Chromosomal analysis of Nicotiana asymmetric somatic hybrids by dot blotting and in situ hybridization

• Published in: Molecular & general genetics Vol. 222; no. 1; p. 97
• Main Authors: Piastuch, W C, Bates, G W
• Format: Journal Article
• Language: English
• Published: Germany 01-06-1990
• Subjects: Chromosomes; Cloning, Molecular; DNA - analysis; Karyotyping; Nicotiana - genetics; Nucleic Acid Hybridization; Plants, Toxic; Polymorphism, Restriction Fragment Length; Repetitive Sequences, Nucleic Acid; Translocation, Genetic
• ISSN: 0026-8925
• DOI: 10.1007/BF00283029

A species-specific, dispersed repetitive DNA sequence was cloned from Nicotiana plumbaginifolia and used in dot blots and in situ hybridizations to analyze asymmetric somatic hybrids of N. tabacum(+)kanamycin-resistant N. plumbaginifolia. Dot blot hybridization data, using the cloned, species-specific repetitive DNA as a probe, showed that some of the hybrids contain only 1%-5% N. plumbaginifolia DNA, whereas others contain 15%-25%. In situ hybridization of the probe to chromosome spreads showed that the extremely asymmetric hybrids retain a single N. plumbaginifolia chromosome; the hybrids with higher dot blot values were found to have 8 to 12 N. plumbaginifolia chromosomes and chromosome fragments. In situ hybridization also revealed translocations between N. plumbaginifolia and N. tabacum chromosomes in 3 of 8 hybrids studied. RFLP analysis using a 5S gene probe showed the presence of N. plumbaginifolia-specific 5S banding patterns in most hybrids examined, including those that retain only a single N. plumbaginifolia chromosome.