Recombinase Systems in Plants, 1997 Biological Sciences Symposium Proceedings

Several site-specific DNA recombination systems have been shown to function in plants. Excision and integration of DNA relevant to genetic transformation have been described. Site- specific excision can remove selectable marker genes from plant genomes, permitting subsequent rounds of gene transfer with the same selection protocol. The elimination of marker genes from transgenic crop plants also eases concerns over the widespread release of antibiotic resistance genes. Site-specific integration of DNA has demonstrated the precise insertion of single-copy DNA into recombination sites previously placed in the plant genome. The reproducible insertion of DNA constructs into the same site permits analysis of gene alleles in the same chromosome configuration. Site-specific recombination has also been used to restructure plant genomes. Recombination between sites placed on the same or on different chromosomes has generated chromosome deletions, inversions and reciprocal chromosome translocations. Site-specific recombination of chromosomes in vitro can also fractionate large chromosome fragments. In this session, we will present findings on the ongoing development of site-specific recombination for monocot transformation, chromosome rearrangements, interspecies chromosome recombination, and analysis of transgene expression.