title: A genetic analysis of a tomato (Lycopersicon esculentum) genotype with a high frequency of twin spots.
abstract: Among pale-green tomato plants heterozygous for the xanthophyllic2 (xa-2) mutation that were transformed with a T-DNA harbouring the NPTII and GUS gene, a plant with a high frequency of green/white twin spots was found. The genetic analysis of this plant indicated that the occurrence of these twin spots was caused by a genetic defect located at the distal end of chromosome 10S, where xa-2 also is located. The genetic analysis of green plants regenerated from leaf expiants of this twin-spot plant revealed that the green sectors derive from non-disjunction of the xa-2 (+) allele. In an analysis of mitotic chromosome behaviour bridges were observed in approximately 5% of the anaphases, providing arguments that a breakage-fusion-bridge cycle caused by a tissue culture-induced genomic instability is the most likely cause of this aberrant behaviour of chromosome 10.
authors.affiliation: Department of Genetics, Wageningen Agricultural University, Dreijenlaan 2, 6703, HA Wageningen, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Zhu
authors.forename: H C
authors.initials: HC
authors.lastname: Schoenmakers
authors.forename: A M
authors.initials: AM
authors.lastname: Wolters
authors.forename: M
authors.initials: M
authors.lastname: Koornneef