In an Accomplishment-Based Renewal, Dr. Linda Maxson will continue her productive investigations of the phylogenetic relationships of select groups of amphibians, emphasizing especially the hylid and myobatrachid frogs of the world. To analyze the evolutionary divergences among these species, Dr. Maxson estimates the amino acid differences in serum albumin proteins, using a serological technique known as micro-complement fixation. The amino-acid differences have been shown to provide reliable genomic markers of evolutionary descent. In comparisons between species separated by geographic or geological barriers of known geological age (for example, the Straits of Gibraltar), estimates will also be made of the timing of evolutionary events, thus enabling a test of the idea of a molecular albumin clock. Finally, Dr. Maxson will capitalize on a gift of serological antisera from a study of crocodiles (reptiles, not amphibi- ans) to compare results from two different serological methods in estimating phylogenetic patterns.
