DISSERTATION RESEARCH: Investigating recombination and the origin of genetic variation in apomictic ferns

无性植物和动物谱系长期以来被认为是进化的死胡同，不能产生显著的遗传变异。然而，最近的证据表明，一些无性谱系可能经历了亚性过程，这可能导致遗传变异的增加，从而提高了适应极端环境的进化潜力。本论文的研究将探讨重组是否可以记录在一个无融合的蕨类谱系。无融合蕨类植物具有一种独特的孢子发生类型（一种在开花植物中未知的类型），在减数分裂期间同源染色体配对并重组遗传信息的可能性。利用现代基因组学方法结合细胞学研究，本研究旨在确定这些蕨类植物中是否存在这种遗传变异，以及这种现象在自然种群中可能存在的程度。蕨类植物是维管植物的早期分支，与动物和被子植物具有某些无性特征。增加对植物间无融合生物学的认识不仅与蕨类植物遗传变异的进化和生态学研究有关，而且对农业和作物科学也有广泛的影响。

Asexual plant and animal lineages have long been considered evolutionary dead ends, incapable of generating significant genetic variability. Recent evidence, however, suggests that some asexual lineages may undergo subsexual processes that can lead to an increase in genetic variation, thereby improving evolutionary potential for adaptation in extreme environments. This dissertation research will examine whether recombination can be documented in an apomictic fern lineage. Apomictic ferns are capable of a unique type of sporogenesis (one not known to occur in flowering plants) where there is a possibility for homologous chromosomes to pair and recombine genetic information during meiosis. Using modern genomic approaches in combination with cytological studies, this study aims to identify whether such genetic variation exists in these ferns and the possible extent of this phenomenon in natural populations.The proposed research will enhance current understanding of apomixis in ferns, an early diverging lineage of vascular plants that shares certain asexual traits with both animals and angiosperms. An increased knowledge of the biology of apomixis across plants is relevant not only for evolutionary and ecological studies of genetic variability in ferns, but can have wide-ranging implications for agricultural and crop sciences.