DISSERTATION RESEARCH: Transposable Element Sequence Evolution in Natural Saccharomyces Populations

转座因子是一种DNA片段，具有将自身或自身拷贝插入宿主基因组新位点的能力。这个项目将研究自然选择的力量如何影响这些元素的维持和分布。这些问题将通过检测两种酵母菌天然分离物中的转座因子Ty3的DNA序列来解决：酿酒酵母（常见的酿酒酵母和面包师酵母）及其近亲悖论酵母。将分析Ty3 DNA序列变异的数量和类型，以揭示自然选择如何作用于这些人群中的Ty3元素。转座因子已经在几乎所有具有良好特征的基因组的生物体中被发现，包括人类基因组。这些元件的移动和复制是有害基因突变的主要来源，这一观察结果导致了转座元件是DNA寄生虫的理论。这种“自私的DNA”假说还有待在不同的自然种群中进行严格的检验。本项目主要研究现代基因组研究中的主要生物（酵母），并将基因组和分子方法与进化方法相结合，以进一步了解转座因子的生物学意义。

Transposable elements are stretches of DNA with the ability to insert themselves, or copies of themselves, into new sites in the genomes of their hosts. This project will study how the force of natural selection affects the maintenance and distribution of these elements. These questions will be addressed by examining DNA sequences of the transposable element Ty3 in natural isolates of two yeast species: Saccharomyces cerevisiae (the common brewers' and bakers' yeast) and its close relative Saccharomyces paradoxus. The amount and type of variation in Ty3 DNA sequences will be analyzed to reveal how natural selection is acting on Ty3 elements in these populations.Transposable elements have been discovered in virtually every organism with a well-characterized genome, including the human genome. The movement and replication of these elements is a major source of harmful genetic mutations, and this observation has led to the theory that transposable elements are DNA parasites. This "selfish DNA" hypothesis remains to be tested rigorously in diverse natural populations of organisms. The project described in this proposal focuses on the primary organism studied in modern genomic research (yeast) and integrates genomic and molecular methods with evolutionary approaches to further our understanding of the biological significance of transposable elements.