Plant & Animal Genome VI Conference

W66

TARGETED EXTRACTION OF GENE AND LANDMARK SEQUENCES FROM SORGHUM/MAIZE GENOMES

Crop Biotechnology Center, Texas A&M University, College Station, Texas 77843

We have adapted the method of "Flanking PCR", developed by Siebert et al (1995), for numerous uses in genome analysis. Flanking PCR provides a rapid method to amplify unknown sequences adjacent to any known sequence using a single primer. Our group has been using this method to clone DNA flanking SSRs, to locate CAPs markers adjacent to genes or other genome landmarks, and to clone promoter regions adjacent to open reading frames. Multiple rounds of flanking PCR can be used to clone fairly large regions of DNA. For example, DNA adjacent to teleomere sequences has been cloned using a sequence of flanking PCR steps. We have also used Flanking PCR to completely sequence targeted regions of the sorghum genome using multiple flanking PCR libraries. This approach was used to obtain the genomic sequence of PhyB from sorghum. PhyB corresponds to a locus in sorghum that regulates flowering time. The connections between PhyB, other genes that encode phytochrome, and maturity loci in sorghum and corn will be discussed. Finally, our team has been developing methods to create a physical map of the sorghum genome. Preliminary results from this effort will be discussed.