603 research outputs found
Genes and translocations involved in POF
No full textChanges at a single autosomal locus and many X-linked loci have been implicated in women with gonadal dysgenesis [premature ovarian failure (POF) with deficits in ovarian follicles]. For the chromosome 3 locus, a forkhead transcription factor gene (FOXL2) has been identified, in which lesions result in decreased follicles by haploinsufficiency. In contrast, sporadic X; autosomal translocations are distributed at many points on the X, but concentrate in a critical region on Xq. The association of the breakpoints with genes involved in ovarian function is thus far weak (in four analyzed cases) and has not been related to pathology in other POF patients. While many more translocations can be analyzed in detail as the human genome sequence is refined, it remains possible that translocations like X monosomy (Turner syndrome) lead to POF not by interrupting specific genes important in ovarian development, but by causing aberrations in pairing or X-inactivation during folliculogenesis. It is noted that the critical region has unusual features, neighboring the X-inactivation center and including an 18 Mb region of very low recombination. These suggest that chromosome dynamics in the region may be sensitive to structural changes, and when modified by translocations might provoke apoptosis at meiotic checkpoints. Choices among models for the etiology of POF should be feasible based on studies of ovarian follicle development and attrition in mouse models. Studies would prominently include gene expression profiling of developmental-specific pathways in nascent ovaries with controlled levels of Fox12 and interacting proteins, or with defined changes in the X chromosome. Published 2002 Wiley-Liss, Inc
Molecular Markers Applied to Maize Breeding
No full textThree experiments were conducted to develop methods to practically apply restriction fragment length polymorphisms (RFLPs) to maize (Zea mays L.) breeding. Applications included those requiring linkage between marker loci and loci governing traits of interest and those not requiring linkage.In the first experiment, cluster analysis based on RFLPs resulting from 46 probe-enzyme combinations was used to reveal associations among 148 U.S. inbreds and assign inbreds to heterotic groups. Relationships were estimated using Gower's Coefficient of Similarity and inbreds were grouped by average linkage. Inbreds were ordered into two major groups generally coinciding with distinctions between breeding groups derived from 'Lancaster Sure Crop' open pollinated variety and from Iowa Stiff Stalk Synthetic. Within these two groups, 11 subgroups were formed, each containing an elite inbred (WF9, MO17, C103, PA91, OH43, B14, B73, N28, B37, or OH07).In the second experiment, the classification described above was evaluated to determine if it could represent the true associations among the inbreds. The estimates of relationship were substantiated by pedigree information, using the Hubert statistic. Congruence between the phenogram and the proximity matrix indicated that the phenogram depicted estimated relationships accurately. The grouping generally agreed with those obtained in three other cluster analyses utilizing different methods for computing proximities. Thus, the classification appeared to reasonably represent the true associations among the 148 maize inbreds.In the third experiment, RFLP and testcross performance data for yield and harvest moisture for an F\sb2:S\sb4 population resulting from two related lines were used to explore genotype x environment interaction at the chromosomal level and to evaluate its impact on marker-assisted selection. Differences in the additive effects of chromosomal segments linked to markers across five diverse locations suggested that distinct loci may be operative or the same loci to differing degrees. Indices that assign scores based on genotypes for markers significantly influencing testcross performance in one set of environments were developed to employ MAS for each trait and for both traits simultaneously in three other environments. Generally, significant additive effects were reasonably stable across a diverse range of environments, facilitating gains using MAS beyond those realized using phenotypic selection.Made available in DSpace on 2014-12-17T23:49:57Z (GMT). No. of bitstreams: 1
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Previous issue date: 1993Embargo set by: Seth Robbins for item 72784
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community indefinitely during batch ingest of legacy ETDsU of I Only244 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993
IL -24; a glycosylated dimeric cytokine affecting monocytes and cytotoxic to melanoma cells
No full textIL-24 is an unusual member of the IL-10 family, which is considered a Th1 cytokine that exhibits tumor cell cytotoxicity. I describe the purification of this novel cytokine from the supernatant of IL-24 gene transfected human embryonic kidney cells and define the biochemical and functional properties of the soluble, human IL-24 protein. I showed IL-24 non-covalently associates with bovine albumin. Immunoaffinity purification followed by cation exchange chromatography resulted in the significant enrichment of N-glycosylated IL-24. This protein elicited dose-dependent secretion of TNF-α and IL-6 from purified human monocytes and TNF-α secretion from PMA differentiated U937 cells. I showed this same protein was cytotoxic to melanoma tumor cells via the induction of IFN-α. I reported IL-24 associates as at least two disulfide linked, N-glycosylated dimers. Enzymatic removal of N-linked-glycosylation from purified IL-24 partially diminished its cytokine and cytotoxic functions. Disruption of IL-24 dimers via reduction and alkylation of intermolecular disulfide bonds nearly abolished IL-24s cytokine function. I elucidated IL-24 induced TNF-α secretion was pSTAT1, pSTAT3 as well as the class II heterodimeric receptors IL-20R1/IL-22R2 independent. I identified a requirement for the heterodimer of Toll-like Receptors 1 and 2 for IL-24s cytokine function and show a physical interaction between IL-24 and the extracellular domain of TLR-1. Thus, I demonstrated that purified N-glycosylated, soluble, dimeric, human IL-24 exhibits both immunomodulatory and anti-cancer activities and these functions remain associated during purification. IL-24 induced TNF-α secretion required an interaction with the heterodimeric receptor TLR-1/2 and IL-24s cytotoxic affect to melanoma tumor cells was in part due to its induction of IFN-β
The standpoint we share: An intersubjective constructivist account of normative reasons
No full textI defend an intersubjective constructivist account of practical reasons. On this account, practical reasons are constructed from a deliberative standpoint that could be shared with anyone with whom we could enter into meaningful normative discourse. This view promises to avoid the most pressing challenge to metanormative constructivism: that it ultimately collapses into subjectivism. I argue that my account can save our everyday intuitions about normative objectivity, including the thought that there are correct answers to normative questions that do not depend on our individual desires and attitudes. My argument advances in a few major stages. First, I argue that the problems facing realism are deep enough that we ought to explore anti-realist alternatives. Second, I argue that constructivism is our most promising option, but that popular versions of the view fail to capture our everyday normative intuitions. Third, drawing on arguments advanced by expressivists and contractualists, I argue that the function of normative discourse is interpersonal coordination. I refine this suggestion by arguing that this coordination involves co-deliberation from a shared standpoint. In fact, my contention is that our individual deliberative standpoints, insofar as they involve normative thoughts, are parasitic on this shared standpoint
The Hackathon Phenomenon
No full textdate-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +000
Survey of plant density tolerance in U.S. maize germplasm
No full textGlobal demand for cereal crops like maize is rising at a rapid pace as the world population expands beyond 7 billion people. To meet these needs, productivity (i.e. grain yield) per unit area must be increased. A survey of U.S. maize germplasm was conducted to identify sources of favorable alleles for plant density tolerance and better understanding the genetics involved. Hybrids created using a genetically diverse set of inbreds representing parentage of key heterotic sub-groups were evaluated at plant densities ranging from 19,000 plants per acre (ppA) to 54,000 ppA. Five categories of traits were hypothesized to be associated with plant density tolerance: photosynthetic capability, growth responses, source-sink relationship, general stress tolerance, and plant architecture. Fifty phenotypic traits from these five categories were evaluated in three environments that differed for levels of moisture availability. The relationship between plant density and grain yield was assessed for each hybrid, with a wide range of responses observed. Five hybrids showed substantial tolerance to plant densities ≥47,000 ppA based on grain yield. Phenotypic trait correlations revealed a subset of traits associated with grain yield. Further analysis provided insight into relationships among traits that ultimately influence grain yield. All 5 categories of traits were found to have an association with grain yield directly and indirectly. Analysis of environments with differing moisture levels suggested that the 5 top-performing hybrids at high plant density have exceptional capacity for light utilization and translation of that energy into kernel mass. Estimates of heritability for grain yield at high plant densities were found to be similar to those at other plant densities, therefore requiring no alteration with breeding strategies used for new and improved maize lines. Results of this work will be used to create plant materials for further characterization of the trait through QTL mapping and candidate gene approaches.Item withdrawn by Mark Zulauf ([email protected]) on 2012-07-17T19:25:55Z
Item was in collections:
University of Illinois Theses & Dissertations (ID: 1)
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Original Data
Group with Access Administrator
Release Date: 2014-09-18 16:27:16 UTC
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemItem marked as restricted to the 'Administrator' Group (id=1) by Seth Robbins ([email protected]) on 2012-09-18T21:27:24Z
Item is restricted until 2014-09-18T21:27:16ZLimited Restriction Lifted for Item 34813 on 2014-09-18T10:00:47Z
Computer simulation to guide choice of breeding strategies for maker-aided multiple trait integration in maize
No full textWith the rapid rate of adoption by farmers worldwide of crop varieties containing multiple value-added traits, mainly genetically modified traits, as many as 15 to 20 transgenic events may be offered in new maize hybrids by 2030 (Que et al. 2010; Fraley 2012). Multiple Trait Integration (MTI) is designed to integrate the specific transgenic events conferring the value-added trait phenotypes into the elite genetic package represented by the target hybrid, regaining the performance attributes of the target hybrid along with reliable expression of the value-added traits. From a breeding standpoint, MTI involves four steps: Single Event Introgression, Event Pyramiding, Trait Fixation, and Version Testing. We considered the breeding process to introgress 15 transgenic events into a target maize hybrid, incorporating 8 into the female parent and 7 into the male parent, to design a comprehensive and efficient approach to MTI overall.
Focusing on the first step, Single Event Introgression which is conducted in parallel streams to convert a given recurrent parent for individual events, the primary breeding goal is to minimize residual non-recurrent parent germplasm remaining from the trait donor, especially in the chromosomal proximity to the event (i.e. linkage drag). Setting a defined lower limit of 96.66% recurrent parent (RP) germplasm recovery (i.e. ≤ 120 cM non-recurrent parent germplasm), conversion for 15 events requires the final selections in Single Event Introgression to have < 8 cM total amount of non-recurrent parent germplasm across the genome with ~ 1 cM non-recurrent parent germplasm in the 20 cM region flanking the event. Using computer simulation, we sought to identify optimal breeding strategies for Single Event Introgression in terms of selection scheme, required population size, and selection intensity. In addition, strategies for choice of donor parent to facilitate conversion efficiency and quality were evaluated. Selection schemes classified as three-stage, modified two-stage, and combined selection conducted from BC1 through BC3, BC4, or BC5 were compared using a moderate constant population size. Criteria for evaluating efficiency included amount of total residual non-recurrent parent germplasm, amount of non-recurrent parent germplasm remaining in the chromosomal region flanking the event in the finished conversion, total number of marker data points required, total population size across generations, and total number of generations. One selection scheme successfully met the defined goals for this breeding step. It involved five generations of marker-aided backcrossing, with BC1 through BC3 selected for the event of interest and minimal linkage drag at population size of 600, and BC4 and BC5 selected for the event of interest and recovery of the RP germplasm across the genome at population size of 400; selection intensity was set at 0.01 for all generations. Furthermore, two essential criteria for choosing an optimal donor parent for a given RP were established: introgression history showing reduction of linkage drag to ~ 1 cM in the 20 cM region flanking the event and genetic similarity between the RP and potential donor parents. Computer simulation demonstrated that a ‘quality’ single event conversion can be accomplished earlier than BC5 given a donor parent with modest levels of genetic similarity. This study lays the groundwork for a comprehensive approach to MTI by providing appropriate starting materials with which to proceed with Event Pyramiding and Trait Fixation.
Next, we focused on the second and third steps in MTI: Event Pyramiding and Trait Fixation. Using computer simulation, we aimed to 1) identify an optimal breeding strategy for pyramiding of 8 events into the female RP (and 7 in the male RP), and 2) evaluate breeding strategies for Trait Fixation to create a ‘finished’ conversion of each RP homozygous for all events in an efficient and effective manner. Building on work by Ishii and Yonezawa (2007a), a symmetric crossing/selfing schedule for Event Pyramiding was devised for stacking 8/7 events in a target RP. Trait Fixation breeding strategies considered self-pollination and doubled haploidy approaches to achieve homozygosity as well as seed chipping and tissue sampling approaches to facilitate genotyping. With self-pollination approaches, 2 generations of selfing rather than 1 for Trait Fixation (i.e. ‘F2 enrichment’ as per Bonnett et al. (2005)) were utilized to eliminate bottlenecking due to extremely low frequencies of desired genotypes in the population. The efficiency indicators such as total number of population size across generations (NT), total number of marker data points (MDP), total number of generations (GEN), number of seeds sampled by seed chipping (NSC), and number of plants requiring tissue sampling (NTS), number of pollinations (NP) (i.e. selfing and crossing) were considered in comparisons of breeding strategies. A breeding strategy involving seed chipping and two-generation self-pollination approaches (SC+SELF) was determined to be the most efficient breeding strategy considering GEN and resource requirements such as MDP, NT, NSC, NTS, and NP. Doubled haploid may have limited utility in Trait Fixation for MTI under the defined breeding scenario. This outcome paves the way for optimizing the last step in the MTI process, Version Testing, which involves hybridization of female and male RP conversions to create versions of the converted hybrid for performance evaluation and commercial release.Item withdrawn by Mark Zulauf ([email protected]) on 2012-07-19T13:12:25Z
Item was in collections:
University of Illinois Theses & Dissertations (ID: 1)
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Original Data
Group with Access Administrator
Release Date: 2014-09-18 16:27:16 UTC
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemItem marked as restricted to the 'Administrator' Group (id=1) by Seth Robbins ([email protected]) on 2012-09-18T21:27:31Z
Item is restricted until 2014-09-18T21:27:16ZLimited Restriction Lifted for Item 34838 on 2014-09-18T10:01:02Z
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