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，它可以导致复制基因的差异表达。异源多倍体（由两个或多个不同物种杂交产生的多倍体）的基因表达模式特别有趣，因为它们揭示了将不同基因组统一在一个细胞核内的结果。已知许多自然形成的异源多倍体反复形成，导致由多个独立衍生谱系组成的物种。异源多倍体的复发起源首先在蕨类植物中被记录，在那里它们似乎特别常见。这些独立的起源是否产生了相似的受规则支配的基因表达模式？或者这个过程是随机的？本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Polypodium hesperium内部和独立衍生谱系之间的基因表达模式。本研究旨在更好地了解基因复制、杂交和循环起源对多倍体物种表型变异和进化潜力的影响。由于许多作物都是多倍体，因此更好地了解多倍体化过程中基因表达的变化可能为潜在的作物改良提供见解。建议的研究也将提供一个研究训练的机会，积极的本科生。

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.