My research focuses on speciation events in amphibians that involve theoretically complex phenomena. Among the vertebrates, bisexual tetraploids and unisexual hybrids that maintain genomes consisting of up to three or four species are only known in amphibians. Additionally, amphibians demonstrate a great diversity in the rates of chromosome evolution which is useful in examining the role that chromosomes play in speciation. Terrestrial breeding frogs have considerable chromosome variation. The significance of this observation is being tested by examining frogs in the genus Eleutherodactylus which is the largest vertebrate genus. These frogs range through Central and South America and have speciated rapidly in the Antilles.
The objectives of my research are to test hypotheses relating to genetic composition, restructuring and regulation that have a selective role in the process of amphibian evolution. My multi-disciplinary investigations combine population genetics and cytogenetics with an examination of reproductive isolating mechanisms used by individuals in natural populations. I investigate gene flow in natural populations of frogs and salamanders, gene probing to determine the location of unique sequences and moderately repeated sequence genes on lampbrush and mitotic chromosomes, morphological attributes o f the vocal apparatus in frogs that may alter the acoustic signal, and the function of major rivers in the tropics as barriers to gene flow. In addition to field studies, artificial hybrid combinations are produced in the laboratory to study gene interaction and regulation of unique combinations of alleles.