Anna Janzen

The Biological Species Concept defines a species as a group of organisms that can interbreed and produce fertile offspring. In order for speciation to occur, there must be a reduction in gene flow between two populations. This can be caused by prezygotic or postzygotic barriers to reproduction. Previously, a postzygotic speciation mechanism known as engineered genetic incompatibilities (EGI) has been created in Drosophila melanogaster. EGI combines a dominant lethal transgene with a recessive resistance allele. The offspring of two EGI parents are viable, but any hybrid between EGI and wild-type is not viable. The purpose of this project is to establish a model system to quantify the impact of postzygotic isolation on the selection of a prezygotic isolation trait. We used EGI as the postzygotic isolation trait; for the prezygotic isolation trait a strain of D. melanogaster from Zimbabwe with a previously observed assortative mating phenotype was used. To begin, we confirmed that the Zimbabwe flies are incompatible with two EGI lines, which opens the door for future experiments involving these two populations. This research could help to understand the impact of multiple barriers to gene flow on the process of speciation.