Jeffrey created several strains of Drosophila (fruit flies) that all have a mutation which causes Parkinson's disease. This mutation is a deletion of a gene called "parkin" that exists in humans, flies, and many other animals. Each strain of these parkin knock-out flies also has a unique mitochondrial genome, which comes from a variety of different types of Drosophila. The idea is to determine if there is any interaction between any genes in the mitochondrial genome with the parkin gene, which is being done by testing these different flies and seeing if any display more or less severe effects of Parkinson's Disease. So far, flies with one particular mitochondrial genotype are unique in that they are the only ones that can survive in a homozygous parkin knock-out state when crossed with flies bearing a certain phenotypic marker, known as "Dropped," which affects wing and eye shape.    Jeffrey created several strains of Drosophila (fruit flies) that all have a mutation which causes Parkinson's disease. This mutation is a deletion of a gene called "parkin" that exists in humans, flies, and many other animals. Each strain of these parkin knock-out flies also has a unique mitochondrial genome, which comes from a variety of different types of Drosophila. The idea is to determine if there is any interaction between any genes in the mitochondrial genome with the parkin gene, which is being done by testing these different flies and seeing if any display more or less severe effects of Parkinson's Disease. So far, flies with one particular mitochondrial genotype are unique in that they are the only ones that can survive in a homozygous parkin knock-out state when crossed with flies bearing a certain phenotypic marker, known as "Dropped," which affects wing and eye shape.