Octoploidy-induced Genome Downsizing and its Effects on Plant Morphology in Arabidopsis thaliana

Abstract

It is known that the tardy asynchronous meiosis-2 (tam-2) mutant of Arabidopsis thaliana produces unreduced gametes by skipping meiosis II, resulting in genome duplication in the next generation. This process of polyploidization continues until it reaches octoploidy that becomes unstable. The progeny of octoploid tam-2 are of reduced ploidy as a result. The purpose of this study was to examine fertility and morphological changes over at least two generations from the octoploid tam-2 of A. thaliana. We hypothesize that the instability of the genome may result in new genome compositions that produce new phenotypes in the generations after the octoploid generation. We found a positive linear relationship between guard cell nuclear area and ploidy level; this relation will be used for determining the ploidy levels in the progeny of the octoploid tam-2. By observing morphological changes due to genomic decay in real time, we may find new varieties of Arabidopsis in the making over one or more generations, which has important implications to the mechanisms of speciation, and to technological development for engineering new crops in the agricultural industry.