DISSERTATION RESEARCH: Evolution of moss organellar genomes and gene transfer from mosses to Amborella

所有的生物体都是由被称为线粒体的微小结构提供能量的，线粒体有自己的DNA。苔藓是一种微小的植物，分布在世界各地；尽管有成千上万种苔藓，但只有一种苔藓线粒体基因组（即所有DNA）被测序。该项目将对10种不同苔藓物种的整个线粒体基因组进行测序，并评估基因组大小、基因顺序和DNA突变率。所有这些特性在大型植物的线粒体基因组中各不相同，但在苔藓中基本上是未知的。该项目还将解释另一种引人注目的生物现象。植物中的线粒体DNA是非常动态的，并且经常从它所在的细胞的其他部分获取DNA。最近，帕尔默实验室已经证明，一种被称为Amborella的小树的线粒体从两种不同的苔藓中获得了完整的线粒体DNA。这是一个惊喜，因为没有已知的机制，这种大规模的DNA转移可能发生。在试图理解这一现象的过程中，它将有助于确切地知道哪些苔藓与Amborella共享线粒体DNA。这可以通过比较Amborella中的苔藓DNA序列与本项目中生成的序列来完成。有可能Amborella从生活在其树干上的苔藓中获得了额外的线粒体DNA。

All living organisms are powered by tiny structures known as mitochondria, which have their own DNA. Mosses are tiny plants that occur all over the world; even though there are thousands of species of moss, only one moss mitochondrial genome (i.e. all the DNA) has ever been sequenced. This project will sequence the entire mitochondrial genome from each of ten diverse species of moss, and will assess genome size, gene order, and DNA mutation rate. All these properties vary among mitochondrial genomes of larger plants, but are largely unknown in the mosses.The project will also permit interpretation of another striking biological phenomenon. The mitochondrial DNA in plants is remarkably dynamic, and frequently picks up DNA from other parts of the cell in which it exists. Recently, the Palmer lab has shown that the mitochondria of a small tree known as Amborella have acquired the entire mitochondrial DNA from two separate species of moss. This was a surprise, because there is no known mechanism by which this massive transfer of DNA might take place. In trying to understand this phenomenon, it would help to know exactly which mosses shared their mitochondrial DNA with Amborella. This can be done by comparing the sequences of the moss DNA in Amborella with the sequences being generated in this project. It is possible that Amborella acquired the extra mitochondrial DNA from mosses living on its trunk.