In one of the longest-running experiments in biology, researchers at the University of Illinois have selected for altered composition of the maize kernel since 1896. Here we use an association study to infer the genetic basis of dramatic changes that occurred in response to selection for changes in oil concentration. The study population was produced by a cross between the high-and low-selection lines at generation 70, followed by 10 generations of random mating and the derivation of 500 lines by selfing. These lines were genotyped for 488 genetic markers and the oil concentration was evaluated in replicated field trials.Three methods of analysis were tested in simulations for ability to detect quantitative trait loci (QTL). The most effective method was model selection in multiple regression. This method detected ‫05ف‬ QTL accounting for ‫%05ف‬ of the genetic variance, suggesting that Ͼ50 QTL are involved. The QTL effect estimates are small and largely additive. About 20% of the QTL have negative effects (i.e., not predicted by the parental difference), which is consistent with hitchhiking and small population size during selection. The large number of QTL detected accounts for the smooth and sustained response to selection throughout the twentieth century. T HE genetic architecture of a quantitative trait con-tries. An objective of our study is to identify genes that sists of a set of parameters that explain the genetic may be used to increase the oil concentration of maize component of trait variation within or among populakernels through plant breeding or genetic engineering. tions. These parameters include the number of quanti-The experiment reported here originated in 1896 tative trait loci (QTL) affecting the trait, their locations when C. G. Hopkins began the Illinois long-term selecin the genome, the frequencies of alternative genotypes tion lines, which have become a "textbook" example of segregating at the QTL, the pattern of linkage disequithe power of artificial selection (see review by Dudley libria among QTL, and the magnitudes of additive, and Lambert 2004). From an open-pollinated variety dominance, and epistatic effects. Knowledge of genetic of maize, Hopkins started two populations that were architecture has applications in two areas: (1) the identiselected divergently for the percentage of kernel dry fication of genes with utility in agriculture and/or treatweight that consists of oil ("oil concentration" or "perment of disease and (2) making inferences about the centage of oil"). These populations are called Illinois evolutionary processes that maintain genetic variation high oil (IHO) and Illinois low oil (ILO). In each generand those that cause divergence between populations.ation and each population, bulked kernels from each Here we report a study of oil variation in maize that has of a number of ears (half-sib families) were analyzed both types of application. and the highest (or lowest) 20% of ears were selected to The kernels of a modern maize (Zea mays L.) hybrid be parents o...

The purpose of the current qualitative investigation was to examine Aboriginal undergraduates' (N ϭ 6) experiences with racial microaggressions at a leading Canadian university. The research team analyzed focus group data using a modified consensual qualitative research approach (Hill, Thompson, & Williams, 1997). The authors identified 5 distinct themes that represented Aboriginal students' experiences with racial microaggressions on campus: (a) encountering expectations of primitiveness, (b) enduring unconstrained voyeurism, (c) withstanding jealous accusations, (d) experiencing curricular elimination or misrepresentation, and (e) living with day-to-day cultural and social isolation. Some themes were similar to previous research, whereas others were novel to the current investigation. Implications for future research and campus interventions are discussed.

To identify and characterize quantitative trait loci (QTL) affecting oil, protein and starch concentration in the corn (Zea mays L.) kernel, plants from Generation 70 of the Illinois High Oil (IHO) and Illinois Low Oil (ILO) populations, previously developed by divergent selection for kernel oil concentration, were crossed. The cross was random mated 10 generations and selfed two generations to develop 500 F1RM10S2 lines. The lines per se and their testcross progenies were evaluated at three locations with two replications for 2 yr. Genotypes were evaluated using 479 SNP markers on a bulk of kernels from each line. Since the parent plants used to make the original cross were not available for genotyping, a multivariable optimization procedure was developed to estimate parental population parameters required for QTL mapping. Simple interval mapping was performed with software specially developed to account for the complex mating structure and the fact that the initial cross was made between populations. Correlations and signs of QTL effects suggest development of high oil–high starch lines would be difficult but that it should be possible to develop high oil–high protein lines. The identification of a large number of QTL (at least 40 each for oil, protein, and starch) with small effects has implications for breeding for improved corn chemical composition.

The authors obtained and analyzed data from 10 weblogs (989 pages of raw data), in which online forum contributors expressed varying views on the discontinuation of a university's racialized mascot (i.e., Chief Illiniwek). First, the authors used a modified consensual qualitative research approach (C. E. Hill, Thompson, & Williams, 1997) to identify common themes among the data. Next, they used the Sue, Capodilupo, et al. (2007) racial microaggressions model to situate the themes from the current investigation within a relevant, parsimonious theoretical framework. The data fit well within the 3 broad categories of racial microaggressions identified previously in the literature (i.e., microinsults, microassaults, and microinvalidations). Extending the previous racial microaggressions model, 7 themes emerged from the data that comprised microaggressions targeting American Indians: (a) advocating sociopolitical dominance, (b) alleging oversensitivity, (c) waging stereotype attacks, (d) denying racism, (e) employing the logics of elimination and replacement, (f) expressing adoration, and (g) conveying grief. Some themes are consistent with previous microaggressions research, whereas others are specific to the current investigation. Implications for future research and campus interventions are discussed.

To identify and characterize quantitative trait loci (QTL) affecting kernel weight and concentrations of protein, oil, and starch in the corn (Zea mays L.) kernel, plants from generations 70 of the Illinois High Protein (IHP) and Illinois Low Protein (ILP) strains, previously developed by divergent selection for kernel protein concentration, were crossed. The cross was random mated (RM) seven generations and selfed twice to develop 500 F1RM7S2 lines. The lines per se were evaluated at three locations with two replications for 2 yr and testcrosses were evaluated at three locations in 1 yr. Genotypes were evaluated using 499 SNP markers on DNA from a bulk of leaf tissue from each line. As the parent plants used to make the original cross were not available for genotyping, previously reported multivariable and modified simple interval mapping (SIM) procedures were used. SIM identified more significant regions for all traits than did single marker analysis. Correlations and signs of QTL effects suggest development of high protein–high starch lines would be difficult but that it should be possible to develop high protein–high oil lines with minimal effects on kernel weight. The identification of a large number of QTL (at least 40 each for oil, protein, starch, and kernel weight) with small effects agrees in general with earlier estimates based on quantitative genetic theory and has implications for breeding strategies for improved corn kernel quality traits.

International reference materials representing a diverse suite of sulfide ores and related lithologies have been analyzed for major and trace element concentrations by XRF, solution ICP-MS, and laser-ablation ICP-MS (LA-ICP-MS) after fusion of the sample to a lithium borate glass. Reference materials analyzed for this study include a wide variety of bulk compositions, including ores of Pb-Zn sulfides, Fe sulfides, Cu-Mo sulfides, and silicate matrices. Concentrations of 33 elements were determined, including lithophile and chalcophile elements of particular interest to economic geochemistry and ore deposit studies. The results of LA-ICP-MS analyses were calibrated using a fused glass standard prepared specifically for the analysis of sulfides. Accuracy of the LA-ICP-MS technique is established by comparison with results obtained by the other methods for abundance variations over several orders of magnitude. Replicate analyses demonstrate a precision of 2-8% (1 RSD) for the LA-ICP-MS data at rock-equivalent concentrations >1 ppm. Matrix effects were not a significant problem at the scale of compositional variation represented by these samples, and no significant differences in the results were produced with the laser operating in either fixedspot or line-scan mode. LA-ICP-MS analysis of fused glasses effectively overcomes problems related to insoluble phases such as cassiterite that are resistant to acid dissolution. Whole-rock analysis of sulfide ores by XRF and LA-ICP-MS provides a fast and convenient approach for determinations of major-and trace-element concentrations in a variety of ores and related materials without the need for wet-chemical dissolutions.

In this article, we review the theoretical and empirical literature on racial microaggressions from 2007 to 2020 ( N = 138 articles). First, we refine racial microaggressions theory and update the definition to address mischaracterizations in the literature and clarify the term (i.e., “micro” refers to microlevel interactions rather than degree of harm). Next, we used four superordinate categories (i.e., pathologizing differences, denigrating and pigeonholing, excluding or rendering invisible, and perpetuating color-blind racial attitudes) in which to situate racial microaggression themes from the extant literature. Moreover, we consolidated and renamed existing themes to privilege targets’ perspectives (e.g., facing assumptions of inferior status and enduring exoticization). We then synthesized qualitative and quantitative research that shows harmful sequelae of racial microaggressions (i.e., psychological and physiological symptoms). Extending prior research on coping with gendered racial microaggressions, we describe empirical findings on collective, resistance, and self-protective strategies to mitigate the harmful impact of racial microaggressions. We conclude with directions for future research.

No abstract