Person: Wright, K
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Wright
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Wright, K
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Publication Cytological techniques to analyze meiosis in Arabidopsis arenosa for investigating adaptation to polyploidy(Frontiers Media S.A., 2014) Higgins, James D.; Wright, K; Bomblies, Kirsten; Franklin, F. Chris H.Arabidopsis arenosa is a close relative of the model plant A. thaliana, and exists in nature as stable diploid and autotetraploid populations. Natural tetraploids have adapted to whole genome duplication and do not commonly show meiotic errors such as multivalent and univalent formation, which can lead to chromosome non-disjunction and reduced fertility. A genome scan for genes strongly differentiated between diploid and autotetraploid A. arenosa identified a subset of meiotic genes that may be responsible for adaptation to polyploid meiosis. To investigate the mechanisms by which A. arenosa adapted to its polyploid state, and the functionality of the identified potentially adaptive polymorphisms, a thorough cytological analysis is required. Therefore, in this chapter we describe methods and techniques to analyze male meiosis in A. arenosa, including optimum plant growth conditions, and immunocytological and cytological approaches developed with the specific purpose of understanding meiotic adaptation in an autotetraploid. In addition we present a meiotic cytological atlas to be used as a reference for particular stages and discuss observations arising from a comparison of meiosis between diploid and autotetraploid A. arenosa.Publication Meiotic Adaptation to Genome Duplication in Arabidopsis arenosa(Elsevier BV, 2013) Yant, Levi; Hollister, J; Wright, K; Arnold, Brian; Higgins, James D.; Franklin, F. Chris H.; Bomblies, KirstenWhole genome duplication (WGD) is a major factor in the evolution of multicellular eukaryotes, yet by doubling the number of homologs, WGD severely challenges reliable chromosome segregation [1, 2, 3], a process conserved across kingdoms [4]. Despite this, numerous genomeduplicated (polyploid) species persist in nature, indicating early problems can be overcome [1, 2]. Little is known about which genes are involved – only one has been molecularly characterized [5]. To gain new insights into the molecular basis of adaptation to polyploidy, we investigated genome-wide patterns of differentiation between natural diploids and tetraploids of Arabidopsis arenosa, an outcrossing relative of A. thaliana [6, 7]. We first show that diploids are not preadapted to polyploid meiosis. We then use a genome scanning approach to show that while polymorphism is extensively shared across ploidy levels, there is strong ploidy-specific differentiation in 39 regions spanning 44 genes. These are discrete, mostly single-gene peaks of sharply elevated differentiation. Among these peaks are eight meiosis genes whose encoded proteins coordinate a specific subset of early meiotic functions, suggesting these genes comprise a polygenic solution to WGD-associated chromosome segregation challenges. Our findings indicate that even conserved meiotic processes can be capable of nimble evolutionary shifts when required.Publication Indirect Evolution of Hybrid Lethality due to Linkage with Selected Locus in Mimulus guttatus(Public Library of Science, 2013) Wright, K; Lloyd, Deborah; Lowry, David B.; Macnair, Mark R.; Willis, John H.Most species are superbly and intricately adapted to the environments in which they live. Adaptive evolution by natural selection is the primary force shaping biological diversity. Differences between closely related species in ecologically selected characters such as habitat preference, reproductive timing, courtship behavior, or pollinator attraction may prevent interbreeding in nature, causing reproductive isolation. But does ecological adaptation cause reproductive incompatibilities such as hybrid sterility or lethality? Although several genes causing hybrid incompatibilities have been identified, there is intense debate over whether the genes that contribute to ecological adaptations also cause hybrid incompatibilities. Thirty years ago, a genetic study of local adaptation to copper mine soils in the wildflower Mimulus guttatus identified a locus that appeared to cause copper tolerance and hybrid lethality in crosses to other populations. But do copper tolerance and hybrid lethality have the same molecular genetic basis? Here we show, using high-resolution genome mapping, that copper tolerance and hybrid lethality are not caused by the same gene but are in fact separately controlled by two tightly linked loci. We further show that selection on the copper tolerance locus indirectly caused the hybrid incompatibility allele to go to high frequency in the copper mine population because of hitchhiking. Our results provide a new twist on Darwin's original supposition that hybrid incompatibilities evolve as an incidental by-product of ordinary adaptation to the environment.Publication Folic Acid and the American Food Supply: A historical account of the FDA's creation of the current folic acid regulations(2003) Wright, K; Hutt, Peter BartonDuring the 1980s, scientific studies began to uncover a link between the B-vitamin folic acid and a reduction in the prevalence of neural tube defects, including spina bifida and anencephaly. When Congress passed the Nutrition Labeling and Education Act of 1990, it included a command that the FDA consider the link between folic acid and neural tube defects to determine whether the evidence was strong enough to permit food manufacturers of products containing folic acid to make a claim that their products may help prevent neural tube defects. Although the FDA initially rejected the use of such a claim, faced with mounting pressure from the scientific community and other government agencies, it reversed course and allowed manufacturers to make certain health claims regarding folic acid. It also required that certain products be fortified with folic acid, while banning its addition to other products. This paper details this process in an attempt to show its complexity and the very serious issues it presents. Since the process is largely complete, the paper also attempts to evaluate the process, as a whole, to determine what the FDA did well and what, if anything, the FDA should have done differently.