Genomic analysis of maize lines introduced in the early stages of a breeding programme

2017 ◽  
Vol 136 (6) ◽  
pp. 845-860 ◽  
Author(s):  
Narjara Fonseca Cantelmo ◽  
Renzo Garcia Von Pinho ◽  
Marcio Balestre
Keyword(s):  
Genomic Analysis ◽  
Breeding Programme ◽  
Early Stages

A swelling power test for selecting potential noodle quality wheats

1991 ◽  
Vol 42 (3) ◽  
pp. 317 ◽  
Author(s):  
KM McCormick ◽  
JF Panozzo ◽  
SH Hong
Keyword(s):  
Breeding Programme ◽  
Eating Quality ◽  
Power Test ◽  
Swelling Power ◽  
Early Stages ◽  
Predictive Method ◽  
Rapid Visco Analyser ◽  
Paste Viscosity ◽  
Noodle Quality

A swelling power test was developed for selecting wheats suitable for the manufacture of Japanese white noodles. The test is rapid, uses less than 0.4 g of sample and is applicable to starch, flour, wholemeal or Quadrumat Junior flour samples. Swelling power values correlated significantly (P < 0.01) with peak paste viscosity monitored on the Rapid Visco Analyser and with noodle eating quality. Paste viscosity of flour or starch is considered an important characteristic governing noodle quality. The swelling power test provides a suitable predictive method for identifying noodle quality wheats in the early stages of a breeding programme.

scholarly journals Temporal and genomic analysis of additive genetic variance in breeding programmes

2020 ◽  
Author(s):  
Letícia A. de C. Lara ◽  
Ivan Pocrnic ◽  
R. Chris Gaynor ◽  
Gregor Gorjanc
Keyword(s):  
Linkage Disequilibrium ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Model Fitting ◽  
Genomic Analysis ◽  
Principal Component ◽  
Complex Trait ◽  
Breeding Programme ◽  
Empirical Bayesian ◽  
Genomic Analyses

AbstractThis study demonstrates a framework for temporal and genomic analysis of additive genetic variance in a breeding programme. Traditionally we used specific experimental designs to estimate genetic variance for a specific group of individuals and a general pedigree-based model to estimate genetic variance for pedigree founders. However, with the pedigree-based model we can also analyse temporal changes in genetic variance by summarising sampled realisations of genetic values from a fitted model. Here we extend this analysis to a marker-based model and build a framework for temporal and genomic analyses of genetic variance. The framework involves three steps: (i) fitting a marker-based model to data, (ii) sampling realisations of marker effects from the fitted model and for each sample calculating realisations of genetic values, and (iii) calculating variance of the sampled genetic values by time and genome partitions. Genome partitions enable estimation of contributions from chromosomes and chromosome pairs and genic and linkage-disequilibrium variances. We demonstrate the framework by analysing data from a simulated breeding programme involving a complex trait with additive gene action. We use the full Bayesian and empirical Bayesian approaches to account for the uncertainty due to model fitting. We also evaluate the use of principal component approximation. Results show good concordance between the simulated and estimated variances for temporal and genomic analyses and give insight into genetic processes. For example, we observe reduction of genic variance due to selection and drift and buildup of negative linkage-disequilibrium (the Bulmer effect) due to directional selection. In this study the popular empirical Bayesian approach estimated the variances well but it underestimated uncertainty of the estimates. The principal components approximation biases estimates, in particular for the genic variance. This study gives breeders a framework to analyse genetic variance and its components in different stages of a programme and over time.

scholarly journals Temporal and genomic analysis of additive genetic variance in breeding programmes

Heredity ◽  
2021 ◽  
Author(s):  
Letícia A. de C. Lara ◽  
Ivan Pocrnic ◽  
Thiago de P. Oliveira ◽  
R. Chris Gaynor ◽  
Gregor Gorjanc
Keyword(s):  
Linkage Disequilibrium ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genomic Analysis ◽  
Complex Trait ◽  
Temporal Analysis ◽  
Breeding Programme ◽  
Breeding Programmes ◽  
Good Concordance ◽  
New Framework

AbstractGenetic variance is a central parameter in quantitative genetics and breeding. Assessing changes in genetic variance over time as well as the genome is therefore of high interest. Here, we extend a previously proposed framework for temporal analysis of genetic variance using the pedigree-based model, to a new framework for temporal and genomic analysis of genetic variance using marker-based models. To this end, we describe the theory of partitioning genetic variance into genic variance and within-chromosome and between-chromosome linkage-disequilibrium, and how to estimate these variance components from a marker-based model fitted to observed phenotype and marker data. The new framework involves three steps: (i) fitting a marker-based model to data, (ii) sampling realisations of marker effects from the fitted model and for each sample calculating realisations of genetic values and (iii) calculating the variance of sampled genetic values by time and genome partitions. Analysing time partitions indicates breeding programme sustainability, while analysing genome partitions indicates contributions from chromosomes and chromosome pairs and linkage-disequilibrium. We demonstrate the framework with a simulated breeding programme involving a complex trait. Results show good concordance between simulated and estimated variances, provided that the fitted model is capturing genetic complexity of a trait. We observe a reduction of genetic variance due to selection and drift changing allele frequencies, and due to selection inducing negative linkage-disequilibrium.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Genomic analysis of C-type lectins

2002 ◽  
Vol 69 ◽  
pp. 59-72 ◽  
Author(s):  
Kurt Drickamer ◽  
Andrew J. Fadden
Keyword(s):  
Biological Effects ◽  
Cell Signalling ◽  
Genomic Analysis ◽  
Binding Activity ◽  
Immunoglobulin Superfamily ◽  
Carbohydrate Binding ◽  
Carbohydrate Recognition ◽  
Calcium Dependent ◽  
Binding Domains ◽  
Carbohydrate Recognition Domains

Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.

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