Genetic and cytological dissection of mechanisms controlling mitochondrial DNA inheritance in Drosophila melanogaster. Jennifer Leigh Page, Patrick O'Farrell. BIOCHEMISTRY AND BIOPHYSICS, UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, SAN FRANCISCO, CA.

   The evolutionary success of one mitochondrial genome over others relies on its partitioning into the cytoplasm of germ cells to contribute to the next generation, while the success of this next generation depends on acquisition of a competent compliment of mitochondrial genomes. Despite the importance of these factors in evolution and genetic health, we know little about the phenomena influencing the outcomes. Inheritance of mitochondrial DNA (mtDNA) follows patterns distinct from nuclear DNA. In higher eukaryotes, mtDNA inheritance is uniparental, provided only by the mother. We want to know how oocyte development in the Drosophila melanogaster female germline influences mitochondrial inheritance to the next generation. In flies, the future germline is specified quite early during oogenesis. Previous reports have suggested that through this process, mitochondria are specifically selected in order to ensure propagation of the most functional mitochondria to the next generation. We want to understand which maternal factors are necessary for recruiting mitochondria to the germ plasm, and whether there are mechanisms which survey mtDNA integrity and promote propagation of the best mitochondria. We propose to use genetic techniques to explore the maternal factors, such as oskar and vasa, that govern mitochondrial recruitment to the germ plasm, and cytological techniques to follow specific mitochondria during oogenesis in order to understand how the mitochondria are chosen. Preliminary evidence suggests that oskar is required for recruitment of mitochondria to the posterior, and that vasa also plays a key role. These and further experiments will help elucidate the mechanisms of mitochondrial inheritance through the female germline in Drosophila.