In Dr. Volkan’s lab, the primary focus of my project is to look at the genes that underlie the neural circuits that deal with sexual behavior in flies, specifically in Drosophila melanogaster. We already know about a gene named Fruitless or Fru in males that controls all male courtship behavior, and another gene named Doublesex that controls experience-dependent sexual behavior. In other words, the level of courtship these flies maintain controls whether or not doublesex is expressed. Additionaly, ChAT (choline acetyltransferase), a gene that encodes an enzyme to make the neurotransmitter acetylcholine, is known to be involved in the neural circuits that deal with courtship behavior. If ChAT is being used, then that means that neural circuits are being used as well.
Furthermore, in my project we are putting male flies (some with mutations in the genes previously mentioned) in different social environments where they are either group housed or isolated and look at the expression of those different genes. Studies have shown that group housed male flies that are mutant for Fru do in fact court one another and form a chain link (Villella et al.), while isolated male flies, when rejoined with other flies after isolation, fail to court alltogether most times (Pan and Baker). Consequently, if we separate male flies by their social experience, we can see what genes are turned on and off by protein markers such as RNA polymerase, H3K27ac (a histone epitope that deals with acetylation and is associated with the higher activation of transcription) and others.
In my project, we are using a method named ChIP, which is “a type of immunoprecipitation experimental technique used to investigate the interaction between proteins and DNA in the cell”. In this method, antibodies made specifically for proteins like RNA polymerase will attach to the proteins, which are also attached to genes, and will be taken out of solution by magnetic beads so that the RNA can be isolated and sequenced into DNA, giving us the DNA sequence related to the behavior we witnessed!
Overall, with this project our lab hopes to find out what genes in the brain let the fly know when to mate and who to mate with, or simply how the fly makes decisions when presented with a mate. This information will give us more insight on the circuit for sexual behavior in flies and can even be used to understand the human brain in the future!