The selective forces that dictate where horizontally acquired genes recombine and how they ameliorate in their new hosts has only been examined using sequence comparisons. The proposed pilot study seeks to begin investigating the mechanisms behind these processes of horizontal gene transfer using laboratory adaptive evolution experiments. We will examine chromosomal gene transfers between different species under various levels of selection to determine where genes recombine and how they are expressed in their new host. Initial experiments will use DNA extracted from different thermophilic hosts to transform mutants of Thermus thermophilus as the host species. Subsequently efforts will be made to grow these T. thermophilus mutants with two of those DNA donors in co-cultures to then determine if the host strains can acquire traits from the donor cells. Fervidobacterium nodosum and Pyrococcus furious will be the test gene donors. Transfer of genes encoding a maltose transporter and the orotate phosphoribosyltransferase (pyrE) will be examined to determine where they recombine and how they are expressed in their new host. The anticipated results of this preliminary study will provide the basis for future work to devise a means to detect failed HGT recombinations to provide data about the mechanisms of gene acquisition. The ability to detect and follow the progress of recombined genes will also allow future experimental examinations of the process of gene amelioration.