title: Chromosomal translocations are a common phenomenon in Arabidopsis thaliana T-DNA insertion lines.
abstract: Ordered collections of Arabidopsis thaliana lines containing mapped T-DNA insertions have become an important resource for plant scientists performing genetic studies. Previous reports have indicated that T-DNA insertion lines can have chromosomal translocations associated with the T-DNA insertion site, but the prevalence of these rearrangements has not been well documented. To determine the frequency with which translocations are present in a widely-used collection of T-DNA insertion lines, we analyzed 64 independent lines from the Salk T-DNA mutant collection. Chromosomal translocations were detected in 12 of the 64 lines surveyed (19%). Two assays were used to screen the T-DNA lines for translocations: pollen viability and genome-wide genetic mapping. Although the measurement of pollen viability is an indirect screen for the presence of a translocation, all 11 of the T-DNA lines showing an abnormal pollen phenotype were found to contain a translocation when analyzed using genetic mapping. A normal pollen phenotype does not, however, guarantee the absence of a translocation. We observed one T-DNA line with normal pollen that nevertheless had a translocation based on genetic mapping results. One additional phenomenon that we observed through our genetic mapping experiments was that the T-DNA junctions on the 5'- and 3'-sides of a targeted gene can genetically separate from each other in some cases. Two of the lines in our survey displayed this 'T-DNA borders separate' phenomenon. Experimental procedures for efficiently screening T-DNA lines for the presence of chromosomal abnormalities are presented and discussed.
authors.affiliation: Genome Center of Wisconsin and Department of Horticulture, 1575 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: Katie A
authors.initials: KA
authors.lastname: Clark
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Krysan
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D004269:DNA, Bacterial; D018744:DNA, Plant / Q000235:genetics; D005838:Genotype; D016254:Mutagenesis, Insertional; D051479:Plant Infertility / Q000235:genetics; D011058:Pollen / Q000254:growth & development; D036226:Seedlings / Q000254:growth & development; D014178:Translocation, Genetic
chemical_list: D004269:DNA, Bacterial; D018744:DNA, Plant; C036483:T-DNA