A BACTERIAL ARTIFICIAL CHROMOSOME LIBRARY FOR SOYBEAN AND IDENTIFICATION OF CLONES NEAR A MAJOR CYST-NEMATODE RESISTANCE GENE

We constructed a bacterial artificial chromosome (BAG) library for soy bean (Glycine max) consisting of approximately 30000 clones with an av erage insert size of 120 kilobase pairs. The library was successfully screened with restriction fragment length polymorphism (RFLP) and micr osatellite markers tightly linked to a major resistance gene for the c yst nematode, Heterodera glycines. Since many soybean RFLPs hybridize to duplicate loci, BACs homologous to duplicate RFLP loci were disting uished by digestion with the restriction enzyme originally used to map the RFLP, followed by a comparison of the hybridizing fragments. Link age mapping of BAC clones identified with markers linked to the cyst n ematode resistance gene demonstrated that these clones were located at the expected chromosomal positions and that there were no indications of chimeras within the genomic inserts.