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Results for “Genetic analysis”

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At least 271 records · Page 15Linked to original sources
PubMed1995

Ethanol-induced anesthesia in inbred strains of long-sleep and short-sleep mice: a genetic analysis of repeated measures using censored data.

We present a repeated-measures, genetic analysis of ethanol-induced anesthesia (sleep time) in mice from the inbred long-sleep (ILS) and short-sleep (ISS) strains of mice and their derived F1 and F2 generations. Mice (total N > 1300) were administered a 4.1 g/kg intraperitoneal dose of ethanol at two times, 7 to 10 days apart. A method suggested by Cohen was used to analyze the resulting data, which contained a known number of unmeasured observations. A genetic model that included both additive and epistatic parameters fitted the adjusted data well. A novel procedure for estimating heritability, based on a comparison of repeatability coefficients from the isogenic and genetically segregating populations, was also employed. Results of this analysis suggested that the heritability for individual measurements of sleep time is about .30, whereas the heritability of average scores is about .40. Results of this analysis also confirm that the ILS and ISS strains differ for genes at seven or more loci that influence sleep time. Since the ILS and ISS were derived by inbreeding the LS and SS lines, these results further suggest that almost all of the genetic variation present in the selected lines have been maintained in the ILS and ISS strains.

Animals↗
PubMed2001

High-throughput genetic analysis using time-resolved fluorometry and closed-tube detection.

Robust methods for genetic analysis are required for efficient exploitation of the constantly accumulating genetic information. We describe a closed-tube genotyping method suitable for high-throughput screening of genetic markers. The method is based on allele-specific probes labeled with an environment-sensitive lanthanide chelate, the fluorescence intensity of which is significantly increased upon PCR amplification of a complementary target. Genomic DNA samples were analyzed in an insulin gene single nucleotide polymorphism (SNP) assay using universal amplification primers and probes that recognized the two different alleles. The feasibility of dry reagent based all-in-one PCR assays was tested using another diabetes-related genetic marker, human leukocyte antigen DQB1 allele *0302 as a model analyte in a dual-color, closed-tube end-point assay. There was a 100% correlation between the novel SNP assay and a conventional PCR restriction fragment length polymorphism assay. It was also demonstrated that using real-time monitoring, accurate genotyping results can be obtained despite strongly cross-reacting probes, minimizing the time and effort needed for optimization of probe sequence. Throughput can be maximized by using predried PCR mixtures that are stable for at least 6 months. This homogenous, all-in-one dry reagent assay chemistry permits cost-effective genetic screening on a large scale.

Alleles↗
PubMed2000

Prenatal diagnosis and genetic analysis of X chromosome polysomy 49, XXXXY.

We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a 49,XXXXY fetus. A 31-year-old, primigravida woman was referred for genetic counselling at 17 weeks' gestation with the sonographic findings of intrauterine growth retardation, generalized oedema, a large septated cystic hygroma colli measuring 5x4 cm, and abnormal posturing of the lower extremities. Quantitative fluorescent polymerase chain reaction (QF-PCR) with small tandem repeat (STR) markers specific for chromosome X and a pentanucleotide marker X22 for the Xq/Yq pseudoautosomal region PAR2 rapidly detected the X-chromosome polysomy from amniotic fluid cells. This abnormality appeared to arise from successive non-disjunction during maternal meiosis I and meiosis II. Cytogenetic analysis revealed a karyotype of 49,XXXXY. Our case shows that a 49,XXXXY fetus in the second trimester may demonstrate hydrops fetalis and a large septated cystic hygroma colli by prenatal ultrasound. Our case also shows that QF-PCR assays with sex chromosome specific STR markers provide rapid prenatal diagnosis of numerical sex chromosome aneuploidy as well as its genetic cause in fetal cystic hygroma.

Abnormalities, Multiple↗
PubMed2006

Collection of pedigree data for genetic analysis in isolate populations.

Pedigree data are useful for a wealth of research purposes in human population biology and genetics. The collection of extended pedigrees represents the most powerful sampling design for quantitative genetic and linkage studies of both normal and disease-related quantitative traits. In this paper we outline an approach for collecting pedigree data in stable isolate populations. As an example, the pedigree for the Jirel population, which was obtained using the methods presented, is described. The Jirel pedigree contains 2,000 study participants and more than 62,000 pairwise relationships that are informative for genetic analysis. Once such pedigrees are genetically characterized by a genome scan for a given trait, they become an invaluable resource for future genetic studies of any quantitative trait.

Female↗
PubMed1992

Genetic analysis of recombination in prokaryotes.

Bacteria provide a simple system for the genetic analysis of homologous recombination. More than twenty genes have been identified in Escherichia coli. The enzymatic activities associated with the products of many of these genes have been revealed by studies with model DNA substrates. It is now possible to pair homologous molecules in vitro and process these through defined intermediates into mature recombinants of the types predicted by genetic crosses.

Bacteria↗
PubMed1995

Genetic analysis of durations: correlated frailty model applied to survival of Danish twins.

Population studies of changes in human morbidity and mortality require models which take into account the influence of genetic and environmental factors on life-related durations, such as age at onset of the disease or disability, age at death, etc. In this paper we show how a bivariate survival model based on the concept of correlated individual frailty can be used for the genetic analysis of durations. Six genetic models of frailty are considered and applied to Danish twin survival data. The results of statistical analysis allow us to conclude that at least 50% of variability in individual frailty is determined by environmental factors. The approach suggests a method of estimation of the lower bound for the biological limit of human longevity. Directions for further research are discussed.

Adult↗
PubMed1998

Genetic analysis of Xenopus transcription factor IIIA.

We describe a method for the genetic analysis of the DNA-binding properties of Xenopus transcription factor IIIA (TFIIIA). In this approach, a transcriptional activator with the DNA-binding specificity of Xenopus TFIIIA is expressed in yeast cells, where it specifically activates expression of a beta-galactosidase reporter gene containing one or more Xenopus 5 S rRNA genes that function as upstream activator sequences. This transcription-promoting activity was used as the basis for a genetic assay of Xenopus TFIIIA's DNA-binding function in yeast, an assay that we show can be calibrated quantitatively to allow the affinity of the Xenopus TFIIIA-5 S rRNA gene interaction to be deduced from measurements of beta-galactosidase activity. We have combined this genetic assay with a simple and efficient method of mutagenesis that makes use of error-prone PCR and homologous recombination to generate and screen large numbers of TFIIIA mutants for those with altered 5 S rRNA gene-binding affinity. Over 30 such mutants have been identified and partially characterized. The mutants we have obtained provide strong support for the application to intact TFIIIA of recent structural models of the N-terminal zinc fingers of the protein bound to fragments of the 5 S rRNA gene. Other mutants permit identification of important residues in more C-terminal zinc fingers of TFIIIA for which high-resolution structural information is not currently available. Finally, our results have interesting implications with respect to the mechanism of activation of transcription by RNA polymerase II in yeast.

Amino Acid Sequence↗
PubMed2006

A Thurstonian model for quantitative genetic analysis of ranks: a Bayesian approach.

A fully Bayesian method for quantitative genetic analysis of data consisting of ranks of, e.g., genotypes, scored at a series of events or experiments is presented. The model postulates a latent structure, with an underlying variable realized for each genotype or individual involved in the event. The rank observed is assumed to reflect the order of the values of the unobserved variables, i.e., the classical Thurstonian model of psychometrics. Parameters driving the Bayesian hierarchical model include effects of covariates, additive genetic effects, permanent environmental deviations, and components of variance. A Markov chain Monte Carlo implementation based on the Gibbs sampler is described, and procedures for inferring the probability of yet to be observed future rankings are outlined. Part of the model is rendered nonparametric by introducing a Dirichlet process prior for the distribution of permanent environmental effects. This can lead to potential identification of clusters of such effects, which, in some competitions such as horse races, may reflect forms of undeclared preferential treatment.

Bayes Theorem↗
PubMed1996

Vocalizations in newborn mice: genetic analysis.

Two kinds of vocalizations are produced by newborn mice: whistles (between 50 and 150 ms in length), having a narrow bandwidth in each strain that ranges from 30 to 90 kHz; and clicks, which are shorter (about 1 ms) and have a larger bandwidth. These vocalizations were individually recorded in 1-day-old pups from seven inbred strains of laboratory mice, at two temperatures (23 +/- 0.5 and 15 +/- 0.5 degrees C). The numbers of clicks and whistles were counted under these two conditions. Moreover, the length and frequencies at the beginning, apex, and end of the whistles were measured during the 15 degrees C condition. Correlations, including several components-additivity, epistasis (between homozygous loci), and maternal environment-were calculated between the characteristics of the whistles during the 15 degrees C condition. Clicks and whistles were also counted from 1 to 8 days of age during the 15 degrees C condition. The numbers of clicks and whistles were age dependent, with a decrease from day 1 to day 8 for the clicks and a consistent production of whistles. A quantitative genetic analysis was also performed on the 1-day-old pups from the Mendelian generations produced by the inbred strains most contrasting for the number of whistles produced in the cold condition: NZB/BINJ and CBA/H. The heterozygous genotype of the mother induced an increment of the number of whistles. Moreover, a significant part of the additive variance was suspected from the first design, and found with the second one, for this variable. Quantitative genetic analysis showed significant dominance and epistasis between homozygous loci and homozygous and heterozygous loci. This points to multigenic correlates for the number of whistles in this population. The significant additive values for all the variables recorded during the 15 +/- 0.5 degrees C condition and for the number of whistles produced during the 23 +/- 0.5 degrees C condition are compatible with an effect that indicates neither directional nor stabilizing selection. This result is examined in the light of the multichannel sensorial process implicated in maternal behavior in mice.

Animals↗
PubMed2005

[Genetic analysis of starch branching enzyme activity in rice grain].

To make an genetic analysis of starch branching enzyme (Q enzyme) inheritance, which is important in catalyzing the formation of amylopectin and thereby raising the amylopectin/amylose ratio of starch in rice grains, a linkage map of 207 DNA markers were constructed by using 247 recombinant inbred lines derived from an indica-indica rice cross Zhenshan 97B/Milyang46. In 2002 and 2003, the activities of starch branching enzyme of the parents and 247 RILs were measured 10 d and 20 d respectively after flowering (Table 1). A total of 3 quantitative trait loci (QTLs) were detected to have significant additive effects on Q enzyme activities 10 d after flowering with 10% phenotypic variations explained for the three QTLs (Table 2, Fig.1). Meanwhile, qQ10-6 with significant QTL x environment interaction was detected. Epistasis analysis detected 5 and 2 significant additive-by-additive interactions for Q enzyme 10 d and 20 d respectively after flowering (Table 3), and three pairs of QTLs 10 d after flowering with significant epistasis x environment interactions were detected, explaining 3% to 12% of the phenotypic variation. The results showed that the environmental factors had obvious effect on the gene expression of Q enzyme activity in rice grain. Meanwhile, the location of qQ10-6 in relation to that of QTLs for gelatinization temperature, gene loci involved in ADPG pyrophosphorylase and soluble starch synthase were discussed with the help of a genetic map.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1994

Alcohol acceptance, preference, and sensitivity in mice. I. Quantitative genetic analysis using BXD recombinant inbred strains.

Although the recombinant inbred strain method was designed for molecular genetic analysis of linkage, it also provides powerful quantitative genetic analyses of heritability and genetic correlations. Measures of alcohol acceptance, alcohol preference, and hypnotic dose sensitivity (HDS) were assessed in 21 strains of mice from the BXD RI series. Sex differences were found to be significant at a phenotypic level. However, heritability estimates for acceptance, preference, and HDS are similar in males and females. Heritability estimates for the three measures are approximately 0.20 for acceptance and preference, and 0.10 for HDS. Analyses of genetic correlations reveal that acceptance and preference share some degree of genetic influence, although they mostly operate under different genetically mediated mechanisms. HDS did not show a significant genetic relationship to either acceptance or preference. Strong correlations were obtained when acceptance, preference, and HDS strain means were correlated across male and female recombinant inbreds, suggesting substantial genetic similarity across sexes.

Alcohol Drinking↗
PubMed1975

Genetic analysis of mitomycin C-induced interchange in Drosophila melanogaster females.

A genetic analysis of an array of mitomycin-induced rearrangements in immature Drosophila oocytes is reported. Induced aberrations were recovered representing detachments of the compound-X chromosome, Y chromosome fragments, X chromosome loss and mosaicism. The spectrum of rearrangements induced by mitomycin C was very similar to that induced by X-ray treatment of immature oocytes. This work suggests that mitomycin C has two models of action. The drug is radiomimetic for it induces the types of aberrations recovered after X-irradiation. Mitomycin C also seems to have a delayed effect which is reflected in the relatively high recovery of mosaics.

Animals↗
PubMed2005

Genetic analysis of learning and memory deficits in senescence-accelerated mouse (SAM).

Genetic analysis of learning and memory deficits (LMD) in senescence-accelerated mouse P8 (SAMP8) was performed by cross-mating SAMP8 and Japanese Fancy Mouse 1 (JF1). The incidence of LMD in the F2 generation showed a 3:1 segregation ratio of mice with LMD to normal mice, and the incidence of LMD in the backcross generation of the F1 to JF1 parental strain was in agreement with a 1:1 ratio of mice with LMD to normal mice. Estimation of the number of genes involved in the development of LMD using Wright's formula showed that at least two to four genes are involved. These results suggest that the inheritance of LMD is polygenically controlled and that there may be a single major gene, but this locus is not sex-linked. Moreover, hormonal influence on the development of LMD in SAMP8 females is of a genotype-dependent manner.

Aging↗
PubMed2001

MEGA2: molecular evolutionary genetics analysis software.

UNLABELLED: We have developed a new software package, Molecular Evolutionary Genetics Analysis version 2 (MEGA2), for exploring and analyzing aligned DNA or protein sequences from an evolutionary perspective. MEGA2 vastly extends the capabilities of MEGA version 1 by: (1) facilitating analyses of large datasets; (2) enabling creation and analyses of groups of sequences; (3) enabling specification of domains and genes; (4) expanding the repertoire of statistical methods for molecular evolutionary studies; and (5) adding new modules for visual representation of input data and output results on the Microsoft Windows platform. AVAILABILITY: http://www.megasoftware.net. CONTACT: s.kumar@asu.edu

DNA↗
PubMedDate not supplied

Reverse genetic analysis of the Caenorhabditis elegans 26S proteasome subunits by RNA interference.

Reverse genetic analysis was performed on the Caenorhabditis elegans 26S proteasome subunit genes by double-stranded RNA-mediated interference (RNAi). Embryonic and post-embryonic lethality was caused by interference of all of the eight tested 20S core subunits and all of the 19S regulatory particle subunits except for Ce-Rpn9, Ce-Rpn10, and Ce-Rpn12, where RNAi caused no abnormality. However, synthetic suppression of Ce-Rpn10 and Ce-Rpn12 was lethal, whereas neither the combination of Ce-Rpn9 with Ce-Rpn10 nor with Ce-Rpn12 resulted in abnormalities in RNAi. These results indicate that the 26S proteasome is indispensable for embryogenesis and post-embryonic development, although Ce-Rpn9, Ce-Rpn10, and Ce-Rpn12 are not essential, at least under the conditions used. Ce-Rpn10 and Ce-Rpn12 are considered to compensate for the suppression of each other.

Animals↗
PubMed2006

[Genetic analysis and RAPD marker of the genes for brachytic stem trait in soybean].

Three crosses between NG94-156 (brachytic stem) and three varieties (normal stem) were made, and F2 segregative population and two recombined inbred line populations(F(7:8)) were obtained. Genetic analysis indicated that the brachytic stem of NG94-156 was controlled by two duplicate recessive genes. In searching for RAPD marker linked to the genes controlling brachytic stem, 260 RAPD primers were applied to screen four parents of three combinations and RIL. Polymorphic bands revealed by the primer S-506 exhibited the best repeatability among all primers. Linkage analysis indicated the genetic distance between S-506(1600) and brachytic stem gene was 6.94 cM.

Genetic Linkage↗
PubMed2005

Genetic analysis of complex cardiovascular traits in the spontaneously hypertensive rat.

Identification of the genetic determinants of common diseases is a major challenge for current biomedical research. Combining linkage analyses of essentially monogenic cis-regulated expression phenotypes with oligogenic intermediate physiological phenotypes represents a promising approach for identification of quantitative trait loci at the molecular level. In the present review, a genetic analysis of cardiovascular phenotypes studied at several levels of complexity in rat recombinant inbred strains is described.

Animals↗
PubMed1998

Longitudinal genetic analysis of menstrual flow, pain, and limitation in a sample of Australian twins.

Genetically informative longitudinal data about menstrual disorders allow us to address the extent to which the same genetic risk mechanisms are operating throughout the reproductive life cycle. We investigate the relative contributions of genes and environment to individual differences in menstrual symptomatology reported at two waves, 8 years apart, of a longitudinal Australian twin study. Twins were questioned in 1980-1982 and 1988-1990 about levels of menstrual pain, flow, and perceived limitation by menses. Longitudinal genetic analysis was based on 728 pairs (466 MZ and 262 DZ) who were regularly menstruating at both survey waves. A bivariate Cholesky model was fitted to the two-wave data separately for flow, pain, and limitation variables. The baseline model comprised common genetic and environmental factors influencing responses at both waves and specific effects influencing only the second-wave response. We also included age as a covariate in the model. Proportions of the longitudinally stable variance in menstrual flow, pain, and limitation attributable to genetic and individual environmental effects were calculated for the best-fitting models. Genetic factors accounted for 39% of the longitudinally stable variation in menstrual flow, 55% for pain, and 77% for limitation. The remaining stable variance was due to individual environmental factors (61, 45, and 23%, respectively). Therefore the stable variance over the 8-year interval was largely environmentally influenced for menstrual flow, was approximately equally determined by genetic and by nonshared environmental influences in the case of pain, and was due almost entirely to genetic influences for limitation by periods. We demonstrate for the first time that the same genetic influences are operative throughout the reproductive life span.

Adolescent↗