962 resultados para Multifactorial Inheritance
Resumo:
The objective of this work was to determine the inheritance of resistance by antixenosis in tomato plants (Lycopersicon esculentum) to tomato leafminer [Tuta absoluta (Lepidoptera: Gelechiidae)]. Evaluations were performed for tomato plants of the generations P1, P2, F1, F2, RC1 and RC2. The measured characteristic in the parents, BGH-1497 (P2 male) and 'Santa Clara' (P1 female), and in the F1, F2, RC1 and RC2 generations was the number of eggs per plant. This number was converted to the oviposition nonpreference index. The inheritance of antixenosis resistance of genotype BGH-1497 is ruled by a gene of greater effect and polygenes in epistatic interactions, with a phenotypic proportion of 13:3 between susceptible and resistant genotypes, respectively.
Resumo:
The Austroalpine nappe systems in SE-Switzerland and N-Italy preserve remnants of the Adriatic rifted margin. Based on new maps and cross-sections, we suggest that the complex structure of the Campo, Grosina/Languard, and Bernina nappes is inherited largely from Jurassic rifting. We propose a classification of the Austroalpine domain into Upper, Middle and Lower Austroalpine nappes that is new because it is based primarily on the rift-related Jurassic structure and paleogeography of these nappes. Based on the Alpine structures and pre-Alpine, rift-related geometry of the Lower (Bernina) and Middle (Campo, Grosina/Languard) Austroalpine nappes, we restore these nappes to their original positions along the former margin, as a means of understanding the formation and emplacement of the nappes during initial reactivation of the Alpine Tethyan margin. The Campo and Grosina/Languard nappes can be interpreted as remnants of a former necking zone that comprised pre-rift upper and middle crust. These nappes were juxtaposed with the Mesozoic cover of the Bernina nappe during Jurassic rifting. We find evidence for low-angle detachment faults and extensional allochthons in the Bernina nappe similar to those previously described in the Err nappe and explain their role during subsequent reactivation. Our observations reveal a strong control of rift-related structures during the subsequent Alpine reactivation on all scales of the former distal margin. Two zones of intense deformation, referred to as the Albula-Zebru and Lunghin-Mortirolo movement zones, have been reactivated during Alpine deformation and cannot be described as simple monophase faults or shear zones. We propose a tectonic model for the Austroalpine nappe systems that link inherited, rift-related structures with present-day Alpine structures. In conclusion, we believe that apart from the direct regional implications, the results of this paper are of general interest in understanding the control of rift structures during reactivation of distal-rifted margins.
Resumo:
Psychological factors, such as depression or depressive symptoms and fear of falling are linked to falls among the aged. According to previous studies, they may increase the risk of falls and injurious falls. In addition, depression or a high amount of depressive symptoms and fear of falling may hinder participation in preventive activities. Despite the severe consequences of both conditions and their high prevalence among the aged, they have rarely been studied in the context of fall prevention. The study aimed to assess the effects of multifactorial fall prevention on the psychological risk factors of falling (depressive symptoms and fear of falling) among the community-dwelling aged at increased risk of falling. In addition, it aimed to determine factors predicting high adherence to preventive activities. Volunteers aged 65 or over, who had fallen during the year previous to randomisation were recruited. Participants (n=591) were randomised into an intervention or a control group. The intervention group received a multifactorial fall prevention programme including geriatric assessment, individual guidance on fall and fracture prevention, group- and home-based physical exercise, psychosocial group activities, lectures and home hazards assessment. The control group had a one-time counselling on fall and fracture prevention. The data on psychological risk factors of falling were collected by self-rated questionnaires. Multifactorial fall prevention was not effective in reducing depressive symptoms or fear of falling compared to one-time counselling in the total sample. However, in subgroup analyses, depressive symptoms reduced statistically significantly more among the men and older participants of the intervention group compared to the control group. Female gender, high physical and cognitive abilities and low self-perceived probability of falling were independent predictors of higher adherence in organised activities. In conclusion, few psychological benefits were gained during this multifactorial fall prevention trial. More attention should be focused on adherence, especially among the aged with functional disabilities.
Resumo:
The objective of this work was to determine the inheritance mode of seed coat color in sesame. Two crosses and their reciprocals were performed: UCLA37 x UCV3 and UCLA90 x UCV3, of which UCLA37 and UCLA90 are white seed, and UCV3 is brown seed. Results of reciprocal crosses within each cross were identical: F1 seeds had the same phenotype as the maternal parent, and F2 resulted in the phenotype brown color. These results are consistent only with the model in which the maternal effect is the responsible for this trait. This model was validated by recording the seed coat color of 100 F2 plants (F3 seeds) from each cross with its reciprocal, in which the 3:1 expected ratio for plants producing brown and white seeds was tested with the chi-square test. Sesame seed color is determined by the maternal genotype. Proposed names for the alleles participating in sesame seed coat color are: Sc1, for brown color; and Sc2, for white color; Sc1 is dominant over Sc2.
Resumo:
The objective of this work was to determine the inheritance of the long juvenile period trait in natural variants of the Doko, BR 9 (Savana), Davis, Embrapa 1 (IAS 5RC), and BR 16 soybean cultivars. Complete diallel crosses were made between the Doko and BR 16 cultivars and their variants. A 3:1 segregation ratio was observed in the F2 populations of the 'Doko' x Doko-18T, 'Doko' x Doko-Milionária, 'Davis' x São Carlos, and 'BR 9 (Savana)' x MABR92-836 (Savanão) crosses, indicating that the long juvenile period trait is controlled by a pair of recessive genes. The difference in late flowering between the Doko cultivar and both of its variants was caused by a recessive spontaneous mutation at the same genetic locus. However, the variants Doko-18T and Doko-Milionária are identical mutants that share a pair of genes that control the long juvenile period under short-day conditions. These mutants can be used in breeding programs to develop cultivars adapted to low-latitude tropical regions.
Resumo:
Interjurisdictional competition over mobile tax bases is an easily understood mechanism, but actual tax-base elasticities are difficult to estimate. Political pressure for reducing tax rates could therefore be based on erroneous estimates of the mobility of tax bases. We show that tax competition provided the overwhelmingly dominant argument in the policy debates leading to a succession of reforms of bequest taxation by Swiss cantons. Yet, we find only very weak statistical evidence of a relationship between tax burdens on bequests and the concerned tax base of wealthy elderly individuals. Moreover, inheritance tax revenues are found to increase in inheritance tax rates even in the long run, and actual tax rates lie well below the revenue-maximising levels throughout. The alleged pressures of tax competition did not seem in reality to exist.
Resumo:
Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.
Resumo:
The inheritance of resistance to powdery mildew in the pea cultivar MK-10 and some histological aspects of infection were assessed. For the inheritance study, F1, F2, backcrosses and F3 generations of MK-10 crossed with two susceptible populations were evaluated. Histological evaluations included percentage of germinated conidia, percentage of conidia that formed appresoria, percentage of conidia that established colonies, and number of haustoria per colony. Segregation ratios obtained in the resistance inheritance study were compared by Chi-square (ײ) test and the histological data were analyzed by Tukey's test at 5% probability. It was concluded that resistance of MK-10 to powdery mildew is due to a pair of recessive alleles since it is expressed in the pre-penetration stage and completed by post-penetration localized cellular death, characteristic of the presence of the pair of recessive alleles er1er1.
Resumo:
Seven sources of resistance to the two predominant races IB-1 and IB-9 of the rice blast pathogen Pyricularia grisea were selected based on leaf blast reaction in tests conducted under controlled greenhouse conditions. Crosses involving resistant and susceptible parents were made to study the inheritance of the disease reaction for different sources of resistance. The F1 and F2 progenies of all crosses, including backcrosses to resistant and susceptible parents, were tested for reaction to leaf blast. The data showed that resistance is controlled by one to three genes that segregate independently in most of the donors. Non-allelic interaction among resistance genes, including dominant epistasis, was identified.
Resumo:
Bean (Phaseolus vulgaris) lines P.I. 207262 and AB 136, both resistant to delta and kappa races of Colletotrichum lindemuthianum, were crossed with Michelite, Dark Red Kidney, and Perry Marrow, susceptible to both races, and with Cornell 49-242, resistant to delta and susceptible to kappa. F1 and F2 reactions demonstrated that P.I. 207262 carries duplicate dominant genes for resistance to the delta race; AB 136 carries a dominant gene. These resistance genes are independent of the Are gene from Cornell 49-242. With respect to the kappa race, F1 and F2 data showed that the resistance controlled by P.I. 207262 and by AB 136 depends on a single dominant gene. Complementary factors were involved with AB 136 resistance to the delta race and with P.I. 207262 resistance to kappa.
Resumo:
Water and saline intake is controlled by several mechanisms activated during dehydration. Some mechanisms, such as the production of angiotensin II and unloading of cardiovascular receptors, activate both behaviors, while others, such as the increase in blood osmolality or sodium concentration, activate water, but inhibit saline intake. Aldosterone probably activates only saline intake. Clonidine, an a2-adrenergic agonist, inhibits water and saline intake induced by these mechanisms. One model to describe the interactions between these multiple mechanisms is a wire-block diagram, where the brain circuit that controls each intake is represented by a summing point of its respective inhibiting and activating factors. The a2-adrenoceptors constitute an inhibitory factor common to both summing points
Resumo:
The anther smut fungus U stilago violacea has been developed as an important model organIsm for genetic, morphological and physiological studies. Valuable information on the nuclear genetics on U stilago violacea has been obtained in the last 20-25 years. However, in this organism almost nothing is known about mitochondria which make up an important aspect of the fungal genetic system. One fundamental aspect, mitochondrial inheritance, was addressed by this investigation. Mitochondrial DNA (mtDNA) of U. violacea was purified and restriction fragments cloned. MtDNA restriction fragment length polymorphisms (RFLPs) were identified among different isolates and were used as genetic markers for studying mitochondrial inheritance in crosses between polymorphic isolates. Matings of the yeast-like haploid cells of opposite mating types resulted in dikaryons containing mitochondria from both parents. The dikaryons were induced to form hyphae and then allowed to revert to haploid growth, resulting 1ll a colony that is bisectored for the two nuclear types. Both nuclear-type progeny of each cross were examined for parental mitochondrial type: Either mitochondrial type was observed 1ll the progeny. Thus, mitochondrial inheritance is biparental in this organism. The recovery of both mitochondrial types in the progeny was non-random. In progeny with the nuclear genotype of the al mating type parent mitochondria from both parents were inherited equally well. However, 1ll progeny with the a2 mating type, mitochondria were inherited almost exclusively (94%) from the a2 parent.
Resumo:
The current thesis investigated the effects of a 12-week multifactorial exercise and balance training program on balance control in older adults. Participants completed a baseline testing session which included a series of questionnaires, anthropometric measures, and 18 stance and walking tests. Those who were randomly assigned to the exercise group participated in the 12-week training program while the comparison group was asked not to change anything in his/her lifestyle during the 12-week control period, but were invited to participate in the training program after his/her control period. The same testing protocol was repeated after the 12-week period. The results indicated that there were improvements in the time to complete the walking tests but no change in trunk sway in both the exercise and comparison groups. No changes in stance durations or trunk sway were observed. The findings suggest that the current training program showed no significant improvement in balance control in healthy older adults.
Resumo:
Tesis (Maestría en Trabajo Social) U.A.N.L.