In general, crustaceans are not typical model organisms for the study of molecular genetics. Yet there are many important reasons to study these ecologically and economically important organisms at the level of their genes. Here at UNCW we have several projects on the molecular genetics of crustaceans, especially the blue crab, Callinectes sapidus.  We are interested in determining genetic differences within and between populations in order to describe population structure and assess larval migration. We have devised molecular genetic methods to distinguish closely-related species. This is critical for identification of larvae, where species can sometimes be nearly indistinguishable by appearance alone. We are “fishing” the crab genome for previously unknown genes that play roles in controlling some very crustacean-specific life processes such as molting, exoskeleton mineralization and the ability to live comfortably in a wide range of temperatures and salinities. We are determining where, that is in what tissues, and when, that is at what life cycle stages or physiological conditions, certain known genes change their expression patterns. Finally, we are producing a database of ESTs, or expressed sequence tags, that will make information and actual cloned genes available to crustacean scientists world-wide as they search our data for sequences of interest to them. This involves high-throughput sequencing somewhat analogous to a “genome project.” Soon we will produce a crab DNA microarray that will allow the expression patterns of many genes to be analyzed at once rather than one at a time. All of these studies on crustaceans utilize a similar suite of molecular techniques including gene cloning, PCR amplification and DNA sequencing. These studies are on-going since crustacean genes still have a lot to tell us.