Plant Genome III Conference Plant Genome III Conference
The development of comparative maps for species of the Gramineae family will allow researchers to pool genetic information from the major cereal crops and will be critical to the efficient use of molecular-marker technology in cereal improvement. The objectives of our comparative mapping research are to 1) identify a set of "anchor" CDNA probes that hybridize to rice, maize, wheat, oat, sorghum, barley, and sugarcane, 2) extend existing species-specific RFLP linkage maps for rice, wheat, and oats based on the anchor probes, 3) analyze gene order between rice- wheat (and -barley), rice-maize (and -sorghum) and rice-oats, and 4) construct a framework map of conserved regions -,i the genomes of these species. We are using rice as the basis for examining gene order among grass species because this well-studied diploid has the simplest genome of any of the crop species in the Gramineae family and thus provides the best available model for ensuring the comparison of orthologous loci. Thus far, we have assembled a set of 150 anchor probes that hybridize to most of the targeted genomes. Many of the anchor probes have been mapped in at least 5 species. Consensus maps among wheat, barley, rye, and Triticum tauschii have been constructed for wheat homoeologous groups 1, 2, and 3 and compared to rice.