Creating a microsatellite library for the study of plants in the genus Monardella

The Lamiaceae family is comprised of over thirty rare species of plants, including the dune- dwelling Monardella crispa and the inland-growing M. frutescens and M. undulata. The phenotypic differences of these three species bring into question whether these plants are genetically identical or if they are, in fact, three completely distinct species. An analysis of microsatellite-containing regions from Monardella will help us address this question. Microsatellites are regions of DNA that contain short tandem repeats of two nucleotides, like CA or CT. The size of these repeats can vary dramatically from individual to individual, and can be used to provide DNA fingerprints of individual plants to tell them apart from one another or from different species. We are in the process of constructing a Monardella crispa microsatellite library, which involves extraction of DNA from plant tissues, cloning small fragments of plant DNA into plasmids, and screening the clones for those that contain microsatellite DNA. Microsatellite regions can be rare or difficult to detect in plants, but once obtained we will generate the DNA sequences of these clones using an ABI 310 Genetic Analyzer. Once the microsatellite sequences are obtained, the numbers and lengths of the short tandem repeats can be used for future comparison between M. frutescens and M. undulata to identify whether these species are genetically different, or whether they are genetically identical and differ physically due to environmental conditions