CONSTRUCTION OF A BACTERIAL ARTIFICIAL CHROMOSOME LIBRARY IN WHEAT Triticum urartu

Department of Agronomy, Purdue University, 1150 Lilly Hall, West Lafeyette, IN 47907-1150 USA

Common wheat (Triticum aestivum L.) is an allohexaploid species of unusally large genome size (16,000Mbp) and containing the A, B, and D genomes. The A genome progenitor is the diploid species T. urartu. We have identified more than 50 DNA markers that are linked to ten Hessian fly resistance genes located on chromosome 5A and 1A. The first step toward isolation of a gene is to develop a large insert library. To date there is none available in wheat. We have begun the construction of a BAC library from the diploid T. urartu by isolating high molecular weight DNA from nuclei. The nuclei are embedded in agarose micro plugs. The plugs were digested with EcoRI plus EcoRI methylase at a ratio of 1:20. Our first ligation produced about 10,000 clones with an insert size range from 30-160 Kb. Our goal is to increase the insert size to an average of at least 100Kb.