specific example of such influence is the accumulation in brain cells of aluminum ions, which may have a relationship to Alzheimer's disease.

Aging↗
PubMed1990

Cloning of the human genomic amiloride-sensitive Na+/H+ antiporter gene, identification of genetic polymorphisms, and localization on the genetic map of chromosome 1p.

We have cloned and mapped a 90-kb region spanning the human genomic amiloride-sensitive Na+/H+ antiporter gene on overlapping cosmid clones. This cloned region extends 27 kb upstream of the 5' end of the longest antiporter cDNA and reveals a primary transcription unit of at least 60 kb. Using these genomic clones we have identified polymorphisms in the antiporter gene in human genomic DNA cleaved with enzymes TaqI and MspI; both are two-allele systems. We have localized both polymorphisms to the same segment within an intron of the antiporter transcription unit. Observed heterozygosity for both markers is 47% in 175 unrelated individuals, with the two polymorphic systems showing complete linkage disequilibrium. We have determined genotypes at the antiporter locus in 667 individuals in 59 reference families. Linkage analysis using 28 other markers on human chromosome 1 precisely locates the antiporter gene (locus APNH) on the genetic map of 1 p. The antiporter gene is closely flanked by two highly informative loci, lying 3 cM proximal to the rhesus blood group locus (Rh) and 4 cM distal to the anonymous DNA marker CMM8 (locus D1S79). These antiporter polymorphisms and informative flanking markers will prove useful in genetic linkage studies employing the antiporter gene.

Amiloride↗
PubMed2026

Mining of important genetic loci and evaluation of genetic effects for growth traits in Baicheng You Chicken.

The Baicheng You Chicken is a precious indigenous breed in Xinjiang, China, prized for its strong disease and stress resistance and superior meat quality. However, the lack of scientific breeding and conservation has led to poor production performance, particularly in growth traits. In this study, we collected phenotypic and whole-genome resequencing data from 1,535 18-week-old Baicheng You Chickens (180 males and 1,355 females). After stringent quality control (SNP call rate > 95%, minor allele frequency > 1%), we constructed the breed's first comprehensive SNP-based genome-wide variation map, which comprised 2,020,743 high-quality SNPs across the genome. The filtered SNPs had high mapping quality (99.73% mapped to the bGalGal1.mat.broiler.GRCg7b reference genome, Q30 = 93.26%) and a reasonable Ti/Tv ratio (2.596), guaranteeing the reliability of subsequent analyses. We estimated genetic effects (SNP-based heritability and phenotypic variance explained (PVE) by individual loci) via the restricted maximum likelihood (REML) method, and performed a genome-wide association study (GWAS) using a mixed linear model (MLM) - with sex as a fixed effect and principal components to correct for population stratification - to identify significant loci and their effect sizes (Beta). All eight growth traits showed moderate to high heritability: body weight (BW) had the highest heritability (0.86±0.11), while chest width (CW, 0.41±0.08) and body slanting length (BSL, 0.43±0.09) were the lowest; keel length (KL), chest girth (CG), pelvic width (PW), chest depth (CD) and shank length (SL) had heritabilities of 0.50±0.09, 0.46±0.09, 0.54±0.09, 0.67±0.10 and 0.74±0.10, respectively. GWAS identified 145 significant SNPs, with a maximum Beta value of 0.39 and PVE ranging from 1.25% to 6.25%. We annotated 22 candidate genes, with TAPT1, IGF2BP1, ADGRB3, LDB2, NCAPG and LCORL as key candidates. These quantifiable genetic markers and effect estimates provide direct targets for marker-assisted selection (MAS) and valuable resources for future genomic selection (GS) programs, offering a practical approach to improve the breed's slow growth while preserving its unique meat quality.

Baicheng You Chicken↗
PubMed2000

PTEN mutation analysis in two genetic subtypes of high-grade oligodendroglial tumors. PTEN is only occasionally mutated in one of the two genetic subtypes.

We recently identified two genetic subtypes of high-grade oligodendroglial tumors (HG-OT): 1p-/19q- HG-OT are characterized by a loss of chromosome 1p32-36 (del(1)(p32-p36) and/or a del(19)(q13. 3); whereas +7/-10 HG-OT harbor a gain of chromosome 7 (+7) and/or a -10 without a loss of 1p32-36 and 19q13.3. Because a -10 and a +7 are most frequently detected in glioblastomas (GBM), the genotype of +7/-10 HG-OT suggests that these tumors are GBM with a prominent oligodendroglial phenotype rather than anaplastic oligodendrogliomas. PTEN is a tumor suppressor gene, located at 10q23.3, which is involved in tumor progression of GBM and other neoplasms. In this study, we screened for PTEN mutations in six low-grade oligodendroglial tumors (LG-OT), five 1p-/19q- HG-OT, seven +7/-10 HG-OT, and nine xenografted GBM. PTEN mutations were detected in none of the LG-OT and 1p-/19q- HG-OT, once in +7/-10 HG-OT, and frequently in GBM. As one of the +7/-10 HG-OT harbored a PTEN mutation, this demonstrates that PTEN can be involved in the oncogenesis of this genetic subtype of HG-OT. The lower frequency of PTEN mutations in +7/-10 HG-OT compared to GBM suggests that these tumors are of a distinct tumor type rather than GBM. Published by Elsevier Science Inc.

Brain Neoplasms↗
PubMed2001

Restoration of genetic variation lost - the genetic rescue hypothesis.

It has been long known that immigrants from surrounding populations might prevent the extinction of small populations, a process known as the 'rescue effect'. This focuses on the demographic effects of migration through the direct positive influence that immigrants have on abundance of the recipient population. Now, two recent papers have indicated another potentially important way that migration might rescue populations from extinction - replenishing genetic variation and reducing inbreeding depression, or what has been termed 'genetic rescue'.

Journal Article↗
PubMed1979

Dependency of concordance probability on gene frequencies in genetic systems for the diagnosis of twin zygosity. A graphical presentation enabling the rapid, optimal choice of genetic system.

The dependency of probabilities of phenotypic concordance of gene frequencies in three-allele genetic systems is presented. A graphical display enables the rapid comparison of the relative effectiveness of different systems, taking into account dominance relationships within each genetic system. Four or more allele systems can also be approximated, while two-allele systems are considered to be special cases of three-allele ones.

Alleles↗
PubMed1996

Genetic analysis of Drosophila virilis sex pheromone: genetic mapping of the locus producing Z-(11)-pentacosene.

Z-(11)-pentacosene, Drosophila virilis sex pheromone, is predominant among the female cuticular hydrocarbons and can elicit male courtship behaviours. To evaluate the genetic basis of its production, interspecific crosses between D. novamexicana and genetically marked D. virilis were made and hydrocarbon profiles of their backcross progeny were analysed. The production of Z-(11)-pentacosene was autosomally controlled and was recessive. Of the six D. virilis chromosomes only the second and the third chromosomes showed significant contributions to sex pheromone production, and acted additively. Analysis of recombinant females indicated that the locus on the second chromosome mapped to the proximity of position 2-218.

Alkenes↗
PubMed2000

Clouston hidrotic ectodermal dysplasia (HED): genetic homogeneity, presence of a founder effect in the French Canadian population and fine genetic mapping.

HED is an autosomal dominant skin disorder that is particularly common in the French Canadian population of south-west Quebec. We previously mapped the HED gene to the pericentromeric region of chromosome 13q using linkage analysis in eight French Canadian families. In this study, we extend our genetic analysis to include a multiethnic group of 29 families with 10 polymorphic markers spanning 5.1 cM in the candidate region. Two-point linkage analysis strongly suggests absence of genetic heterogeneity in HED in four families of French, Spanish, African and Malaysian origins. Multipoint linkage analysis in all 29 families generated a peak lod score of 53.5 at D13S1835 with a 1 lod unit support interval spanning 1.8 cM. Recombination mapping placed the HED gene in a 2.4 cM region flanked by D13S1828 proximally and D13S1830 distally. We next show evidence for a strong founder effect in families of French Canadian origin thereby representing the first example of a founder disease in the south-west part of the province of Quebec. Significant association was found between HED in these families and all markers analysed (Fisher's exact test, P < 0.001). Complete allelic association was detected at D13S1828, D13S1827, D13S1835, D13S141 and D13S175 (P(excess) = 1) spanning 1.3 cM. A major haplotype including all 10 associated alleles was present on 65% of affected chromosomes. This haplotype most likely represents the founder haplotype that introduced the HED mutation into the French Canadian population. Luria-Delbrück equations and multipoint likelihood linkage disequilibrium analysis positioned the gene at the D13S1828 locus (likely range estimate: 1.75 cM) and 0.58 cM telomeric to this marker (support interval: 3.27 cM) respectively.

Alleles↗
PubMed2000

EUROGAPPP PROJECT 1999 - 2000 Public and Professional Policy Committee (PPPC)* Population genetic screening programmes: Proposed recommendations of the European Society of Human Genetics.

Due to an oversight, no page numbers were given to the ESHG Public and Professional Policy Committee report, published in European Journal of Human Genetics volume 8, number 9. This has led to several enquiries by our readership on how to refer to the report. As a service to our readers, it was decided to republish the report in this issue, with proper page numbers assigned. European Journal of Human Genetics (2000) 8, 998-1000.

Journal Article↗
PubMed1999

Spatial and temporal genetic structure in chloroplast and allozyme markers in phacelia dubia implicate genetic drift

For neutral genes, uniparental inheritance is expected to reduce effective population size relative to biparentally inherited genes. In finite populations, the ensuing genetic drift can cause stronger spatial and temporal differentiation. An intrapopulation polymorphism in chloroplast DNA was used to examine relative spatial and temporal population structure of chloroplast and allozyme markers in the annual plant Phacelia dubia. There was significant differentiation among populations at chloroplast markers but not for allozyme loci. A fine-scale analysis showed significant structure among sites within populations for chloroplast markers and local heterozygote deficiencies at allozyme loci. These spatial analyses suggest that gene flow via pollen exceeds that via seed. Temporal variation in chloroplast markers, assessed over a 10-year period, was evident in two of four populations, and allozyme loci were characterized by temporal variation in rare-allele frequencies. Population structure appeared to be related to the intensity and type of human disturbance influencing each population. Habitat destruction promoted isolation and enhanced differentiation, whereas mowing increased seed dispersal and reduced differentiation for chloroplast markers. At this time, genetic drift appears to be the primary force shaping chloroplast gene frequencies.

Journal Article↗
PubMed1999

Genetic clustering of bovine viral diarrhoea viruses in cattle farms: genetic identification and analysis of viruses directly from cattle sera.

The herd-specific genetic clustering of bovine viral diarrhoea virus (BVDV) was studied by phylogenetic analysis of 42 sera collected between 1995-97 from persistently infected cattle on 16 farms in Sweden. The viruses were typed by sequencing a part of the 5' untranslated region of the genome, which had been amplified directly from serum by reverse transcription-polymerase chain reaction. All of the viruses were of BVDV I, either BVDV Ia (NADL-like) or BVDV Ib (Osloss-like) genotypes. No relationship was observed between the geographic region of origin and the character of clinical signs and the typing of the BVDV isolates. However, the phylogenetic analysis revealed a strict herd-specific genetic clustering of the virus. In 15 of the 16 herds, animals were infected with a single strain of BVDV characteristic for that herd. Direct nucleotide sequence analysis from serum can therefore be used as a tool for molecular epizootiology of BVDV infections.

Animals↗
PubMed1983

Genetic-economic evaluation of traits in a broiler enterprise: the relative genetic-economic values.

Selection for growth rate and food utilisation (assuming annual genetic gains of 3 and 1.5% respectively) have about the same economic value and account for 94.3% of the annual potential economic savings in the production costs of an integrated broiler enterprise. Selection for more hatching eggs (annual genetic gain of 1.7 eggs) accounts for only 4.2% and selection for fertility, hatchability and reduced mortality have a value of less than 1% each. The introduction of the dwarf gene (dw) has a questionable economic value. Even if growth rate and fertility are not reduced by using dwarf females, the economic importance will equal no more than two generations of selection for growth rate. As egg production increases, the relative economic value of growth rate and food utilisation will increase, while the advantage of using dwarf females will decrease. Both body weight and body fat content (which are correlated with food utilisation) are moderately heritable and if body fat can be measured reliably in live birds, this may aid breeding for economic advantage.

Adipose Tissue↗