For several decades the northward expansion of Africanized honey bees (AHB) has been extensively studied with morphological, behavioral, and biochemical methods. The Africanized honey bee (AHB) population resulted from some measure of interbreeding between African and European derived honey bees. The genetic composition of this population remains controversial. While some studies have shown that AHB remained primarily African in nesting biology or mitochondrial DNA haplotypes, others have shown varying degrees of introgression based on morphology and molecular markers. In this research, we are examining the genetic composition of AHB obtained from Brazil, Costa Rica, Honduras, and Texas. We expect the data will permit discrimination between the hypothesis that the genetic composition of AHB populations from Texas contain a higher proportion of African genes than those near the original source of introduction (“migrant front” hypothesis) and the alternative hypothesis that AHB populations that reached the U.S. lately have a smaller proportion of African genes than those near the original source of introduction (“hybridization” hypothesis).