DISSERTATION RESEARCH: Patterns of Gene Expression in an Allopolyploid Taxon of Recurrent Origin: A Case Study of the Polypod Ferns

多倍体或全基因组复制是一种重要的进化机制，特别是在植物中。最值得注意的是，这可能会导致复制基因的差异表达。异源多倍体(两个或多个不同物种之间杂交产生的多倍体)的基因表达模式特别耐人寻味，因为它们揭示了将不同的基因组联合在一个核内的后果。许多自然形成的异源多倍体是已知的重复形成的，导致物种由多个独立派生的谱系组成。异源多倍体的反复起源首先在蕨类植物中被记录下来，在那里它们似乎特别常见。这些独立的起始点是否产生了相似的基因表达模式，这是受规则支配的，还是这个过程是随机的？这项研究将使用高通量基因组测序技术来比较异源多倍体蕨类植物水龙骨草独立衍生的谱系内部和之间的基因表达模式。本研究旨在更好地了解基因复制、杂交和重复起源对多倍体物种表型变异和进化潜力的影响。由于许多作物是多倍体，对多倍化伴随的基因表达变化的更好理解可能会为潜在的作物改良提供洞察力。这项拟议的研究还将为有动力的本科生提供一个研究培训机会。

Polyploidy, or whole genome duplication, is an important evolutionary mechanism, especially in plants. Most notably, it can lead to differential expression of the duplicated genes. Gene expression patterns in allopolyploids (polyploids resulting from hybridization between two or more distinct species) are particularly intriguing because they reveal the consequences of uniting divergent genomes within a single nucleus. Many naturally-formed allopolyploids are known to form recurrently, resulting in species composed of multiple, independently derived lineages. Recurrent origins of allopolyploids were first documented in the ferns, where they appear to be especially common. Do these independent origins yield similar gene expression patterns that are governed by ?rules?, or is the process random? This study will use high-throughput genomic sequencing techniques to compare patterns of gene expression within and among independently derived lineages of the allopolyploid fern Polypodium hesperium. This study aims to better understand the effects of gene duplication, hybridization, and recurrent origins on the phenotypic variation and evolutionary potential of polyploid species. Because many crops are polyploids, an improved understanding of the gene expression changes that accompany polyploidization may provide insight into potential crop improvement. The proposed study will also provide a research training opportunity for a motivated undergraduate.