Ma, Daina2010-11-012011-08-242010-11-012011-08-242010-11-01January 20http://hdl.handle.net/10106/5177In this study, I investigate factors underlying reproductive isolation in Drosophila. I begin (Part I) by measuring behavioral isolation between Zimbabwe and cosmopolitan D. melanogaster, and asking the following questions: What is the pattern? What are the sensory cues leading to isolation? In Part II, I present results of a genomic screen for candidate genes underlying behavioral isolation between Zimbabwe and cosmopolitan D. melanogaster. Then I turn to the genomic causes of postzygotic reproductive isolation (Parts III and IV): What are the possible genes associated with hybrid sterility? What are the relationships between fertility/sterility and genotypes and allelic expression? What are the regulatory changes in hybrid sterile males compared to normal males? Finally (Part V), I broaden the analysis from a single gene to a microsatellite mapping of chromosome III, and ask the following question: How many loci are involved in hybrid sterility? What is the degree of microsatellite divergence between species?enPh.D.