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Results for “specific combining ability”

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At least 73 records · Page 4Linked to original sources
PubMed1988

Evaluation of performance characteristics in a diallel among Simmental, Limousin, Polled Hereford and Brahman beef cattle. I. Growth, hip height and pelvic size.

Progeny of a diallel among Simmental, Limousin, Polled Hereford and Brahman breeds of cattle were evaluated over 5 yr for preweaning and postweaning growth, hip height and pelvic size. Calves from Brahman and Simmental dams had the highest preweaning gains and weaning weights, and those from Polled Hereford dams had the lowest (P less than .05). Differences in the availability of milk and postpartum compensatory gains in progeny of Brahman dams could have contributed to these results. However, calves from Simmental, Limousin and Polled Hereford dams had significantly greater feedlot daily gains than those from Brahman dams. Yearling hip height and pelvic area were lower for progeny of Polled Hereford dams, whereas calves from Simmental, Limousin and Brahman dams were not different for these traits. A series of linear comparisons among these four breeds using least-squares means to estimate general and specific combining ability and maternal effects found significant, negative maternal effects for Polled Hereford for preweaning gain and weaning weight. A positive maternal effect (P less than .05) for Limousin was found for feedlot gain. General combining ability and maternal estimates were significant and variable in most comparisons for yearling hip height and pelvic area. Heterosis estimates were positive and significant in all crosses with Brahman for preweaning gain, weaning weight, yearling weight, hip height and pelvic area. Significant, positive heterosis was also found in Polled Hereford crosses with Limousin and Simmental for preweaning gain, weaning weight and yearling weight.

Alleles↗
PubMed1976

[Problems in the genetics of stress. II. Genetic analysis of endocrine gland weight in mice under normal conditions and during exposure to stress].

Relative weight of adrenals, thymus, hypophysis and gonads was studied in female mice after 21 days after parturition and in intact males. One group of females was stressed during pregnancy, and another group was intact. All these animals were a progeny of the full diallele cross of 4 inbred mice strains (BALB/c, C3H/He, C57BL/6, AKR/J). On the basis of analysis of general and specific combining ability the conclusion is drawn that the relative weight of the endocrine glands is inherited additively in females of both experimental groups. However, it was found that the size of additive genetic variation for these characters in the population of females, which had been stressed during their pregnancy was larger, than in the control population. A significant role of non-additive genes in the determination of these characters was observed in males. The degree of hypertrophy of adrenals and lysis of thymus in stressed females corresponded to their emotional reactivity. Significant genotypic correlations between the weight of some endocrine glands, on one hand, and the emotional reactivity and the rate of sexual maturation, on the other hand, were found in both experimental groups of females. In the stressed group these correlations were higher.

Adrenal Glands↗
PubMed2003

Diallel analysis of production traits among domestic, exotic and mutant germplasms of Lycopersicon.

The effects of wild germplasm on tomato fruit shelf life have not yet been completely evaluated. Three different genotypes of Lycopersicon esculentum (a cultivated variety, a homozygote for nor and a homozygote for rin), LA1385 of L. esculentum var. cerasiforme, LA722 of L. pimpinellifolium, and 10 diallel hybrids were assayed. Mean values of fruit shelf life, weight, shape, and mean number of flowers per cluster were analyzed after Griffing (1956, Aust. J. Biology 9: 463-493), method 2, model 1. Both general and specific combining abilities (GCA and SCA) were significant for the four traits. Negative unidirectional dominance was detected for fruit weight and shelf life, while bidirectional dominance was detected for fruit shape and mean number of flowers per cluster. SCA was greater than GCA for shelf life, so nonadditive effects predominantly accounted for this trait. In the heterozygous state, rin had smaller mean effects than nor. Wild accessions were able to prolong shelf life per se, and in crosses to the cultivated variety. The cross between the homozygote for nor and LA722 yielded the longest shelf life among hybrids.

Crosses, Genetic↗
PubMed2004

The influence of morphological differences between sunflower inbred lines on their SCA effects for yield components.

Genetic distances between seven oil sunflower inbred lines expressed in the variability of five morphological traits were analysed in terms of their effect on the specific combining ability (SCA) effects in these lines for yield component traits. The multivariate analysis of variance (MANOVA) and other related multidimensional methods were used to recognize the differences between genotypes with respect to morphological traits. Canonical analysis was applied for a graphical configuration of parental lines and diallele hybrids in the two-dimensional space. As a measure of the difference between parental lines with respect to the analysed morphological traits jointly, i.e. as a measure of the morphological distance between these forms, Mahalanobis' distance was used. Phenotypic differences between lines were estimated using Mahalanobis' distance for each pair of crossed lines calculated for all the analysed morphological traits. The effect of morphological differences between inbred lines on the mean SCA effect for individual yield components, measured by the linear regression, was significant for oil yield per plant and for the number of seeds per plant.

Biomass↗
PubMed2005

Assessing genetic variation to predict the breeding value of winter triticale cultivars and lines.

The objective of this study was to evaluate the usefulness of amplified fragment length polymorphism (AFLP) analyses for selection of the best parents for breeding of hybrid winter triticale. Phenotypic diversity was measured for 8 agronomic traits in 10 parents and 27 F1 hybrids. Genotypic diversity was measured by 91 AFLP markers. Coefficients of correlation of genetic similarity (AFLP-GS) with both Euclidean distances and mean values of the traits were generally not significant. A correction of the preliminary binary matrix into trait-specific derived matrices increased the values of 5 correlation coefficients to a significant level. The correlation of AFLP-GS with mid-parent heterosis of grain weight per plant was low but significant (r = -0.452). Our study confirms the effectiveness of marker preselection for obtaining AFLP-GS better correlated with heterosis. The use of derived matrices is promising for reducing the number of cross combinations tested for specific combining ability.

Agriculture↗
PubMed1981

[Genetic control of the serotonin content in the blood of mice].

The Griffing's method of diallel analysis and hybridological analysis were used to study inheritance of serotonin level in blood in mice. Effects of general and specific combining ability proved to be highly significant, the former being more pronounced. Results of hybridological analysis allowed to suggest a simple genetic control involving a small number of genes. A conclusion is drawn that the level of serotonin was mainly determined by additive affects of genes.

Alleles↗
PubMed2006

Genome-wide screening for cis-regulatory variation using a classical diallel crossing scheme.

Large-scale screening studies carried out to date for genetic variants that affect gene regulation are generally limited to descriptions of differences in allele-specific expression (ASE) detected in vivo. Allele-specific differences in gene expression provide evidence for a model whereby cis-acting genetic variation results in differential expression between alleles. Such gene surveys for regulatory variation are a first step in identifying the specific nucleotide changes that govern gene expression differences, but they leave the underlying mechanisms unexplored. Here, we propose a quantitative genetics approach to perform a genome-wide analysis of ASE differences (GASED). The GASED approach is based on a diallel design that is often used in plant breeding programs to estimate general combining abilities (GCA) of specific inbred lines and to identify high-yielding hybrid combinations of parents based on their specific combining abilities (SCAs). In a context of gene expression, the values of GCA and SCA parameters allow cis- and trans-regulatory changes to be distinguished and imbalances in gene expression to be ascribed to cis-regulatory variation. With this approach, a total of 715 genes could be identified that are likely to carry allelic polymorphisms responsible for at least a 1.5-fold allelic expression difference in a total of 10 diploid Arabidopsis thaliana hybrids. The major strength of the GASED approach, compared to other ASE detection methods, is that it is not restricted to genes with allelic transcript variants. Although a false-positive rate of 9/41 was observed, the GASED approach is a valuable pre-screening method that can accelerate systematic surveys of naturally occurring cis-regulatory variation among inbred lines for laboratory species, such as Arabidopsis, mouse, rat and fruitfly, and economically important crop species, such as corn.

Alleles↗
PubMed2003

The anther-culture response of triticale line x tester progenies.

Seven triticale cultivars (Ampiac, Aubrac, Trinidad, Ticino, Lamberto, Pronto and Prado) and their F1 hybrids obtained after crossing in a line x tester scheme were examined with respect to their androgenetic effectiveness. The embryo induction rate (number of embryos per 100 anthers), green plant regeneration rate (number of green plantlets per 100 embryos), plant yield (number of green and albino plantlets per 100 anthers) and green plant yield (number of green plantlets per 100 anthers) were assessed. The multivariate and univariate effects of general (GCA) and specific (SCA) combining abilities for the studied traits were estimated and tested. Significant differences between the genotypes were found for individual traits as well as for all the traits treated jointly. Hybrids generally showed a better response in anther culture than their parental genotypes. Heterosis effects were observed in some hybrids for embryo induction rate and green plant yield. GCA and SCA variances were significant and a dominance of the GCA over the SCA variation was found. Among the examined cultivars, Ticino and Pronto were characterised by positive and significant GCA for embryo induction and green plant yield, and these cultivars may be recommended for the improvement of anther culture responsiveness in triticale.

Analysis of Variance↗
PubMed1996

Regulation of tumor growth and metastasis by thrombospondin-1.

Thrombospondin-1 (TSP1) is an extracellular matrix glycoprotein that influences cell adhesion, motility, and growth. Based on its effects on tumor and endothelial cell behavior, this member of the thrombospondin gene family has attracted interest as a potential regulator of tumor growth and metastasis. Initial studies have confirmed that increased TSP1 expression suppresses growth or metastasis of some tumors in vivo and inhibits angiogenesis. These activities are cell type specific, however, since overexpression of TSP1 in some tumors causes increased tumor progression. One basis for these apparently conflicting observations may be the complexity of the protein. TSP1 interacts specifically with several cell-surface receptors, heparan sulfate proteoglycans, growth factors, and other matrix components. These multiple binding specificities, combined with the ability of TSP1 to activate latent transforming growth factor beta and inhibit several proteases, suggest that exposure to TSP1 may initiate several intracellular signals. The integration of these signals may allow varied responses to TSP1. Furthermore, these signals may be received by the tumor cells, endothelial cells responsible for neovascularization, stromal cells, or cells of the host immune system. TSP1 influences specific behaviors of each cell type. Relating these phenomena to the molecular interactions of TSP1 observed in vitro may lead to novel therapeutic strategies for controlling cancer progression and metastasis.-Roberts, D. D. Regulation of tumor growth and metastasis by thrombospondin-1.

Amino Acid Sequence↗
PubMed2004

Detection of thyrotropin-receptor messenger ribonucleic acid (mRNA) and thyroglobulin mRNA transcripts in peripheral blood of patients with thyroid disease: sensitive and specific markers for thyroid cancer.

Because thyroid cancer cells express functional TSH receptors (TSHR), TSHR-mRNA in peripheral blood might serve as a tissue-/cancer-specific marker. We measured circulating TSHR-mRNA by RT-PCR in 51 normal controls, 27 patients with benign thyroid disease, 67 patients with treated differentiated thyroid cancer (DTC), and eight patients with newly diagnosed DTC, preoperatively. Results were compared with thyroglobulin (Tg) mRNA and serum Tg levels. TSHR-mRNA signals were not detected in normal controls and in 24 of 27 (89%) patients with benign thyroid disease. All 19 patients with treated DTC with evidence of distant or local disease tested positive for TSHR-mRNA (sensitivity 100%). Among patients with no evidence of disease, TSHR-mRNA was detected in 1 in 48 (specificity 98%). Six of the eight newly diagnosed DTC patients tested preoperatively were positive for TSHR-mRNA. The concordance between TSHR-mRNA and Tg-mRNA and between TSHR-mRNA and serum Tg was 95%. Fourteen patients with DTC (21%) had Tg antibodies, three with local disease (all positive for TSHR-mRNA), and 11 with no evidence of disease (all negative for TSHR-mRNA). Our results indicate that TSHR-mRNA and/or Tg-mRNA in peripheral blood are both equally sensitive and specific markers for monitoring thyroid cancer patients. Their principal value resides in the Tg antibody-positive patients in whom a positive or a negative mRNA value might have indicated or obviated the need for a whole-body scan. Furthermore, the high specificity combined with their ability to predict thyroid cancer preoperatively suggests a potential role in detecting thyroid cancer in patients with thyroid nodules.

Adult↗
PubMed1995

Characterization of monoclonal antibodies recognizing amino- and carboxy-terminal epitopes of the herpes simplex virus UL42 protein.

A panel of monoclonal antibodies (MAbs) directed against the herpes simplex virus type 1 (HSV-1) DNA polymerase (Pol) accessory protein, UL42, was developed and characterized. Thirteen different MAbs were isolated which exhibited varied affinities for the protein. All MAbs reacted with UL42 in ELISA, Western blot and immunoprecipitation analyses. Competitive ELISA was used to show that 6 different epitopes within UL42 were recognized by the MAbs. Immunoprecipitation of amino- and carboxy-terminal truncations of UL42 mapped the epitopes to regions containing amino acids 1-10, 10-108, 338-402, 402-460, and 460-477. All but one of these epitopes were outside the minimal active portion of the protein previously mapped to amino acids 20-315. None of these MAbs, alone or in combination, specifically neutralized the ability of UL42 to stimulate Pol activity in vitro. These results are consistent with structure-function studies that showed that N- and C-terminal regions of the UL42 protein, those recognized by the MAbs, are not involved in UL42 function in vitro.

Animals↗
PubMed1960

Antigen-antibody reactions in allergic human tissues. I. Preparation and use of fluorescein-conjugated reagins for staining the reaction sites.

Skin sensitizing human antibodies were conjugated with various fluorescent dyes without significant loss in their ability to combine with specific antigen in vitro. A biopsy of the skin site challenged with egg albumin in a patient sensitive to this antigen could be stained specifically by the fluorescent reagins. The epithelial cells of the epidermis, sweat glands, hair follicles, and sebaceous glands in such a challenged site showed specific staining. In addition to the epithelial cells, the most intense staining was in macrophages and in pericapillary cells. The endothelium of the small blood vessels stained less intensely. Fibrous tissue bundles were specifically stained. The immunologic staining with the conjugated reagins was similar to but more intense than that obtained with conjugated rabbit anti-egg albumin globulins.

Animals↗
PubMed2001

The combination of SKY and specific loci detection with FISH or immunostaining.

Spectral karyotyping (SKY) represents an effective tool to detect individual chromosomes and analyze major karyotype abnormalities within an entire genome. We have tested the feasibility of combining SKY and FISH/protein detection in order to combine SKY's unique abilities with specific loci detection. Our experimental results demonstrate that various combined protocols involving SKY, FISH and immunostaining work well when proper procedures are used. This combined approach allows the tracking of key genes or targeted chromosome regions while monitoring changes throughout the whole genome. It is particularly useful when simultaneously monitoring the behavior of both protein complexes and DNA loci within the genome. The details of this methodology are described and systematically tested in this communication.

Animals↗
PubMed1990

Introduction of a lacZ reporter gene into the mouse int-2 locus by homologous recombination.

We demonstrate that the frequency of gene targeting is unaffected by the length of nonhomologous DNA transferred to a target chromosomal sequence. A result of this finding is that a much wider spectrum of designed genomic alterations is now feasible. As a first application, we inserted a 5.4-kilobase cassette of nonhomologous DNA into the int-2 locus in mouse embryo-derived stem cells by gene targeting. The inserted DNA contained a lacZ gene positioned to create an in-frame fusion with the int-2 protein-coding region. Upon differentiation of these cells to embryoid bodies, the int-2-lacZ fusion faithfully reproduced the expression pattern of int-2 RNA. This ability to target reporter genes, such as lacZ, to specific mouse loci, combined with the ability to move the tagged gene into different mutant backgrounds, may provide an ideal approach for analyzing interactions among genes that participate in a developmental network.

Animals↗
PubMedDate not supplied

PCR-SSO typing in HLA-disease association studies.

Associations between a large number of diseases and markers within the major histocompatibility complex (MHC) have been described. In particular, susceptibility to several autoimmune disorders, including type I diabetes mellitus and rheumatoid arthritis, is linked to genes within the MHC and strong population associations are demonstrable between certain HLA class II alleles and these conditions. Genetic mapping of HLA susceptibility loci has traditionally relied on the use of phenotypic markers defined by alloantisera, cellular typing reagents and biochemical analysis of histocompatibility antigens. Polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) typing combines the ability to define the finest of HLA specificities, by analysis of the corresponding DNA sequences, with the possibility of study large populations of normal and affected individuals. The applications of this technology to characterizing precisely the MHC loci associated with susceptibility to autoimmune diseases such as rheumatoid arthritis, type I diabetes mellitus, coeliac disease and pemphigus vulgaris are reviewed here.

Alleles↗
PubMed1996

A strategy for multiple immunophenotyping by image cytometry: model studies using latex microbeads labeled with seven streptavidin-bound fluorochromes.

Multiple immunophenotyping is aimed at identifying several cell populations in a single labeling procedure by their ability to bind combinations of specific labeled antibodies. The present work demonstrates the simultaneous discrimination by using image cytometry of aminomethylcoumarin acetate (AMCA), Lucifer yellow (LY), fluorescein isothiocyanate (FITC), R-phycoerythrin (PE), PE-Texas red tandem (Red613), peridinin-chlorophyll protein (PerCP), and allophycocyanin (APC), which were all bound to latex beads as streptavidin-conjugated fluorochromes. This has been the result of a step-by-step optimization of the several factors affecting the sensitivity and specificity of multiple immunofluorescence analysis. First, 14 streptavidin-conjugated fluorochromes were evaluated by using spectrofluorometry. A primary selection was then made of ten spectrally separable dyes that could be evaluated by using image cytometry. These dyes were bound to latex particles, and specific filter combinations were assembled to minimize crosstalk between fluorophores while preserving sufficient fluorescence intensity and counting statistics. Potential probe associations were then assessed by measuring the emissions of all fluorochromes that were detected by each filter combination. The resulting crosstalk matrix served as the basic tool both for final selection of the optimal filter combination and for dye set (composed, in this case, of the seven fluorochromes described above) and for mathematical correction of residual spectral overlap. Next, an image cytometry system was adapted to collect seven images of matched brightness with the selected combination of excitation/emission filters and dichroic mirrors. Finally, seven-parameter synthetic images were generated by digital image processing.

Automation↗
PubMed1979

Lectins as probes in studies of intestinal glycoproteins and glycolipids.

The abilities of lectins to combine specifically with particular carbohydrate residues have made them valuable probes in the analysis of the surface components of intestinal epithelial cells. Fluorescence microscopy studies using FITC-labeled lectins have shown that the surfaces of these cells change as the cells move up the villi and that these changes are dependent upon the region of intestine in which the villi are located. The lectins have been used in radioassays developed to quantitate these cell surface components and have proven useful in monitoring the extraction and purification of these substances. Lectin affinity columns have been successfully used to isolate some of these components. Although lectins offer the advantage of specific recognition of relatively small defined carbohydrate units on complex molecules, they have the limitation of not being able to distinguish among different molecules bearing the same carbohydrate units. It is thus necessary to use the lectins in conjunction with other tools as one proceeds further in the analysis of the complex carbohydrates that constitute the cell surface.

Animals↗
PubMed1988

Melbourne trial of adjuvant immunotherapy in operable large bowel cancer.

A controlled randomized clinical trial was undertaken to assess the ability of combined non-specific and specific immunotherapy to alter the disease-free interval and overall survival of patients with Stage B or C large bowel cancer. The immunotherapy consisted of a 2 year programme of vaccinations with BCG and neuraminidase-treated autologous tumour cells. Three hundred and one patients entered the trial. At 5 years of follow-up there is no evidence that this form of immunotherapy can alter either the disease-free interval or survival in this group of patients.

Antigens, Neoplasm↗