The main goal of this project is to study the population biology of transposable genetic elements (parasites of the genome) using Drosophila as a model system in conjunction with quantitative theoretical analysis. During this period, the research has focused on two topics: 1) What is the primary mechanism containing the numbers of transposable elements? and 2) Is the evolutionary diversity observed between copies of elements at the DNA sequence level consistent with quantitative models of the dynamics of the elements in natural populations? The cloning and DNA sequencing of copies of the transposable element hobo from sampled individuals, populations and species is ongoing. The genetic and molecular characteristics of spontaneous deletions arising from unequal crossing over is ongoing. The role of heterozygosity on the rate of unequal crossing over is under investigation.