scholarly journals Fluxes and Metabolic Pools as Model Traits for Quantitative Genetics. I. The L-Shaped Distribution of Gene Effects

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 2001-2012 ◽  
Author(s):  
Bruno Bost ◽  
Christine Dillmann ◽  
Dominique de Vienne

Abstract The fluxes through metabolic pathways can be considered as model quantitative traits, whose QTL are the polymorphic loci controlling the activity or quantity of the enzymes. Relying on metabolic control theory, we investigated the relationships between the variations of enzyme activity along metabolic pathways and the variations of the flux in a population with biallelic QTL. Two kinds of variations were taken into account, the variation of the average enzyme activity across the loci, and the variation of the activity of each enzyme of the pathway among the individuals of the population. We proposed analytical approximations for the flux mean and variance in the population as well as for the additive and dominance variances of the individual QTL. Monte Carlo simulations based on these approximations showed that an L-shaped distribution of the contributions of individual QTL to the flux variance (R2) is consistently expected in an F2 progeny. This result could partly account for the classically observed L-shaped distribution of QTL effects for quantitative traits. The high correlation we found between R2 value and flux control coefficients variance suggests that such a distribution is an intrinsic property of metabolic pathways due to the summation property of control coefficients.

1991 ◽  
Vol 279 (1) ◽  
pp. 55-65 ◽  
Author(s):  
A K Sen

Within the premises of the flux-oriented theory of Crabtree & Newsholme [(1987) Biochem. J. 247, 113-120], I have used a graph-theoretic approach for calculating the Control Coefficients of metabolic pathways. It is shown that a directed graph representing the control structure of a metabolic pathway can be constructed in a heuristic manner directly from the reaction diagram of the pathway, without the necessity of writing down the governing equations for the Control Coefficients. The Control Coefficients are derived from an analysis of the topology of the directed graph. The graph-theoretic approach also provides a visual framework for analysing the functional relationships of the individual enzymes. The control structures of the following pathways are examined here: (a) a simple unbranched pathway with four enzymes, (b) a simple branched pathway with three enzymes, and (c) a branched pathway with both carbon and energy (ATP) fluxes.


2021 ◽  
Vol 22 (12) ◽  
pp. 6274
Author(s):  
María Fernández ◽  
Alicia de de Coo ◽  
Inés Quintela ◽  
Eliane García ◽  
Márcio Diniz-Freitas ◽  
...  

Severe periodontitis is prevalent in Down syndrome (DS). This study aimed to identify genetic variations associated with periodontitis in individuals with DS. The study group was distributed into DS patients with periodontitis (n = 50) and DS patients with healthy periodontium (n = 36). All samples were genotyped with the “Axiom Spanish Biobank” array, which contains 757,836 markers. An association analysis at the individual marker level using logistic regression, as well as at the gene level applying the sequence kernel association test (SKAT) was performed. The most significant genes were included in a pathway analysis using the free DAVID software. C12orf74 (rs4315121, p = 9.85 × 10−05, OR = 8.84), LOC101930064 (rs4814890, p = 9.61 × 10−05, OR = 0.13), KBTBD12 (rs1549874, p = 8.27 × 10−05, OR = 0.08), PIWIL1 (rs11060842, p = 7.82 × 10−05, OR = 9.05) and C16orf82 (rs62030877, p = 8.92 × 10−05, OR = 0.14) showed a higher probability in the individual analysis. The analysis at the gene level highlighted PIWIL, MIR9-2, LHCGR, TPR and BCR. At the signaling pathway level, PI3K-Akt, long-term depression and FoxO achieved nominal significance (p = 1.3 × 10−02, p = 5.1 × 10−03, p = 1.2 × 10−02, respectively). In summary, various metabolic pathways are involved in the pathogenesis of periodontitis in DS, including PI3K-Akt, which regulates cell proliferation and inflammatory response.


1966 ◽  
Vol 12 (5) ◽  
pp. 308-313 ◽  
Author(s):  
Albert W Opher ◽  
Charles S Collier ◽  
Joseph M Miller

Abstract A convenient electrophoretic procedure for the separation and quantitation of lactate dehydrogenase (LDH) isoenzymes is described. The system uses polyacetate Sepraphore III strips.* The areas of activity are shown by incubation with an LDH substrate combined with tetra-nitro-blue-tetrazolium. The reduction of the latter to the purple formazan is quantitatively related to the enzyme activity. Quantitative determination of the individual colored areas is performed by densitometry.


2018 ◽  
Vol 70 ◽  
pp. 11-23 ◽  
Author(s):  
Oleg Marenkov ◽  
Mykola V. Prychepa ◽  
Julia Kovalchuk

In the experiment with marbled crayfishProcambarusvirginalis(Lyko, 2017), chronic effects of various concentrations of heavy metal ions on the physiological state and enzyme activity were investigated. The obtained results showed that among the investigated heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. According to the results of the research, significant changes were noted in the individual biochemical parameters of marbled crayfish under the influence of manganese, lead and nickel ions. The most significant changes in the activity of lactate dehydrogenase were detected in muscle tissues affected by manganese and nickel ions. A significant decrease in the activity of succinate dehydrogenase in muscle of marbled crayfish was determined after the action of heavy metal ions. Investigation of changes in the activity of alkaline phosphatase under the influence of the ions of manganese, lead and nickel has its own characteristics, which indicates certain violations in the tissues of cell membranes. Changes in the activity of enzymes were also reflected in the overall protein content. Changes in these parameters may indicate a rapid biochemical response of crustaceans to the toxic effects of heavy metals.


Author(s):  
Harinarayan Bind ◽  
Baudh Bharti ◽  
M. K. Pandey ◽  
Sanjeev Kumar ◽  
Vishwanath ◽  
...  

The experimental material for present study consisted of 30 diverse genotypes of oat. Observation were recorded on 11 quantitative traits in oat. High estimates of heritability (broad sense) were obtained for all the characters. The magnitude of PCV as expected was greater than the corresponding GCV for all the characters indicating importance of environment in expression of characters On the basis of result Out of 11 characters studied seeds per panicle, dry matter yield per plant, green fodder yield per plant and harvest index showed high GCV and heritability coupled with high genetic advance as percent of mean which revealed that these four traits might be under control of additive gene effects and therefore they are more reliable for effective selection.


Author(s):  
Shayla Bindra ◽  
R. K. Mittal ◽  
V. K. Sood ◽  
H. K. Chaudhary

Gene effects for 13 characters in four crosses of Vigna mungo were studied by six parameter generation mean model to determine the potential for the improvement of yield components. Scaling tests revealed inadequacy of the additive-dominance model for all the traits indicating the presence of non-allelic interactions. Duplicate gene action was observed for six characters in KUG-216 x HPBU-111, five in KUG-216 x Palampur-93, two in IPU-05-13 x Palampur-93 and one in IPU-05-13 x HPBU-111 and complementary gene action for one character each in KUG-216 x Palampur-93 and IPU-05-13 x HPBU-111 cross. Selection in later generations for duplicate gene action and early generation selection involving intermatings in F2 f or complementary gene action should be adopted for harnessing desirable recombinants.


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