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.
