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Full-Text Articles in Life Sciences
All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang
All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang
Doctoral Dissertations
Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O.sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Using population genetics analyses of South Asian and US weedy rice, my research reveals multiple independent evolution events giving rise to weed groups in the two geographic areas. Weeds in South Asia have highly heterogenous genetic backgrounds, with contributions from both cultivated varieties (aus and indica) …
Hybridization As A Stimulus For Adaptation To A Novel Environment, Dylan Robert Dittrich-Reed
Hybridization As A Stimulus For Adaptation To A Novel Environment, Dylan Robert Dittrich-Reed
Doctoral Dissertations
Understanding processes contributing to the origin of novelty, including ecological transitions in resource or habitat use, is fundamental to evolutionary biology. Early geneticists speculated about the sudden appearance of new species via special macromutations, epitomized by Goldschmidt’s infamous “hopeful monster”. Transgressive segregation during hybridization is a more plausible mechanism for producing “monstrous” phenotypes beyond the range of parental populations. Transgressive hybrid phenotypes can be products of epistatic interactions or additive effects of multiple recombined loci. However, the importance of hybridization in the origin of novelty is contested because we do not know how often hybridization enhances the probability of an …