Our Research
My laboratory focuses on using genetic tools to examine the history of living organisms. We use DNA and protein comparisons to study how animal and plant populations are structured, addressing questions such as whether geographic separation reduces the likelihood of gene flow among populations, the role of host plant specificity in the evolution of new insect species, and how organisms move via human-mediated dispersal. Our research in this area has been used to determine what fish must be present to ensure the successful reproduction of certain freshwater mussels, what the implications might be for the introduction of non-native plants for native insects, and to examine the global dispersal of quarantine fruit flies, such as the Mediterranean fruit fly. We also use DNA sequences to reconstruct the phylogeny of organisms.
The main focus of our work at present is on the true fruit flies in the family Tephritidae. These flies are the subject of research to examine mechanisms of speciation in animals – the host specificity of some species appears to have led to the evolution of new species as gene flow was reduced during the process of adaptation of new, host-associated populations to their host plants. Tephritid flies are also important from an agricultural perspective – many of the most important quarantine species both in the United States and internationally are members of this fly family. Fly larvae feed directly in fruit, rendering them unmarketable. The spread of these pest species is a long-standing concern, and our work has provided new tools both for identification of fly species in all life stages (i.e., egg, larvae and pupae in addition to the recognizable adult stage) and to assess the geographic source of certain species when they appear in a new location due to trade or other human-associated movements.
Our current projects include a detailed analysis of the West Indian fruit fly, Anastrepha obliqua, and Mexican fruit fly, Anastrepha ludens, population structure (graduate student Raul Ruiz), focused analyses of microgeographic and host-associated genetic variation in the West Indian fruit fly (undergraduate students Rachelle Christie, Sam Gum, and Sonya Park), and DNA-based phylogenetic analysis and the development of DNA barcodes for identification of tephritid fruit flies (postdoctoral scientists Sajed).
