Degree Of Genetic Determination Research Articles

Analysis of genetic determination of partial resistance to white rot in sunflower

Abstract Sunflower is usually affected by white rot (WR), a disease produced by Sclerotinia sclerotiorum. Thus, breeders select WR resistant hybrids by means of field experiments replicated in different environments. The WR selection will be effective when the correlation between the phenotype and the set of genes controlling the trait is high. This study aimed to estimate the relationship between the genotype and phenotype for components of WR partial resistance in hybrids. Also, the genotypic merit of these hybrids is estimated to determine their value in breeding programs. To this end, 37 cultivars were used during three years in Balcarce (southeast of Buenos Aires Province, AR). Plants were inoculated with S. sclerotiorum in their capitula. The WR variables evaluated were the relative incubation period (RIP), the daily lesion growth (DLG) and the relative DLG. By using transformed data, the degree of genetic determination (DGD) reached values of 0.78 (RIP), 0.63 (relative DLG) and 0.35 (DLG). Although all error variances and their relative contributions to the total variance had the highest values, the DGD values for RIP and relative DLG were higher than those reported in the bibliography. The best linear unbiased predictors (BLUPs) detected six hybrids with most suitable genetic merit for RIP and relative DLG. The BLUP correlation coefficient suggested that resistance genes involved in RIP and relative DLG were not the same. Thus, these genes could be used simultaneously to develop new sunflower hybrids with more complex WR resistance.

Genetic variation, phenotypic stability, and repeatability of drought response in European larch throughout 50 years in a common garden experiment.

Assessing intra-specific variation in drought stress response is required to mitigate the consequences of climate change on forest ecosystems. Previous studies suggest that European larch (Larix decidua Mill.), an important European conifer in mountainous and alpine forests, is highly vulnerable to drought. In light of this, we estimated the genetic variation in drought sensitivity and its degree of genetic determination in a 50-year-old common garden experiment in the drought-prone northeastern Austria. Tree ring data from larch provenances originating from across the species' natural range were used to estimate the drought reaction in four consecutive drought events (1977, 1981, 1990–1994, and 2003) with extremely low standardized precipitation- and evapotranspiration-index values that affected growth in all provenances. We found significant differences among provenances across the four drought periods for the trees’ capacity to withstand drought (resistance) and for their capacity to reach pre-drought growth levels after drought (resilience). Provenances from the species' northern distribution limit in the Polish lowlands were found to be more drought resistant and showed higher stability across all drought periods than provenances from mountainous habitats at the southern fringe. The degree of genetic determination, as estimated by the repeatability, ranged up to 0.39, but significantly differed among provenances, indicating varying degrees of natural selection at the provenance origin. Generally, the relationship between the provenances’ source climate and drought behavior was weak, suggesting that the contrasting patterns of drought response are a result of both genetic divergence out of different refugial lineages and local adaptation to summer or winter drought conditions. Our analysis suggests that European larch posseses high genetic variation among and within provenances that can be used for assisted migration and breeding programs.

An Integrative Approach to the Study of Individuality of Subjects of Educational Activity in the Ontogeny from the Positions of Sex and Gender

Scientists are trying to study the peculiarities of men and women by adding biological and social components of the human, however since gender is not the natural givenness, but a social construct assuming self- awareness and self-determination, the connections between these components will be refracted through a variety of conditions. The purpose of the article is an integrative study of non-linear relationship of biological and social characteristics of socialization and individualization in development of students of different sexes at different periods of their development based on psychological research. The nature of non-linear relationships was investigated in our study, using discriminant, correlation and factor analyses. The linear relationships were studied using Student's t- test for the control comparison. We have created models of sex and gender structure of integrated individuality of the taught boys and girls from preschool age to adolescence and conducted their comparative analysis. The psychological development programs have been developed that change the personality structure, increasing the number of flexible non-linear interdependencies of the biological and the social. Based on the research, we found that individuality of students with low level of development is characterized mainly by a high degree of genetic determination of the set of natural properties and a high role of objective conditions. High level of individuality development is characterized by non-linearity of interdependent biological and social properties and students of different sexes have their own specifics at different periods of their development. The essence of the author's approach to the training and education of the students is that the study of variable, multi-level non-linear relationships of the individuality's properties determines the specificity of social and biological potentiality of boys' and girls' development and opens great opportunities for the creation of optimum adaptation conditions of students in the educational environment and effective modalities for the training and education of students of different sexes.

English

A total of 389 accessions and a local cultivar Duorado precoce were evaluated in a simple 30 × 13 alpha lattice design with two replications under four experimental environments (N-P-, no N or P application; N-P+, P applied; N+P-, N applied and N+P+, both N and P applied) at the rate of 60 kg P and 90 kg N ha-1. Data was recorded on Days to heading, anthesis and maturity (days), P and N tolerance, plant height (cm), above ground biomass (g), number of panicles (absolute numbers per ten plants), days to maturity (days), 1000 grain weight (g), and grain yield (kg ha-1). The genotypes and environments were highly significant for all the traits studied. The degree of genetic determination (H2) ranged from 6.8% for P tolerance to 36.5% for above ground biomass. The phenotypic coefficient of variation of genotypes ranged from 14.3% for days to maturity to 159.7% for top biomass. The genetic advance (GA) ranged from 0.2 for phosphorous tolerance to 1080.5 for grain yield, while the genetic advance expressed as percent of the mean was 5.7% for days to maturity and 87.9% for top biomass. The top biomass seems to be highly heritable trait and simple phenotypic selection is possible. The ten characters studied had wide variability under the four environments with days to maturity ranging from 188 for genotype ARCCU1Fa1-L4P3-HB under N+P+ to 177 for genotype CT16333(1)-CA-1-M under N-P- condition. The highest yielding genotype was CT16328-CA-18-M under N-P- with 5916 kg ha-1. The germplasm showed variability for low soil N and P adaptation, and hence improvement was possible to take advantage of the vast unexploited upland environments for increased rice productivity. There was high variability in the genotypes to warrant rice improvement for yield. Key words: Soil fertility, genetic advance, genotypes, heritability, Kenya, rice.

Race, genetic determinism and the media: An exploratory study of media coverage of genetics and Indigenous Australians

Social scientists and Indigenous people have voiced concerns that media messages about genetics and race may increase the public's belief in genetic determinism and even increase levels of racism. The degree of genetic determinism in media messages has been examined as a determining factor. This study is the first to consider the implications of this area of scholarship for the indigenous minority in Australia. A search of the last two decades of major Australian newspapers was undertaken for articles that discussed Indigenous Australians and genetics. The review found 212 articles, of which 58 concerned traits or conditions that were presented in a genetically deterministic or antideterministic fashion. These 58 articles were analysed by topic, slant, and time period. Overall, 23 articles were anti-deterministic, 18 were deterministic, 14 presented both sides and three were ambiguous. There was a spike in anti-deterministic articles in the years after the Human Genome Diversity Project, and a parallel increase in deterministic articles since the completion of the Human Genome Project in 2000. Potential implications of the nature of media coverage of genetics for Indigenous Australians is discussed. Further research is required to test directly the impact of these messages on Australians.

Physical Activity and Physical Fitness: Weighing the Relative Importance of Each

The last decade has seen a shift in emphasis from the goal of attaining physical fitness (a product) to the behavior of physical activity (a process) to achieve health benefits. A central question is whether the achievement of physical fitness (PF) is necessary or if participation in physical activity (PA) is sufficient. Three basic tenets of this shift are examined by using representative studies. They are: (1) both PA and PF will lead to health benefits; PF is simply a surrogate measure for PA, (2) the impact of genetics will be avoided if PA, not PF, is emphasized and that is desirable, and (3) it is easier to motivate “the masses” to accumulate lifestyle moderate activity than to undergo a vigorous exercise prescription. Results indicate that PA and PF might be independent risk factors, that both have a degree of genetic determination, and that participation rates for PA have changed little and remain insufficient. Both PA and PF need to be evaluated, promoted, and attained.

Genetic determination of variation and covariation of bone mineral density at the hip and spine in a Chinese population

Bone mineral density (BMD) is a significant determinant of risk for osteoporosis. Genetic factors are known to account for a major proportion of variation of BMD in Caucasians. However, the degree of genetic determination of BMD in Chinese populations has seldom been investigated. The aim of our study was to investigate the magnitude of the genetic determination of BMD at the spine and hip, and their genetic covariation, in a population of Shanghai city in P. R. China. The subjects consisted of 44 full-sib pairs of females aged 19-43 years, 186 mother-daughter pairs, and 270 nuclear families. For BMD at the spine and hip, the values for narrow-sense heritability h2 (+/-SE) were 0.72+/-0.14 and 0.87+/-0.14, respectively, when estimated by full-sib pairs, and 0.44+/-0.07 and 0.77+/-0.07, respectively, when estimated by mother-daughter pairs. There was a significant genetic correlation r(g) (+/-SE) of BMD between the spine and hip, of 0.97+/-0.01 and 0.76+/-0.04, respectively, when estimated by full-sib pairs and mother-daughter pairs. The common household impact on BMD in our study was negligible according to the statistical estimate. We conclude that genetic factors play a major role in the determination of the variation and covariation of BMD at the spine and hip in our Chinese sample.

Evaluation of Italian ryegrass (Lolium multiflorum Lam.) populations naturalized in the flooding pampa of Argentina: I – Morphological and physiological characters at the juvenile stage

Twenty populations of Italian ryegrass (Lolium multiflorum) naturalized in the flooding pampa of Argentina and a commercial cultivar were evaluated in two representative soils of the region (environments). Seeds were sown individually in pots and maintained outdoors to evaluate seedling emergence, growth habit, tillering and leaf characters at the juvenile stage, to determine the degree of genetic determination (DGD) and resource allocations. Variability in final emergence, growth habit, tiller number, tillering index, leaf width and leaf area per plant was detected among entries, while (soil × entry) interaction or differences between soils were observed for characters related to emergence and number and size of leaves. The DGD could not be estimated for some characters due to the variance of (soil × entry) interaction component exceded the genetic component, but it ranged from 14 to 72 for the other attributes. To improve DGD estimations in future experiments, modification of experimental design by increasing the number of environments, replications or plants was discussed for each character.

Complex segregation analyses of bone mineral density in Chinese.

China has the largest population in the world; approximately 7% of the total population suffers from primary osteoporosis. Osteoporosis is mainly characterized by low bone mineral density (BMD). In the present study, familial correlation and segregation analyses for spine and hip BMDs have been undertaken for the first time in a Chinese sample composed of 401 nuclear families with a total of 1260 individuals. The results indicate a major gene of additive inheritance for hip BMD, whereas there is no evidence of a major gene influencing spine BMD. Significant familial residual effects are found for both traits, and heritability estimates (+/-SE) for spine and hip BMDs are 0.807(0.099) and 0.897(0.101), respectively. Sex and age differences in genotype-specific average BMD are also observed. This study provides the first evidence quantifying the high degree of genetic determination of BMD variation in the Chinese.

Animal-intrinsic variation in the partitioning of body protein and lipid in growing pigs

AbstractBody composition in the pig, and its variation, is mostly referred to in terms of body protein and lipid content of the whole body. This study was made to check for animal-intrinsic variation in the partitioning of body protein into protein pools and of body lipid into lipid depots. Results from serial slaughter trials on 316 Danish Landrace and 76 Danish Yorkshire pigs were used to estimate additive genetic and litter-associated variance components for several traits. These traits were total body protein and lipid mass (TOTPROT and TOTLIPD), the proportions of total body protein that are present in the muscles (PROTMUS) or in the (sub-)cutaneous tissue plus bones (connective tissue protein, PROTCON), and the proportions of total body lipid that are present in the (sub-)cutaneous tissue (LIPDSUB), in the muscles (inter- and intramuscular fat, LIPDMUS), or in the bones (LIPDBON). TOTPROT and TOTLIPD were adjusted by regression for body weight; PROTMUS and PROTCON were adjusted for PROTCON, and LIPDSUB, LIPDMUS and LIPDBON were adjusted for TOTLIPD. The pooled estimates (± s.e.) of the degree of genetic determination (the sum of the additive genetic and litter-associated variance components, which approximates the repeatability) of these traits were 0·48 ± 0·19 for TOTPROT, 0·56 ± 0·20 for TOTLIPD, 0·56 ± 0·12 for PROTMUS, 0·57 ± 0·15 for PROTCON, 0·32 ± 0·10 for LIPDMUS, 0·33 ± 0·12 for LIPDSUB, and 0·22 ± 0·10 for LIPDBON. It is concluded that there is animal-intrinsic variation in partitioning of body protein and lipid.

Gènes et Milieu

Many quantitative characters depend on the action of a large number of genes and environmental factors. The mode of inheritance of these characters is polygenic. The phenotypic variance of the character is the sum of the components, thus the genetic and the environmental variances (VP = VG + VE). The degree of genetic determination VG/VP and VE/VP are difficult to estimate in man. The heritability a related coefficient to VG/VP can be estimated from the degree of ressemblance between relatives. The heritability is the additive genetique variance as a proportion of the phenotypic variance. Polygenic threshold inheritance can account for the familial non mendelian distribution of multifactorial diseases.

Mapping of provisional quantitative trait loci influencing temporal variation in locomotor activity in the LS x SS recombinant inbred strains.

The finding that stress-induced locomotor activity exhibited a significant strain x time interaction in the LS x SS RI strains prompted examination of QTL influencing this behavior as a function of time. The degree of genetic determination for locomotor activity was 0.26 for the first 5 min and decreased to 0.16 for the last 5 min of a 30-min test but the number of genetic factors stayed relatively constant (three or four) across time. A QTL point analysis revealed a total of 15 QTL, 5-8 per 5-min time block. Few of the QTL were detected across all time points and different combinations of QTL were evident for each time period. Five of the QTL were in common with those reported by other investigators for similar behaviors. The results suggest that locomotor behavior is under a greater degree of genetic control during the initial part of the test but environmental factors become increasingly important as the test progresses. Furthermore, different genetic factors appear to be mediating genetic variation in locomotor behavior at any given time point.

Inheritance of the ability for ectomycorrhizal colonization of Pinus strobus by Laccaria bicolor

Ectomycorrhizal colonization of Pinus strobus by monokaryotic and dikaryotic progeny of two strains of Laccaria bicolor was studied. The monokaryotic progeny of one strain formed ectomycorrhizae with between 1.5 and 80% of the available short roots. In the other case, the monokaryotic progeny formed ectomycorrhizae with between zero and 22% of the available roots. Percent ectomycorrhizal colonization by the dikaryotic progeny of both strains was continuously distributed from 30 to 84% in one case and from zero to 80% in the other. The results indicate that percent ectomycorrhizal colonization is polygenically controlled. A quantitative analysis of the dikaryotic progeny of one of the strains indicates that the degree of genetic determination, under the conditions of this study, are 19.7 and 4.4%. The interactive genetic component accounted for most of the genetically determined variation in this study.

Age variations in sibling correlations for height, sitting height and weight

SummaryFamilial correlations for height, sitting height and weight have been studied in a sample of 1278 siblings for the Biscay province (Basque Country), aged 4+ to 24+ years. The data have been internally standardized according to sex and age of the individuals. The degree of resemblance among sibling has been expressed by intraclass correlation coefficients. The total sample has been divided into three age categories: <12 years, 12–15 years, and ≥15 years, in order to examine the effect of age on sibling correlations. In general, changes with age have been observed: sibling correlations for height show a clear upward trend through the considered growth period, reaching a value of 0·48 from 15 years of age. Intra-correlations for weight show a slight downward trend with age. Sitting height shows a rather low correlation before 12 years of age, but equally high values in the other two ranges of age (0·48 and 0·47, respectively). This study confirms that the sibling resemblance for the analysed traits fluctuated through the growth period—height and sitting height showing similar patterns of variation with age—and that, after puberty, the degree of genetic determination is higher for bone measurements than for weight.

Plot design effects on phenotypic variability and dynamics of field competition between Six Pinus sylvestris L. varieties

Competition effects between six varieties of Scots pine in a field trial were studied from age 5 to 15. The spacing was 1.5 ∗1.5 m. Different plot sizes were compared with respect to varietal means, coefficient of variation, and “degree of genetic determination”;, as a substitute for heritability, Differences between plot types were explained well by the hypothesis of a characteristic balance between above‐ and belowground competitive bias, changing over time. ANOVA of data from contrast plots, consisting of pairwise varietal mixtures, allowed estimation of direct varietal, and associate varietal effects. The associate effect was suggested as a measure of the belowground share of competition‐induced variance. Height growth was less sensitive to competition, especially aboveground, than were diameter and volume growth. A competition adjustment method, based on height differences, was applied. The feasibility of this method was related to plot design and competition dynamics.

Genetic determination of heart and kidney weights studied using a set of recombinant inbred strains: the relationship to blood pressure

The effects of genetic factors and blood pressure levels on heart and kidney weights were estimated in a set of recombinant inbred (RI) strains obtained by crossing normotensive rat (BN.lx) and genetically hypertensive rat (SHR) progenitor strains. Renal or cardiac hypertrophy in several normotensive RI strains, together with low organ weights in some hypertensive strains, indicate that genetic factors play an important role in heart and kidney weight determination. In RI strains, there was a slight positive correlation between systolic blood pressure and relative heart weight, while relative kidney weight correlated negatively with blood pressure. Indeed, the analysis of the degree of genetic determination in RI strains revealed higher values for the relative kidney weight than for the relative heart weight. Blood pressure has a lower degree of genetic determination than both organs. Several polymorphic loci were found to be associated with organ weight determination. Thus, the analysis of organ weights in RI strains revealed the influence of primary genetic factors rather than secondary blood pressure effects.

Bias of heritability estimates from twin data in presence of errors of zygosity determination

Simple heritability estimators of continuous as well as discrete traits from twin data are known to overestimate the degree of genetic determination of the measured traits for several reasons. Errors of zygosity determination will, however, underestimate the true heritability. The bias due to wrong assignment of dizygous twin pairs into monozygous type is evaluated here, and the results indicate that this negative bias has a compensatory effect on the estimate of the degree of genetic determination when other factors of similarity between twin pairs are taken into account. It is shown that when an estimate of zygosity error is available, the bias due to this factor can be evaluated quantitatively, and hence the adjustment for zygosity error can be incorporated in the estimation of the degree of genetic determination of a trait.

Twin study on myopia.

In order to reassess the relative importance of genetic and environmental factors in the development of myopia in Chinese schoolchildren, 90 pairs of MZ and 36 pairs of like-sex DZ twins were enrolled for detailed ophthalmological examination about their ocular refractions. Corneal curvatures and axial lengths were also measured. With equivalent settings of the range for concordance, corneal curvatures showed higher concordance rate (84%) than ocular refractions (65%) and axial lengths (59%) in MZ twins. F-test on the intrapair variances between MZ and DZ twins revealed a significant hereditary role in determining the ocular refraction and its optical components. The degree of genetic determination was expressed by heritability indices, which were derived from intraclass correlation coefficients. The diversity of sample ages and refractions, while making the obtained data difficult to further explore the gene-environment interaction, led to the observation of more intrapair differences with age and myopic progression in MZ twins.

Genetic analysis of blood pressure in the Milan hypertensive strain of rat (Rattus norvegicus)

Estimates of heritability (h2) of blood pressure level and the number of loci controlling the trait were derived from two genetic crosses involving the Milan hypertensive strain of rat and its control with normal blood pressure. In the genetic cross involving backcrosses, the estimates were h2 = 64% and the number of loci was two or three; there was some evidence of dominance of the alleles for normal blood pressures. In the other cross with only F2's, the degree of genetic determination (heritability in the broad sense) was 45%, involving at least three loci.

Genetic analysis of blood pressure and sodium balance in spontaneously hypertensive rats.

Blood pressure and parameters of sodium balance were measured during the first 16 weeks of life in male Okamoto spontaneously hypertensive rats (SHR, n = 22), Wistar-Kyoto rats (WKY, n = 25), and the F1 (n = 27) and F2 (n = 81) hybrids of the SHR and WKY. Genetic analysis revealed that blood pressure in SHR was controlled by approximately four independent genetic loci and the degree of genetic determination was 64.5%. No difference in blood pressure was discernible before 12 weeks of age between those F2 rats that at 16 weeks had blood pressures either higher or lower than one standard deviation from the mean. Exchangeable sodium was measured sequentially in individual rats of all populations by determining their whole-body radioactivity while receiving 37.5 mM 22Na/23NaCl drinking fluid of constant specific activity as their sole source of sodium. The SHR had consistently higher exchangeable sodium levels than WKY and showed evidence of relative sodium retention during the early developmental phase of hypertension. Sodium intake was higher in SHR than WKY from 4 to 16 weeks of age, although saline preference was the same in both strains. None of these parameters of sodium balance were found to correlate with blood pressure in the F2 population. It is concluded that the heritable abnormalities of sodium balance in SHR appear to represent coincidental inbred characteristics controlled by genetic loci that are unrelated to those loci responsible for the expression of hypertension in this model.