We have begun to map our two mutations using the sequence tagged site for C. elegans that was devised by Ben Williams and his group in St. Louis and multiplex PCR techniques. The STS strategy requires the use of the Bergerac strain which has several of these seqeunce markers along the length of each of its chromosomes. Using a specific primer for one of these markers on each chromosome in a PCR reaction, allows us to express one band for each linkage group (all six bands are within the 100-300 base pair range). In order to map our recessive learning mutations, male N2 mutants are crossed with hermaphrodite Bergeracs and the F2 generation is tested for their learning ability. Since the learning mutations are both recessive, at the F2 stage, we expect to recover approximately 25% learning mutants. When these N2 mutant/Bergerac hybrid animals that are associative learning defective are then PCR'd, on gel analysis, we are looking for the band that occurs less frequently. Because our mutation is recessive, any hybrid that is learning defective needs both copies of the mutant chromosome in order to demonstrate the learning defective phenotype. Since only the Bergerac chromosomes contain the STS sites, then the marker that is missing most likely indicates the linkage group that the learning mutation is located on. Once we have determined which chromosone has the learning mutation, then using the same strategy, this time with markers for sequence tagged sites along the length of the chromosome, we can get a more precise map location. Then using a cosmid map, we should be able to find out what our learning muation encodes.Back to Wormie Home Page.